低渗碳酸盐岩稠油油藏热采渗流特征研究——以叙利亚O油田为例

Percolation Characteristics of Low-permeability Carbonate Heavy Oil Reservoir: A Case Study from O Oilfield in Syria

叙利亚O油田Sh油藏是典型的低渗碳酸盐岩稠油油藏;该油藏具有渗透率较低,原油黏度高的特点,国内外对低渗碳酸盐岩稠油渗流特征的系统研究较少。为此,针对Sh油藏为例开展了低渗碳酸盐岩稠油油藏的渗流特征研究,采用非稳态法对比分析了低渗碳酸盐岩稠油油藏与高渗砂岩稠油油藏渗流特征差异性。应用"压差-流量"的方法进行驱替实验,测量了不同温度下地点压力梯度的变化特征。采用解析法计算了不同开采阶段温度剖面沿垂直水平井方向的变化规律,建立了变启动压力梯度渗流模式;并通过在数值模拟中考虑启动压力梯度,对比研究了水平井热采与冷采的开发效果差异。研究结果表明,Sh油藏高黏原油呈假塑性流型特征,加热能够显著改善地下渗流能力、提高驱替效率,水平井渗流过程呈现变启动压力梯度深流模式,热采能够显著增加鞋油半径。研究为确定热采有效动用条件与界限、论证合理井网井距奠定了基础。

Low-Permeability carbonate heavy oil reservoir is a special type of reservoir. It strikingly features in low permeability and high viscosity. At present,there are only a few researches about low permeability carbonate heavy oil,especially about percolation characteristics. The typical low permeability carbonate heavy oil reservoir of Sh reservoir in Syria was studied comprehensively. The change of temperature profile along the vertical direction of horizontal well was calculated by the analytic method for different production stages,also the flow model of a variable start-up pressure gradient was built and this guides the thermal recovery numerical simulation research,the difference between thermal recovery and cold production was compared. These lay foundations for determining the effectively producing conditions and limits of the thermal recovery and reasonable well pattern and demonstration.