The purpose of open-hole multi-stage (OHMS) fracturing is to improve hydrocarbon production and recovery in moderate to tight reservoirs. To date, 17 OHMS fracturing systems have been installed in deep gas carbonate and sandstone wells in Saudi Arabia. Of these, 14 installations have been stimulated (acid or proppant fractured) and flowed back.1  Overall, the production results from the use of OHMS systems deployed in the southern area gas fields have been very positive with some variation – most of the wells responded positively and are excellent producers (>20 million standard cubic feet per day (MMscfd)), some showed average results, 8-12 MMscfd, and a few, completed in tight reservoir, produced at relatively low rates, <3 MMscfd, and did not carry enough wellhead pressure to be connected to the production grid. This paper will explore the factors that impact successful OHMS completion systems. Some important factors include types of OHMS used, formation properties, completion liner size, packer types, number and size of stimulation stages, treatment types, well azimuth, and fluids pumped. Conclusions are drawn based on careful data analysis to confirm the best practice for successful OHMS deployment and conducting effective fracture treatment.

This paper uses extensive field data and correlates factors to show the applicability of OHMS technology. Analysis will cover pre- and post-stimulation data showing the results from the treatments. This analysis will show the factors that contribute to successful deployment of the completion system, higher production rate, and the choice of the right candidates to obtain positive results from the treatment. This paper will show that while the various well and reservoir characteristics have a significant influence on overall well productivity, the completion type is critical and plays a central role on the success of the stimulation treatment and final production levels.

OHMS systems have been deployed extensively in North America, but they are relatively new in the Middle East. This is because the conventional horizontal wells are usually high producers and only require small stimulation treatment to clean up the near wellbore area from drill-in induced damage. With the exploration of tight gas and unconventional resources, the need to conduct multi-stage fracturing (MSF) is increasing. The tight gas zones in Saudi Arabia are typically deeper and more complex with higher temperatures and pressures than most tight gas zones in North America and therefore require much more accuracy and precision in OHMS technology applications. This paper discusses the factors that contribute to the higher production levels for these types of completion systems.

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