The Gravel Fill Sand Control Of Viscosity Steady Acidizing Fluid For Gu Dong's Sensitivity Sandstone Reservoir

The production of sensitive sandstone reservoir in Gudong Oilfield accounts for nearly 33%of the whole oilfield,so the stable productivity of sensitive sandstone reservoir plays a crucial role in the output of the whole field.For the development of this type of reservoir,the main measures were taken for Gudong included firstly removing plug by acidizing,and then implementing High Saturation Squeeze Packing for sand control and production increase.Now a kind of NWS-I acid proppant carrier fluid has been developed in China,which has the functions of acidizing,sand carrying and consolidation,and could meet the needs of operating acidizing and sand packing at the same time in sensitive sandstone reservoir.While this proppant carrier fluid are less used in Gudong,since the adaptability to sensitive sandstone reservoir needs to be improved,and the suitable operating parameters of sand packing are not determined especially for Gudong sensitive sandstone reservoir.Therefore,it is important to do research in sand control techniques with acid proppant carrier fluid to improve application effect in Gudong.seensitive sandstone reservoirs.This thesis take the typical sensitive sandstone reservoirs 827 block in Gudong Oilfield as study object.The bulk rock mineral X-diffraction was analyzed,the potential formation damage factors were preliminarily evaluated,and the focus is put on evaluation of reservoir sensitivities including water sensitivity,acid sensitivity,alkali sensitivity and velocity sensitivity,etc.According to the evaluation result,the main agent of NWS-I acid proppant carrier fluid was optimized to improve its acid corrosion and slow release effect.The additives of acid proppant carrier fluid was also optimized to improve the antiswelling of clay,carrier ability,and sand consolidation,etc.Afterwards,the material and construction of the packing pipe string was optimized,to improve the acid corrosion resistance.The operating parameters of calculation model for acid proppant carrier fluid was optimized to improve operating efficiency.The project was applied in 5 wells of the oilfield,and 100% success rate was achieved.The contrast before and after operation was obvious.For example,as for well GD827-P1,fluid production of 10.2 t/d and oil production of 0.7 t/d before operation increased to fluid production of 29.8t/d and oil production of 8.6 t/d after operation.The study and application result shows that the optimized NWS-I acid proppant carrier fluid is suitable to Gudong seensitive sandstone reservoirs.While acidizing and breaking the plugging near wellbore adjacent,its ability for sand consolidation and sand carrier completely meet the requirements of operation of proppant packing.