Ensuring Success on an Extended-Reach Well with Expandable Liner Hangers and Advanced Software Modeling
Authors: Wardak Ajmal , Williford James , Walker Angus , Nughaimish Faisal 
Published: February 2011

The oil and gas industry has continually made an effort to stay abreast of oilfield needs so that operators could meet the challenges of deeper reserves as well as access the oil and gas reserves that were previously considered as technically and/or economically prohibitive. To meet the challenges, the engineering companies have continued to develop state-of-the-art equipment and advanced software. Today’s well designs are inherently more complex, since the current targets are deeper, requiring extended-reach configurations, or are in locations that present greater difficulties in developing appropriate well designs. Success, therefore, is even more dependent upon careful up-front planning so that the proper technologies will be employed to ensure that the sought-after goals are attained.

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 a long liner is the risk of pre-setting the liner hanger and/or the liner hanger packer. This paper will focus on an expandable liner hanger (ELH) system recently introduced to the industry that can mitigate these risks. The ELH design and unique setting procedure will be 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.

Other risks in the extended-reach sections of these wells concern problems relating to friction (drag) during the deployment of the liner hanger. This phenomenon can be addressed with a new ‘torque and drag’ software program that can be used to optimize the solution. This software produces a detailed analytical output that will provide a model with guidelines to aid in deployment of the liner into the wellbore. The analysis also 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 or a need of floating the liner assembly to depth.

To summarize, the ultimate goal of the well designer is to use the available software to assess the wellbore, and then, to build an optimized plan of the liner assembly and how it should be deployed so that the liner, expandable liner hanger and drill pipe can reach depth with minimal risks. Using this approach can help eliminate non-productive time and relieve the potentials for high-cost impact.

The case history used here will illustrate how the proper planning in this well and use of the ELH system selected was capable of addressing the challenges of successful deployment of an expandable liner hanger system in an extended-reach well for Saudi Aramco. These wells typically have measured depths (MD) of 19,000 to 31,000+ feet and true vertical depths (TVD) between 7,000 and 9,000 feet. The liner lengths range from 5,000 to 10,000 feet in length.