Gas Field Sandstone Gas Reservoirs In The Balance Of Acid Pressure Closed Acidification And Simulation Technology Research

Acid fracturing is generally applied in carbonate reservoir. It is believed that sandstone reservoir generally uses hydraulic fracturing, and acid-washing or matrix acidizing when removing the plug near wellbore. But whether sandstone reservoir can be stimulated with acid fracturing or not causes people's great concern in recent years. Some oilfield has succeeded when trying by acid fracturing in sandstone reservoir. The results show that it can be stimulated by acid fracturing, when the composition of sandstone that can be dissolved by HCL is higher than 20%.XinChang gas reservoir is a low permeability, tight sandstone reservoir. Its rock constituents are very complicated and the composition of carbonate ranges from 20% to 70%. The distribution of carbonate is very heterogeneous along the hole section. In this paper, we define the rock type to complicated sandstone. According to the characters of the formation and the potential damage factor of XinChang gas reservoir in acidizing , this paper presents the research of optimizing the acid fluid system and acidizing technology. The velocity of acidizing fluid filtration, effective distance of live acid and fracture conductivity are also simulated. There is the groundwork that the thesis finishes:1 .Based on the characters of the formation, a novel acid fluid system which adapted to Xin-855 was selected. The research of performance test and the property of acid-rock reaction were also run.2.According to the property of acid fluid system and the evaluation of kinds of acidizing technology, an equilibrium acid fracturing was selected.3.The overall equilibrium acid fracturing model which contains the model of 3D fracture propagation, the model of acidizing fluid filtration, the model of effective distance of live acid and fracturing conductivity was developed and the numerical solution technique was given.4.The project of optimization was presented for equilibrium acid fracturing in XinChang gas reservoir.5.Based on the acid fracturing in Xin-855, the results of spot-practice application of equilibrium acid fracturing were evaluated and its spot-practice application acquired good effect.