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

摘要：

应用洛伦兹曲线评价储层的非均质性，通过反解洛伦兹曲线的方法得到具有统一地层传导系数均值的不同非均质程度油藏的渗透率分布，建立了典型底水油藏地质模型。采用数值模拟方法研究了非均质底水油藏水淹规律。结果表明,当变异系数 V _k≤0.2时，油藏可被视为均质的；底水沿高渗透条带突进，渗透率剖面与含水剖面、产液剖面具有一致性；无水采收率与变异系数之间呈修正的逻辑斯蒂函数关系；半对数坐标系下含水率随采出程度的变化关系曲线呈S型，且含水率与可采储量采出程度呈函数关系；V _k＜0.3时，油藏见水模式为线状见水整体水淹，0.3≤V _k＜0.7时，油藏见水模式为点状见水整体水淹，V _k≥0.7时, 油藏见水模式为点状见水局部水淹。

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