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.
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.
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.
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.
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.
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.
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.
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.
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).
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.
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 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.
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.
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.
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 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.
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.
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 (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.
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.
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.
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.