Design and analysis of the effect of acid fracturing in the high pressure and high temperature Raudhatain field

Global economies, after being built on the principles of modernization, have become heavily reliant on fossil fuel-based energy. Additionally, energy consumption from non-renewable resources continues to rise steadily. The oil and gas sector remains the primary source to meet this energy demand and has thus far been considered the backbone of energy supply. However, global energy consumption from oil and gas is expected to increase by 34% from today until 2030. HPHT wells have become a focal point in the search for additional reserves. In Kuwait's Jurassic reservoirs, new projects aim to drill 40 wells and complete 13 workover operations, with the goal of raising the production of non-associated gas to 1 Bcf by 2024. Some sections of the Jurassic formation in North Kuwait, however, present challenges such as tight nature, low permeability, heterogeneity, and low production rates, necessitating the application of new stimulation technologies and acid fracturing to achieve optimal production from drilled wells. This study focuses on the acid fracturing design of well RA-X, located in the Raudhatain field and targeting the Middle Marrat reservoir. The goal of this work is to achieve optimal production by inducing fractures in the desired direction, thereby creating a reservoir drive mechanism despite the tight nature of the formation. In the Middle Marrat, fractures longer than 180 ft are intended to establish effective conductivity within the main reservoir drainage area. The study examines fracture conductivity and acid penetration distance to enhance production in naturally fractured wells. During the acid fracturing operation of well RA-X, SRT and mini-frac tests were conducted to determine fracture extension and closure pressures. The SRT test indicated a fracture extension pressure of 8,920 psi, while the mini-frac test identified a closure pressure of 7,262 psi. Due to the tight nature of the Marrat formation, a high surface injection pressure of 11,500 psi and significant fluid leak-off were observed. The increase in well productivity post-acid fracturing contributed significantly to achieving reservoir targets. The well simulation was performed using StimPlan and MEM programs, with the Nierode-Kruk correlation applied for acid conductivity calculations. Simulation results showed a fracture length of 266 ft, a height of 234.1 ft, and a width of 0.24 ft. When carbonate reservoirs were exposed to acid, high reactivity resulted in the formation of wormholes, increasing the acid leak-off coefficient.