Research and application of low concentration fracturing fluid in Changqing tight reservoirs

According to the characteristics of low porosity, low permeability and low movable fluid saturation in Changqing tight reservoirs, a kind of low concentration fracturing fluid (LCG) was developed with concentration of 0.15%-0.20%. The fluid has strong temperature and shearing resistance, good rheological properties, high demulsification performance and quick and through gel breaking performance. The average damage rate of permeability was 25.1%. The residue content of LCG was only 156 mg/L, less than one-third of the previously used fracturing fluid. It had achieved good application results in Changqing Oilfield. After fracturing treatment, the three months’ average production index of 7 test wells was 1.59 times as high as the compared well of the same well group. And the specific productivity index of test wells was 1.93 times as high as the compared well of the same well group. Using this fracturing fluid is one of the highly effective ways to stimulate the tight reservoirs.