Injection Wells Weak Acid Technology Research

Liu Chang Hu Changqing Oilfield long two Triassic reservoirs in the Eagle’s Nest development process, high pressure water injection, water injection allocation amounted to less than the required injection wells continue to emerge。Geological characteristics of the reservoir through research, combined with injected water and formation water quality analysis results, a clear cause high pressure water injection wells during the short shot of two main reasons.On the basis of preliminary research results, developed a set of weak acid-based liquid injection system and an ancillary device. Laboratory evaluation results show that a weak acid of the solution A clogging of the system has a certain ability of dissolution of scale, the interfacial tension of 6.7 × 10-3m N / m, the contact angle of 68.97 °, the corrosion rate is 0.071 mm / a; liquid B of a weak acid the interfacial tension of 5.6 × 10-4m N / m, the contact angle of 73.32 °, the corrosion rate is 0.016 mm / a, adsorption 8.0mg / g; Weak acids A \ B system on the core water oil displacement efficiency by an average of 3.6 percent, reducing the average displacement pressure 1.91 MPa, meet the test conditions. Weak acid injection well developed equipment suitable for water injection pressure 20 MPa following dosing, equipment safety factor of 1.2, to meet construction safety requirements. After application of a well site, into a weak acid of the fluid system, day to improve water from 17m3 to 30m3, reached with injection; cumulative injection of weak acid 2037m3, water pressure dropped 1.5MPa, the cumulative increase in injection 2400m3, up to a certain pressure to increase Note the effect of post-injection wells in the block blood pressure by injection provided technical support.