Unconventional reservoir is characterized by its low permeability, insufficient reservoir energy and low production. To develop unconventional resource economically and efficiently, the industry has been spending tremendous resources to optimize completion, energy supplement and cluster spacing in stimulation technology by piloting – a trial approach. However, this approach tends to be time consuming and cost significant amount of money. As the fracturing modeling and stimulation technology advances, we question: "Can we use the fracturing modeling and reservoir simulation technologies to optimize well energy supplement and cluster spacing based upon Fracture Controlling Fracturing (FCF) technology, which is the latest concept for stimulation technology with successful applications in China's unconventional oil and gas development?", so that the industry can significantly save piloting time and money, and quickly find the optimal energy supplement method and cluster spacing corresponding to optimal completion. Based on the actual geological conditions of the horizontal well group of An83 block in Changqing oilfield in Ordos basin, we first built a 3-D geological and petrophysical model by Petrel and Eclipse softwares, and then calibrated the model with multi-stage fracturing production history data of each well. Local grid refinement and equivalent permeability simulation of fractures were used to optimize the crack system and cluster spacing parameters. FCF is a new generation hydraulic fracturing technology to move all the controllable reserves per well, and develop unconventional resources economically and efficiently by making fractures matching ‘sweet spots’ and ‘non-sweet spots’. The FCF emphasizes on making all the oil and gas movable by the hydraulic fracturing for the first time, the integration of reservoir pressurization, stimulation and production. It aims at moving all the oil and gas in place, developing unconventional oil and gas resources sustainable and profitable. The FCF has been successfully applied to the Ma56 block of Santang Lake in Tuha Oilfield of China. The average cluster spacing is 39.4 ft, and each stage has 5 clusters. The ‘fracture-controlled reserves’ was raised by optimizing well energy replenishment and cluster spacing based upon FCF technology. The total fluid volume injected is 151421.4bbl per well, and the formation energy is fully supplemented. Compared with neighboring wells, the oil production has increased by 1.7 times. With outstanding performance in production enhancement for unconventional oil and gas plays, FCF is worthy of extensive promotion.

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Shale gas hydraulic fracturing usually activates nearby faults and makes them slip. In horizontal wells, fault slip can result in serious casing deformation. Casing deformation slows the fracturing process, lowers production, and raises the cost of a shale gas well. It is challenging to obtain underground data on fault activation because of the deep shale reservoirs. As a result, the current study needed to indicate how hydraulic fracturing affects fault activation length. This made it challenging to control casing deformation. The fluid-structure coupled finite element method was used in this study to create a coupled seepage-stress model for heterogeneous shale formation. With microseismic signs and hydraulic fracking for shale gas, this model examined the variation law of pore pressure and ground stress. The fault activation coefficient was created to assess the fault activation duration and the impact of hydraulic fracturing. The model was verified by the microseismic signal. The outcomes of the numerical simulation demonstrate how the rapid rise in formation pore pressure during hydraulic fracturing affected the ground stress at the fault interface. The influence of ground stress variation at the fault interface on fault activation could not be ignored. Increased fault elastic modulus, fracture pressure, fracture time, and the fault Poisson ratio result in longer fault activation lengths. The length of the fault’s activation was decreased by the increase in fracture stage, distance from the fault, friction angle within the fault, and fault angle. Finally, a shale gas horizontal well with casing deformation in block C was analyzed. The results showed that reducing the fracturing duration can reduce the activation length of the fault by 68.25%, resulting in a 9.1 mm fault slide and a 0.86 mm casing deformation, respectively. This study offers theoretical guidelines for preventing fault activation during hydraulic fracturing in horizontal shale gas wells.