Application of a fuzzy-ball temporary plugging agent to the diverting fracturing of deep carbonate reservoirs
Jiang Jianfang, Zhai Xiaopeng, He Jiayuan, Geng Yudi, Cui Jia & Wei Panfeng
(1. State Key Laboratory of Petroleum Resources and Prospecting//China University of Petroleum, Beijing 102249, China; 2. Lost Circulation Prevention and Control Laboratory, National Engineering Laboratory for Oil and Gas Drilling Technology//Yangtze University, Wuhan, Hubei 430100, China; 3. Sinopec Exploration & Production Research Institute, Beijing 100038, China; 4. Research Institute of Engineering Technology, Sinopec Northwest Oilfield Company, Urumqi, Xinjiang 830011, China)
To clarify the adaptability of a fuzzy-ball temporary plugging agent to the diverting fracturing of deep carbonate reservoirs, this paper selected the cores taken from Well THX in the Ordovician carbonate rocks of the Tahe Oilfield in the Tarim Basin as the research object. After the experiments were conducted for evaluating the rock mechanical characteristics before and after the injection of fuzzy-ball temporary plugging agent and for measuring the plugging pressure after the injection of fuzzy-ball temporary plugging agent into fractured cores, as well as field tests in Well THX. In addition, the application effect of the fuzzy-ball temporary plugging agent to the temporary plugging and the acidizing of deep carbonate wells was evaluated for the first time. And the following research results were obtained. First, after the injection of fuzzy-ball temporary plugging agent, the elastic modulus of rock decreases and the Poisson's ratio and the elastic–plastic strain of cores increases, so that the ductile deformation capacity of cores is improved. Second, the plugging pressure experiment results show that the bearing capacity of the fracture increases gradually after it is temporarily plugged by fuzzy balls, and no "cliff-like" steep drop occurs after the peak injection pressure, which indicates that the ductile plugging zone of the fuzzy-ball temporary plugging agent has been formed and exerted a plugging effect obviously. After the fracture is temporarily plugged by fuzzy balls, its plugging pressure is in a negative exponential relationship with its width. And with the increase of the fracture width, the time that the bearing capacity of the temporary plugging agent takes to reach the stable state decreases gradually. Fourth, after the injection of the temporary plugging agent into the rock, the deformation resistance of the rock is improved. After the fracture is temporarily plugged by fuzzy balls, pressure is built in the fracture and when the net pressure in the fracture is higher than the horizontal ground stress difference, the fracture is forced to divert. What's more, the temporary plugging agent can withstand a high temperature of 130 ℃. Therefore, it can satisfy the demand of temporary plugging and diverting fracturing in deep carbonate rocks.
蒋建方,翟晓鹏,贺甲元,耿宇迪,崔佳,魏攀峰. 绒囊暂堵剂在深层碳酸盐岩储层转向压裂中的应用[J]. 天然气工业, 2019, 39(12): 81-87.
Jiang Jianfang, Zhai Xiaopeng, He Jiayuan, Geng Yudi, Cui Jia & Wei Panfeng. Application of a fuzzy-ball temporary plugging agent to the diverting fracturing of deep carbonate reservoirs. NATURAL GAS INDUSTRY, 2019, 39(12): 81-87.