Abstract

The first extended reach horizontal well installed with autonomous ICD (AICD) technology has been deployed by Lukoil in a heterogeneous thin oil rim reservoir with a large gas cap located in the North region of the Caspian sea. The Yuri Korchagin field development has been challenging for geosteering to remain in the thin net pay, for the completion engineers to get planned tallies to TD, for reservoir engineers to minimize risk of rapid increase in GOR after several days of production. To address the later challenge, passive ICD's (PICD) have been trialled with limited success to mitigate gas production from the overlying gas cap and therefore an AICD lower completion was specifically chosen to delay and mitigate gas coning. The gas sensitive completion component reacts to viscosity differences between fluids, essentially choking the more mobile gas autonomously by reducing the flow area due to higher gas production in the local vicinity of where gas breakthrough is occurring. AICDs have been run by other operators and the success criteria has seen a reduction in GOR relative to other wells installed with PICDs but knowing where the gas breakthrough is occurring and is being choked back could not be identified. Traditional permanent monitoring technology and production logs were considered too risky and costly. Distributed temperature sensing may have been ideal to identify gas breakthrough location but was considered prohibitive due to the need to rotate the completion string to reach TD. Running coil tubing conveyed PLTs periodically required medium term planning to schedule the intervention due to active drilling activity on the platform. Moreover, the need for tractors, often failed to reach the toe of the well where it is most critical to verify flow contributions in typically 7000 mMD extended reach wells. A relatively new monitoring technology was identified, that overcame the mentioned installation and intervention challenges by installing intelligent downhole chemical sensors in the drainage area of the sand screens during the manufacturing phase. The sensors can be placed in discrete locations from heel to toe to meeting the Lukoil monitoring objectives of providing flow profiles, identifying the location of gas breakthrough and if the AICD actually chokes gas over time. By obtaining surface samples, analyzing for unique chemical tracers and interpreting their corresponding tracer signals created by well transients and during steady state production. This paper will discuss the first well installation of its kind in Russia and in the world, to be equipped with integrated autonomous inflow control and monitoring technology with no cables to control flow, nor power to operate the devices.

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