Multistage Completion and Hydraulic Fracturing of the Extended Zones of the Longest Long-String Horizontal Well in Saudi Arabia Enabled by Adopting Completion Technology and Experience from North American Shale

Drilling and completion of extended horizontal wells is far more economical than drilling new wells for further access to the pay zone. We are already in the well; why not advance further? However, perforation of the extended section has been a challenge. Although openhole completion was suggested and has been practiced as a solution, it is not as reasonable an approach for shale, as cemented completion with selective perforations provides more efficient and accurate coverage of the horizontal section. For the first time, the longest long-string horizontal well in Saudi Arabia was cemented, completed, and hydraulically fractured in zones previously inaccessible with technology and experiences that were developed for and shared from US shale completion.

The challenge is to access the formation through casing in the extended horizontal section that is beyond the reach of wireline or coiledtubing. Openhole completion is not a sufficient option because injected fluid takes the path of least resistance to the formation, which rarely covers the pay zone entirely and efficiently. High-pressure treatment also requires more support on the annulus side of the long-string casing. For this well in Saudi Arabia, built-in casing nozzles are presented as an engineered approach. They are installed as part of the casing in the toe as well as the extended-reach zones. The toe stage consists of two clusters of built-in nozzles, and the three following stages each consist of three clusters of built-in nozzles. They are to be activated hydraulically in an orderly fashion during hydraulic fracturing operation. Completion with this technology are designed to mimic the rest of the upper stages that are completed with plug-and-perforation techniques.

The toe stage and all three following stages were successfully installed and hydraulically fractured as per the treatment schedule. Results are presented in a comparing fashion for technical performance measurement. In addition, a time performance index is presented to demonstrate the economical competency of completion with this technology compared to the plug-and-perforation method for completion in zones that allow either options. With implementation of this technology at the toe, the need for tubing-conveyed perforation is eliminated.

Even if plug-and-perforation technology advances enough to overcome the challenges of extended-reach drilling and completions, the cost of operation, time involved, and adverse effects of needing a large over-displacement of fluid to run a gun down, makes it uneconomical compared to built-in-casing nozzles. With the i-Frac technology, not only extended out-of-reach zones, but also an entire well, can be completed. The technology has already found its place in the North American market as a proven option, is the only method for extended-reach wells, and is an economical alternative for areas where mobilization of wireline or coiled-tubing units is costly.