Ensuring Success on an Extended Reach Well: Expandable Liner Hangers and the Use of Advanced Software Modeling

Abstract

Over the course of time, the oil and gas industry has increased its usage of state-of-the-art equipment and advanced software to access oil and gas reserves that were previously considered as technically and/or economically prohibitive. Today's well designs are inherently more complex since the current targets are deeper, require extended reach configurations or are in locations that present greater difficulties in developing appropriate well designs. Success, therefore, depends upon careful up-front planning to ensure that the goals sought are attained. The planning requires detailed calculations at each step of the well development ? from the geological survey to drilling to completing the well. The advanced modeling software available in the market today has made the required analysis possible. Extended-reach wells carry significant risks where cost of failure regarding the deployment of the liner and liner hanger system could consume the whole well. One of the major risks with deploying such a long liner is the risk of pre-setting the liner hanger and/or the liner hanger packer. An expandable liner hanger (ELH) system, recently introduced to the industry, inherently eliminates this risk with its design and setting procedure and is the focus of this paper. When the liner is deployed using the detailed analysis generated during the planning stages, the risks mentioned above can be significantly reduced and greater assurance that the liner can be run to depth can be provided. The extended-reach section of these wells creates additional problems relating to friction during the deployment of the liner hanger. This phenomenon can be addressed with 'torque and drag' software as well as 'surge and swab' software to optimize the solution with a detailed analytical output that will determine the best method to use to deploy the liner into the hole. The analysis will help determine whether centralizers should be used (and if so, specific spacing), whether fluids that will reduce the friction coefficients should be considered, and will also examine whether there is the possibility of floating the liner hanger to depth. To summarize, the ultimate goal of the well designer is to apply the available software to develop and optimize a plan to reduce friction during deployment of an expandable liner hanger to depth while reducing cost impact and eliminating nonproductive time. The case history in this well will verify how the proper planning and use of the ELH system selected was capable of addressing the challenges of successfully deploying the ELH system in an extended-reach well for Saudi Aramco. These wells have a measured depth (MD) of 19,000 to 31,000+ feet and true vertical depths (TVD) between 7,000 and 9,000 feet. The liner lengths ranged from 5,000 to 10,000 feet in length.