The objective is to increase the production/injection rate of the existing old sick vertical wells that are completed with 7" casing, by extending the reservoir exposure with converting those wells to horizontal producer/injector.
In the initial Field Development stage, many wells were drilled and completed with 7" casing up to the surface. Several of those old wells are lying inactive in North Kuwait which has one of the largest oil reservoirs in the country. In addition, of the limited surface locations in the field combined with the growing anti-collision challenges, feasibility studies were carried out for reviving such sick wells which can't be delivered via limited hole sections; accordingly, an innovative idea introduced to complete those wells with 3 7/8" or 4 1/8" Open Hole Completion. To address the required challenges, 2-7/8" PAC HT DP had been used along with 3 1/8" Motor.
Consequently, DP had to be spaced out every trip to maximize the WOB transfer and mitigate Buckling issues.
This paper provides an overview of 3 7/8" slim horizontal hole by taking the challenge to the next level by drilling the longest 3 7/8" horizontal slim hole in the world with a total footage of 4,565 ft. Total 7-runs had been performed to achieve this lateral length due to the limitation of BHA/LWD Battery life. Thirteen such wells have already been drilled consisting of 7 Injectors and 6 Producers. The Slim Wells are completed as an Injector with 5" seal assembly along with 4 ½" Tubing, or as a Producer with 3 ½" tubing and ESP. All wells (both Injectors and Producers) have yielded results commensurate to the potential of any new conventional horizontal well. Consequently, Slim Hole Horizontal wells were successfully drilled in Kuwait Oil Company fields. As such, the campaign of reviving the sick wells helped KOC to achieve higher return on investment in mature assets through minimizing top hole construction cost and time. The success has opened up new avenues for KOC.
Re-entry wells helped to achieve higher return on investment in mature assets through minimizing top hole construction cost and have been drilled at 1/3rd the cost of a new well. It also accelerates time to oil production from existing wells and has minimized the prevailing location constraints. KOC has launched an aggressive plan to complete more such sick wells.