Hydraulic fracturing is widely used all over the world, and in the Middle East in particular. Although superhigh-quality reservoirs do not need stimulation, the current expansion of reserves is mostly in newly found tight and unconventional resources that require extensive multistage fracturing for commercial production. Saudi Aramco embarked on stimulation and fracturing of wells at the beginning of its nonassociated conventional gas development endeavor and has been expanding and improving continuously in the areas of fracture design, use of novel materials, and field implementation. With newly discovered fields and the extension of existing areas, the challenges related to reservoir heterogeneity, tight rock, layered systems, and field maturity have led to innovative ideas and to testing and application of technologies.
The use of biodegradable novel diversion systems (NDSs) has allowed fracturing multiple intervals in a single-stage operation, thereby reducing time and significantly cutting operational cost. On the basis of petrophysics and reservoir and geomechanical characteristics, multiple mesh sizes of an NDS are carefully designed and used to divert fluids in the wellbore, ensure simultaneous treatment of lower-quality intervals, and control excessive leakoff inside the fracture, creating longer and planar fractures for improved production.
Diagnostics using production logging, temperature logs, and injecting and measuring nonradioactive tracers have shown expected production contribution and increase from target intervals, in both acid- and proppant-fracturing treatments. The superiority of NDSs lies in their natural formulation, simultaneous use in near-well and far-field applications, robustness in creating barriers and diversions, and easily degradable nature and flowback.
Among other technology being developed and adopted in Saudi Arabia is the use of seawater-based fracturing fluids that will save the more-valuable fresh water. The laboratory experiments and the few field applications to date have shown stability at high temperatures and pressures, compatibility with formation fluids and fracturing additives, and resilience against scale formation. The use of seawater will serve the environment tremendously and will provide substantial economic benefits in remote areas where access to fresh water is challenging and costly.
Saudi Aramco also has initiated the use of local sand as proppants combined with the channel fracturing technique, where proppants serve as pillars supporting and maintaining the induced fractures, keeping them open while the actual fracture conductivity is provided by the open areas within the system. The crushing of pillars by high in-situ stress and the friable quality of sand and consequent release of fines are controlled and contained by the use of resin during the treatment. This technology is also designed to reduce fracturing cost by eliminating more-expensive intermediate-strength proppant (ISP) or high-strength proppant (HSP) during channel fracturing. Sand cannot substitute for ISP or HSP in conventional fracturing because of its low compressive strength and friable nature.
The economic advantage achieved by the use of new technologies will help expansion, exploration, drilling, and fracturing in new frontiers and territories. The world’s increasing energy demand, which, for the most part, is hydrocarbon dependent, requires growth and advancement in the oil and gas industry, increasingly environmentally friendly practices, the use of more natural resources, and the application of innovative ideas and new technology that will reduce development and management cost and increase efficiency and effectiveness.
SPE 180207 Effects of Hydraulic Fractures on the Treatment of Condensate by Huff ’n’ Puff Gas Injection in Eagle Ford Shale by S. Yang, University of Calgary, et al.
SPE 181353 Best Practices and Lessons Learned From More Than 1,000 Treatments: Revival of Mature Fields by Hydraulic Fracturing in Khalda Ridge, Egypt’s Western Desert by Mohamed Salah, Khalda Petroleum Company, et al.
SPE 184840 Innovative Diversion Technology Ensures Uniform Stimulation Treatments and Enhances Gas Production: Examples From Carbonate and Sandstone Reservoirs by Zillur Rahim, Saudi Aramco, et al.
Zillur Rahim, SPE, Senior Petroleum Engineering Consultant, Saudi Aramco
01 March 2017