【作者】 陈杰；

【导师】 查明；

【作者基本信息】 中国石油大学 ， 地质资源与地质工程， 2011， 博士

【摘要】 随着油气勘探程度的提高,不整合油气藏越来越来受到人们的重视,已成为油田增储上产的重要目标。关于不整合的研究,前人做了大量工作,但是对于不整合输导性能方面的研究还较少,而成岩作用对不整合输导性能的影响的研究在国内外更是属于一个全新的课题。论文在消化和吸收前人大量研究成果的基础之上,根据野外露头观察、岩心观察描述、所采样品的多种分析测试结果以及对收集到的大量地震、录井、地化和测井资料的统计分析整理,研究克夏断裂带不整合的类型划分及分布、空间结构及厚度、岩性配置类型及分布等多种特征。研究区不整合平面上可划分为(多期)削截不整合、超覆不整合、断褶不整合、褶皱不整合及平行不整合五种类型,不整合油气藏主要分布于多期削截不整合和削截不整合分布区域;纵向上不整合具有不整合面之上岩石、风化粘土层及半风化岩石带三层结构;从山前到盆地依次发育多期削截不整合→褶皱不整合、断褶不整合、削截不整合→超覆不整合→平行不整合,不整合面之上岩石厚度逐渐变薄,而风化粘土层逐渐变厚;不整合面之上岩石存在5种岩性,半风化岩石带存在7种岩性;侏罗系顶部不整合、三叠系顶部不整合、二叠系顶部不整合分别组成16种、22种、28种岩性配置类型,不整合油气藏主要分布在AHJ(砾-泥-砂)、AHK(砾-泥-砾)、BHJ(砂-泥-砂)和BHK(砂-泥-砾)四种岩性配置分布区域。不整合可形成以不整合面之上岩石(主要为底砾岩)和半风化岩石带为主的两种有效运载层。油气沿不整合运移存在录井、包裹体、薄片及地球化学等多方面显示,证明不整合在研究区内是重要的油气运移通道;样品中发现三期流体包裹体,说明不整合内至少发生过三次大规模油气运移和三次大规模胶结作用;地化特征表明不整合输导体系内油气大规模运移的方向为玛北地区→乌夏地区和玛北地区→克百地区。在不整合特征研究的基础上,选取了重32井区、夏9井区、玛北油田和克75井区四个典型不整合油气藏进行精细解剖。结果表明,研究区不整合油气藏输导体系均表现为以断裂-不整合为主的复合型;不整合面之上岩石原始物性较好,利于形成超覆油气藏;半风化岩石带溶蚀孔隙发育,利于形成不整合遮挡型油气藏。不整合油气藏的发育和分布受“两线一结构”的控制,即超覆线控制不整合面之上岩石中超覆型油气藏的分布范围,剥蚀尖灭线控制半风化岩石带内不整合遮挡型油气藏的分布范围,风化粘土层的发育程度及封闭能力是成藏的关键。通过对115块普通薄片样品、6块扫描电镜样品的观察和分析总结大量前人薄片、扫描电镜、X衍射等实验分析结果,对上述四个不整合半风化岩石带的成岩序列、成岩阶段进行了划分;并分析总结了其成岩特征,认为半风化岩石带成岩特征比较显著,主要体现为:溶蚀孔隙发育,微裂缝较为发育,岩石蚀变现象普遍而有规律。半风化岩石蚀变规律表现为不同不整合之间,从浅到深,蚀变作用逐渐变强;同一不整合,蚀变作用随距离不整合面距离的增加而减弱。综合不整合特征及成岩特征研究,对成岩作用对不整合输导性能的影响进行了定性评价及定量描述。研究区影响不整合半风化岩石带储集性能的成岩作用主要是压实作用、胶结作用、溶蚀作用和破裂作用;压实作用和胶结作用使孔隙减少,溶蚀作用和破裂作用使孔隙增加。将视压实率、视胶结率和视溶蚀率作为衡量的压实作用、胶结作用和溶蚀作用的作用强度的定量参数,根据对研究区不整合资料的统计结果明确了几种成岩作用程度的划分界限,并按影响程度对不同不整合几种成岩作用所起作用的先后进行了排序。重32井区侏罗系顶部不整合半风化岩石带为压实作用>胶结作用>溶蚀作用>破裂作用;夏9井区三叠系顶部不整合半风化岩石带和克75井区佳木河组顶部不整合半风化岩石带为压实作用>溶蚀作用>胶结作用>破裂作用;玛北油田二叠系顶部不整合半风化岩石带压实作用>胶结作用=溶蚀作用>破裂作用。另外,风化粘土层的突破压力随深度的增加呈指数关系增加,推断稳定地区埋深较大的不整合风化粘土层具有较好的封闭能力,可以达到符合封盖油气的标准。最后,综合研究区不整合的分布特征、成藏特征以及成岩特征,预测乌尔禾油田-夏子街油田-玛北油田结合部的玛北斜坡二叠系～三叠系地层为不整合油气藏的有利分布区。更多还原

【Abstract】 With the higher level of hydrocarbon exploration, unconformity reservoirs have being paid more and more attention and become primary exploration targets in oilfields. Predecessors have done a lot of work about unconformity, but less work about the capability of unconformity. The study about the impacts of diagenesis on carrying capability of unconformity is a new topic in domestic.On the basis of a large number of previous studies, this dissertation studied several characteristics of unconformity, such as the type, the distribution, the spatial structure, the depth, and the lithology combination, according to the observation of the outcrop, the core and the samples and a mass of collected data of seismic, mud logging, geochemical and well logging. There are six types of unconformity in study area: muti-truncation unconformity, truncation unconformity, overlap unconformity, fault-fold unconformity, fold unconformity and parallel unconformity, and unconformity reservoirs mainly distribute in multi-truncation unconformity and truncation unconformity. The unconformity has three parts in vertical from top to bottom: rock above the unconformity, weathered clay and semi-weathered rock. From uplift belt to depression, there are muti-truncation unconformity→fold unconformity, fault-fold unconformity, truncation unconformity→overlap unconformity→parallel unconformity in order, and the thickness of rock above the unconformity become thinner, weathered clay become thicker. The rock above the unconformity has five types of lithology, and the semi-weathered rock has seven. The conformity above the top of Jurassic, Triassic, Permian has six, twenty-two, twenty-eight types of lithology combination separately. And unconformity reservoirs mainly exist in the following four types: AHJ (conglomerate- clay- sandstone), AHK (conglomerate- clay- conglomerate), BHJ (sandstone- clay- sandstone), BHK (sandstone- clay- conglomerate). The unconformity may have two effective transport passages: rock above the unconformity (conglomerate above the unconformity especially) and semi-weathered rock.The evidence of hydrocarbon migration in unconformity, which was showed in logging, inclusions, slices and geochemistry characteristics, indicated that the unconformities were important migration pathways. It was found that the hydrocarbon experienced wide-ranging migrations and cementations three times at least. And the directions of hydrocarbon migration, which were from Mabei oilfied to Wuxia district and from Mabei oilfied to Kebai district, can be shown from the characteristics of the geochemistry.Based on the unconformity characteristic research, making fine anatomy for four typical unconformity reservoirs, which locate in Wellblock Zhong32, Wellblock Xia9, Mabei Oilfield, Wellblock Ke75. The transportation system of unconformity reservoirs performs as compounded type of fault and unconformity mostly in study area.The rock above conformity, the original physical characteristics of which are good, is beneficial to form overlap reservoirs. And the semi-weathered rock, which has more dissolution pores, is propitious to form unconformity-screened reservoirs. The distribution of unconformity reservoirs are mainly controlled by“two lines and one structure”, ie., overlap line controls the distribution of overlap reservoirs in the rock above unconformity, pinch-out line controls the distribution of unconformity-screened reservoirs in semi-weathered rock, the development ability and sealing ability of weathered clay are crucial to the formation of unconformity reservoirs.Through the observation of 115 common thin sections and 6 scanning electron microscope samples and the analysis of previous test result of lots of thin sections, scanning electron microscope and X-diffraction, diagenetic sequences and diagenetic stages of semi-weathered rock in the four unconformity above are divided. And diagenetic characteristics were summarised, which are distinct. It has a lot of dissolution pores and more cracks. Rock’s alteration characteristics are widespread and regular, which become stronger between different unconformities and become weaker in the same uncomformity with increasing depth.Based on the study of the characteristics of unconformity and diagenesis, the impacts of diagenesis on carrying capability of unconformity were studied by qualitative evaluation and quantitative description. The main diagenesis, which influence the physical character of the reservoirs, are compaction, cementation, dissolution and fracturing. Compaction and cementation make pores decrease, dissolution and fracturing make pores increase. Using apparent compaction rate, apparent cementation rate and apparent dissolution rate to measure compaction, cementation and dissolution separately as quantitative parameters, then determined the classification boundaries and distinguished various levels for different diagenesis according to statistics. The sequences about the effect level that the four kinds of diagenesis are different in distinct areas, which is compaction> cementation> dissolution> fracturing in Wellblock Zhong32, compaction> dissolution> cementation> fracturing in Wellblock Xia9 and Wellblock Ke75, compaction> dissolution= cementation> fracturing in Mabei Oilfield. In addition, weathered clay has enough sealing capability in stable region and a deeper depth, which would reach the standard to seal hydrocarbon, as breakthrough pressure of weathered clay increases exponentially with depth.Finally, based on the study of unconformity characteristics of distribution, hydrocarbon accumulation and diagenesis, predicting Mabei slope area is the favorable zone of unconformity reservoirs, which located in the junction among Wuerhe Oilfield, Xiazijie Oilfield and Mabei Oilfield.更多还原