Western Siberia Sees Improvement in Drilling Efficiency

Abstract

Achieving significant improvements in drilling efficiency is most often the result of an integrated approach. First, the appropriate combination of hardware and software tools must be selected for the particular task to be accomplished. The second requirement is an experienced, dedicated directional-drilling team capable of seamless timely communication with the operator. This combination recently delivered excellent results on a large-scale field-development program in western Siberia. Sibneft-Khantos operates the South Priobskoye field in the Khanty-Mansiysk autonomous region of western Siberia (Fig. 1). The Priobskoye fields straddle the Ob River and are among the most productive oil fields in a region known for prolific oil fields. Starting in 2005, the company launched an ambitious development program designed to place 200 wells on production each year while optimizing drilling processes and while saving time and money by streamlining procurement and logistics programs. A combination of Russian and foreign service/supply companies was to be used, so it was essential to establish clear procedures and work able metrics by which progress could be monitored and evaluated. Specific goals included using the best-substantiated drilling technologies to reduce drilling time, simplify well design, reduce environmental impact, and improve well quality. Historically, all drilling had been performed employing local service companies using rigs equipped with nonrotating aluminum drillpipe and locally manufactured mud turbines. The operator identified five focus areas for improvement:Upgrading of drilling rigs and drillstring components.Drill-bit procurement and supply-chain management.Drilling efficiency and wellbore quality.Improvement in drilling-fluid properties.Improvement of cementing efficiency and quality. Wells at South Priobskoye are pad drilled, generally following an S-shaped profile with average lateral displacement of 3,182 ft from the surface location. Typically, the casing program consists of 12 3/4-in. surface pipe, a 9 5/8-in. intermediate section, and a 7-in. production interval. In addition to improving drilling efficiency, Sibneft was concerned with ensuring that all wells were landed precisely in the target formation and that borehole angle-build rates never exceeded design criteria. In addition, because of the number of wells emanating from each drilling pad, there was a risk of borehole collisions. Accordingly, procedures to prevent this were an essential part of the plan and the subsequent practice. Finally, the company was determined to minimize unnecessary borehole extensions or sidetracks.