Enhancing Fracturing of Tight Carbonate Using Plug and Perf Technique- Case Study

Abstract

The 1st oil in Kuwait was discovered in Bahrah in 1936. However, it was found uneconomical to develop this field due to complicated geological structure, formation tightness, cost and lack of technology at that time. In 2016, KOC has accomplished subsurface evaluation study to re-develop Bahrah field utilizing advanced fracturing technique. In last 5 years, the outcome of this study was applied successfully and resulted in remarkable production incremental from from ~3 MBOPD to more than 40 MBOPD. Multi-stage fracturing helped to unlock potential in most tightness carbonate formation in North Kuwait fields. Nevertheless, more studies was conducted to optimize the fracturing and completion design to improve well productivity as well as uniform production profile through well bore. Multi stage fracturing in open hole was the common technique since new development plan started. Although this technique had positive impact on overall field production, but it was observed uneven flow through wellbore. An approach using Plug and Perforation technique was implemented successfully to reduce dissipate of fracturing energy during pumping and improve acid propagation. Multi-stage fracturing completion in open hole horizontal wells has negative impact on acid propagation in comparison to the same for Plug and Perforation (PnP) Technique. The production logs was run in both cases and proved uniform production contribution in Plug and Perforation (PnP) technique. The paper will discuss results of applied cases with two different fracturing techniques. In addition, it will share practical operation experience including upsides and downsides of each technique to reduce risk of execution.