Standard Oil Company (indiana)

The Standard Oil Company

Robert P Murphy

Roger L Smith

Dwight L Dauben

James W Spurlock

Frank O Jones, Jr

Wiliam W Owens

Ovner R Wagner, Jr

Method of logging a plurality of underground formations wherein a first and a second gamma ray emitting radioactive tracers with different energy levels are introduced into the formations. Logs are produced of the tracers as the traced fluids pass through the formations and thereafter the logs are analyzed to determined changes in effective permeabilities and sweep of the formations.

Multi-tracer logging technique

This invention relates to determining the movable oil saturation in underground rock reservoir by use of a log-inject-log technique. The formation rock adjacent to the wellbore is prepared such that the saturation conditions are representative of those in the interwell area. A pulsed neutron log is then run. A crude oil is injected into the formation. A second pulsed neutron log is then run. A chlorinated crude oil is injected into the formation to displace the previously injected crude oil. A third pulsed neutron log is then run. A salt water of known salinity is then injected into the well to displace a portion of the chlorinated crude oil and all of the formation water. A fourth pulsed neutron log is then run. Fresh water is then injected into the formation to displace the injected salt water. A fifth pulsed neutron time log is then run. These five logs are then used to determine the reservoir characteristics.

Determination of movable oil saturations

This invention relates to a method of determining oil saturation in an underground rock formation penetrated by a wellbore by use of a log-inject-log technique. In such techniques, thermal neutron decay time logs are taken with the formation in the native state and then again after fresh water has been injected into the formation. These logs determine water saturations which are used to determine oil saturation. The method of this invention is directed to a method to prepare an aqueous salt solution so that clay and shale impairment of the formation is prevented but such that the thermal neutron capture cross section of the injected fresh water is not significantly different from that of the fresh water typically used.

Minimizing clay and shale damage in a log-inject-log procedure

A procedure for obtaining data to determine both residual and mobile oil saturations in the vicinity of a test well. The steps are (1) drill with oil or oil-base mud, (2) produce to remove oil filtrate, (3) run laterolog, microlaterolog and pulsed neutron capture log, (4) inject high salinity water, (5) run a second microlaterolog and pulsed neutron capture log, (6) inject fresh water, and (7) run a third pulsed neutron capture log. The data obtained from the logs of the procedure is sufficient to determine the residual oil saturation, the capture cross section of the rock matrix, the saturation exponent, the salinity of the water in the formation after production, and mobile oil saturation both in the oil filtrate invaded zone and beyond the invaded zone.

Measuring reservoir oil saturation

A method is described for gathering information for the determination of the adequacy of placement of sand consolidating plastic for sand control in oil and gas wells. The method uses a high neutron cross-section tracer which becomes part of the plastic and uses pulsed neutron logging before and after injection of the plastic. Preferably, the method uses lithium, boron, indium, and/or cadmium tracers. Boron oxide is especially useful and can be dissolved in alcohol and mixed with the plastic ingredients.

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Bixby, OK, United States of America

Robert P Murphy