Interwell Residual Oil Saturation at Leduc Miscible Pilot Available to Purchase

An interwell test for residual oil saturation to waterflood (S_orw) was successfully conducted at the Leduc miscible pilot during August of 1987. Although the principle of the test was first disclosed by Cooke in 1971, lack of suitable tracers and interpretative techniques would have hindered previous attempts to apply the test in the field. Recent advances in radioisotope tracing technology make it possible to use the test as a cost effective alternative to conventional techniques. The Leduc test appears to be the first successful interwell S_orw test to be reported in the literature. To verify the interwell method, two other independent measurements of S_orw were made at the pilot by well-established conventional methods, namely, single well test and sponge coring. The excellent agreement between the measurements strengthens the credibility of the interwell test for determining residual oil saturation. The paper describes and compares the three techniques, focussing on the design and interpretation of the interwell test.