Reducing Well Cost Utilizing Liner-Drilling Operations in South Texas

Abstract

Recent technological advances are driving casing and liner drilling from a niche market into the mainstream environment. Improved connections, tubulars, advances in rig technology and pipe handling have enabled operators to consider drilling with casing/liner as an option on many new wells 1,2 . Escalating deepwater costs and the need to further reduce onshore drilling expenses in low cost fields continue to push the technology forward.In a mature South Texas field, an operator discovered the difficulties of drilling into formations with weak matrix strengths, loss circulation zones, and tight pore pressure/fracture gradient windows.These issues have deemed the field sensitive to aggressive drilling techniques and the operator has been forced into a conservative drilling program with reduced flow rates and lower weight-on-bit capacity. The operator needed to reduce trouble time, lower costs and make the wells more economically feasible.A service company introduced a new liner drilling system solution to get through the extensive problematic zones. The system is engineered so the operator can ream to bottom and then continue drilling with the liner to the required target depth. The system is comprised of a drillable fixed cutter casing bit and a drill-in liner assembly designed to handle the rigors of a drilling environment (rotation, reciprocation and drilling torque). The liner system utilizes a running tool that allows the liner to be used in drilling mode handling all the required drilling loads without fear of release. Once at desired setting depth, the hydraulically balanced liner-running tool is released with a setting ball. The casing bit is manufactured from a specialized steel alloy that allows technicians to braze polycrystalline diamond compact (PDC) cutters directly to the one-piece bit ensuring a robust cutting structure capable of efficiently drilling new formation as well as reaming existing hole. The system allowed the operator to drill in the liner to TD, cement, and then drill out to the next casing point.To date, nine intervals have been drilled with this system in South Texas. This paper will focus on the problems encountered in the field, the development work in establishing a solution for the operator, the results attained, and lessons learned through using this new technology. TX 75083-3836, U.S.A., fax 1.972.952.9435.

Successful Development and Field Qualification of a 95/8 in and 7 in Rotary Steerable Drilling Liner System that Enables Simultaneous Directional Drilling and Lining of the Wellbore

“…Compared to the excising "Drill-In Liner" which is used for well applications with very short drilling intervals without steering and logging capabilities, the SDL system has been designed to drill longer, complex 3D well trajectories with the same directional and logging capabilities as conventional drilling [Ref. 1,2,3]. This paper describes the SDL system development along with results from the full-scale testing phase and the first offshore field piloting in a live well on the NCS.…”