Technical Limits of Tight Gas Fracturing in Oman – An Innovative Exploration Approach that Incorporates Global Practices

Abstract

AbstractIn Oman, hydraulic fracturing is an established tight gas completion technique in which fluid viscosity is used to build the necessary fracture geometry and transport proppant toward the fracture tip. This process has been very successful in reservoirs that demonstrate high gas permeability values and display normal stress regimes. However, in the deeper, hotter, lower-productivity horizons, these techniques are less effective.A data collection and engineering method is required for local exploration and appraisal wells in this area because some of the tight gas reservoirs display unique physical properties that prevent actual analogue comparisons with other developed reservoirs. Furthermore, current industry practices, which are primarily influenced by the North American tight and unconventional gas market, merely transfer and apply different types of fracture design techniques. Here though, an engineering process is necessary to account for the reservoir properties and the potential impact on post fracturing well performance, along with potential scenarios for treatment failure.Recent discoveries have occurred in the deep Amin formation that has resulted in an improved fracture design process. The technical challenges of fracturing a deep, high-pressure, high-temperature formation required evaluating alternative stimulation approaches than the traditional crosslinked gel fractures. This included deploying a high-density, crosslinked fracturing fluid incorporating a weighted sodium bromide–base fluid to generate high bottomhole pressures required to frac while not exceeding completion limitations. Likewise, the application of abrasive perforating technology has resulted in success where previous attempts using conventional techniques were not successful because of high near wellbore frictions and stresses. Finally, the evaluation of a hybrid fracturing technique has improved understanding of reservoir behavior in relation to hydraulic fracturing performance.The continued emphasis and focus on low-permeability sandstone reservoir in this work is justified and useful by the continued importance of these reservoir types in Oman and other Middle East countries.