Drilling techniques and equipment have changed throughout the decades from cable tools to rotary-based ones, from straight holes to sidetrack and GPS-based directional drilling, and from “guess-timates” and “feel” to computer-based accuracy.
The biggest improvement in oil well drilling, however, has been in the preparations prior to ever breaking ground.
The drilling of a well, especially a “wildcat” , is a milestone event, involving practically every sub-discipline of the oil business, and signifies the start of direct field investigation.
For the oil exploration and production company, the drilling of the well represents final exploration sunk costs prior to the possibility of recovering those costs through well production revenues. For the petroleum geologist and the reservoir engineer, the drilling of the well represents the final confirmation of the interpretation of numerous strands of indirect evidence of oil’s presence. For the production and facilities engineers, it represents the soon to be realized asset requiring sub-surface and surface management and equipment to maximize production . And, for the drilling engineer, well, it is time to earn their pay!
Through experience and communications with geologists, reservoir engineers, production engineers, and facilities engineers - the technical team - the drilling engineer develops a plan for reaching the targeted formation at the bottomhole location identified, from the surface location specified – at the cost authorized.
Before ever setting up on the drilling location, the drilling engineer has gained all of the necessary approvals to drill from company and regulatory authorities . The appropriate hole dimensions, the wireline testing procedures, the well casing program, and the cement volumes are all known upfront .
The drilling engineer has already scheduled an oil well drilling rig, alerted a wireline and cementing service company, and ordered necessary drilling fluids, tanks, pipe and safety equipment (including blowout prevention equipment;.
Operations normally proceed on a 24 hours per day basis and depending on methods, depths, and rock types encountered, can last anywhere from a few days to several months.
History has shown that rarely do operations proceed in a “normal” fashion. Each well is its own story. It is quite normal to encounter hard rock zones, and experience sand control problems, as well as for minor equipment breakdowns to occur - right next to a well which didn't experience half of the problems! Drill bits wear out, wrong auxiliary equipment is delivered, and various other events happen that slow progress, raise corporate anxieties, and compromise schedules.
Due to all of the problems, which can and do happen on site, oil companies have increasingly focused on safe operations. This is something everyone can control.
Most oil well drilling operations are actually completed by drilling service companies, with oil company drilling engineers supervising. Oil companies are using their natural leverage by insisting on safe operations by contractors, which minimize employee “accidents” and environmental impacts, and maximize accountability. Drilling service companies with poor safety records are not kept for long.