Study On Productivity Evaluation Method Of Yanchang Continental Facies Shale Gas Reservoir

Along with the large-scale development of shale gas in domestic and foreign,the theory and technology of the continental shale gas has achieved many breakthroughs.However,during the development process,the exploitation effect of the continental shale gas in Yanchang is not ideal.Therefore,this paper will study the exploitation effect of the continental shale gas in Yanchang from three aspects of reservoir damage evaluation methods,productivity evaluation method and the injection of CO₂ to enhance shale gas recovery.Based on the analysis of the characteristics of continental shale reservoir in Yanchang and the mechanism of reservoir damage,it is considered that the reservoir damage evaluation should be mainly based on damage of fracturing reservoir.The productivity evaluation model considering fractured reservoir fracturing layer damage is established,and the evaluation of fracturing fluid filtration,proppant embedment,mud cake,fracturing agent filling layer residual night effect on extending the productivity of fractured wells is considered.The results show that the invasion of fracturing fluid has the greatest impact on productivity,and the production capacity is about 20%.By the establishment of the shale gas"corresponding binomial productivity equation"force sensitive,spondylolisthesis,gas diffusion factors were found to extend the sensitivity analysis of shale reservoir with strong stress sensitivity,considering slippage effect,some measures should be taken to prevent the development process.On the basis of discussing the feasibility of prolonging the recovery of CO₂ in the continental shale,we find that the excellent properties of supercritical CO₂ fluid are often reflected in the relevant parameters near the critical point.Injection of supercritical CO₂and reservoir gas reservoir of mixed good original excellent performance will be greatly reduced,and in consideration of the actual reservoir temperature,pressure,porosity,gas component often makes the effect of supercritical CO₂ from the performance area.By calculating and evaluating the change of adsorption capacity of CH₄ and CO₂ under different water saturation conditions,it is found that the existence of water will seriously affect the efficiency of CO₂ replacement methane.Pressure conditions,extended six blocks of shale reservoir temperature and physical parameters based on the CO₂ injection EOR feasibility analysis found that the optimization of the Chang 7 and Chang 9 block as CO₂ injection EOR experiment block,provide technical support for the efficient development of shale gas in continental basin Erdos.