A split injection valve with equal dryness for staged steam injection in thermal recovery horizontal wells

Abstract

The invention provides an equal-quality split injection valve for segmental steam injection in a thermal recovery horizontal well, wherein the central pipe is connected to the gasoline injection pipe, the outer wall of the central pipe is a split flow control pipe, and an equal dry split flow is installed in the split flow control pipe. Nozzle; a cyclone and a gas core collection pipe are installed in the central tube, and the gas core collection pipe distributes gas core diversion nozzles along the circumference, and a liquid film mainstream nozzle is installed in the annular cavity between the gas core collection tube and the central tube; the liquid film mainstream nozzle and the gas core A liquid film diverting nozzle is installed on the central pipe wall between the diverting nozzles, and the liquid film diverting nozzle communicates with the diverting control pipe; the advantage is that the present invention overcomes the influence of the difference in resistance of each steam injection unit on the dryness distribution of steam and water , to achieve equal dryness distribution of steam-water two-phase fluid at different flow rates; the device is small in size, simple and compact in structure, has no moving parts, and requires no maintenance, and is suitable for equal dryness flow distribution within the inner diameter of 157mm in the steam injection well; the suction of the horizontal section Steam profile increased from 40% to over 60%.

Description

technical field [0001] The invention relates to the field of steam injection in thermal oil recovery in petroleum engineering, in particular to an equal dryness split injection valve for segmental steam injection in thermal recovery horizontal wells. Background technique [0002] Horizontal well development technology is a very effective technology in the recovery of heavy oil and super heavy oil, and has been widely used in thermal recovery of heavy oil. This technology has obvious advantages in tapping the potential of mature areas, producing marginal reserves, and developing heavy oil reservoirs with thin layers and bottom water. Compared with vertical wells, horizontal wells have the characteristics of long production intervals, large controlled reserves, and high single well production. Therefore, in recent years, the number of blocks and reserves dominated by overall horizontal well development in heavy oil reservoirs has become more and more important. Main well type...

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Problems solved by technology

However, with the increase of development rounds, the well temperature test of thermal recovery horizontal wells shows that due to the long horizontal well section, the current steam injection technology cannot guarantee the uniform production of the long horizontal well section, mainly because the physical properties of the long horizontal section difference, resulting in the traditional single-point steam injection unable to balance the adjustment of the steam suction profile

[0003] In 1993, Xu Minghai of China University of Petroleum published the heat transfer and mass transfer analysis of steam injection in horizontal wells in the Journal of Petroleum University. According to the characteristics of variable mass flow of steam in horizontal wellbore, it was proposed to arrange oil pipes or not arrange oil pipes in the horizontal section. Two simple steam injection strings can partially improve the steam absorption profile in the horizontal section, but cannot effectively adjust the steam absorption result in the long horizontal section

[0004] In 2006, Liubo and Liuxin et al. studied the problem of uneven steam injection or recovery of heavy oil horizontal wells in the SPE literature Increasing Oil Recovery of Channel Sandstone Reservoirs with Extra High Water Cut by Using Horizontal Wells, and proposed to optimize perforation to achieve water cut. The method of uniform steam injection in flat wells, but with the increase of steam injection rounds, the method of optimizing perforation cannot be adjusted dynamically

[0005] In 2008, Xue Shifeng et al. proposed an article to improve the calculation model of horizontal well steam absorption profile in special oil and gas reservoirs. According to the established horizontal well uniform steam absorption model, the method of evenly arranging perforated screens is used to realize multi-point steam injection. The control results are mainly based on the reservoir simulation results, but as the number of cycles increases, the physical properties of the on-site reservoirs change greatly, resulting in poor steam distribution effects, and at the same time, it is impossible to control the dryness of each steam outlet point

[0006] In 2013, Gai Pingyuan, Du Yongxin and others published the Uniform SteamInjection Technology Used in Thermal Wells article at the International Oil and Gas Conference on the uniform steam injection technology of horizontal wells. Through the model solution, it is shown that setting flow regulators in horizontal wells can be effective. Uniform steam injection in horizontal wells is achieved, but effective isolation is not performed in the long horizontal section of the pipe and the regulator cannot achieve equal dryness

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