NEW TOOL DETECTS HYDROCARBONS BEHIND PIPE

ParaMagnetic Logging Inc. (PML) of Palo Alto, Calif., and Woodinville, Wash., has licensed a cased hole logging tool to Schlumberger Ltd. after Western Atlas Logging Services, its first industrial partner, proved the feasibility of its new technology. The U.S. Department of Energy said the tool can detect oil and gas pays behind casing. The device resulted from a joint effort among PML, DOE's Bartlesville, Okla., project office, and the Gas Research Institute.

May 15, 1995

3 min read

The U.S. Department of Energy said the tool can detect oil and gas pays behind casing. The device resulted from a joint effort among PML, DOE's Bartlesville, Okla., project office, and the Gas Research Institute.

DOE said PML's electric logging tool overcomes resistivity distortion caused by steel pipe by using a technique to effectively render casing transparent. The tool also corrects for subtle variations along irregular, sometimes corroded walls of casing.

DOE also said the new tool will enable producers to reenter wells and reexamine promising formations that may have been bypassed when the well was drilled.

FIELD TESTS

PML's licensing agreements follow a series of field trials in which the tool determined electrical resistivity of formations through casing with equal or greater precision than conventional, open hole, deep induction logs run prior to installing casing.

The most recent tests were at a shallow well drilled in Woodinville, Wash., and with Western Atlas in a deep well DOE drilled near Rifle, Colo. GRI administered the Colorado test. PML had no prior access to open hole resistivity data.

DOE said, "Tests showed the new tool may be a more accurate indicator of hydrocarbons than conventional devices in uncased wells, as well as in cased wells.

"Drilling fluids may flush oil back into a formation during drilling. In some cases, this may cause the open hole resistivity log to give less accurate readings. After casing is set and cemented, oil and other fluids in the formation equalize back against the cement and casing.

"By measuring the formation resistivity after casing has been installed and fluids have returned to their original state, operators may locate additional production potential that was overlooked during earlier logging."

DOE said between Western Atlas and Schlumberger, PML will have most of the U.S. logging service industry covered.

The department said the tool may help operators in evaluating wells, "but an even wider application of the new tool may be in analyzing the effect on the reservoir from other production enhancements such as fracturing, waterflooding, or chemical enhanced oil recovery."

DOE first funded PML in 1984 to develop the concept and earl), prototypes of the device. GRI joined the effort in 1988.