致密油藏有效储层物性下限及其形成的动力学机制与应用

发布时间：2018-06-08 04:49

本文选题：致密油藏 + 有效储层　；参考：《中国石油大学(北京)》2016年博士论文

【摘要】：致密油是非常规油气资源的重要组成部分,资源潜力巨大,是今后较为现实的油气资源接替领域之一。我国致密油藏勘探开发起步较晚,总体研究程度较低,特别是对致密油藏有效储层物性下限的研究相对薄弱。在勘探实践中发现,致密油藏有效储层物性下限在不同埋深存在差异,并且当储层物性降低到一定程度时,地层全部变为干层。为什么有效储层物性下限会随着埋深发生变化?影响有效储层物性下限的因素有哪些?如何确定有效储层的物性下限?这些问题的解决对于合理预测致密油藏的分布,准确计算致密油藏资源量以及指导致密油藏的勘探都有重要意义。在综合分析准噶尔盆地吉木萨尔凹陷芦草沟组致密油藏地质特征的基础上,采用分布函数曲线法得到吉木萨尔凹陷致密油藏有效储层物性下限,发现有效储层物性下限具有随着地层埋深增大逐渐减小的趋势。设计物理模拟实验模拟地质条件下石油向致密储层充注的过程,从而分析有效储层物性下限的影响因素及变化规律。利用实验过程中的充注动力模拟地质条件下石油向致密储层充注的动力,利用不同的人工岩心模拟地质条件下不同岩石学特征的致密储层。通过研究石油向人工岩心充注时启动压力的变化来分析储层岩石学特征对有效储层物性下限的影响。研究认为:储层岩石粒径越粗、分选性越好、石英含量越高则石油向致密储层充注的临界注入压力越小,说明石油在储层中越容易发生渗流,则有效储层物性下限越低。通过分析致密油成藏动力学机制,建立石油向致密储层充注的地质模型,其中生油增压是充注的主要动力,毛细管压力是主要阻力。根据地下渗流理论,建立了生油增压表达式,并建立判别致密油藏有效储层物性下限的方法。在此基础上分析了烃源岩排烃强度、烃源岩厚度和地层温度对有效储层物性下限的影响。研究认为:在其它地质条件一定的情况下,烃源岩排烃强度越大、烃源岩厚度越大、地层温度越高,则有效储层物性下限越低。应用所建立的有效储层物性下限的判别方法计算出吉木萨尔凹陷芦草沟组致密储层在埋深为2000~2500m、2500~3000m、3000~3500m、3500~4000m和4000~4500m时有效储层的临界孔喉半径分别为0.352μm、0.287μm、0.230μm、0.187μm和0.147μm;所对应的临界孔隙度分别为6.9%、5.7%、4.4%、3.2%和1.8%;所对应的临界渗透率分别为0.249×10-3μm~2、0.148×10-3μm~2、0.085×10-3μm~2、0.051×10-3μm~2和0.028×10-3μm~2。并与分布函数曲线法的研究结果进行对比,发现这两种方法得到的结果具有较好的一致性,利用试油结果对有效储层物性下限进行可靠性检验,综合分析认为研究结果较为可靠。基于该研究结果评价研究区有效储层,并采用容积法计算出吉木萨尔凹陷芦草沟组致密油藏资源量为21.6×10~8t。
[Abstract]:Compact oil is an important part of unconventional oil and gas resources. The exploration and development of dense reservoirs in China started late, and the overall research level was low, especially for the lower limit of effective reservoir properties in dense reservoirs. In exploration practice, it is found that the lower limit of physical properties of effective reservoirs in dense reservoirs is different at different burial depths, and when the physical properties of the reservoirs are reduced to a certain extent, all the strata become dry beds. Why does the lower limit of effective reservoir properties change with burial depth? What are the factors that affect the lower limit of effective reservoir properties? How to determine the lower limit of physical properties of effective reservoir? The solution of these problems is of great significance for reasonably predicting the distribution of dense reservoirs, accurately calculating the resources of dense reservoirs and guiding the exploration of dense reservoirs. On the basis of comprehensive analysis of the geological characteristics of dense reservoir in Luchaogou formation in Jimusar depression of Junggar Basin, the lower limit of physical properties of effective reservoir in dense reservoir of Jimusar sag is obtained by using distribution function curve method. It is found that the lower limit of effective reservoir properties decreases with the increase of formation depth. Physical simulation experiments were designed to simulate the filling process of oil into tight reservoir under geological conditions, and the factors affecting the lower limit of physical properties of effective reservoir and its variation law were analyzed. The injection dynamics in the experiment process is used to simulate the filling power of the oil to the tight reservoir under geological conditions and the different artificial cores are used to simulate the tight reservoir with different petrological characteristics under the geological conditions. The effect of reservoir petrological characteristics on the lower limit of effective reservoir properties is analyzed by studying the change of start-up pressure when oil is injected into artificial core. The study shows that the coarser the grain size of reservoir rock, the better the sorting property and the higher the quartz content, the smaller the critical injection pressure of oil to tight reservoir, which indicates that the more easily percolation of oil in reservoir, the lower limit of effective reservoir physical property. Based on the analysis of the dynamic mechanism of tight oil reservoir formation, a geological model of oil filling into tight reservoir is established, in which oil source pressurization is the main driving force and capillary pressure is the main resistance. According to the theory of underground percolation, the oil source pressurization expression is established, and the lower limit of physical properties of effective reservoir in dense reservoir is established. On this basis, the effects of hydrocarbon expulsion intensity, source rock thickness and formation temperature on the lower limit of effective reservoir properties are analyzed. The study shows that under certain geological conditions, the lower limit of effective reservoir property is, the greater the hydrocarbon expulsion intensity of source rock is, the greater the thickness of source rock is and the higher the formation temperature is. The critical pore throat radius of effective reservoir is 0.352 渭 m, 0.287 渭 m, 0.230 渭 m ~ 0.230 渭 m and 0.147 渭 m, respectively, when the buried depth of the dense reservoir of Lucaogou formation in Jimusar sag is 2000 ~ 2500m ~ 2500m ~ (3000m) ~ 3000m ~ 3500m ~ 3500m and 4000m ~ 4500m respectively, and the critical pore throat radius of the reservoir is 0.352 渭 m ~ (0.287) 渭 m ~ (0.230) 渭 m ~ (0.187) 渭 m and 0.147 渭 m ~ (m) respectively. The critical permeability is 0.249 脳 10 ~ (-3) 渭 m ~ (-2), 0.148 脳 10 ~ (-3) 渭 m ~ (2), 0.085 脳 10 ~ (-3) 渭 m ~ (2) 渭 m ~ (2) ~ (2) 0. 051 脳 10 ~ (-3) 渭 m ~ (2) and 0.028 脳 10 ~ (-3) 渭 m ~ (2), respectively. Compared with the results of the distribution function curve method, it is found that the results obtained by the two methods are in good agreement, and the reliability of the lower limit of effective reservoir properties is tested by the oil test results. The comprehensive analysis shows that the results of the study are more reliable. Based on the results of the study, the effective reservoirs in the study area are evaluated, and the volume method is used to calculate the resource quantity of the dense reservoir of Luchaogou formation in Jimusar depression for 21.6 脳 10 ~ (8) t.
【学位授予单位】：中国石油大学(北京)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P618.13

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