This paper aims to discuss completion of deepwater open-hole gas wells that were completed using an alternate paths system (APS) and a state-of-the-art viscoelastic surfactant (VES) carrier fluid. The wells presented multiple design and operational complexities such as high bottomhole temperature, narrow fracturing window, extended horizontal laterals, and unstable shale zones. Operational and design steps considered to overcome these complexities are discussed, making this literature a resource that maps obstacles and presents viable solutions faced in any similar operation. These complexities combined with deepwater operational requirementsand economics made cost of failure unacceptable.

Two 8.5-in. openhole depleted gas wells upto bottomhole temperature of 230 °F were completed with gravel pack treatments using a VES carrier fluid to counter sand settling, minimize friction pressures, and optimize fluid viscosity. The operations pumped 200% excess proppant compared to design volume to ensure complete packs downhole, countering any thief zones or open-hole washout regions. Returns were taken through the BOPvia mud line to avoiding high fluid friction in the choke line. In one case, the riser was displaced with lighter base oil to reduce the bottomhole pressures.

Using the alternate path system and VES carrier fluid proved to be highly successful in these wells, as compared to the pre-drilled liners and standalone screens used previously in the same field. Complete packswere obtained within narrow fracture gradient windows inall cases. After reversing out the slurry, a filter cake dissolver treatment was also performed to decrease the flow initiation pressure for the well. Case studies have been presented elaborating completions plan and execution of open hole gravel pack treatment for two 8.5-in wells.

This literature is a case study elaborating operational procedures that have proved to be successful in performing open-hole gravel packs under complex constraints. This paper serves as a reference, highlighting obstacles faced and presenting viable solutions for any similar operation.

You can access this article if you purchase or spend a download.