Applications for Polycrystalline Diamond Compact Bits From Analysis of Carbide Insert and Steel Tooth Bit Performance

Abstract

Summary A thousand field runs of typical roller cone and diamond drill bits were studied to form a comparative basis for assessing the impact of the polycrystalline diamond compact bit. Statistical analysis of mud log data was conducted on a formation-by-formation basis involving 2,581 data intervals. Baseline performance in general drilling was established, and key drilling situations for improved performance with the new bits were determined. Introduction During 1979, a study was conducted to document performance of specific commercially available drill bits in more than 1,000 actual field runs to form a comparative basis for assessing the impact of a new innovation - the polycrystalline diamond compact bit. Three basins were studied - the Williston and Permian basins in the U.S. and the North Sea basin. Sedimentary environments ranged from easily drilled, soft sediments to dense, extremely hard and abrasive rock, with an associated range of drilling practices and problems. Statistical analysis of data derived from mud logs was conducted on a formation-by-formation basis, involving 2,581 data intervals. The resulting information is a computerized bit performance data base detailing rate of penetration, footage, rotary hours, and key drilling parameters including mud properties, weight on bit, rotary speed, and rock type. In addition to forming a baseline to evaluate performance of new bit designs, the study highlights key problem drilling situations where polycrystalline diamond compact bits can provide improved performance - e.g., overbalanced drilling, deviation control, high-rpm drilling, slim-hole drilling, and other applications. Actual testing of polycrystalline diamond compact bits in these applications has been in progress both in the U.S. and Europe, with favorable results to the baseline data. The paper outlines the study and offset comparisons of polycrystalline diamond compact bits with conventional bits in slim-hole drilling, oil-base fluids, pressure coring, and offshore drilling. Early Development Efforts on Polycrystalline Diamond Compact Drag Bits The U.S., consuming some 40% of the free world's oil production while producing only 19%, is faced with the challenge of rapidly boosting production to avoid increasing dependence on expensive foreign oil and the resulting consequences to the economy. This must result in more drilling. Drilling costs have increased at almost exponential rates, and the industry continually is looking to new technology to halt this trend. This new technology includes advances in drill bit design directed toward improving both overall performance and performance of specific designs in particular problem drilling situations.