Real-Time Hybrid Coiled Tubing Service Overcomes the Issue of Pipe Stuck in a Challenging Kuwait Well

Abstract

Many unforeseen circumstances can occur when coiled tubing (CT) is deployed into a well with differential pressure sticking being one such potential problem. Diagnosing wellbore data before operating on a well is important but does not eliminate the possibility of stuck CT. With the increase in use of CT on wells with extreme conditions, the requirement to find solutions that can help retrieve the CT and its bottom hole assembly (BHA) is crucial. When using conventional CT equipment, the operator will have access to several parameters, such as weight, circulating pressure, wellhead pressure (WHP), and depth. However, all these are surface parameters, meaning they are obtained based on the surface conditions. Having accurate downhole information to accompany the surface data can be much more helpful when encountering differential pressure sticking situations. This paper presents the application of real-time hybrid CT (RTHCT) technology to overcome stuck CT. The technology incorporates a 4mm hybrid cable injected into a CT string and includes a modular sensing bottom-hole assembly (MSBHA) providing key downhole information. Internal and external pressure and temperature, casing collar locator, gamma-ray, compression, and tension are all examples of the downhole data. A flow-through camera was also added to the BHA to provide 360° visibility in the multilateral well, resulting in a high-value BHA with a total length of approximately 36ft. The RTHCT technology was initially utilized to stimulate a multi-lateral well composed of 2 legs. The CT became stuck while displacing L1 lateral, which had 6-1/8in internal diameter and 2,647ft lateral length. The reason the CT became stuck was ambiguous. But upon careful evaluation of the wellbore information, it was determined that it was likely due to the differential pressure because L1's lateral open-hole section had a large variance in reservoir pressure (up to 680psi difference). This paper presents some lessons learned when encountering a stuck CT scenario and the benefits of utilizing the RTHCT technology in challenging well conditions to successfully retrieve the CT. With the RTHCT technology, the bottom hole pressure (BHP) was determined allowing the downhole sticking point to be estimated. Higher overpull values were then applied along with additional pumping whilst remaining within the operating limits of the BHA.