Research Of In-situ Generation Gas Technology Cleanup And Viscosity Reduction Adaptability In Low Permeability Reservoirs

The main purpose of this study is selecting in-situ generating gas formulas, which are of good effect of cleanup and visbreaking, in low permeability, low temperature and low pressure reservoir condition. Since generation of nitrogen, carbon dioxide and composite gas, which is composed of nitrogen and carbon dioxide, as the research object, first, to generation gas quantity as the index, in-situ generation nitrogen, carbon dioxide and composite gas system formulas are screened by static generation gas quantity experiment. Then through the dynamic test, compatibility between the in-situ generation gas recipes and reservoir fluid, compatibility between the in-situ generation gas recipes and physical property, cleanup effect of the in-situ generation gas recipes, increasing pressure effect of in-situ generation nitrogen and carbon dioxide recipes, and viscosity reducing effect of carbon dioxide are studied.Experimental results show that the in-situ generating nitrogen and composite gas esters system recipes effectively avoid the reservoirs damage caused by the acids recipe. In-situ generating carbon dioxide system acid recipe is suitable for middle-low temperature in low permeability reservoirs. In-situ generating carbon dioxide system acid recipe increase reservoir pressure, cleanup the fracture fluid, breake viscosity obviously in mesotherm and microtherm reservoirs. In-situ generating nitrogen and composite gas system cleanup the fracture fluid and increase reservoir pressure obviously.