Maximizing Coiled Tubing Reach during Logging Extended Horizontal Wells Using E-line Agitator

Abstract

Abstract The implementation of extended reach horizontal wells in Saudi Aramco, and in the southern area of Ghawar field in particular, is being increased for production and cost optimization. Logging these wells is a challenge, as production profile of a horizontal section cannot be entirely recorded with conventional coiled tubing (CT). This is mainly because of friction forces between the CT and the wellbore, which cause CT to lock-up significantly shallower than total depth (TD). Although with availability of this limited technique, such as metal to metal friction reducer, still CT reach cannot be maximized effectively. This paper will describe a successful utilization of agitator tool with custom designed e-line bypass that helps CT maximize the coverage of the horizontal section for logging purposes. The agitator tool was incorporated into the Production Logging Tool (PLT) and bottom-hole assembly (BHA). It was activated by pumping to cause the CT string to vibrate, and subsequently reduce the friction contact between the CT and the wellbore to allow CT running beyond the normal lock-up depth. The tool was trial tested in an extended reach horizontal well which has a TD of 12,118 ft. The simulator was showing a predicted lock at 10,400 ft while a dummy run proved a lock-up point occurs at 10,800 ft without activating the agitator. The e-line agitator was activated while the well was flowing at a restricted rate which maximized the reach to the TD and reducing the friction coefficient by around 26%. Different conditions and parameters were conducted in order to understand the best performance of the e-line agitator tool. The implementation of the e-line agitator resulted in extending the reach of CT by an additional 1,300 ft and reaching TD. This additional reach was significant as the last part of horizontal section was contributing water. The production log has been reviewed and showed acceptable measurements. This paper will cover the whole cycle of candidate selection, job design, execution, post job evaluation, lessons learned and conclusion. Introduction Drilling strategy has been shifted from vertical to horizontal at most oil fields in Saudi Arabia due to proven advantages in optimizing production and cost. Even the existing vertical wells, they are being converted to horizontal to prolong their life, improve productivity index and delay water encroachment. Furthermore, the drilling strategy is being developed by drilling more complex wells, such as extended reach horizontal wells, to maximize reservoir contact. This type of well is widely implemented in Saudi Aramco, particularly in the Haradh area, which is located at the southern part of the giant Ghawar field. The extended reach horizontal well can be defined as a well with measured depth (MD) to true vertical depth (TVD) ratio that is equal to or greater than 2 (MD/TVD)1, 2. For this particular field, the horizontal well can be considered as extended reach when its horizontal section is equal to or more than 6,000 ft. These wells act as a challenge for most of the rigless well intervention operations, such as acid treatment and logging, using conventional coiled tubing (CT). The challenge came from CT limitation to cover the entire long horizontal section.