Innovative Diversion Technology Ensures Uniform Stimulation Treatments and Enhances Gas Production: Example from Carbonate and Sandstone Reservoirs

摘要

Saudi Arabian nonassociated natural gas development programs are continuously expanding to meet local energy demand. The challenges faced in these new development areas, attributed to reservoir heterogeneity, high-pressure and high temperature, and low reservoir quality, have been thoroughly evaluated and addressed with the application of novel fit-for-purpose technologies and the implementation of best practices. Drilling of horizontal wells and the use of multistage fracturing (MSF) have been preferred practices to obtain and maintain high and sustainable production. Stimulation also helps marginal wells become economical. One main focus area for the enhancement and improvement of stimulation efficiency is fracturing fluid additives. Regardless of the base gel and loading used, the additives play a major role in acid etching or proppant transport in heterogeneous reservoirs. Additives are needed to attain uniform stimulation, maintain high fracture conductivity and accelerate post-fracture cleanup. Because of reservoir heterogeneity, the varying extent of permeability and the multiple net pay sections that need to be stimulated in a horizontal well, ensuring uniform fracture propagation, acid penetration and proppant placement is challenging. Effective completion and stimulation design is necessary. The location of perforations is important and can impact fracture growth. The diversion additives in the fracturing fluid ensure that perforation clusters are all treated sequentially. They assist and enhance acid interaction or proppant distribution inside the fracture, and they increase the effective fracture geometry, contact area and overall conductivity. This article high-. lights the importance of perforation placement and discusses in detail a novel diversion technology, including a control pressure pumping (CPP) mechanism for additive deployment. This technology has been successfully applied in several high-pressure and high temperature tight gas condensate reservoirs to optimize breakdown, acid penetration and proppant transport. The result has been to maximize stimulated volume and well productivity. Several wells that have been acid fractured, matrix acidized or proppant fractured using these novel diversion materials are discussed in this article. Various diagnostics used to verify stimulation coverage in these wells include running production and temperature logs, conducting distributed acoustic and temperature measurements, and pumping nonradioactive tracers. Although these wells exhibited a wide range of porosity and permeability variation along the drilled section, each perforated interval was effectively stimulated using the novel diversion materials. Compared to offset wells where diversion was not used, wells treated with the novel diversion showed a distinct difference in acid etching or proppant placement profiles, indicating greater stimulation. The total production rate observed was much higher in the wells where the novel diversions were applied.