472 results about "Bound water" patented technology

Many reservoirs of interest include heavy oil. In such reservoirs, parti at normal temperatures, many instruments commonly used for formation evaluation may not be able to distinguish between heavy oil and bound water in the formation. Passive or active heating is used to elevate the temperature of the fluids in the formation. At elevated temperatures, distinguishing between heavy oil and bound water is easier. Of particular interest is the increase in the resolvability of the transverse relaxation time T2 of NMR spin echo measurements. Additionally, the dielectric constant and the loss tangents of water and heavy oil show different temperature and frequency dependence.

A method and apparatus for determining abnormal pressure zones of a geologic formation using NMR measurements, preferably for logging-while-drilling applications. In a preferred embodiment, a normal compaction trend is constructed using NMR-derived clay bound water volume (CBW) content for non-consolidated subsurface formations or bulk volume irreducible (BVI) and CBW for consolidated formations versus depth. Deviations from this normal compaction trend are used to indicate the presence of shale sections with higher porosity that directly corresponds to an overpressured top seal or transitional zone.

Wireline NMR well logging measurements suffer from disadvantages of poor vertical resolution, logging speeds less than 20 ft / min, and power consumption in excess of 200 W. In spite of these disadvantages, NMR well logging is used because it is capable of providing estimates for a number of petrophysical parameters that are difficult to obtain from other wireline data. These include estimates of the bulk volume irreducible (BVI) of fluids in the formation. The present invention targets BVI and clay bound water (CBW) measurements. Logging speeds of up to 60 ft / min are attainable with little or no loss of resolution. In one preferred embodiment, the tool has four sensors circumferentially distributed around the logging tool and in contact with the borehole wall. A horseshoe like magnet is used to generate the static magnetic field. The magnet poles are designed such that the magnetic field is uniform perpendicular tool motion, as well as provide a sufficiently large extent of the static field to provide polarization for bound water in rock formations. The RF portion of the sensor is comprised of at least one coil configured for transmission of an RF magnetic field into rock formations and at least two coils configured to separately receive the NMR signal from the formation. In another embodiment a coil is wound around the pole pieces or the iron yoke for the purpose of field shifting to enable acquisition of phase-alternated measurements.