Selective Perforation for Thin Separated Layers Using Addressable Switches: Operation Design and Limitations Overcome

Abstract

This paper aims to highlight the benefits of using selective perforation as a method of risk reduction and optimization during perforating thin separated oil-bearing intervals going through selection criteria, job design, economic evaluation and precautions during the operation. During the design of four perforation jobs in a campaign using the conventional through tubing perforation (TTP) technique, it was noticed that the number of runs were too much with consequent high intervention risk, thus alternatives were evaluated to mainly reduce intervention risk with a smart, reliable, cost effective and simple perforation technique within the pre-determined operation time frame. The other options included alternative deployment methods such as coiled tubing (CTU) perforation, extended reached perforation (ERP) and selective perforation techniques. A comparison between options has been made based on the following criteria: availability, simplicity, reliability, intervention risk and feasibility. As a result of proper filtration and comparison between all different options, the selective perforation using addressable switches was selected to be the optimum solution for this case based on the comparison criteria mentioned above. Going through the design phase, multible loading sheets for guns laydown have been generated and optimized to reach the simplest operational procedures and minimum number of runs. Then, workshops have been made for engineers in both office and field to be familiar with the operation to reduce operational risks and consolidate the operational procedures. The design of service for the whole job including the final operational procedures, risk assessment and gun loading sheets was finalized and distributed to all disciplines to assure alignment during the operation. During job execution, operation has been followed step by step using single point of accountability (SPA) to accelerate and align decision making and plan modification during operational issues. Finally, a post job evaluation has been made to document the whole procedures of design and execution and the lessons learned during the operations. A final comparison between conventional and actual selective perforation job showed the reduction in number of runs and thus time and intervention risk by 33%. In addition, the incremental increase in cost was completely covered by the time saving from the utilization of supporting vessels (Rig & boats). The major aim of this paper is to clarify in a step-by-step style the method of evaluating the well for addressable switches technique and how to properly prepare the people for the job and the design of service till execution followed by post job evaluation.