Improvement of 4 ư inches cemented monobore design to reduce well cost

Abstract

This study focuses on the improvement of 4½ inches cemented monobore completion conceptual design through a detailed engineering analysis where it is one of the efforts to reduce well cost without jeopardizing safety and well integrity. A thorough planning on well completion design is imperative to ensure successful delivery of the well. In this research work, the initial plan was to develop overpressured K reservoir with 4½ inches tieback monobore completion. It is a proven concept which can deliver the well safely and without any well integrity issues. During the conceptual design planning in 2013, the oil price was high at USD110/bbl and the tieback monobore well completion design was optimized to 4½ inches cemented monobore with lower cost to improve the project economics. When the detail design planning in 2016, the global oil price crash to USD30/bbl and high MYR vs. USD exchange rate was observed. There was a need to redesign the cemented monobore well to further reduce the overall well cost and improve the project economic of the well. The study also focused on collaborative well planning with multi-disciplinaries teams, selection of critical well completion equipment, and tubing stress analysis using WELLCATTM simulation program to improve the cemented monobore well design to lower the cost without jeopardizing safety and well integrity. The improved cemented monobore design has reduced the well casing schemes; from five casing schemes to four casing schemes through the collaborative well planning initiative. The selection of Weatherford multi-latch in plug, Welltec well annular barrier, and Halliburton SP cement-thru TRSV as critical well completion equipment for cement plug and accessories, and cement-thru packer have preserved the well safety and integrity. The 4½ inches, 12.6 ppf, 13Cr-L80, JFE BEAR tubing string and 9? inches, 47 ppf, L80, JFE BEAR casing string satisfy the tubing load and the annular fluid expansion requirement from WELLCATTM simulation.