Drilling - Three Decades Back, One Ahead
Authors: Bobo Roy A. 
Published: December 2007

Abstract
In the three decades since 1937, three significant steps have been taken in the drilling industry.
- Drilling rigs have advanced from the jaw-clutched v-belt power and the old steam-drive types, to modern ones with consolidated mechanical and electric drives.
- Rock bits have evolved from the blacksmith-forged fishtail, the four-cutter crossroller and the early tricone to a tricone that is a marvel of metallurgy with a cutting structure of a tungsten carbide type.
- Drilling mud, formerly used at a weight of 10 lb/gal, is now used at over 18 lb/gal, and centrifugal and chemical treatments have been perfected.
The drilling engineer, once accorded only scant recognition, now exercises great influence on both drilling operations and the direction of the drilling industry.
Ahead to 1978, there are three areas where major work is anticipated.
- Improved jet placement will evolve the chip-hold-down phenomenon.
- Continuous reeling of the drillstring, and computer controlled feedback drilling will highlight automation advancements.
- Commercial development of high velocity jet drilling and jet erosional drilling are likely.

Introduction
In discussing 40 years of progress in the drilling industry, 30 past and 10 in the future, two questions are raised. How advanced is this industry, and can its progress be charted as man's quest for speed can be charted?
Although man has resided on earth for several million years, it was not until 1800 that he learned to move faster than a horse could convey him. In the 150 years following, man moved, in succession, with the speed of the steamship, the locomotive, the automobile and the airplane. And recently he developed enough velocity to go into orbit.
Today, we are in the midst of an exploding technology, and the drilling industry is a definite part of this. In fact, future progress may occur at a rate much greater than we presently can predict. The developments of three decades ago provide a point of departure.

Three Decades Back - 1937 to 1947
In 1937, the rotary drilling process had been perfected. The marvel of the age, a hydratable clay known as bentonite had been introduced. Mud had become known as water plus bentonite. Steam power was being used widely. Alternating Current (AC) energy from electric highlines was prevalent. Direct current drives, employing the Ward Leonard system of speed control, had been in service since 1930. A few 350 hydraulic-hp mud pumps were in use. The principal driving linkage was through v-belts rather than chains. A friction clutch had its familiar place in front of the drawworks, where it was used for reversing. Both ram and encompassing types of preventers were in service.
The emerging drilling engineer scarcely was recognized as a technical man. Generally he was judged by his ability to withstand loss of sleep, by the load he could lift or convey to the derrick crown, and by his ability to conceal or forget what he had learned. Primarily the drilling engineer was tolerated because he was educated sufficiently to tally and keep track of pipe. The engineers who actually were assets to the drilling industry during this era were employed by the equipment manufacturing firms.
The contractor depended upon either his pushers or his drillers to make hole. The story is told of one contractor who bid low on a well in one particular fault block of a developing West Texas field. Drilling inside this block was much more difficult than drilling in the surrounding area. (The superintendent of one group of company rigs had already recognized this and had kept his tools out of the territory.) The unsuspecting contractor ran off six succesive drillers on one location because of what he thought was poor performance, never realizing he had been trapped.
The great depression was lifting about this time. The industry was booming. Oklahoma had become the primary oil producing state.
The trend toward portable rigs began in 1937 with the appearance of the L. C. Moore mast. The first field analysis of drilling muds is said to have been started in 1938 with filter press measurements. Bentonite was to become one of the most thoroughly studied of all earthly materials. At first its use seemed simple, but it rapidly became exceedingly complex. Thinners, flocculants, deflocculants, and a myriad of chemicals were beginning to appear, and these gave the desired drilling property to muds containing bentonite.