Experimental Research On The Gel & Surfactant (polymer/surfactant Compound System) Alternating Injection Flooding After Polymer Flooding

As most reservoirs still have lots of residual oil in formation after polymer flooding, and the enhanced oil recovery effect of some replacement technologies after polymer flooding is not very ideal, so how to find more effective methods of further tapping this part of residual oil is the urgent problem to be solved for the oilfields which have used polymer flooding technology. Now the researching on the further enhanced oil recovery after polymer flooding is the focus of the oilfields with polymer flooding.The mechanism of further profile control and flooding of the gel and surfactant alternative injection is detailed analysis in this paper, according to the structural feature and the oil layer's physical property of experimental area, according to the characteristics of the gelation and the stability evaluation of the gel system, the measured interfacial tension of the surfactant and the compatibility of gel system and surfactant , the gel system and surfactant used for the further profile control and flooding are selected for the polymer flooding reservoirs. The gel system is chromium ion gel which the molecular weight is 25 million, the polymer concentration is 1800mg/L and the cross-linking ratio is 40:1. The surfactant system is the RMA-1 surfactant which concentration is 0.3%.The gel and surfactant injection characteristics experiment was carried out using the selected gel and surfactant flooding system, choosing the appropriate slug size and injection rounds of gel and surfactant alternating injection. Using the artificial large flat-panel model, the oil drive experiments are carried out to study the injecting and the displacing characteristics of the gel system and surfactant alternating injection, the experimental results show that, the recovery of the gel and surfactant (p/s) slug alternating injection experiment can enhance more than 10% on the basis of the polymer flooding in the premise of the gel and surfactant (p/s) slug is 0.05 PV, the total amount is 0.65 PV. This shows that the gel and surfactant (p/s) alternating injection after polymer flooding is a great potential and worth in-depth study of the extraction of new technology, which can further tapping the remaining oil, enhancing oil recovery.