Research On Technology Of Horizontal Well Energizing And Returning To The Low-pressure Tight Sandstone Gas Reservoir In Luodai

Horizontal well fracturing technology has become an important means to improve the recovery rate of tight sand gas reservoir and exploit difficult recoverable reserves. This technology is more and more widely used. Due to the presence of long fracturing treatment time, large amount of injected fluid and proppant, the post-treatment production is directly related to the flowback after gas well treatment.In the later period of the gas reservoir development, as the formation pressure decreases, the flowback of staged-fracturing horizontal wells exhibits large fluid loss volume, slow flowback, low flowback rate, proppant flowback and other phenomena, which directly affects post-treatment effect. Thus, for staged fracturing of horizontal wells in low pressure tight sandstone gas reservoirs, we should not only reduce the reservoir damage by optimizing the fluid system, but also optimize the technology and strictly control the flowback pattern to increase the flowback energy, further reducing formation damage.By combining the laboratory experiments with numerical simulation, this paper utilized low damage fracturing and high-efficiency flowback technologies to effectively stimulate the typical low pressure tight sandstone gas reservoirs in western Sichuan, namely Luodai gas field Penglaizhen Formation and Suining Formation. First, based on the damage mechanism of the fracturing fluid, a low damage anti-water block fracturing fluid system with ultra-low thickener concentration was developed. Second, through horizontal well fracturing fluid loss and energizing pressure profile simulation analysis, combined with proppant flowback critical velocity calculations and laboratory experiments amendments, this paper proposed and optimized liquid nitrogen energized fracturing technology and separate-stage gel breaking technology for low pressure gas reservoir. Under the premise of increasing the reservoir flowback energy, flowback rate and flowback rate, the separate-stage gel breaking technology can control proppant flowback and ensure optimal conductivity of the propped fracture. This paper eventually formed the energized fracturing technology for horizontal wells in low pressure tight sandstone gas reservoirs. The technology was applied to Penglai 2-1H well, and achieved good post-treatment production. The energized fracturing technology for low pressure tight sandstone gas reservoirs proposed in this paper enriches and improves the low damage and high efficiency flowback theory and technology for horizontal wells in low pressure gas reservoir, and is of certain significance to improve well productivity and overall reservoir recovery of similar gas reservoirs.