Multistage fracturing (MSF) ball drop completion systems have been utilized around the globe for effectively treating formations completed as open hole and cemented. Multiple, high-rate hydraulic fracturing stages are pumped through these completions while gaining efficiency during pumping operations. A challenge within the industry was developing systems that are capable of higher pressures (greater than 10k psi) while still being able to be deployed in challenging openhole environments with minimum equipment and intervention requirements. This paper will discuss the planning, deployment and fracturing execution operations of an improved version of one of these systems.
To be able to effectively utilize any MSF completion system; formation properties, deployment environment, lateral length, openhole size, liner size, and tubing movements during fracturing should be thoroughly analyzed and equally considered. To create a reliable system, another important consideration is how the system will be deployed; a long string to surface, or will it be deployed as part of a liner hanger system? In the case of the latter, it should be compatible with the liner hanger system by accommodating multiple balls to set and release the hanger system and actuate the openhole packers. In tight formation environments, where treating pressure differentials reaches as high as 15,000 psi during fracturing operations, openhole packers that are capable of holding these pressures in challenging openhole conditions are needed. Not only the packers but also the remaining completion system components need to be capable of withstanding, including burst, collapse, and ball-to-ball seat differential while simultaneously accommodating the pressure with cooling and ballooning induced tubing movement caused by these high pressure treatments. Improving such a robust design with innovative solutions, such as dissolvable frac balls that can handle 15,000 psi differential, optimizes the overall process.
The completion design, deployment, and subsequent fracturing operations on a well showcases how effective consideration of components operates as a system can create a reliable MSF system. It also demonstrates how close collaboration between reservoir management, production engineering, completion experts, and vendor results in a coordination of efforts that eliminates operational hazards, thus ensuring smooth operations.
The successful deployment of an openhole MSF completion system that can handle 15,000 psi with dissolving frac balls and eliminating openhole anchors helped pave the way to deal with tighter formations in an efficient and cost-effective manner. With the help of this new technology, the well planners were able to address operational challenges that would have otherwise required additional equipment or would have limited deployment capabilities. The engineering approach and design to develop this completion system and utilization in the right candidate confirmed the benefit of the novel completion for field development options.