Perforation Design and Gun Selection Workflow – A Successful Case History for Deep Penetrating Gun

Abstract

Perforation design including gun size, type, charge weight, configuration (shot density, entrance hole, phasing) and deployment options can significantly impact well productivity post perforation. Gun selection is a key process to ensure that the optimum gun that can yield maximum well productivity and minimum skin due to perforation has been considered. Gun performance modelling and sensitivity analysis should be conducted to compare the performance of various guns and to select the optimum gun suitable for well and reservoir conditions. Gun performance under downhole condition is a complex process and uncertainty analysis should be considered when converting API gun test data into downhole condition. It is always preferred to use stressed-core test data such as API section II/IV. However, data analysis and alteration might still be required to replicate the exact downhole condition. This paper presents a successful case history of perforating 130 m in a single coiled tubing conveyed run using Live Well Deployment system in 6,000-m deep gas and condensate reservoir with an average permeability of 10 mD and reservoir pressure of 12,500 psi. Production has increased by 20% compared to reference wells due to the intensive perforation testing and design process conducted to this well prior to operation. Extensive modelling work has been conducted to evaluate the performance of deep penetrating guns compared to conventional guns, in addition to uncertainty analysis and risk assessment regarding the impact of using API section-I compared to Section-II/IV data. The paper demonstrates a robust workflow for gun selection and gun performance evaluation process, which can be used as guideline to perforation design process.