Perfectly Stressed Out: Surface and Downhole Imaging Relations

Abstract

Abstract So many guns and so many charges – how can an operator make quick design change decisions with confidence for gun and charge system performance in the wellbore? Typically, the industry tests gun and charge performance at the surface, assuming that the systems will perform similarly downhole. Through multiple studies, it has been shown that this is not always the case (Horton 2021, Roberts et al, 2022). Another consideration is the advertised performance specifications versus measured performance (Cramer et al, 2023). Many operators design their gun systems to target a prescribed perforation friction based on performance drivers like stage length, horsepower available on location, casing specs, etc. A problem arises when designing in this manner – the industry changes its mind constantly as we learn. When a design change occurs, it may be prudent to confirm how systems are performing with diagnostic tools like a camera or ultrasonic imaging. These tools are insightful but expensive, require a wellbore, and take time. This paper will explore a workflow that has the potential to increase the agility an operator can change perforation sizing for whatever hydraulic goals they are trying to achieve. In this study, a wellbore was selected to test different stage architecture configurations and tie them back to performance. The performance portion of the study will be covered in Tying Stage Architecture to Wolfcamp Performance (Barhaug et al, 2024), and the focus here is on a workflow that was spun off the main experiment. Ovintiv has a large database of downhole perforations imaged with a camera in the Permian Basin. The Company leveraged that dataset to develop relationships between similar charge performance at the surface – under no-stress conditions and how the same charges performed downhole, under-stress conditions. Once those relationships were built, a new perforation design change was executed in three steps: 1) work with the charge/gun provider to design a charge to shoot a known diameter at the surface, 2) run the newly developed charge on a horizontal development, and 3) image the new holes downhole and measure them against what the predicted hole size was.