Molecular Morphology and Viscoelasticity of ASP Solution under the Action of a Different Medium Injection Tool.

In order to improve the oil displacement effect of alkali/surfactant/polymer (ASP) solution in low-permeability oil layers, Daqing Oilfield has proposed a separate injection technology. The objective of separate injection technology is to reduce the viscosity of ASP solution through a different medium injection tool and increase the injection amount of ASP solution in low permeability oil layer, thus improving the oil displacement effect. In order to study the effect of the different medium injection tool on ASP solution, SEM is used to observe the changes in molecular micromorphology before and after the ASP solution flows through the tool.

The efficiency of migration and profile control with emulsion systems in class III reservoirs.

In order to reveal the migration law and profile control efficiency of the emulsion system in the core of class III reservoir (the permeability less than 100 mD), the influence of the size and distribution of the droplets, the effect of the migration law and the adjustment of the interlayer contradiction to class III reservoir are studied in this paper. By measuring the droplet distribution in the emulsion system, we found that the average droplet diameter decreases with the increase in water cut. But, the droplet distribution is the most uniform when the water cut is 50%, which is the transition point of the emulsion.

Rheological Model and Transition Velocity Equation of a Polymer Solution in a Partial Pressure Tool.

In order to solve the problem of the low production degree of oil layers caused by an excessively large permeability difference between layers during polymer flooding, we propose partial pressure injection technology using a partial pressure tool. The partial pressure tool controls the injection pressure of a polymer solution through a throttling effect to improve the oil displacement effect in high- and low-permeability reservoirs. In order to analyze the influence of the partial pressure tool on the rheological property of the polymer solution, a physical model of the tool is established, the rheological equation of the polymer solution in the partial pressure tool is established according to force balance analysis, the transition velocity equation for the polymer solution is established based on the concept of stability factor, and the influence of varying the structural parameters of the partial pressure tool on the rheological property of the polymer solution is analyzed.