Search results
Results From The WOW.Com Content Network
Well logging, also known as borehole logging is the practice of making a detailed record (a well log) of the geologic formations penetrated by a borehole.The log may be based either on visual inspection of samples brought to the surface (geological logs) or on physical measurements made by instruments lowered into the hole (geophysical logs).
A caliper log is a well logging tool that provides a continuous measurement of the size and shape of a borehole along its depth [1] and is commonly used in hydrocarbon exploration. The measurements that are recorded can be an important indicator of wash-outs, cave ins or shale swelling in the borehole, which can affect the results of other well ...
Example gamma ray log. Blue and black lines indicate the measured gamma rays. Sand section of interest is located at bottom of log where the log moves to the left. Gamma ray logging is a method of measuring naturally occurring gamma radiation to characterize the rock or sediment in a borehole or drill hole.
During such drilling, data is acquired from the drilling rig sensors for a range of purposes such as: decision-support to monitor and manage the smooth operation of drilling; to make detailed records (or well log) of the geologic formations penetrated by a borehole; to generate operations statistics and performance benchmarks such that ...
Density logging is a well logging tool that can provide a continuous record of a formation's bulk density along the length of a borehole.In geology, bulk density is a function of the density of the minerals forming a rock (i.e. matrix) and the fluid enclosed in the pore spaces.
The log must run in holes containing electrically conductive mud or water, i.e., with enough ions present in the drilling fluid. Indeed, in the borehole fluids the electrical charge carriers are only ions (cations and anions) present in aqueous solution in the fluid. In the absence of dissolved ions, water is a very poor electrical conductor.
Corrections can be made automatically if the cave is no more than a few inches deep. A caliper arm on the sonde measures the profile of the borehole and a correction is calculated and incorporated in the porosity reading. However, if the cave is much more than four inches deep, the density-neutron log is reading little more than drilling mud.
Discrepancies between seismic data and sonic log data [1] are due to upscaling and anisotropy considerations, which can be handled by using Backus Averaging on sonic log data. Some suggest that to investigate how the varying size of a borehole has affected a sonic log, the results can be plotted against those of a caliper log. However, this is ...