Zero Losses Implementing a Heavyweight Engineered Spacer While Cementing a Rotatable V0 Expandable LinerHanger

Abstract

The high-pressure/high-temperature (HPHT) environment poses different challenges for a cement design. In addition, there are challenges with the tight annular clearances across the liner overlap with the previous casing, and then finally achieving the desired top of cement. Engineering solutions and best practices can be implemented to overcome the challenges encountered while cementing under these conditions. A heavyweight engineered spacer with loss circulation material and an expandable-rotatable liner hanger were key components of the success. Thoughtful analysis of the equivalent circulating density (ECD) resulted in the design of the train of fluids with a density difference of no more than 0.5 ppg. However, to overcome the risk of losses, an engineered spacer with a tailored load of its main component based on extensive lab testing was used. The weighting agent was carefully selected to ensure stability and rheological hierarchy. The cement job was performed with backside pressure applied with Managed Pressure Cementing (MPC) to keep a constant downhole pressure. To improve displacement efficiency and enhance cement bonding, an expandable liner hanger was rotated throughout the entire job and set afterwards. The best practices implemented to cement the 9 5/8in liner resulted in performing the cement job without losses or flow. The ECD was kept within 5% from the mud weight density, based on the pressure match simulation. No abnormal pressures were observed while pumping and displacing indicating no settling issues were endured with the engineered spacer. Additionally, the liner hanger's unrestricted bypass area assisted in reducing the ECD's as no slips were required to keep it in place. The liner hanger was successfully rotated at 15 rpm throughout the job providing good cement placement. After the cementing job, the Liner hanger expanded successfully which confirmed the liner top integrity with a metal-to-metal seal. The expandable liner hanger also allows for less leak paths in the system along with providing high sealing and loading capability in high temperatures with a gas tight seal rating. After the wait on cement (WOC) time, the positive and negative tests were performed successfully meaning that a sustainable barrier was achieved. This paper describes a success story while cementing under HPHT conditions with very narrow margins between pore pressure and fracture gradient and depicts the best practices that contributed to the success of the job, such as using a heavyweight engineered spacer with LCM and an expandable/rotatable liner.