Gas-liquid driven in-situ fracturing technology and equipment for a low permeability formation
HOU Bing, CUI Zhuang, ZHANG Fengshou, XU Quan, FENG Shijin, CHEN Hongxin, JI Dongqi
1 College of Petroleum Engineering, China University of Petroleum (Beijing) at Karamay, Karamay 834000, China 2 National Key Laboratory of Petroleum Resources and Engineering, China University of Petroleum, Beijing 102249, China 3 College of Civil Engineering, Tongji University, Shanghai 200092, China 4 College of New Energy and Materials, China University of Petroleum, Beijing 102249, China 5 College of Energy, China University of Geosciences, Beijing 100083, China
China’s land has been affected by industrial development for a long time, and the pollution of low-permeability formations is very serious, so low-permeability contaminated sites need to be efficiently and quickly restored. Traditional ex-situ restoration technology has strong soil disturbance and slow restoration of the ecological environment, which is not enough to solve the current restoration dilemma. Therefore, the in-situ three-dimensional fracture network remediation technology needs to be studied urgently. At present, three-dimensional remediation of low permeability contaminated sites is faced with problems such as unknown mechanism of soil fracture propagation, easy settlement of existing proppant at the main fracture mouth and fracturing equipment fragmentation. Restricted by experimental conditions and mechanism research, further breakthroughs are needed into fracture network spreading mechanisms, multi-field coupling, new proppants and integrated fracturing equipment in a low permeability soil layer. This paper focuses on the mechanical behavior of low-permeability media under multi-field coupling and the progress and feasibility of fracturing equipment to improve the effective support of in-situ fractures. The key research points, such as the mechanism of soil fracture initiation and propagation, the fluid-solid-chemical multi-field coupling model, the new controllable mussel film-like proppant and gas-hydraulic driven fracturing technology and equipment, are put forward. It can guide the design of gas-liquid driven fracture network fracturing and infiltration enhancement repair of low permeability polluted formation, improve the transmission efficiency and placement range of agents, and realize the in-situ three-dimensional and efficient repair of low permeability contaminated sites.
