Geophysical inspection in boreholes, supported wells

and groundwater monitoring wells

Our measuremts are based on the common geophysical methods listed below . It is possible to expand the investigation program for complex problems

 

 

 

 Measuring methods Exploration objective
 GR
Gamma logs 

 Gamma logs record the amount of natural gamma radiation emitted by the rocks surrounding the borehole. The most significant naturally occurring sources of gamma radiation are potassium-40 and daughter products of the uranium- and thorium-decay series. Clay- and shale-bearing rocks commonly emit relatively high gamma radiation because they include weathering products of potassium feldspar and mica and tend to concentrate uranium and thorium by ion absorption and exchange.

 

 FEL
Focused resistivity logs

 Resistivity logs record the electrical resistivity of the borehole environment and surrounding rocks and water as measured by variably spaced potential electrodes on the logging probe.Resistivity logs are affected by bed thickness, borehole diameter, and borehole fluid and can only be collected in water- or mud-filled open holes. Electrical conductivity and resistivity are affected by the porosity, permeability, and clay content of the rocks and by the dissolved-solids concentration of the water within the rocks. 

 SP
Spontaneus-potential logs 

 Spontaneous-potential logs record potentials or voltages developed between the borehole fluid and the surrounding rock and fluids. Spontaneous-potential logs can be used in the determination of lithology. Collection of spontaneous-potential logs is limited to water- or mud-filled open holes. 

 SUS
Magnetic susceptibility logs

 The magnetic susceptibility (MS) of a volume of rock is a function of the amount of magnetic minerals, (mainly magnetite and pyrhotite), contained within the rock. MS measurements can provide a rapid estimate of the ferromagnetism of the rock. These measurements can be interpreted to reflect lithological changes, degree of homogeneity and the presence of alteration zones in the rock mass. Although the construction of the well or metallic remains in a borehole are detectable. 

 CAL
Caliper logs

 Caliper logs record borehole diameter. Changes in borehole diameter are related to well construction, such as casing or drilling-bit size, and to fracturing or caving along the borehole wall. Because borehole diameter commonly affects log response, the caliper log is useful in the analysis of other geophysical logs, including interpretation of flowmeter logs. 

 BA
Borehole deviation 

 It reports borehole inclination, bearing, true vertical depth, northing, and easting. These parameters are calculated in real time using the quantities measured by the probe. 

 FLOW-01.../FLOW-11...
Flowmeter logs 

 Flowmeter logs record the direction and rate of vertical flow in the borehole. Borehole-flow rates can be calculated from downhole-velocity measurements and borehole diameter recorded by the caliper log. Flowmeter logs can be collected under non-pumping and(or) pumping conditions. Impeller flowmeters are the most widely used. 

 FLOW.P
Packer flowmeter logs 

 This advanced flowmeter tool for boreholes have included devices for use in well bores with packers. Such flowmeters generally include a passageway open at inlet and outlet orifices to the exterior of the tool and a spinner section which measures the rate of fluid flow through the passageway. So it is able to detect the flowrates through the filter and the backfill for inspection and regeneration. 

 TEMP-01/TEMP-11...
Temperature logs 

 Temperature logs record the water temperature in the borehole. Temperature logs are useful for delineating water-bearing zones and identifying vertical flow in the borehole between zones of differing hydraulic head penetrated by wells. Borehole flow between zones is indicated by temperature gradients that are less than the regional geothermal gradient. 

 SAL-01/SAL-11...
Fluid resistivity logs

 Fluid-resistivity logs record the electric resistivity of water in the borehole. Changes in fluid resistivity reflect differences in dissolved-solids concentration of water. Fluid-resistivity logs are useful for delineating water-bearing zones and identifying vertical flow in the borehole. 

 TFL-01…/TFL-11…
Tracer-Fluid-Logging

 A form of resitivity log used in production logging for the study of tracer movements and, therefore, fluid movements in the immediate vicinity of the well bore (e.g., in casing. tubing, annulus, open hole). Usually a calculated amount of salt are ejected into the fluid phase to be studied, and the direction and velocity of the introduced slug is monitored over different parts of the well bore. Tracer logs are helpful in estimating fluid flowrates, points of fluid exit or entry into the well bore, crossflow, leaks, etc. 

 SAMP-01.../SAMP-11...
Discrete level sampling

 At sites where discrete level sampling has been successful, a detectable stratification of water chemistry existed within screened intervals. This fact implies that little vertical mixing occurred in the screened intervals and that the water at discrete depths had equilibrated to the groundwater chemistry at the corresponding depth. Discrete level sampling strategies are appropriate if no vertical gradients exist in the well column and when lateral groundwater flow is sufficient to re-establish lateral chemical equilibrium after any previous activities that would mix the water in the well column, such as purging. The approach is useful to delineate areas of concentrated contaminants and plume boundaries in vertical profile. Stratification can only be detected if the water column is relatively undisturbed during sampling and all discrete level sampling techniques employ minimal or no purging. 

 TEMP.MON
Temperatue-Monitoring

(temperature measurement while sinking water level)

 Directly proof of hydraulic effectivity of of sealing tubes