Tight gas and unconventional hydrocarbon wells bring forward HPHT well construction requirements. Typically, these wells require multistage high pressure stimulation, and, in most cases desired to be completed with openhole stage frac tools. These stage frac tools are exposed to repeated high pressure and temperature cycles during various stimulation and subsequent production activities. The increasing need to exploit such tight reservoirs pushes the endurance limits of conventional designs and elastomeric technologies required to deliver completion tools. This paper encapsulates invaluable information covering application, design and development of a complete HPHT multistage fracturing completion system with ball activated frac sleeves and packers. This system not only delivers a unique completion solution for HPHT stimulation and production, but, also incorporates distinct features from the pilot design to overcome common operational challenges in deploying this type of completion in difficult wells.
In order to ensure the completion tools can handle this extreme well environment, the tools were tested at expected bottom hole conditions with numerous repetitive cycle tests beyond minimum acceptable API norms. During testing, various tool components and elastomers had to be redesigned or changed to pass the minimum qualification criteria; while maintaining compatibility to the well environment.
During development and testing, the team had to employ Additive Manufacturing technologies for critical components to enable high expansion and to eliminate any extrusion gap of the openhole packer’s packing element. Further, in order to withstand the frequent temperature swings during operations, a more resilient elastomer was selected for the packer over traditional hydrogenated nitrile, FKM or FEPM compounds. Together, these provide increased functionality, by enabling handling of repeated loads and pressure cycles and pipe movement. This along with the other components of the multistage frac completion system and full 15,000 psi liner hanger and liner top packer provide a one of a kind robust HPHT stimulation system designed to enable well integrity at all times. The detailed design, functionality and testing performed eliminate the need for deployment of openhole anchors that are typically used to prevent movement of the packer due to pressure and temperature induced tubing movement. In addition, the system incorporates rotational and high circulation rate features to overcome common operational challenges for deployment in difficult wells.
This unique multistage fracturing system brings the industry’s first openhole completion packer that utilizes additive manufacturing to go outside the boundaries of conventional tool manufacturi ng capabilities for HPHT stimulation application. Further, this system integrates the lower stage completion to deployment tools and upper completion providing a complete HPHT Stage Frac system from well head to toe. This reduces need for systems integrity testing or compatibility between tools during later planning and execution phase which is paramount for HPHT well construction.
