Multilateral Re-Entry Technology Compounding Benefits and Extending Production Life Past Two Decades

Abstract

Abstract For over two decades multilateral technology has extended the production life of fields in the North Sea by continuing to evolve to meet the demands of increasingly complex deepwater applications. The use of multilateral technology delivers a higher recovery factor supported by the cumulative production of the multiple laterals. Over this history, multilateral applications have evolved from dual-laterals with standalone screens and commingled flow to the subject well of this paper whose slot has been kept active for over two decades through the use of re-entry multilateral systems. The well was originally completed as a dual-lateral and has since been recompleted twice to produce reserves previously left behind. As investment and availability of new fields decline, operators face challenges to extend the production life of mature fields while also working to reduce overall development cost, cycle times, and carbon footprint. Further challenges include delivery of wells and facility systems using less in-field construction hours at a lower baseline cost. The expectation is that the projects will also reduce typical greenhouse gas emissions compared with traditional pads. This paper will focus on the evolution of a mature field in a region that has been installing multilateral wells for over two decades. Wells originally drilled as dual-laterals have several years later been re-drilled as tri-lateral installations. As the wells once again reached the end of their expected production life, the use of re-entry multilateral technology has been utilized to extend field life for further economic production. This paper discusses three multilateral installations on the same subsea well over a 20-year period. It highlights the technology used to keep this well slot active for over two decades and the benefits of expanding the use of this technology as fields become slot restricted. It also highlights the benefits this technology delivers in enhancing reservoir exposure and the time savings brought by drilling new lateral legs in existing subsea wells without spending significant time having to first retrieve the xmas tree or tieback liner. The case study will include discussion of workover operations, completions, isolation methods, and lateral creation systems. Through three separate multilateral installations in one subsea slot, the production life has been extended beyond 20 years. The paper focuses on a particular multilateral well and the technology used to extend its production life past two decades. The paper also provides insight as to methodology for continually improving reliability of multilateral installations to maximize efficiencies.