Fracturing is an important technique for stimulating production in low-permeability formations, and requires special consideration in designing the preceding perforating job. Aligning the perforations along the direction of maximum geological stress, known as the preferred fracture plane (PFP), provides significant opportunities to improve the efficiency of the fracture job, maximizing ultimate production from the well.
Wells are frequently completed with multiple tubing strings (up to four in some cases), sensor lines, control lines, or other hardware that can be damaged during perforation. The traditional approach of hiring a workover rig to remove the completion prior to perforating is, in many cases, not cost effective, leading to foregone opportunities to extend production by perforating new intervals or reperforating existing producing zones. With casingless completions, even this option is not available.
A downhole orienting and imaging platform has the unique capability to orient guns along the PFP for optimal fracturing efficiency while simultaneously avoiding damage to complex downhole completions, without the expense of workover. This technology enables the enhanced production from wells that may otherwise have been uneconomical. The technique was applied during a pre-fracturing perforating job for Total E&P USA, Inc. (Total) in their Bethany field located in east Texas. The job addressed the dual objectives of orienting the perforations along the PFP, while simultaneously avoiding the parallel completion, which if perforated would open a communication path between reservoirs with different pressures.