Study On Injection Well Reservoir Protection Technology Of Chang8Layer In Xi41Block

Chang8reservoir of Xi41block in Xifeng oil ifeld features in low permeability, fargileto damage，huge seepage resistance, great kickoff pressure and quickly increasing injectionpressure. Consideirng these characters, this passage had conducted a seires research onformation damage, reservoir sensitivity, reservoir protection, as well as the compatibility ofinjecting fluid. Major measures employed in the study include SEM, casting thin section ofcore, X-ray, mercury injection, and dynamic core flow test.Research shows that the shape of the pore passages are various like point, sheet and tube,but they acr basically inter-granular and intcr-particlc pores. Because of the low surfaceporosity, strong heterogeneity and small pore channel, mecrury test showed that the ejectionefifciency is low. Reservoir rock is mainly consists of quartz, feldspar, geoschwitzite andchlorite. Besides severe water sensitivity and acid sensitivity, reservoir is also sufTeirng fromwettability, Jamin action, water lock effect and unqualified injection water. This passage aimsat finding the fitted additives for reservoir protection. At the same time，it provides themechanics of damage prevention by effectively preventing fluid intruding.Through analyzing mechanism of damage, this passage can help to improve recovery andwell deliverability of low permeability reservoir, like Xifeng oil ifeld.