The Standard Oil Company

Standard Oil Company (indiana)

Roger L Smith

Robert P Murphy

Dwight L Dauben

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.

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Tulsa, OK, United States of America

Roger L Smith