关键词: 非均质, 底水油藏, 水平井, 变异系数, 水淹规律, 数值模拟

Abstract:

The present paper used the Lorenz curve to evaluate the heterogeneity of reservoirs and obtained permeability distributions of different heterogeneous reservoirs with a mean value of uniform formation conductivity by calculating the Lorenz curve inversely. A typical geological model for reservoirs with bottom water was established, and the flooding law of heterogeneous reservoirs with bottom water was studied by means of numerical simulation. The results indicated that when the variation coefficient (V_k) was lower than 0.2, the reservoir could be regarded as a homogeneous one, where bottom water was moving along high permeable zones and the permeability profile, flooding profile and liquid-producing profile were consistent with each other. There existed a modified logistic function between the breakthrough recovery and variation coefficient. The curve of variations between water cut and oil recovery in the semi-logarithmic coordinate system was in an S-like form and there was a function equation between water cut and the produced degree of recoverable reserves. When V_k<0.3, the flooding mode was a linear breakthrough with flooding in the whole horizontal plane; when 0.3≤V_k<0.7, the flooding mode became to a punctiform breakthrough with flooding in the whole horizontal plane; and when V_k≥0.7, the flooding mode turned to punctiform breakthrough with flooding in the local horizontal plane.

Key words: heterogeneity, reservoir with bottom water, horizontal well, coefficient of variation, flooding law, numerical simulation