用试井资料研究低渗透裂缝性油藏渗流模式及演化特征——以准噶尔盆地火烧山油田为例

对于注水开发多年,尤其是多次采取增产增注措施后的油藏,如何准确地判定低渗透非均质储集层渗流特征及其演化规律,难度比较大。针对火烧山低渗透裂缝性油藏,根据不稳定试井曲线识别储层模型,分析了不同开发阶段储层渗流系统的演化规律。由于火烧山油田天然裂缝发育,而且多数井采用压裂方式进行投产,开发初期储层模型主要表现为人工裂缝或双孔模型。开发过程中,随着地层压力的降低及调剖堵水措施的实施,油井渗流特征往单孔模型转变、注水井渗流系统向径向复合模型转变;渗流系统的演化改变了储层的有效渗透率,使其整体上呈现降低的趋势。储层初期有效渗透率场与油井水窜特征基本吻合,有效渗透率的逐步下降与油藏含水上升速度的下降基本吻合,从而为油藏下一步开发调整可行性评价提供了重要依据。

Research on Flow Patterns and Evolution Characteristics of Low Permeable Fractured Reservoir Based on Well Test Data: A Case from Huoshaoshan Oilfield in Junggar Basin

It is still very difficult to determine the seepage characteristics and evolution pattern of a low permeable heterogeneous reservoir after many years’ development by water injection ,especially those reservoirs that have been dealt with by many different methods to increase their productivity .In this paper ,the reservoir models of the low permeable fractured reservoirs in Huoshaoshan oilfield are identified ,and the evolution patterns of the reservoir flow systems in different development stages are also analyzed . There are many natural fractures in Huoshaoshan oilfield , and a lots of them are developed by use of fracturing mode ;therefore the reservoir models in initial development are mainly manufacturing fractures or dual pore model .During development ,the flow characteristics of production well change to single pore model and the flow characteristics of injection well change to radial fitting model caused by decreasing of formation pressure and the application of deep profile control technology . The evolution of flow systems changes the effective permeability of reservoir ,and makes it decrease gradully over the whole process .The initial reservoir effective permeability field fits to water channeling characteristics of oil well ,and the decreasing tendency of the effective permeability also fits to the decrease of rising rate of water in the research area .The above results provide important bases for further adjustment and development to the feasibility of reservoir evaluation .