Well Integrity Improvement: CCA Preventive Actions in HPHT Offshore Gas Wells in the Arabian Gulf

Abstract

Abstract Well integrity is critical in the petroleum industry, and needs to be maintained throughout the entire well's life cycle. Cement is the main element that provides isolation and protection for the well. To provide an additional protection beside the cement, mechanical isolation packers can be utilized to mitigate the chance of having fluid communication to the surface. Pressure buildup prevention in the casing/casing annulus remains a challenge in High pressure, high temperature (HPHT) offshore gas wells in the Arabian Gulf due to the presence of shallow gas, abnormal pressure formations, and highly fractured loss zones, which makes all cement jobs critical to isolate the well properly. This paper will discuss the preventive methods put in place to avoid casing-casing annulus (CCA) pressure buildup and sustain well integrity. Cementing strategies and mechanical isolation packers were considered to ensure the presence of competent barriers to prevent fluid bypass to surface. With regard to cement strategies, some methods will be discusses such as use of resin-based cement, which enhance the shear bond and mechanical properties to prevent cement cracking. For the mechanical barriers, conventional staging tools in the 9-5/8-in. production casing will be replaced with high differential pressure liner hanger packers and will be tied and cemented to surface to ensure maximum sustainability. In the future, they will be replaced with HPHT cement staging tools with a packer that is gas-tight to decrease the operating time while having the same reliability. In addition, a lab tested casing joint with elastomers that can swell in any fluid medium are considered to provide isolation in case the casing-cement bond failed at a later stage. Having a locked potential well due to CCA will increase the operation cost by early workover, in addition to losing the production. Enhancing cement strategies and utilizing mechanical isolation packers will help with preventing pressure build-up in the CCA and maintaining well integrity for the entire well life cycle.