Compound perforation fracturing technology is a space combination type ultra-deep perforating that can overcome some flaws conventional perforation has, such as shallow penetration and compaction damage. It can remove the compaction band and near wellbore pollution in rock matrix which results from conventional perforation. This paper introduces the theory of effect and influence factor of compound perforation fracturing technology and summarize the advantages for low permeability gas well on the basis of analyzing the mechanism of action about increase production of compound perforation. In order to evaluate the effects of application of this technology in in low permeability reservoir, 11 compound perforation wells and 12 conventional perforation wells were selected which have the similar physical property and the evaluation was conducted in two blocks. The results show that compound perforation can make the formation fracture pressure decrease in 3~5MPa and increase the permeability near the perforation channel. This technology has better effects than the conventional and decrease the cost effectively, improving production in low permeability oil and gas field.

The fine grain, poor sorting and high cement content in low permeability reservoirs lead to poor reservoir property, low porosity and permeability and have strong damage to the reservoir .The conventional way of low permeability oil mining is mainly fracture and chemical flooding, which cost is relatively high and will cause serious irreparable damage to formation. People are in favor of physical oil production technology because it is no harm and pollution to the reservoir, more flexible to operate and it has wide range of application and low cost. By using high frequency pulse pressure servo system and ZC-type I, this paper examines the low-frequency vibration oil recovery indoor simulation test device hydraulic pulse oil displacement effect of low permeability cores. The experiment selecting the artificial core (permeability are less than 50), examines the effects of different hydraulic pulse parameters (frequency, static pressure and dynamic pressure) on low permeability core permeability and recovery factor. The results showed that only when the three parameter ,hydraulic pulse frequency, static pressure and dynamic pressure, suitably combined will greatly increase the reservoir recovery efficiency and reduce residual oil saturation.

The flow pattern is unique in a certain range of pore size divided by the Knudsen number. In order to characterize permeability of nanopore in shale gas reservoir more accurately, the formulas of nanopore permeability are put forward considering the influence of adsorption gas and flow patterns. After the calculated results were compared and analyzed, the conclusions are obtained as follows: (1) Pore size is the main factor to determine the flow pattern; (2) There are three main flow pattern in the nanopore of Longmaxi formation shale reservoirs, slip flow, Fick diffusion and transition diffusion, meanwhile Darcy percolation and Knudsen diffusion do not exist; (3) Flow pattern has great influence on apparent permeability and adsorption has a greater impact in a high pressure condition (greater than 20MPa).

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