Wellfield Services Ltda.
About us
Wellfield Services Ltda. is a company specialized in providing geophysical services for mining, oil and energy industries as well as for groundwater, environmental and geotechnical studies. For 25 years has forged a trajectory of excellence, joining technical competence and capability, innovation, qual...MORE +
Organization
Wellfield Services Ltda. is organized in 5 divisions each one related to a specific service.
The company workforce of over 200 people is diverse and includes professionals like geophysicists, geologists, engineers and technicians. MORE +
History
Founded in 1993 to perform exploration and assessment for groundwater, Wellfield Services was pioneer in offering services related to hydrological resources for the northern Chile mining industry.
Between 1995 and 1997 the company went through a process of expansion as well as professionalization, which paved the road for the continuous innovation politics that characterizes Wellfield. MORE +
Location
Brasil
Geomag, Praia de Botafogo, 501 – Ed. Mourisco, Torre Pão de Açúcar – 1º. Piso Sala 153, RJ CEP 22.250-050, Rio de Janeiro, Phone: +55 (21) 2586-9958
wslbrasil@wellfieldservices.
Wellfield Servicios Geofisicos Do Brasil Ltda., Praia de Botafogo, 501 – Ed. Mourisco, Torre Pão de Açúcar – 1º. Piso Sala 153, RJ CEP 22.250-050, Rio de Janeiro, Phone: +55 (21) 2546-9958
wslbrasil@wellfieldservices.
Bolivia
Wellfield Services Bolivia
Calle Saavedra Esq. Cochabamba, Centro Empresarial Torres Cainco, Ed. La Vitalicia Piso 2. Oficina 4 N°710, Santa Cruz
Phone: 59 13-3224752
wslbolivia@wellfieldservices.
In this section you will find a compendium of our services organized under two criteria: Alphabetical and thematic by service areas. Both can be traveled without changing windows.
Services by area
Oil and Gas
Reflection Seismic 2D/3D
Reflection Seismic 2D/3D
The reflection seismic acquisition consists of generating acoustic waves on surface and registering the amplitude variations for the waves train reflected from subsoil. These wave amplitude variations are caused for acoustic impedance (density x velocity) changes between different subsoil layers.
Acoustic waves can be generated using mechanical punchers and/or explosive (located source) or Vibroseis (controlled source). The amplitude variations are measured using several geophones (2D profiles or 3D mesh) and registered by a centralized acquisition system (seismograph) or by decentralized nodes.
In both 2D and 3D cases, the horizontal dimension is space and the vertical one is time which with processing is converted to depth, after estimation of subsoil velocities.
Microseimic Acquisicion and processing
Microseimic Acquisicion and processing
Monitoring of induced microseismic events is key to hydraulic fractures evaluation and optimization. Its main objective is to characterize the induced fractures structure and the density distribution for a specific formation.
The microseismic activity is measured using geophones located to map a sector related to the studied induced fracture, leading to its geometry estimation.
Reflection seismic processing 2D/3D
Reflection seismic processing 2D/3D
Data processing consists in transforming seismic data to interpretable information. Wellfield processing center in Buenos Aires offers time based (PSTM) and depth based (PSDM) data processing for terrestrial and marine seismic surveys. The professional staff counts with experience all over South America.
Well logging
Multifingers Caliper
Multifingers Caliper
This tool is ideal to provide high resolution details on well casing conditions at depth. Several fingers allow detecting small anomalies, easing the finding of deformations, incrustations or casing metal thinning caused by corrosion. The tool counts on 20 to 80 fingers, depending on well casing diameter.
CBL, VDL and CCL
CBL, VDL and CCL
Cement Bond Log (CBL), Variable-Density Log (VDL) and Casing Collar Locator (CCL) services offer a complete evaluation of well wall and casing to reduce the uncertainty about hydraulic isolation quality in the production zone, making possible more efficient well refining operations at a minimum cost.
Gravity
Gravity
The gravity geophysical method detects the gravity field variations on the earth surface related with the subsoil density distribution. From these results is possible to locate formations, reservoirs, basement and other structures with density contrast.
High Pressure (P) and Temperature (T) well logs
High pressure P and temperature T well logs
Wireline logs in geothermal high P and T wells with memory tools.
Neutron porosity
Neutron porosity
Porosity well log based on slowing down and capture of neutrons by the hydrogen contained in the subsoil formations. This technique allows registering the correct porosity for specific formations, (limestone, sandstone, dolomite), assuming that formation pores are fluid-filled and in units related to formation type (vol/vol or u.p.). The measurement is statistical and based on thermal neutron detection, so precisions is higher for high counting speed, i.e. low porosity.
Free Point / pipes rescue
Free Point / pipes rescue
The rescue of a pipe or a flexible pipe string stuck deep in a well but free to move, is based on cutting it and locating its free point in such a way to eliminate the problem down below the cut.
Gamma Ray
Gamma Ray
Gamma Ray log is used to discriminate different lithologies through their specific natural radioactivity, and for Uranium exploration. Gamma ray count increments can be related to lithological changes, alterations and radioactive mineralizations.
16 / 64 Resistivity
16 / 64 Resistivity
The Formation Resistivity well log is measured through 2 current (A and B) and 2 potential (M and N) electrodes. A and M are located on the probe, B is on the cable armature and N on the surface.
Slickline
Slickline
Wellfield uses Slickline units for services in production wells, such as memory profiling, well depth determination, well diameters calibration, pipes integrity, locating and /or recovering of production accessories (foot valves, BN, gas mandrels, blind stoppers, packers, etc.), deep and bottom sampling.
Sonic (FWS)
Sonic (FWS)
The technique for a sonic or acoustic velocity well profile uses acoustic transducers to transmit ultrasonic waves through the well fluid into the surrounding rock. This technique allows to determine in-situ compressional and shear waves to calculate the rock mechanical properties. Also, these registries can detect fractured zones and estimate permeability.
High resolution acoustic Televiewer
High resolution acoustic Televiewer
Wellfield Services introduced the Borehole Televiewer technique in Chile in 1996, developing a wide experience in its application.
The high resolution acoustic Televiewer provides well wall pseudo-images to investigate the subsoil structure features through computer assisted images reconnaissance. It consists of a transductor operating at high frequency in pulse-eco mode. The important amount of obtained information, combined with a classification scheme for structural features and with the lithological, geological, chronology and tectonic information, all together, are ideal for structural statistical analysis. The technique is applicable to large scale structure, up to various meters size, as well as to microstructures.
Vertical seismic profile (VSP)
Vertical seismic profile (VSP)
This borehole seismic register is realized on correlation with surface seismic data to obtain higher resolution images to support interpretation. The measurements are obtained placing geophones along vertical wells and the seismic source on the nearby surface. In addition to wells and seismic data correlation, the VSP allows conversion of seismic data to cero phase data and discrimination of primary reflection from multiple reflections.
Mining
Surface geophysics
Gravity
Gravity
The gravity geophysical method detects the gravity field variations on the earth surface related with the subsoil density distribution. From these results is possible to locate formations, reservoirs, basement and other structures with density contrast.
3D Inversion/modeling (MT, IP, Mag, Grav)
3D Inversion/modeling (MT, IP, Mag, Grav)
3D Inversion and Modeling of Magnetoteluric (MT), Induced Polarization (IP) and potential methods (Gravity – Magnetometry) data.
Wellfield counts on important data processing centers in Santiago, Chile and Buenos Aires, Argentina, equipped with legally licensed specific software and with 500 parallel processing cores to handle large datasets with short timing.
Magnetometry
Magnetometry
The magnetic prospection investigates the earth magnetic field variations recording both the total magnetic value as well as its gradient. The anomalies are caused by rock physical properties variations such as magnetic susceptibility and/or remaining magnetization.
2D and 3D Magnetotellurics (AMT/MT)
2D and 3D Magnetotellurics (AMT/MT)
Magnetotellurics is a geophysical passive technique which permits to map the subsoil electrical resistivity distribution, from shallow up to several thousand meters depth. It is applied to the Earth crust and mantle investigation as well as to oil & gas, geothermal, groundwater and mining explorations. This method records both the Earth electric and magnetic fields in stations located on the ground surface. The relation among these 2 fields, in the frequency domain, is named as “impedance tensor” and is directly related to the underneath subsoil electrical resistivity distribution.
MASW/REMI
MASW / REMI
Both MASW (Multichannel Acquisition Surface Waves) and REMI (Refraction Microtremor Arrays) consist in the characterization of surface seismic waves and specifically for Vs (shear wave velocity). MASW uses an active seismic source and registers high frequencies signal while REMI uses passive sources and registers medium-low frequencies. Together they allow obtaining the total velocity dispersion over the complete frequency range to obtain Vs.
Environmental Monitoring using ERT (Electrical Resistivity and Humidity content, natural and intervened subsoils, leach heaps and Pads)
Environmental Monitoring using ERT (Electrical Resistivity and Humidity content, natural and intervened subsoils, leach heaps and Pads)
Monitoring of subsoil humidity content and its resistivity variations through periodical measurements using the Electrical Tomography technique (ERT). The regular follow up in time allow to check the status for known risk situations as well to detect any new potential threat.
Induced Polarization (IP) - classic and deep (Telluric Correction), VIP; 2D and 3D
Induced Polarization (IP) - classic and deep (Telluric Correction), VIP; 2D and 3D
IP studies are used to investigate mineralization of interest, especially disseminated Sulphur, based on formation chargeability and resistivity measurements. Also, it allows estimation of permeability in groundwater studies.
Time Domain Electromagnetics (TDEM) and nano TDEM
Time Domain Electromagnetics (TDEM) and nano TDEM
Time Domain Electromagnetics (TDEM) is a geophysical exploration technique to assess the subsoil electrical resistivity, especially for stratified geology. TDEM measurements are widely applied in hydrogeology and especially in groundwater detection. This technique uses a transmitter Tx and a receptor Rx connected to conductive cable loops. The Tx is connected to the external loop and cause a current pulse at specific frequency and for a determined time interval, inducing an electromagnetic field propagating through the stratified subsoil. The Rx is connected to the internal loop and is configured to record the subsoil electromagnetic behavior when the current pulse in the external loop is suddenly shut off. This behavior provides information about the subsoil electrical resistivity distribution. The loops can also be concentric and coincident.
The differences between normal TDEM and nano TDEM are basically loop size, current frequency and timing, resulting in different investigation depth (DOI): the TDEM presents higher DOI but less resolution at shallow depth, (and starting from about 30-40 m depth), while the nano TDEM investigates a minor DOI but with much higher shallow resolution, starting from a few meters depth.
Well Logging
Structures confirmation
Structures confirmation
Acoustic and optical televiewers records offer a precise confirmation of wells orientation with respect to geological mapping, identifying structure in cores and comparing this information with the televiewer data, discriminating faults type and shear zones allover along the well depth.
Density
Density
Well wall in-situ density continuous recording is performed with a formation-density sensor, which provides data to identify low density as well as high density stratus related, for instance, to coal presence and basic metal mineralogy, respectively.
Wells diameter (Caliper)
Wells diameter (Caliper)
The mechanic caliper well profiling represents the average well diameter, as detected by the tool mobile fingers that are adjusted through springs.
The caliper anomalies could represent fractures, stratification plans, fluid transmission cavities and, usually, show the distance between the fractures that cross with wells.
North seeking Gyroscope
North seeking Gyroscope
This tool records the well orientation with no need for a surface azimuth reference. Knowing the tool depth and the azimuth and inclination registries, it is possible to determine the well´s North and East deviations as well as the altitude with respect to its surface well collar.
Wellfield Services performs these measurements with both single stations and continuous methods, applying a plan of quality assurance to guarantee the registry precision.
Mechanic Gyroscope
Mechanic Gyroscope
Since 1994, Wellfield Services performs mechanic gyroscope registries of wells trajectory. This technique is not affected by magnetic effects and allows high precision recording of azimuth and inclination in both open wells and inside bars.
Maxibor
Maxibor
Maxibor tools allow measuring the well deviation, functioning in memory mode without needing acquisition system and winch. It is particularly useful for the pipeline assisted ascending logs because does not require a cable and is not affected by the drill rods rotation. Anyway, it needs the azimuth as a start reference which must be measured using another tool.
Ascending well profiling
Ascending well profiling
Wellfield Services counts on a wide experience in positive (ascending) well logs, such as in underground mining tunnels toward the surface, which require special installation and additional well tools.
Induced Polarization (IP) - classic and deep (Telluric Correction), VIP; 2D and 3D
Induced Polarization (IP) - classic and deep (Telluric Correction), VIP; 2D and 3D
IP studies are used to investigate mineralization of interest, especially disseminated Sulphur, based on formation chargeability and resistivity measurements. Also, it allows estimation of permeability in groundwater studies.
Neutron porosity
Neutron porosity
Porosity well log based on slowing down and capture of neutrons by the hydrogen contained in the subsoil formations. This technique allows registering the correct porosity for specific formations, (limestone, sandstone, dolomite), assuming that formation pores are fluid-filled and in units related to formation type (vol/vol or u.p.). The measurement is statistical and based on thermal neutron detection, so precisions is higher for high counting speed, i.e. low porosity.
Gamma Ray
Gamma Ray
Gamma Ray log is used to discriminate different lithologies through their specific natural radioactivity, and for Uranium exploration. Gamma ray count increments can be related to lithological changes, alterations and radioactive mineralizations.
Magnetic Susceptibility
Magnetic Susceptibility
Magnetic susceptibility (MS) measurements provide a fast assessment for rock magnetic minerals content. This useful information is used for geological and hydrothermal alteration interpretations as well as to evaluate deposits with highly magnetic minerals such as some kinds of iron minerals.
High resolution acoustic Televiewer
High resolution acoustic Televiewer
Wellfield Services introduced the Borehole Televiewer technique in Chile in 1996, developing a wide experience in its application.
The high resolution acoustic Televiewer provides well wall pseudo-images to investigate the subsoil structure features through computer assisted images reconnaissance. It consists of a transductor operating at high frequency in pulse-eco mode. The important amount of obtained information, combined with a classification scheme for structural features and with the lithological, geological, chronology and tectonic information, all together, are ideal for structural statistical analysis. The technique is applicable to large scale structure, up to various meters size, as well as to microstructures.
High resolution optical Televiewer
High resolution optical Televiewer
If the well is dry or filled with clean transparent fluid, it is possible to obtain a well wall high resolution true colors optical image. This also provides information about the fractures infilling material, besides of all the other information. The best performance is for diamond drilled smooth and even well walls, intercepting colored rocks.
Geothermal
Surface geophysics
Gravity
Gravity
The gravity geophysical method detects the gravity field variations on the earth surface related with the subsoil density distribution. From these results is possible to locate formations, reservoirs, basement and other structures with density contrast.
3D Inversion/modeling (MT, IP, Mag, Grav)
3D Inversion/modeling (MT, IP, Mag, Grav)
3D Inversion and Modeling of Magnetoteluric (MT), Induced Polarization (IP) and potential methods (Gravity – Magnetometry) data.
Wellfield counts on important data processing centers in Santiago, Chile and Buenos Aires, Argentina, equipped with legally licensed specific software and with 500 parallel processing cores to handle large datasets with short timing.
2D and 3D Magnetotellurics (AMT/MT)
2D and 3D Magnetotellurics (AMT/MT)
Magnetotellurics is a geophysical passive technique which permits to map the subsoil electrical resistivity distribution, from shallow up to several thousand meters depth. It is applied to the Earth crust and mantle investigation as well as to oil & gas, geothermal, groundwater and mining explorations. This method records both the Earth electric and magnetic fields in stations located on the ground surface. The relation among these 2 fields, in the frequency domain, is named as “impedance tensor” and is directly related to the underneath subsoil electrical resistivity distribution.
Time Domain Electromagnetics (TDEM) and nano TDEM
Time Domain Electromagnetics (TDEM) and nano TDEM
Time Domain Electromagnetics (TDEM) is a geophysical exploration technique to assess the subsoil electrical resistivity, especially for stratified geology. TDEM measurements are widely applied in hydrogeology and especially in groundwater detection. This technique uses a transmitter Tx and a receptor Rx connected to conductive cable loops. The Tx is connected to the external loop and cause a current pulse at specific frequency and for a determined time interval, inducing an electromagnetic field propagating through the stratified subsoil. The Rx is connected to the internal loop and is configured to record the subsoil electromagnetic behavior when the current pulse in the external loop is suddenly shut off. This behavior provides information about the subsoil electrical resistivity distribution. The loops can also be concentric and coincident.
The differences between normal TDEM and nano TDEM are basically loop size, current frequency and timing, resulting in different investigation depth (DOI): the TDEM presents higher DOI but less resolution at shallow depth, (and starting from about 30-40 m depth), while the nano TDEM investigates a minor DOI but with much higher shallow resolution, starting from a few meters depth.
Well Logging
CBL, VDL and CCL
CBL, VDL and CCL
Cement Bond Log (CBL), Variable-Density Log (VDL) and Casing Collar Locator (CCL) services offer a complete evaluation of well wall and casing to reduce the uncertainty about hydraulic isolation quality in the production zone, making possible more efficient well refining operations at a minimum cost.
High Pressure (P) and Temperature (T) well logs
High pressure P and temperature T well logs
Wireline logs in geothermal high P and T wells with memory tools.
Neutron porosity
Neutron porosity
Porosity well log based on slowing down and capture of neutrons by the hydrogen contained in the subsoil formations. This technique allows registering the correct porosity for specific formations, (limestone, sandstone, dolomite), assuming that formation pores are fluid-filled and in units related to formation type (vol/vol or u.p.). The measurement is statistical and based on thermal neutron detection, so precisions is higher for high counting speed, i.e. low porosity.
Free Point / pipes rescue
Free Point / pipes rescue
The rescue of a pipe or a flexible pipe string stuck deep in a well but free to move, is based on cutting it and locating its free point in such a way to eliminate the problem down below the cut.
Gamma Ray
Gamma Ray
Gamma Ray log is used to discriminate different lithologies through their specific natural radioactivity, and for Uranium exploration. Gamma ray count increments can be related to lithological changes, alterations and radioactive mineralizations.
Geotechnics
Surface geophysics
Multifrequency EM
Multifrequency EM
Frequency Domain Electromagnetic prospection registers the secondary EM field resulting from induction currents propagation, allowing a continuous recording of electrical resistivity on surface as well as in wells to quickly investigate the subsoil at low cost.
In situ thermal resistivity test
In situ thermal resistivity test
Thermal resistivity describes the subsoil capability to oppose to thermal flow.
Thermal resistivity measurements are performed using a needle-shapes thermal sensor introduced into subsoil and registering the temperature changes produced by heating it.
Ground Probing Radar - Georadar (GPR)
Groud Probing Radar - Georadar (GPR)
The Ground Probing Radar (GPR) is a high-resolution tool recording high frequency subsurface EM waves reflection, allowing a precise estimation of depth for the detected objects, as well as of their nature and origin. It is a non-invasive method which permits investigations without excavations and that is normally required for environmental, engineering, archeology and other shallow studies.
MASW/REMI
MASW / REMI
Both MASW (Multichannel Acquisition Surface Waves) and REMI (Refraction Microtremor Arrays) consist in the characterization of surface seismic waves and specifically for Vs (shear wave velocity). MASW uses an active seismic source and registers high frequencies signal while REMI uses passive sources and registers medium-low frequencies. Together they allow obtaining the total velocity dispersion over the complete frequency range to obtain Vs.
Nakamura-HVSR (Horizontal Vertical Spectral Ratio)
Nakamura-HVSR (Horizontal Vertical Spectral Ratio)
The HVSR method (H/V Spectral Ratio or Nakamura) is a non-intrusive assay based on environment micro-vibrations recording (on ground surface according to the vertical and to N-S and E-W perpendicular directions). The horizontal and vertical components relation results in a composite signal which process and analysis lead to the Soil Fundamental Period. This parameter is critical to prevent that a man-made structure’s period matches the soil period resulting in seismic amplification for resonance with the consequent structural damage.
Refraction seismic
Refraction seismic
Seismic Tomography is a geophysical method for subsoil exploration through waves transmission. It consists in generating seismic waves by hitting the ground (manually or using mechanical systems such as portable Propelled Energy Generators and Accelerated Weight Drop Systems or thumper trucks) and detecting them in different locations through geophones equally spaced along a profile. This technique allows recording the subsoil compressional velocity Vp.
Vertical Electrical Sounding (VES)
Refraction seismic
Seismic Tomography is a geophysical method for subsoil exploration through waves transmission. It consists in generating seismic waves by hitting the ground (manually or using mechanical systems such as portable Propelled Energy Generators and Accelerated Weight Drop Systems or thumper trucks) and detecting them in different locations through geophones equally spaced along a profile. This technique allows recording the subsoil compressional velocity Vp.
Electrical Resistivity Tomography (ERT) 2D and 3D
Electrical Resistivity Tomography (ERT) 2D and 3D
The Electrical Resistivity Tomography (ERT) allows obtaining 2D sections and 3D models for the subsoil resistivity distribution. The difference with the related and simpler VES technique is the much higher measurements density and the 2D/3D algorithms to model and interpret data.
ERT is a contact method which uses a set of several electrodes installed on the surface along a profile (2D) or according a regular mesh (3D). Direct current injection into subsoil through pairs of electrodes allows voltage measurements between other electrodes pairs. A switching device, configured according specific protocols, automatically performs all the possible combination, of injection and voltage electrodes pairs, resulting in high density data laterally as well as with depth. This data set allows a detailed reconnaissance of the subsoil electrical resistivity distribution.
Well Logging
Density
Density
Well wall in-situ density continuous recording is performed with a formation-density sensor, which provides data to identify low density as well as high density stratus related, for instance, to coal presence and basic metal mineralogy, respectively.
Wells diameter (Caliper)
Wells diameter (Caliper)
The mechanic caliper well profiling represents the average well diameter, as detected by the tool mobile fingers that are adjusted through springs.
The caliper anomalies could represent fractures, stratification plans, fluid transmission cavities and, usually, show the distance between the fractures that cross with wells.
Downhole / Crosshole
Downhole / Crosshole
Dowhole and Crosshole are seismic techniques to measure wave’s propagation velocity in wells, with higher precision and resolution compared to surface recordings.
The Downhole registry consists in a tri-axial geophone lowered into a well while seismic waves are generated on surface. At specific depths, the geophone records directly the waves transmission times.
The Crosshole utilizes two wells, one to generate the seismic waves and the other to register the wave’s transmission times from one to the other.
Structures orientation
Structures orientation
Using the high definition acoustic and optical televiewers registries, (equivalent and complementary), Wellfield Services analyzes discontinuities and structures and evaluates the fracture index (FI).
Neutron porosity
Neutron porosity
Porosity well log based on slowing down and capture of neutrons by the hydrogen contained in the subsoil formations. This technique allows registering the correct porosity for specific formations, (limestone, sandstone, dolomite), assuming that formation pores are fluid-filled and in units related to formation type (vol/vol or u.p.). The measurement is statistical and based on thermal neutron detection, so precisions is higher for high counting speed, i.e. low porosity.
Sonic (FWS)
Sonic (FWS)
The technique for a sonic or acoustic velocity well profile uses acoustic transducers to transmit ultrasonic waves through the well fluid into the surrounding rock. This technique allows to determine in-situ compressional and shear waves to calculate the rock mechanical properties. Also, these registries can detect fractured zones and estimate permeability.
High resolution acoustic Televiewer
High resolution acoustic Televiewer
Wellfield Services introduced the Borehole Televiewer technique in Chile in 1996, developing a wide experience in its application.
The high resolution acoustic Televiewer provides well wall pseudo-images to investigate the subsoil structure features through computer assisted images reconnaissance. It consists of a transductor operating at high frequency in pulse-eco mode. The important amount of obtained information, combined with a classification scheme for structural features and with the lithological, geological, chronology and tectonic information, all together, are ideal for structural statistical analysis. The technique is applicable to large scale structure, up to various meters size, as well as to microstructures.
High resolution optical Televiewer
High resolution optical Televiewer
If the well is dry or filled with clean transparent fluid, it is possible to obtain a well wall high resolution true colors optical image. This also provides information about the fractures infilling material, besides of all the other information. The best performance is for diamond drilled smooth and even well walls, intercepting colored rocks.
Water
Surface geophysics
Time Domain Electromagnetics (TDEM) and nano TDEM
Time Domain Electromagnetics (TDEM) and nano TDEM
Time Domain Electromagnetics (TDEM) is a geophysical exploration technique to assess the subsoil electrical resistivity, especially for stratified geology. TDEM measurements are widely applied in hydrogeology and especially in groundwater detection. This technique uses a transmitter Tx and a receptor Rx connected to conductive cable loops. The Tx is connected to the external loop and cause a current pulse at specific frequency and for a determined time interval, inducing an electromagnetic field propagating through the stratified subsoil. The Rx is connected to the internal loop and is configured to record the subsoil electromagnetic behavior when the current pulse in the external loop is suddenly shut off. This behavior provides information about the subsoil electrical resistivity distribution. The loops can also be concentric and coincident.
The differences between normal TDEM and nano TDEM are basically loop size, current frequency and timing, resulting in different investigation depth (DOI): the TDEM presents higher DOI but less resolution at shallow depth, (and starting from about 30-40 m depth), while the nano TDEM investigates a minor DOI but with much higher shallow resolution, starting from a few meters depth.
Electrical Resistivity Tomography (ERT) 2D and 3D
Electrical Resistivity Tomography (ERT) 2D and 3D
The Electrical Resistivity Tomography (ERT) allows obtaining 2D sections and 3D models for the subsoil resistivity distribution. The difference with the related and simpler VES technique is the much higher measurements density and the 2D/3D algorithms to model and interpret data.
ERT is a contact method which uses a set of several electrodes installed on the surface along a profile (2D) or according a regular mesh (3D). Direct current injection into subsoil through pairs of electrodes allows voltage measurements between other electrodes pairs. A switching device, configured according specific protocols, automatically performs all the possible combination, of injection and voltage electrodes pairs, resulting in high density data laterally as well as with depth. This data set allows a detailed reconnaissance of the subsoil electrical resistivity distribution.
Well Logging
Mineral incrustations and bacteria analysis (WSE USA)
Mineral incrustations and bacteria analysis (WSE USA)
Mineral and bacteria incrustations in pipes and well walls can plug and collapse water wells. Preventive detection and analysis allow early diagnosis and specific treatment to inhibit this development. There are several ways (mechanic and chemical) to remove and/or inhibit incrustation, which choice depends on source and sediment nature, so analysis are critical issues to efficiently solve each specific case.
Water quality: pH, temperature, conductivity, Redox
Water quality: pH, temperature, conductivity, Redox
Wellfield Services offers trustable Temperature, Salinity, pH, Eh and Pressure registries in water wells, using sensors that are periodically calibrated using patron solutions, verified by USA laboratories measurements.
Density
Density
Well wall in-situ density continuous recording is performed with a formation-density sensor, which provides data to identify low density as well as high density stratus related, for instance, to coal presence and basic metal mineralogy, respectively.
Wells diameter (Caliper)
Wells diameter (Caliper)
The mechanic caliper well profiling represents the average well diameter, as detected by the tool mobile fingers that are adjusted through springs.
The caliper anomalies could represent fractures, stratification plans, fluid transmission cavities and, usually, show the distance between the fractures that cross with wells.
Lefranc test
Lefranc test
Test to measure permeability in permeable or semi-permeable soils. The test measures the flow needed to maintain a constant water level in a well (static load) or, alternatively, the water level decay velocity (variable load).
Lugeon test
Lugeon test
Test to estimate the permeability in rocky soils, measuring the water flow that can be injected at constant pressure in different well sections.
Flowmeter, spinner
Flowmeter, spinner
A rotating instrument is utilized to measure the fluid flow inside a well. An helicoidal-shaped (blade) rotor gains a certain rotation speed which is related to the effective flow velocity.
High Pressure (P) and Temperature (T) logs
High pressure P and temperature T well logs
Wireline logs in geothermal high P and T wells with memory tools.
Neutron porosity
Neutron porosity
Porosity well log based on slowing down and capture of neutrons by the hydrogen contained in the subsoil formations. This technique allows registering the correct porosity for specific formations, (limestone, sandstone, dolomite), assuming that formation pores are fluid-filled and in units related to formation type (vol/vol or u.p.). The measurement is statistical and based on thermal neutron detection, so precisions is higher for high counting speed, i.e. low porosity.
Hydraulics test
Hydraulics test
The test consists of a pressured water injection into an isolated sounding portion, closed on one or both sides by one or two packers, to measure the amount of water that can be absorbed by the ground. It is applied on rock or consolidated ground with medium to low permeability.
Gamma Ray
Gamma Ray
Gamma Ray log is used to discriminate different lithologies through their specific natural radioactivity, and for Uranium exploration. Gamma ray count increments can be related to lithological changes, alterations and radioactive mineralizations.
Environment
Surface geophysics
Mineral incrustations and bacteria analysis (WSE USA)
Mineral incrustations and bacteria analysis (WSE USA)
Mineral and bacteria incrustations in pipes and well walls can plug and collapse water wells. Preventive detection and analysis allow early diagnosis and specific treatment to inhibit this development. There are several ways (mechanic and chemical) to remove and/or inhibit incrustation, which choice depends on source and sediment nature, so analysis are critical issues to efficiently solve each specific case.
Multifrequency EM
Multifrequency EM
Frequency Domain Electromagnetic prospection registers the secondary EM field resulting from induction currents propagation, allowing a continuous recording of electrical resistivity on surface as well as in wells to quickly investigate the subsoil at low cost.
Electrical Resistivity Tomography (ERT) 2D and 3D
Electrical Resistivity Tomography (ERT) 2D and 3D
The Electrical Resistivity Tomography (ERT) allows obtaining 2D sections and 3D models for the subsoil resistivity distribution. The difference with the related and simpler VES technique is the much higher measurements density and the 2D/3D algorithms to model and interpret data.
ERT is a contact method which uses a set of several electrodes installed on the surface along a profile (2D) or according a regular mesh (3D). Direct current injection into subsoil through pairs of electrodes allows voltage measurements between other electrodes pairs. A switching device, configured according specific protocols, automatically performs all the possible combination, of injection and voltage electrodes pairs, resulting in high density data laterally as well as with depth. This data set allows a detailed reconnaissance of the subsoil electrical resistivity distribution.
Well Logging
Water quality: pH, temperature, conductivity, Redox
Water quality: pH, temperature, conductivity, Redox
Wellfield Services offers trustable Temperature, Salinity, pH, Eh and Pressure registries in water wells, using sensors that are periodically calibrated using patron solutions, verified by USA laboratories measurements.
CBL, VDL and CCL
CBL, VDL and CCL
Cement Bond Log (CBL), Variable-Density Log (VDL) and Casing Collar Locator (CCL) services offer a complete evaluation of well wall and casing to reduce the uncertainty about hydraulic isolation quality in the production zone, making possible more efficient well refining operations at a minimum cost.
Structures confirmation
Structures confirmation
Acoustic and optical televiewers records offer a precise confirmation of wells orientation with respect to geological mapping, identifying structure in cores and comparing this information with the televiewer data, discriminating faults type and shear zones allover along the well depth.
Density
Density
Well wall in-situ density continuous recording is performed with a formation-density sensor, which provides data to identify low density as well as high density stratus related, for instance, to coal presence and basic metal mineralogy, respectively.
Deviation / Wells trajectory
Deviation / Wells trajectory
The well trajectory or deviation is registered through directional tools which spatially locate each sector with respect to the well collar. These tools consist of electronic sensors which are lowered into the well using a winch.
Wellfield Services apply a plan of quality assurance consisting of tools calibration control, trajectory registries in both lowering and uprising sensor phases, pre and post well drilling checks, in conjunction with a strict control of the processing center proceedings.
Wells diameter (Caliper)
Wells diameter (Caliper)
The mechanic caliper well profiling represents the average well diameter, as detected by the tool mobile fingers that are adjusted through springs.
The caliper anomalies could represent fractures, stratification plans, fluid transmission cavities and, usually, show the distance between the fractures that cross with wells.
Downhole / Crosshole
Downhole / Crosshole
Dowhole and Crosshole are seismic techniques to measure wave’s propagation velocity in wells, with higher precision and resolution compared to surface recordings.
The Downhole registry consists in a tri-axial geophone lowered into a well while seismic waves are generated on surface. At specific depths, the geophone records directly the waves transmission times.
The Crosshole utilizes two wells, one to generate the seismic waves and the other to register the wave’s transmission times from one to the other.
Lefranc test
Lefranc test
Test to measure permeability in permeable or semi-permeable soils. The test measures the flow needed to maintain a constant water level in a well (static load) or, alternatively, the water level decay velocity (variable load).
Lugeon test
Lugeon test
Test to estimate the permeability in rocky soils, measuring the water flow that can be injected at constant pressure in different well sections.
Flowmeter, spinner
Flowmeter, spinner
A rotating instrument is utilized to measure the fluid flow inside a well. An helicoidal-shaped (blade) rotor gains a certain rotation speed which is related to the effective flow velocity.
North seeking Gyroscope
North seeking Gyroscope
This tool records the well orientation with no need for a surface azimuth reference. Knowing the tool depth and the azimuth and inclination registries, it is possible to determine the well´s North and East deviations as well as the altitude with respect to its surface well collar.
Wellfield Services performs these measurements with both single stations and continuous methods, applying a plan of quality assurance to guarantee the registry precision.
Mechanic Gyroscope
Mechanic Gyroscope
Since 1994, Wellfield Services performs mechanic gyroscope registries of wells trajectory. This technique is not affected by magnetic effects and allows high precision recording of azimuth and inclination in both open wells and inside bars.
Maxibor
Maxibor
Maxibor tools allow measuring the well deviation, functioning in memory mode without needing acquisition system and winch. It is particularly useful for the pipeline assisted ascending logs because does not require a cable and is not affected by the drill rods rotation. Anyway, it needs the azimuth as a start reference which must be measured using another tool.
Structures orientation
Structures orientation
Using the high definition acoustic and optical televiewers registries, (equivalent and complementary), Wellfield Services analyzes discontinuities and structures and evaluates the fracture index (FI).
Ascending well profiling
Ascending well profiling
Wellfield Services counts on a wide experience in positive (ascending) well logs, such as in underground mining tunnels toward the surface, which require special installation and additional well tools.
High Pressure (P) and Temperature (T) well logs
High pressure P and temperature T well logs
Wireline logs in geothermal high P and T wells with memory tools.
Neutron porosity
Neutron porosity
Porosity well log based on slowing down and capture of neutrons by the hydrogen contained in the subsoil formations. This technique allows registering the correct porosity for specific formations, (limestone, sandstone, dolomite), assuming that formation pores are fluid-filled and in units related to formation type (vol/vol or u.p.). The measurement is statistical and based on thermal neutron detection, so precisions is higher for high counting speed, i.e. low porosity.
Hydraulics test
Hydraulics test
The test consists of a pressured water injection into an isolated sounding portion, closed on one or both sides by one or two packers, to measure the amount of water that can be absorbed by the ground. It is applied on rock or consolidated ground with medium to low permeability.
Free Point / pipes rescue
Free Point / pipes rescue
The rescue of a pipe or a flexible pipe string stuck deep in a well but free to move, is based on cutting it and locating its free point in such a way to eliminate the problem down below the cut.
Gamma Ray
Gamma Ray
Gamma Ray log is used to discriminate different lithologies through their specific natural radioactivity, and for Uranium exploration. Gamma ray count increments can be related to lithological changes, alterations and radioactive mineralizations.
16 / 64 Resistivity
16 / 64 Resistivity
The Formation Resistivity well log is measured through 2 current (A and B) and 2 potential (M and N) electrodes. A and M are located on the probe, B is on the cable armature and N on the surface.
Slickline
Slickline
Wellfield uses Slickline units for services in production wells, such as memory profiling, well depth determination, well diameters calibration, pipes integrity, locating and /or recovering of production accessories (foot valves, BN, gas mandrels, blind stoppers, packers, etc.), deep and bottom sampling.
Sonic (FWS)
Sonic (FWS)
The technique for a sonic or acoustic velocity well profile uses acoustic transducers to transmit ultrasonic waves through the well fluid into the surrounding rock. This technique allows to determine in-situ compressional and shear waves to calculate the rock mechanical properties. Also, these registries can detect fractured zones and estimate permeability.
Magnetic Susceptibility
Magnetic Susceptibility
Magnetic susceptibility (MS) measurements provide a fast assessment for rock magnetic minerals content. This useful information is used for geological and hydrothermal alteration interpretations as well as to evaluate deposits with highly magnetic minerals such as some kinds of iron minerals.
High resolution acoustic Televiewer
High resolution acoustic Televiewer
Wellfield Services introduced the Borehole Televiewer technique in Chile in 1996, developing a wide experience in its application.
The high resolution acoustic Televiewer provides well wall pseudo-images to investigate the subsoil structure features through computer assisted images reconnaissance. It consists of a transductor operating at high frequency in pulse-eco mode. The important amount of obtained information, combined with a classification scheme for structural features and with the lithological, geological, chronology and tectonic information, all together, are ideal for structural statistical analysis. The technique is applicable to large scale structure, up to various meters size, as well as to microstructures.
High resolution acoustic Televiewer
High resolution acoustic Televiewer
Wellfield Services introduced the Borehole Televiewer technique in Chile in 1996, developing a wide experience in its application.
The high resolution acoustic Televiewer provides well wall pseudo-images to investigate the subsoil structure features through computer assisted images reconnaissance. It consists of a transductor operating at high frequency in pulse-eco mode. The important amount of obtained information, combined with a classification scheme for structural features and with the lithological, geological, chronology and tectonic information, all together, are ideal for structural statistical analysis. The technique is applicable to large scale structure, up to various meters size, as well as to microstructures.
High resolution optical Televiewer
High resolution optical Televiewer
If the well is dry or filled with clean transparent fluid, it is possible to obtain a well wall high resolution true colors optical image. This also provides information about the fractures infilling material, besides of all the other information. The best performance is for diamond drilled smooth and even well walls, intercepting colored rocks.
Vertical seismic profile (VSP)
Magnetic Susceptibility
Magnetic susceptibility (MS) measurements provide a fast assessment for rock magnetic minerals content. This useful information is used for geological and hydrothermal alteration interpretations as well as to evaluate deposits with highly magnetic minerals such as some kinds of iron minerals.
Surface geophysics
Reflection seismic processing 2D/3D
Reflection seismic processing 2D/3D
Data processing consists in transforming seismic data to interpretable information. Wellfield processing center in Buenos Aires offers time based (PSTM) and depth based (PSDM) data processing for terrestrial and marine seismic surveys. The professional staff counts with experience all over South America.
Microseimic Acquisicion and processing
Microseimic Acquisicion and processing
Monitoring of induced microseismic events is key to hydraulic fractures evaluation and optimization. Its main objective is to characterize the induced fractures structure and the density distribution for a specific formation.
The microseismic activity is measured using geophones located to map a sector related to the studied induced fracture, leading to its geometry estimation.
Downhole / Crosshole
Downhole / Crosshole
Dowhole and Crosshole are seismic techniques to measure wave’s propagation velocity in wells, with higher precision and resolution compared to surface recordings.
The Downhole registry consists in a tri-axial geophone lowered into a well while seismic waves are generated on surface. At specific depths, the geophone records directly the waves transmission times.
The Crosshole utilizes two wells, one to generate the seismic waves and the other to register the wave’s transmission times from one to the other.
Multifrequency EM
Multifrequency EM
Frequency Domain Electromagnetic prospection registers the secondary EM field resulting from induction currents propagation, allowing a continuous recording of electrical resistivity on surface as well as in wells to quickly investigate the subsoil at low cost.
In situ thermal resistivity test
In situ thermal resistivity test
Thermal resistivity describes the subsoil capability to oppose to thermal flow.
Thermal resistivity measurements are performed using a needle-shapes thermal sensor introduced into subsoil and registering the temperature changes produced by heating it.
Ground Probing Radar - Georadar (GPR)
Groud Probing Radar - Georadar (GPR)
The Ground Probing Radar (GPR) is a high-resolution tool recording high frequency subsurface EM waves reflection, allowing a precise estimation of depth for the detected objects, as well as of their nature and origin. It is a non-invasive method which permits investigations without excavations and that is normally required for environmental, engineering, archeology and other shallow studies.
Gravity
Gravity
The gravity geophysical method detects the gravity field variations on the earth surface related with the subsoil density distribution. From these results is possible to locate formations, reservoirs, basement and other structures with density contrast.
3D Inversion/modeling (MT, IP, Mag, Grav)
3D Inversion/modeling (MT, IP, Mag, Grav)
3D Inversion and Modeling of Magnetoteluric (MT), Induced Polarization (IP) and potential methods (Gravity – Magnetometry) data.
Wellfield counts on important data processing centers in Santiago, Chile and Buenos Aires, Argentina, equipped with legally licensed specific software and with 500 parallel processing cores to handle large datasets with short timing.
Magnetometry
Magnetometry
The magnetic prospection investigates the earth magnetic field variations recording both the total magnetic value as well as its gradient. The anomalies are caused by rock physical properties variations such as magnetic susceptibility and/or remaining magnetization.
2D and 3D Magnetotellurics (AMT/MT)
2D and 3D Magnetotellurics (AMT/MT)
Magnetotellurics is a geophysical passive technique which permits to map the subsoil electrical resistivity distribution, from shallow up to several thousand meters depth. It is applied to the Earth crust and mantle investigation as well as to oil & gas, geothermal, groundwater and mining explorations. This method records both the Earth electric and magnetic fields in stations located on the ground surface. The relation among these 2 fields, in the frequency domain, is named as “impedance tensor” and is directly related to the underneath subsoil electrical resistivity distribution.
MASW/REMI
MASW / REMI
Both MASW (Multichannel Acquisition Surface Waves) and REMI (Refraction Microtremor Arrays) consist in the characterization of surface seismic waves and specifically for Vs (shear wave velocity). MASW uses an active seismic source and registers high frequencies signal while REMI uses passive sources and registers medium-low frequencies. Together they allow obtaining the total velocity dispersion over the complete frequency range to obtain Vs.
Environmental Monitoring using ERT (Electrical Resistivity and Humidity content, natural and intervened subsoils, leach heaps and Pads)
Environmental Monitoring using ERT (Electrical Resistivity and Humidity content, natural and intervened subsoils, leach heaps and Pads)
Monitoring of subsoil humidity content and its resistivity variations through periodical measurements using the Electrical Tomography technique (ERT). The regular follow up in time allow to check the status for known risk situations as well to detect any new potential threat.
Induced Polarization (IP) - classic and deep (Telluric Correction), VIP; 2D and 3D
Induced Polarization (IP) - classic and deep (Telluric Correction), VIP; 2D and 3D
IP studies are used to investigate mineralization of interest, especially disseminated Sulphur, based on formation chargeability and resistivity measurements. Also, it allows estimation of permeability in groundwater studies.
Reflection seismic processing 2D/3D
Reflection seismic processing 2D/3D
Data processing consists in transforming seismic data to interpretable information. Wellfield processing center in Buenos Aires offers time based (PSTM) and depth based (PSDM) data processing for terrestrial and marine seismic surveys. The professional staff counts with experience all over South America.
Refraction seismic
Refraction seismic
Seismic Tomography is a geophysical method for subsoil exploration through waves transmission. It consists in generating seismic waves by hitting the ground (manually or using mechanical systems such as portable Propelled Energy Generators and Accelerated Weight Drop Systems or thumper trucks) and detecting them in different locations through geophones equally spaced along a profile. This technique allows recording the subsoil compressional velocity Vp.
Vertical Electrical Sounding (VES)
Vertical Electrical Sounding (VES)
The Vertical Electrical Sounding (VES) allows to measure a subsoil resistivity vertical profile (1D), using a four electrodes array. Two current electrodes are installed with a specific spacing on the ground and are used to transmit the electrical current to the subsoil. The other two electrodes, also installed on the ground, are used to measure the voltage difference. The investigation depth is directly related to the current electrodes spacing.
Time Domain Electromagnetics (TDEM) and nano TDEM
Time Domain Electromagnetics (TDEM) and nano TDEM
Time Domain Electromagnetics (TDEM) is a geophysical exploration technique to assess the subsoil electrical resistivity, especially for stratified geology. TDEM measurements are widely applied in hydrogeology and especially in groundwater detection. This technique uses a transmitter Tx and a receptor Rx connected to conductive cable loops. The Tx is connected to the external loop and cause a current pulse at specific frequency and for a determined time interval, inducing an electromagnetic field propagating through the stratified subsoil. The Rx is connected to the internal loop and is configured to record the subsoil electromagnetic behavior when the current pulse in the external loop is suddenly shut off. This behavior provides information about the subsoil electrical resistivity distribution. The loops can also be concentric and coincident.
The differences between normal TDEM and nano TDEM are basically loop size, current frequency and timing, resulting in different investigation depth (DOI): the TDEM presents higher DOI but less resolution at shallow depth, (and starting from about 30-40 m depth), while the nano TDEM investigates a minor DOI but with much higher shallow resolution, starting from a few meters depth.
Electrical Resistivity Tomography (ERT) 2D and 3D
Electrical Resistivity Tomography (ERT) 2D and 3D
The Electrical Resistivity Tomography (ERT) allows obtaining 2D sections and 3D models for the subsoil resistivity distribution. The difference with the related and simpler VES technique is the much higher measurements density and the 2D/3D algorithms to model and interpret data.
ERT is a contact method which uses a set of several electrodes installed on the surface along a profile (2D) or according a regular mesh (3D). Direct current injection into subsoil through pairs of electrodes allows voltage measurements between other electrodes pairs. A switching device, configured according specific protocols, automatically performs all the possible combination, of injection and voltage electrodes pairs, resulting in high density data laterally as well as with depth. This data set allows a detailed reconnaissance of the subsoil electrical resistivity distribution.
Well diagnosis, repair and cleaning
Mineral incrustations and bacteria analysis (WSE USA)
Mineral incrustations and bacteria analysis (WSE USA)
Mineral and bacteria incrustations in pipes and well walls can plug and collapse water wells. Preventive detection and analysis allow early diagnosis and specific treatment to inhibit this development. There are several ways (mechanic and chemical) to remove and/or inhibit incrustation, which choice depends on source and sediment nature, so analysis are critical issues to efficiently solve each specific case.
Video well inspections
Video well inspections
Video recording of well walls to evaluate screens conservation state and possible logs.
Report of improvement for deep-water wells
Report of improvement for deep-water wells
Report relating the deep-water wells optimization through improvement of their electrical and mechanical systems, habilitation and/or cleaning.
Water well mechanic cleaning
Water well mechanic cleaning
There is a wide variety of tools and techniques to eliminate the mineral deposits and incrustations, each one strictly related to well characteristics and incrustations type. Mechanical cleaning tools are positive displacement motors, drills, impact hammers, etc.
Water wells chemical cleaning
Water wells chemical cleaning
Incrustations chemical removing is the cheapest and most used technique to clean water wells, especially for difficult well internal locations and/or access conditions.
Well electrical systems maintenance
Well electrical systems maintenance
Integral maintenance for water well pumping systems electrical mechanisms.
Instruments checking and repairs.
Mechanic maintenance, well development and embanking removal (silt)
Mechanic maintenance, well development and embanking removal (silt)
Water wells pumping systems maintenance and operational optimization (correct well development). Removal of embanked silt.
Hydraulics test
Lefranc test
Lefranc test
Test to measure permeability in permeable or semi-permeable soils. The test measures the flow needed to maintain a constant water level in a well (static load) or, alternatively, the water level decay velocity (variable load).
Lugeon test
Lugeon test
Test to estimate the permeability in rocky soils, measuring the water flow that can be injected at constant pressure in different well sections.
Services in alphabetical order
