稠油油藏蒸汽驱评价新方法

现有的蒸汽驱评价方法都是针对某一特定油藏，并且只能对蒸汽驱生产的结果进行评价。从注采特征曲线和累积产油量-累积产液量关系曲线出发，得到采出程度与累积油汽比等5个指标的经验公式。在经验公式中引入了表征油藏生产特征的参数M_r，同时通过调研实际生产数据获得M_r的取值。利用正交分析获得对油藏最终采收率影响比较大的地质因素。利用回归法得到经验公式中4个待定系数与地质参数和井网参数的关系式。进而得到不同阶段采收率条件下，采出程度与累积油汽比等5个指标的理论模版。5个理论模版初步形成一套蒸汽驱评价体系，该评价体系具有一定的普遍意义，可以对蒸汽驱生产的过程进行评价和指导。通过对单83块稠油油藏的蒸汽驱生产进行实际评价的结果表明，该方法简单可靠。

A new evaluation method of steam flooding for heavy oil reservoirs

Steam flooding is an important approach for extracting heavy crude oil. The existing methods for evaluation of steam flooding are mainly designed for specific reservoirs and only target the production results. In this study, a theoretical formula of five indicators (e.g., degree of reservoir recovery and cumulative oil/steam ratio) is obtained by taking advantage of injection-production history and cumulative oil-liquid production curves. A parameter indicative of the reservoir production characteristic, M_r is introduced into the theoretical formula and its value is determined by regression analysis of the actual production data. Geological factors that have great impact on the ultimate recovery of reservoirs are identified by orthogonal analysis. The relationship among the four undetermined coefficients in the empirical formula, the geological parameters, and the well network parameters is evaluated using regression analysis. Further, theory templates for the five indicators (e.g., degree of reservoir recovery and cumulative oil/steam ratio) are obtained at different recovery stage of steam flooding. The five theory templates preliminarily form an evaluation system for steam flooding, which has certain universal significance and guidance value for the production process of steam flooding. The simplicity and reliability of the proposed method is verified by practical evaluation of steam flooding in the Dan-83 heavy oil reservoir.