二元复合体系与油藏适应性

ADAPTABILITY OF THE BINARY COMPOUND SYSTEM WITH THE OIL RESERVOIRS

大港油田港西三区储层以高孔高渗为主,非均质性严重,目前已处于特高含水开采阶段,亟待实施大幅度提高采收率技术。以物理化学、高分子化学和油藏工程理论为指导,以仪器分析、化学分析和物理模拟为技术手段,以港西三区油藏条件为工程依据,开展聚/表二元复合体系油藏适应性研究。结果表明,驱油剂与油藏间适应性受岩石渗透率、聚合物质量浓度、相对分子质量以及溶剂水化学组成等因素的影响;随聚合物相对分子质量增加和溶剂水矿化度减小,聚合物分子线团尺寸D_h增大,油藏适应性变差;随表面活性剂加入,二元复合体系中聚合物分子线团尺寸D_h增加,油藏适应性变差;与港西三区油藏储层地质特征和流体性质相适应聚合物相对分子质量为2 500×10~4,"孔隙半径中值(R_p)/D_h"范围为7~10;与聚合物溶液相比较,二元复合体系中聚合物分子线团尺寸增加,导致聚合物岩心渗透率极限提高10×10^(-3)~20×10^(-3)μm^2。

Gangxi Block 3 in Dagang Oilfield is generally characterized by high porosity/permeability and and seri- ous heterogeneity. At present, it is at the stage of extra-high water cut and eager to stimulate EOR techniques to any great degree. Using the theories of physical chemistry, macromoleeular chemistry and reservoir-engineering as guide, the reservoir adaptability studies of polymer-surfactant binary compound system are investigated by means of experimental and theoretical analyses and physical simulation and morover the engineering evidence of the oil reser- voir conditions in Gangxi Block 3. The results show that, the adaptability between the oil-displacing agents and res- ervoir is affected by the following factors： rock permeability, polymer mass concentration, relative molecular weight, the chemical compositions of solvent water and so on. The adaptability becomes worse with the increase of the polymer molecular weight, the decrease of the solvent water salinity and the expansion of polymer molecular group size （ Dh ） and furthermore so does the surfactant add, the size （ Dh } of the binary compound system expand. The suitable relative molecular weight of the polymer for the reservoir geological characteristics and the fluid proper- ties of Gangxi Block 3 is 2 500~104. And the range of the ＂pore radius median （Rp） /Dh＂. Comparing with the polymer solution, the Dh of the polymer/surfactant binary compound system is bigger and results in the rise of the permeability limit of the polymer cores-up to 10xl0-3-20 10-3 m2.