Deep Drilling Basic Research: Volume 4 - System Description. Final Report, November 1988--August 1990

Abstract

The first section of this Volume will discuss the ''Conventional Drilling System''. Today's complex arrangement of numerous interacting systems has slowly evolved from the very simple cable tool rigs used in the late 1800s. Improvements to the conventional drilling rig have varied in size and impact over the years, but the majority of them have been evolutionary modifications. Each individual change or improvement of this type does not have significant impact on drilling efficiency and economics. However, the change is almost certain to succeed, and over time--as the number of evolutionary changes to the system begin to add up--improvements in efficiency and economics can be seen. Some modifications, defined and described in this Volume as Advanced Modifications, have more than just an evolutionary effect on the conventional drilling system. Although the distinction is subtle, there are several examples of incorporated advancements that have had significantly more impact on drilling procedures than would a truly evolutionary improvement. An example of an advanced modification occurred in the late 1970s with the introduction of Polycrystalline Diamond Compact (PDC) drill bits. PDC bits resulted in a fundamental advancement in drilling procedures that could not have been accomplished by an evolutionary improvement in materials metallurgy, for example. The last drilling techniques discussed in this Volume are the ''Novel Drilling Systems''. The extent to which some of these systems have been developed varies from actually being tested in the field, to being no more than a theoretical concept. However, they all have one thing in common--their methods of rock destruction are fundamentally different from conventional drilling techniques. When a novel drilling system is introduced, it is a revolutionary modification of accepted drilling procedures and will completely replace current techniques. The most prominent example of a revolutionary modification in recent history was the complete displacement of cable tool rigs by rotary drilling rigs in the late 1920s.