Drilling Operations

One of the earliest methods of drilling, and the one that Drake used, is cable-tool drilling. Cable-tool drilling can be very effective, especially in hard-rock formations. Since the rate of penetration is high, the drilling rate is fast. However, two features of cable-tool drilling can be disadvantageous. One is that drilling must be stopped frequently and the bit pulled from the hole so that pieces of rock, or cuttings, chipped away by the bit can be removed. The other disad­vantage with cable-tool drilling is that the method cannot drill soft-rock formations. In spite of its disadvantages, modern versions of cable-tool rigs are still used in a few instances, particularly where shallow wells are drilled or where, for other reasons, using another type of rig is not desirable. The first rotary drilling rig was developed in France in the 1860s, but it did not catch on at first. Because it was erroneously believed that most petroleum was associated with hard-rock formations, which could be very effectively drilled with cable tools, cable-tool rigs dominated the scene. Then, in the 1880s, two brothers named Baker gained a reputation for drilling successful water wells in the soft formations of the Great Plains of the United States, an area where cable-tool rigs were not having much success. The rig the Bakers used was a rotary unit with a fluid-circulating system. The rotary technique proved equally successful in the unconsolidated soft rocks of Texas, where the Corsicana oilfield was discovered while the drillers were searching for water. Finally, around 1900, several unsuc­cessful attempts were made with cable tools to drill the great Lucas well at Spindletop, which lay near Beaumont, Texas. Anthony Lucas,

Drilling for Oil 83

an Austrian-born.mining engineer, was convinced that oil did indeed exist under the dome of Spindletop; the problem was how to drill for it. Rotary drilling provided the answer. With the advent of Spindletop, where some historians estimate that the well flowed over 80, 000 bar­rels of oil per day, rotary drilling was launched in a big way.