Magnolia Deepwater Development – Striving for Best in Class Drilling Performance

Abstract

Abstract ConocoPhillips is developing the Magnolia field with a Tension Leg Platform (TLP) in 4674 ft of water at Garden Banks (GB) block 783 in the Gulf of Mexico (GOM), see Figure 1. The field was discovered in 1999 and appraisal wells were drilled in 2000 and 2001. The well construction strategy included drilling six additional development wells from a mobile offshore drilling unit (pre-drilling) prior to the installation of the TLP. Drilling the new wells consisted of two phases; batch setting all six wells through 20 in. casing followed by deepening the wells to total depth (TD). The wells targeted multiple zones resulting in complex, designer directional wells with 50°-60° maximum hole angles. This paper examines the application of drilling best practices that were used to deepen the wells to TD after batch-setting operations were complete1. To minimize drilling costs while deepening the wells to TD, project goals were to eliminate trouble time; minimize combined drilling, circulating and tripping time per interval; maximize simultaneous activities; and reduce the number of trips necessary to drill the well. The goal of achieving Best-n-Class performance required detailed planning, documenting and implementing results and lessons learned, effective communications, equipment quality control, and implementation of a team environment with all the companies involved in the drilling program. The complex high angle wells required employing extended reach best practices to balance on-bottom drilling performance with the ability to effectively clean the hole to allow trouble free tripping of the bottom hole assembly (BHA), running of casing, and obtaining primary cement jobs. The best practices discussed in this paper include changes made to improve rotary steerable reliability; simultaneous drilling and under reaming BHA design2; hole cleaning; and torque and drag monitoring. The paper will also discuss activities that reduced the number of required trips and activities that were conducted out of critical path such as moving the subsea BOP from wellhead to wellhead with an innovative bottom hole assembly (BHA), BHA run and retrieve wear bushings, subsea guidebase installation via a winch and ROV, off critical path make-up of BHA components, and drill string management.