【作者】 文浩；

【导师】 楼一珊； 刘德华；

【作者基本信息】 长江大学 ， 油气田开发工程， 2012， 博士

【摘要】 目前我国大多数油田已进入特高含水阶段,油田储量动用程度高,水淹情况十分复杂,剩余油分布难以预测。针对这一难点,本文提出了储层非均质性综合研究,从多个角度,动静态、微观和宏观相结合,定性、定量表征油藏非均质特征,分析油藏特高含水期剩余油控制因素,揭示其剩余油富集规律,为调整挖潜提供了科学依据。针对油层非均质性对采收率影响的现状,调研了国内外非均质性的分类,根据我国陆相储层的特点,将非均质性分为宏观非均质性和微观非均质性两大类,宏观非均质性又分为层内非均质性、层间非均质性以及平面非均质性,微观非均质性包括孔隙结构非均质性。在油藏非均质性的地质特点研究中,从宏观和微观两方面对油藏非均质性描述进行定性、定量表征。在微观非均质性研究中,前人多是通过均质系数、结构系数、分选系数等参数对孔隙结构进行描述,而单一参数无法全面描述微观孔隙结构特征。基于此,本文创造性的提出利用孔隙结构综合指数(SQRT(K/Φ))来研究孔隙微观结构,根据赵凹油田H3IV2层的岩心资料分析结果发现孔隙结构综合指数与平均孔喉半径呈指数递增关系,驱油效率与孔隙结构综合指数呈递增的关系,采出程度与孔隙结构综合指数呈递增的关系,表明它们有较好的相关性；并且孔隙结构综合指数的分维数与孔隙结构综合指数呈递减的关系,表明孔隙结构综合指数值越小,分维数则越大,其分形结构的复杂程度越大,储集性能变差。可见孔隙结构综合指数(SQRT(K/Φ))是一能够比较真实反映样品结构分布特征的参数,用它能更为准确的表征储层微观孔隙结构的非均质程度。在宏观储层非均质性研究中,由于目前孔隙结构微观参数与宏观特征之间的联系少有研究,本文创造性的提出将孔隙结构综合指数应用到宏观层内非均质性研究。针对H3IV21(1,2)～H3IV23(1,2)三个层内的孔隙结构综合指数的分析,研究结果表明层内SQRT(K/Φ)的分维数越大,层内的非均质性越强；在平面非均质性研究中,创造性的利用一种随机模拟技术分析了粘性指进前缘的分形生长规律,发现指进现象的分形维数df随粘度比的增加而减少,驱扫效率随粘度比的增加而减小,表明指进现象越明显,df越小,对应的驱油效率也随之减小,这在油田现场往往会引起油田过早见水,或使油井含水量上升过快,驱油效率降低；并且指进过程中注采井间将大量剩余油沿流线方向分割成诸多小“孤岛”,这势必会造成油田高含水而采出程度不高的现象。针对非均质油藏剩余油分布的研究方法以及存在的不足,提出了基于地质构型剩余油分布预测的研究方法,特别是将孔隙结构综合指数用来做剩余油分布规律的分析和预测。在以赵凹油田安鹏H3IV2层为实例的剩余油预测的过程中,利用孔隙结构综合指数对剩余油在微观、平面、层内的分布进行预测与利用数值模拟出来的剩余油分布结果相一致。研究结果发现剩余油一般在孔隙结构综合指数分布很不均匀的地方,并且多是富集在孔隙结构综合指数比较小的区域,这一点与利用随机模拟技术分析粘性指进的研究结论相一致。结合赵凹油田安棚区H3IV2层目前已进入特高含水期,而采出程度仅为22.64%的反常现象,因此我们可以通过降低并筒附近阻力的同时应强调降低阻力的均匀性,进行注采调整的同时还可改变井网来改变液流方向,来达到更好的剩余油开发效果。这种研究方法为剩余油预测方法提供了一个新的方向。更多还原

【Abstract】 At present,many oil fields in our country have entered the stage of ultra-high-water-cut.The remaining oil distribution becomes hardly to be predicted,with the high producing degree of reserves and the complexity of the condition of submergence.In view of this difficulty,the paper puts forward the comprehensive research of reservoir heterogeneity,which characterized the feature of oil reservoir heterogeneity qualificatively and quantitatively from several angles,combining with dynamic and static,macro and micro datas.It analyses the control factors of remaining oil during ultra-high-water-cut stage,and reveals the concentrating rules of remaining oil,offers scientific basis for adjustment and tapping potential of remaining oil.For the status of influence of oil reservoir heterogeneity to the recovery,the paper has researched the heterogeneity of classification at home and abroad. Acorrding to continental reservoir features in China, it proposed that heterogeneity was divided into macroscopic heterogeneity and micro heterogeneity, macroscopic heterogeneity included inner heterogeneity, interlayer heterogeneity and areal heterogeneity, micro heterogeneity included pore structural heterogeneity. In the research on geological features of the reservoir heterogeneity, it characterized the reservoir heterogeneity description qualificatively and quantitatively from the macro and micro aspects.On the micro heterogeneity study,predecessors always described pore structure with some parameters,such as uniformity coefficient,structure coefficient,separation coefficient and so on,but the micro pore structure can’t be described by the single parameter.Based on this point,the paper puts forward the composite index of pore structure (SQRT (K/Φ)) creatively,which is used to research pore structure.The Core analysis result indicates that the composite index of pore structure shows exponetial grow with the average pore radius, with oil displacement efficiency is under the relationship of the increasing, degree of reserve recovery is also under the relationship of the increasing, and fractal dimension of composite index of pore structure follows an diminishing rule, which show that the bigger the numeric of fractal dimension is, the more complex fractal structure is, and the stronger heterogeneity is, the wores reservoir property is. The results show that the composite index of pore structure can really reflect microstructure distribution and characterize accuratly heterogeneous degree of miscroscopic pore structure.On the macro reservoir heterogeneity study,due to few research on relationship between micro pore structure parameters and macro pore structure feature,the paper creatively puts forward the research of the composite index of pore structure applied to inner heterogeneity research.According to analysis on the composite index of pore structure in layers from H3IV21to H3IV23, it is found that the bigger fractal dimension of the composite index of pore structure (SQRT (K/Φ)) in layers is,the stronger reservoir inner heterogeneity is. In the areal heterogeneity study, it analyses the fractal growing law of viscous fingering front using a stochastic simulation technique,it is found that the greater value of the viscosity ratio is, the less fractal dmension df and sweep efficiency is, which lead to earler water breakthrough in oilfield and lower oil displacement efficiency, and remaining oil in stream dirction inner well can be divided into isolated islands during the growing of viscous fingering which lead to high water cut, but degree of reserve recovery is low.In view of the research method of remaining oil distribution of heterogeneous reservoirs and existent insufficiency, the paper put forward the forecasting method of remaining oil distribution based on geological configuration, especially analyses and predicts remaining oil using the composite index of pore structure. Taking AnPeng district of ZhaoAo oilfield as an example, microscopic, plane and in-layer of remaining oil can be predicted through the composite index of pore structure, the same results can be obtained using numerical simulation, it is found that remaining oil distribution is usually in heterogeneous place where the composite index of pore structure is uneven and low, which matchs results of fractal growing law on viscous fingering front using a stochastic simulation technique. Combined with development characteristics of of ZhaoAo oilfield, it can decrease the resistance of well bore nearby and special attention is given to unifomity of the resistance in tapping measures of oil and water well, we can change stream dirction through well pattern adjustment, which can get better development effect for remaining oil potential tapping. The research method can offer new direction for prediction of remaining oil in the oilfield.更多还原