Coiled Tubing Operational Guidelines in Conjunction with Multistage Fracturing Completions in the Tight Gas Fields of Saudi Arabia

摘要

Open hole multistage fracturing completions are becoming standard practice in the southern gas fields development in Saudi Arabia, with more than 40 wells completed to date using open hole packers and selective port technology. Overall, the production results from the use of multistage fracturing completions have been very positive, and the forecast is that multistage fracturing technology usage will grow considerably over the next several years. In general, multistage fracturing completions provide an excellent advantage in that they are intervention-less in their standard mode of operation. An evolving aspect of such completions is the secondary use of coiled tubing (CT) to handle the planned and unplanned (contingency) operations occasionally required to reach well production objectives. Without optimum operational planning and the selection of correct CT downhole tools, completion problems can be encountered, and this ultimately can result in not reaching the job objective at all or only at increased costs. In addition, the use of CT to function ball-activated ports to shut-off zones or to restimulate wells is starting to be appreciated. This article presents multistage fracturing case studies where CT has been deployed, and then investigates the operational impact and productivity enhancement of CT deployment. Correlations taken from the key hardware variables, such as fracturing port size and type, motor type, mill type and CT size, are also considered and analyzed. Following the lessons learned and best practices derived from these experiences, the findings from this article, with correct implementation, should increase the potential for successful multistage completion operations and ultimate improvements in productivity. These guidelines can therefore be transferable to other operators using similar multistage fracturing completion technologies.