How to Constantly Deliver 100 Packing Efficiency in Openhole Gravel Packs: A Field Study in Colombia

摘要

Although the application of openhole gravel packs has been well documented, only a few cases using this type of completion in openhole intervals greater than 800 ft in length have been implemented in Latin American land wells. Recent field studies involving openhole gravel packs in long intervals were carried out in the Ocelote field in the Llanos basin of Colombia. The operating company of the field is Hocol S.A., (subsidiary of Ecopetrol) and after many trials and the use of various service providers and tools, the final customized methodology and equipment of one particular service company were selected and implemented for the openhole completion campaign of the entire field. The wells completed previously in this field were thoroughly analyzed. Because of operational and design issues, pack efficiency in one well was greater than 90%; however, in all of the other wells, only 50% pack efficiency was achieved. This analysis covers the reason why pack efficiency was consistently low in the first three wells, steps taken by the operator and new service company to guarantee 100% pack efficiency in the subsequent openhole gravel packs, and the new tool designs implemented to solve the existing issues that guaranteed the successful gravel-pack operation in the remaining wells in the campaign. The step-by-step methodology chosen and implemented in the design of each job are presented, including the type of proppant and selection of the correct gravel-pack tools to mitigate potential problems and the selection of the appropriate screens impacting the final outcome. Finally, data from the subsequent wells that were gravel packed using the new methodology are presented, including the tools used and the technology used to consistently achieve 100% pack efficiency in all of the remaining wells in the field. Conclusions are presented, in addition to individual well performance comparisons.