Abstract
In order to solve the problem of the poor oil displacement effect of high molecular weight alkali/surfactant/polymer (ASP) solution in low permeability reservoirs, Daqing Oilfield uses a partial quality tool to improve the oil displacement effect in low permeability reservoirs. In the formation, the partial quality tool degrades the polymer through active shearing action, reducing the molecular weight of the polymer, to improve the matching degree to the low permeability oil layer and the oil recovery. In order to study the ability of the partial quality tool to improve the oil displacement effect, the matching degree of high molecular weight ASP solution to low permeability cores is studied, and the ability of quality control tools to change the molecular weight is studied. Then, experimental research on the pressure and oil displacement effect of high molecular weight ASP solution before and after the actions of the partial quality tool is carried out. The results show that ASP solutions with molecular weights of 1900 × 104 and 2500 × 104 have a poor oil displacement effect in low permeability reservoirs. After the action of the partial quality tool, the injection pressure is reduced by 5.22 MPa, and the oil recovery is increased by 7.79%. The injection pressure of the ASP solution after shearing by the partial quality tool is lower than that of the ASP solution with the same molecular weight and concentration without shearing, but the oil recovery is lower. On the whole, the use of the partial quality tool can obviously improve the oil displacement effect in low permeability reservoirs.
Highlights
The demand for petroleum products in modern society is increasing, and the exploitation of depleted oil fields is increasing
The results show that when the injected CO2 reached about 2.0 PV, Berea sandstone’s soil recovery was 74.80%, Sarukawa sandstone’s oil recovery was 71.39%, and CO2 diffused into Berea sandstone evenly from the injected part
The results showed that under the current formation pressure (32 MPa), the minimum miscible pressure of CO2 flooding was 32.6 MPa, the CO2 solubility of crude oil was large, and after injecting CO2, the crude oil had a strong swelling capacity, which was conducive to improving the oil recovery
Summary
The demand for petroleum products in modern society is increasing, and the exploitation of depleted oil fields is increasing. The research results provided an experimental basis for the research on the effect of the separation tool and the improvement of the oil recovery of the ASP solution in low permeability reservoirs These studies only addressed the theoretical and microscopic mechanisms of the partial quality tools. It is necessary to conduct oil displacement experiments from the point of view of actual production and consider the influence of different polymer solutions and oil layers with different permeability on the oil displacement process of partial quality tools, which provides a thought and technical methods for later research on using physical methods to improve the oil recovery of heterogeneous reservoirs. The research results are of great significance for improving the oil recovery of low permeability reservoirs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
