Southwest Petroleum University

Liqiang Zhao

Pingli Liu

Zhifeng Luo

Juan Du

Nianyin Li

Kun Xu

Weiyu Chen

Yong Yang

Guangyan Du

Donghe Yu

Hang Che

Guohua Liu

Ruyi Gou

Yuxin Pei

Nanlin Zhang

Bingxiao Liu

The present disclosure discloses a rotary downhole cavitation generator, including an upper connector, a lower connector, and a casing. Said casing is internally provided with a transmission shaft, an alignment bearing, a drive assembly, a thrust bearing, a rotating disk, a rectification cylinder, an inner sleeve, and an outer sleeve. Said transmission shaft is provided with a deep hole, a diversion hole radially communicating with said deep hole, and a diversion channel radially communicating with said deep hole. Said alignment bearing and said drive assembly are sleeved on an upper end of said transmission shaft, and said rotating disk, said inner sleeve, and said thrust bearing are sleeved on a lower end of said transmission shaft. Said rectification cylinder and said outer sleeve are mounted on an inner wall of said casing, and said upper connector and said lower connector are respectively connected to both ends of said casing.

Rotary downhole cavitation generator

The present invention relates to an automatic cleaning device for suction port of electric submersible pump. The pipe string joint is connected between the oil pipe and the electric submersible pump. A plurality of oil drain passage inlets, steel balls, return springs, sealing plugs and oil drain passage outlets are evenly distributed in circumferential direction of a boss. The upper end of the connecting pipe is connected with the outlet of the oil drain passage, and the lower end is connected with the nozzle. The retaining ring secures the connecting pipe on the housing of the electric submersible pump. A high-pressure fluid ejected from the nozzle directly acts on the suction port of the electric submersible pump. The present invention can automatically clean the suction port of the electric submersible pump by relying on the pressure difference between the outlet and the suction port of the electric submersible pump.

Automatic cleaning device for suction port of electric submersible pump

The present invention relates to a carbonate reservoir filtration-loss self-reducing acid fracturing method. The carbonate reservoir filtration-loss self-reducing acid fracturing method comprises the steps: (1) calculating a fracture pressure and a fracture extension pressure of a reconstructed reservoir; (2) injecting an agent A into a stratum under a pressure higher than the stratum fracture pressure, so that fractures are generated on the stratum; (3) injecting an agent B into the stratum under a pressure higher than the stratum fracture pressure, such that the agent B extends the fractures and communicates with a natural fracture net; (4) pumping an acid liquor system agent C with a high etching power into the stratum under a pressure higher than the extension pressure but lower than the fracture pressure to improve the conductivity of the fractures; (5) injecting a displacing liquid agent D under a pressure lower than the stratum fracture pressure to jack acid liquor in a well casing into the stratum; and (6) shutting down a well and performing flow-back. The agent A is a gel acid or VES acid, the agent B is a filtration-loss self-reducing gel acid or filtration-loss self-reducing VES acid, the agent C is closed acid, and the agent D is a displacing liquid. According to the method of the present invention, precipitation type solid filter cakes are formed on wall surfaces of the fractures by utilizing a filtration-loss self-reducing system, so as to perform temporary blocking to reduce the filtration loss. The technology is simple with easy injection, and the filtration-reducing agent is easy to disperse and flow back, and the method is safe and environment-friendly.

Carbonate reservoir filtration-loss self-reducing acid

The present invention discloses a phase change fracturing fluid system for phase change fracturing, including the following components in percentage by weight: 10%-40% of supramolecular construction unit, 0-40% of supramolecular function unit, 0.5%-2% of surfactant, 0-5% of inorganic salt, 0.5%-2% of oxidizing agent, 0-2% of cosolvent and the remaining of solvent. The supramolecular construction unit is melamine, triallyl isocyanurate, or a mixture thereof. The supramolecular function unit is vinyl acetate, acrylonitrile, or a mixture thereof. The solvent is methylbenzene, ethylbenzene, o-xylene, m-xylene or p-xylene. In the fracturing construction process, a conventional fracturing fluid is used for fracturing a formation first; the phase change fracturing fluid is then injected into the formation, or the phase change fracturing fluid and other fluids which cannot be subjected to phase change are injected into the formation together.

Phase change fracturing fluid system for phase change fracturing

A phase-change hydraulic fracturing process, including the following steps: (1) injecting clean water or conventional fracturing fluid to a formation, so that the formation fractures; (2) placing non-phase-change liquid and phase-change liquid in different liquid mixing tanks and injecting into a shaft at the same time, an injection volume ratio of the non-phase-change liquid to the phase-change liquid is (0-0.7):(0.3-1); (3) injecting a displacement fluid into the shaft, so that the non-phase-change liquid and the phase-change liquid in the shaft completely enter a reservoir; (4) performing well shut-in and pressure-out for 30-200 min, so that solid-phase matters generated by the phase-change liquid are laid in the fracture; and (5) relieving pressure to finish the construction.

Phase-change hydraulic fracturing process

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Chengdu, China

Liqiang Zhao