The First Successful Field Demonstration of Alkaline Surfactant and Polymer Flooding through Thin Layer

Abstract

Abstract The Alkaline Surfactant and Polymer (ASP) demonstration block has 49 injectors and 63 producers, with area of 1.92 km2. The target zone has bigger reservoir span and consists of many thin layers with narrow fluvial sand body, smaller thickness, lower permeability, higher clay contents. The layers combination and well spacing have been determined basing on the fine geological research and existing ASP flooding performance. The ASP formula, injection parameters and system slug combination are determined through the lab research and numerical simulation. Field data show injection and production rate maintain an acceptable level at the decline of 7.91and 17.1% in volume respectively. Producers have good response with the average WC decreased from 96.2 to 78.6% for center wells. Profile measurements results show that, for higher permeable zone, the adsorbing thickness has been improved by 13.4 and 7.1% respectively by contrast to water and polymer flooding, and for lower permeable zone, it is 46.1 and 37.1 respectively. The analysis on produced oil shows that, during ASP injection process, the C16-38 content has increased gradually from51.9 to 63.7.This result indicates that the oil displacement efficiency has improved. The ultralow IFT between water phase and oil phase has been incounted, whose liquid was produced from 28 wells, which are among 36 total center wells. That states ultralow IFT has been achieved widely in the reservoir. At present, chase water has been injected, with WC 92.0% and incremental oil recovery 26.0% OOIP. The ultimate oil recovery predicted to be 28.0% OOIP with production cost at $24.6 / bbl.