Efficient Installation of a Modular Straddle System for Deep Water Gas or Water Shut Offs

Abstract

Abstract A well with a high gas-oil-ratio (GOR) was experiencing gas coning due to the recycling of injected gas. A gas shut off was recommended to improve gas handling efficiency due to the constraints on surface processing capacity. The strategy was to install a 138 m, retrievable straddle assembly across a zone spanning from 2572 m measured depth (MD) to 2719 m MD in the 5 ½" open hole gravel pack (OHGP) screens. The client's considerations included coiled tubing (CT) and slickline. It was also necessary to be as efficient as possible to keep time and costs down. Based on these considerations, the operator decided to use an electric line (e-line) tractor combined with a hydraulic stroking tool for its high reliability. The stroking tool also provided the benefit of delivering the required force at the exact point where it was needed downhole as compared to coiled tubing, which would exert the force from the surface. The complete straddle packer assembly was successfully installed in 17 runs without any non-productive or lost time incidents. As a result of the intervention, gas production was greatly reduced and oil production was returned to normal levels. The operation was so successful that the client saved nearly 30 days on an operation that was planned for 45 days. Due to the success of the initial operation, the client decided to execute several other, similar water and gas shut off operations in the field replicating the same methodology. This paper highlights the methodology used and the cost and HSE benefits provided by selecting the e-line solution with the tractor and stroking tools to perform the gas shut off. The paper will also discuss the details of the job planning as well as the execution of the operation, marking a first in this West African country.