Perforation Optimization Of Self-flowing Horizontal Wells In Pressure-depleted Unconsolidated Sandstone Gas Reservoirs

DF gas field capacity has a larger decline, using artificial wells the higher pressure on the Ⅲ group of high pressure failure containing CO2 gas injected into the Ⅱ lower high hydrocarbon gas group. With casing cementing Ⅱ lower to protect the weakly consolidated sand formation of depleted gas reservoir and perforated the long horizontal section of Ⅱ lower gas group.First, established the artesian well of horizontal well perforation completion of the reservoir seepage flow and wellbore phase coupling mathematical model of gas injection capacity evaluation, give full consideration to the well completion parameters, permeability distribution, drilling pollution, the influence of such factors as well as track. Considering the effects of high CO2 content with temperature and pressure changes and optimizing the reasonable calculation model. With the node system analysis method, getting the Ⅲupper containing CO2 gas group, horizontal well and high hydrocarbon Ⅱ lower gas group as a whole note system, analysis and evaluate of the perforation completion parameters, gas production and gas injection characteristic parameters influence in the horizontal injection volume of artesian well, respectively, meets the target volume and recommends program perforation completion plan.Second, when perforating the long horizontal interval of artesian well are more likely to cause sand setting and buried gun. In addition, no perforating experience can be used in the block. Therefore, for sand production prediction in the horizontal well with casing perforation completion, we established critical pressure differential model, analyzed critical drawdown pressure. Also, we discussed the feasibility of oriented perforation compared with conventional perforation. The perforating direction and sand production prediction were determined. In the paper, we show that the different influence on sand production and gas injection rate between negative pressure perforating and balanced pressure perforating as well as positive-pressure perforating, and finally established perforating process optimization theory and developed perforation scheme for the requirement of the safety instrument system in artesian well perforation.Finally, this paper gave an example of an artesian well and optimized the perforating parameters to meet the requirements of gas well injection volume and the security of the implementation of the perforating technology, which ensured the gas field production and has important guiding significance.