The World's Deepest Frac-Pack Completions Using a Single-Trip Multi-Zone System: A Gulf of Mexico Case Study in the Lower Tertiary Formation

摘要

Single-trip multi-zone (STMZ) Frac-Pack completions can significantly reduce the time to complete wells with long productive intervals. This technique was used successfully in two Lower Tertiary completions in the deepwater Gulf of Mexico (GOM) Cascade/Chinook project in 2010 (26,000 ft TVD, 8900 ft water depth). With interval lengths exceeding 1,000 ft, reservoir pressures greater than 18,500 psi, and bottomhole temperatures higher than 250oF, these STMZ completions were the first of their kind. With a STMZ completion, all completion intervals in a well are perforated at once. Then all the lower completion hardware (screens, sleeves, packers, etc.) is assembled and run in the well and the packers are set. Through the manipulation of sliding sleeves, each interval is individually opened and frac-packed sequentially from the bottom interval to the top. Before moving to the next interval, the sleeves are closed and pressure tested, providing isolation between the wellbore and the reservoir. The steps are repeated until all the intervals are stimulated. The STMZ system saves a great deal of rig time over conventional stacked frac-pack systems by significantly reducing the number of trips in and out of the well with the work string. This paper discusses the challenges, planning, execution, and results of these STMZ completions with a focus on the downhole completion hardware. Also discussed are some planned modifications to the system that will reduce risk and improve performance in the future.