First Novel Intervention in High Pressure Gas Well to Improve Productivity in SPDC/Nigeria

Abstract

The GBN NAG reservoir development project is part of the GBNRC Phase 1-6 project which involves the development of 6 wells with the potential to deliver additional 410MMscf/d to the GBNRC export gas market. The wells were drilled with heavily weighted POBM at 0.68 – 0.72 psi/ft. The lower completion was ran with the heavily weighted mud in hole and isolated with a Formation Isolated Valve (FIV) while the upper completion was completed with brine at 0.48 psi/ft. The wells were completed with 7" 13 Cr tubing, Reslink as sand control with potential of 120 MMscf/d each from each well. Post clean up and Multi Rate Test activities some of the wells were observed to produce with drawdown higher than the acceptable limit therefore necessitating the reduction of well potential to adhere to the draw down limit and prevent possible well integrity incident. The team was therefore charged with the responsibility to proffer feasible well intervention options in a High-Pressure environment to restore full wells potential of 410MMscf/d at the most economical way possible without compromising on safety and well integrity. This paper documents the integrated approach taken by the team to identify the cause of high drawdown in these wells, feasible intervention options and selection criteria leading to restoration of planned potential therefore meeting up company obligations to GBNRC supply and preventing possible well integrity incident in these wells.