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.

Optimized perforation and stimulation approach was developed to maximize production and overcome heavy oil based mud (OBM) associated damage for HPHT condensate wells (matrix-dominated flow) from Jurassic formation in Kuwait. This paper shares the challenges, approach and results of this novel methodology that led to significant production enhancement. Heavy OBM is the drilling and completion fluid for deep carbonate formation of Jurassic era reservoirs in Kuwait. Conventional tubing conveyed perforation (TCP)/Wireline perforation requires well killing to run final completion. Production tests carried out before and after running final completion showed significant drop in production of hydrocarbon. Conventional coil tubing acid jobs was performed to bypass the damage but still production was well below expectations. After analyzing pros and cons of multiple perforation and completion methodologies, finally gun hanger shoot and drop perforation system was re-introduced for Jurassic wells. Robust design and completion process was developed for successful execution as previous attempts of gun hanger shoot and drop system was not successful due to extreme environment (16,000 ft Depth, 11,500 psi Reservoir Pressure, 4% H2S, 3% CO2). Successful execution using gun hanger shoot and drop system with ‘just in time’ firing facilitated underbalanced perforation with immediate production tests and no requirement of further killing of well. Engineered perforation and gun design helped in optimizing space available below zone of interest for any well intervention activities. Initial well tests showed encouraging production result with significant oil and gas flow. Thick walled coil tubing was successfully deployed in live well to perform well activation in extreme environment to bypass formation damage caused during drilling process and improved acid placement. Combination of acid and produced hydrocarbon led to In-situ generation of emulsified acid providing deeper penetration of acid. Acid pumping rate and pressure was optimized to generate conductive acid etched channels and avoid creation of inefficient fractures. Cross-segment collaboration led to successful execution in challenging conditions leading to five-fold increase in production post stimulation. Gun hanger shoot and drop system was successfully re-introduced for underbalanced perforation in extreme Jurassic environment. Coil tubing operation was performed for the first time in a live Jurassic well with bottom hole pressure close to 15,000 psi and H2S close to 4%.

Drilling a multilateral well is generally recommended for several reasons such as achieving higher productivity indices and improving recovery in tight, low-permeable zones. While the many benefits of multilateral wells are attractive, they also have drawbacks which make these wells challenging. A key challenge is how to effectively stimulate all the laterals after they have been drilled. This paper presents the application of a unique intervention technique in a multilateral well to stimulate several laterals in a single run. To increase reservoir contact area the operator drilled a multilateral well composed of 4 legs. This was carried out despite the absence of proven ways to stimulate each lateral individually. This intervention would also present the following challenges: Well displacement and stimulation would require multiple re-entries into each lateral, all conducted from a drilling rig. All the laterals were known to branch off from the low side of the bore, so individual lateral and main-bore selection would be complex. Extended reach laterals require accurate friction lockup modelling and mitigations. The unique solution presented in this paper includes the use of real-time Hybrid cable coiled tubing (RTHCT) technology. This incorporates a hybrid cable installed in the coiled tubing (CT) string and a modular sensing bottom-hole assembly (MSBHA). Electrically controlled indexing tool, inclination sensor, tool-face sensor, and hydraulic knuckle joint were used as part of the BHA to enable real-time diagnostics and dynamic controls from surface to successfully enter the lateral legs. The MSBHA enabled the orientation of the BHA electrically to any position required using software to determine and control the exact position of the BHA. This paper presents a solution to all the above-mentioned challenges. It discusses the successful implementation of the RTHCT to displace and stimulate all the 4 laterals in a single CT trip in less than seven days, pumping over 7,000 bbls of various chemical systems and covering an open-hole length of 11,176 ft. Unlike other technologies, the RTHCT technology confirmed entries into the laterals without the need to tag the bottom of the lateral, saving substantial time. Enabling re-entry in these 4 laterals represented a world record translating into major efficiency improvements and cost savings for the project. This intervention also represented the first time in Kuwait that more than 2 laterals have been accessed in a CT run.