A Coiled Tubing Perforating Solution Incorporating a Gun Deployment System and Dynamic Underbalance Technique Improves Well Production in High Angle Deep Gas Wells in Saudi Arabia

SaudiAramco has recently initiated a change in gas well design in the Ghawar fieldof Saudi Arabia. The new approach is to drill deviated cased hole gas wellsthrough the reservoir to increase the length of contact of the productive zoneand thereby s wells were drilled as avertical cased hole through the reservoir or open hole horizontal gas wells. Theincreased well deviations, measured depths and resultant increase in reservoirsections required a new approach to the perforating solution for these wells toconnect them to the gas plants. Various techniques were reviewed, consideringsafety, operating efficiency and well performance. The final solution was todeploy the perforating systems on electric coiled tubing (CT) and run all theguns in one run using completion insertion and retrieval under pressure (CIRP) asa deployment system, which allowed the guns to be run and pulled under livewell conditions without having to kill the well. Thispaper details the learning curve and lessons learned of the implementation ofthis technique in five gas wells. The deployment system and pressure controlequipment were optimized to satisfy Saudi Aramco's requirement for threebarriers. A CT cleanout run was added before perforation to remove any debrisfrom the wellbore causing a problem to the depth correlation tools. An existingmCT tower was used to support the very long wellhead stack, but due to its height limitation a special solution was implemented to enable safe CToperations. A deployment system under live well conditions was used to minimizeCT runs, operating time and cost savings. The static underbalance condition was set before running the guns, combined with the dynamic underbalance perforatingtechnique and deep penetrating charge gun design were implemented to optimizethe well performance. This technique allowed safe and efficient perforating in a single underbalance run of these five gas wells. Thepaper also covers the planning of the perforating solution, Health, Safetyand Environment (HSE) considerations, equipmentselection, operational procedures, job execution and results