ALCOHOL-BASE FRACTURING FLUID USED FOR TIGHT SANDSTONE GAS RESERVOIRS,BAKA OILFIELD

In Baka oilfield,water lock often takes place during fracturing tight sandstone gas reservoirs.So,a kind of alcohol-base fracturing fluid with low concentration is developed to improve a fracturing effect.At first,during selecting some main and additive agents including alcohol,thicker and cross-linking agents,the effect of alcohol to guar gum fracturing fluid,the anti-temperature,anti-shearing and gel-breaking properties of alcohol-base fracturing fluid are evaluated.And then,some experiments are implemented,which show that this fracturing fluid can decrease the surface tension of gel-breaking fluid and remove the water lock to increase the flowback efficiency.As a result,its damage ratio to core may reduce over 30% comparing to conventional water-base fracturing fluid;and for some wells which alcohol-base fracturing fluid is used,their yield may increase by 9.5 times and the spray flowback ratio of residual fluid may also reach more than 55%.