【作者】 陈琰；

【导师】 梅廉夫；

【作者基本信息】 中国地质大学 ， 油气田开发工程， 2010， 博士

【摘要】 在世界范围内,随着石油天然气勘探和研究程度的不断深化,对各种复杂、非常规油气藏的重视和研究程度越来越高,基岩油气藏就是其中之一。柴达木盆地目前已发现多个基岩油藏并获得高产工业油流,主要分布于盆地北缘和西部,大多都以裂缝性变质岩为储集层。由于裂缝性基岩储层的非均质性极强、预测研究的难度很大,导致勘探开发较为盲目和被动。裂缝油气藏目前国内已发现不少,但如何从测井、地震资料识别裂缝储层并描述裂缝的空间分布和定向,目前是石油工业界尚未解决而正在积极研发的关键技术之一。本文以柴达木盆地马北油田基岩储层为例,在区域构造背景和盆地演化研究地质研究工作基础上,对变质岩储层进行了描述及预测和方法研究。论文选择了研究难度较大的基底变质岩裂缝性储层,结合岩心、常规测井及成像测井等资料,采用先进的三维地震数据叠前反演技术,综合分析研究,首次探索柴达木盆地基底变质岩储层裂缝的描述及预测方法。裂缝油气藏研究难度大,特别是马北油田基岩裂缝油气藏,由于该区基岩埋深较浅,相对而言裂缝宽度小且延伸距离短,增加了预测的难度。目前还缺乏针对基底变质岩裂缝油气藏研究及预测的方法与手段。开展裂缝研究工作,准确识别、预测裂缝的空间展布及发育规律,对于油气勘探以及油气开发中如何确定该区开发井网、开发井位、井距的选择、工艺技术措施等都起着决定性的作用,意义重大。本研究取得的的主要研究成果及进展有：(1)马北油田基岩储集层为为变质岩中裂缝集中发育段和井壁严重崩落段,储集空间类型主要包括裂缝、溶孔及溶洞。裂缝的发育为溶孔的形成提供了前提条件,对于改善基岩储层的储渗条件起着重要的作用。裂缝主要在马北三号基岩中的整个变质岩段集中发育,大体可分为低角度缝、高角度缝和微细不规则网状缝三种类型。裂缝倾向优势方位为NNE和SSW两个方向,裂缝倾角以低角度为主,多在30°-40°左右。马北三号地区钻井基岩井段井壁崩落较为普遍,崩落优势方位为NW-SE向,反映现今最大水平主应力方向为NE-SW向。(2)马北油田基岩储层以变质岩为主,埋藏深度不大,对三维地震资料的保幅处理要求高。分析地震数据的方位角和偏移距的分布,对提取方位角地震数据体有实际的意义,也是裂缝检测的最重要的第一步。由于储层中声波特征和厚度的差异造成的调谐频率的不同,可以利用频谱成像技术,通过选取不同频率下的振幅能量和相位值在空间的变化识别储层,有效地描述地质在空间的非连续性,并建立起储层的空间地质模型。结合其它的属性剖面,建立储层的垂向地质模型,了解储层的地质特征。正确地建立储层地质模型是我们研究储层内裂缝分布特征的基础。此外,通过建立马北3井的岩石物理模型,模拟了含油、水的裂缝储层的振幅随方位角变化,建立地震反射振幅方位椭园与裂缝定向的关系。结果表明基岩裂缝发育段,振幅椭圆的长轴方向代表了裂缝的走向方向,短轴方向代表了裂缝的法向方向。裂缝定向与储层断裂系统分布有关。(3)通过研究平面裂缝发育特征发现,马北三号基岩储层裂缝发育区主要位于马北3井及以南斜坡一带,在马北302井一带裂缝发育较差。各向异性特征在横向上变化较大,尤其是在构造斜坡带及构造端部,开启裂缝表现出更好的发育特征。马北油田基岩储层段开启裂缝发育程度主要是由局部构造的位置及结构特点和岩性成分所决定的,与工区内的构造大断裂的位置关系不大。叠前检测裂缝的研究结果表明,对于裂缝发育带与大断裂远近的关系要重新考虑。实际上,我们研究结果表明了裂缝和断层之间的关系主要表现在断层走向的方向和一组主要裂缝组系的方向是一致的,如北北东向等。(4)各类地震属性的计算如吸收衰减、AVO/FVO、叠前弹性波阻抗等,也能较好地反映裂缝储层特性信息,分析结果与方位振幅和方位频率的分析结果基本一致。(5)马北油田基底变质岩裂缝方向主要有两组,一组是北北东向,另一组是北西西向,可以认为分别是由印支期和喜山期运动所致,裂缝发育的期次作用对储层有重要的影响。马北三号试油成果证明,马北油田三维区基岩裂缝发育区带是寻找裂缝性油气藏的有利地区。本文利用已有的地质、测井、地震资料和各种先进技术,对该区块基岩裂缝储层进行综合分析研究,进一步确定马北三号基岩裂缝储层展布特征及厚度变化规律,为后续勘探开发提供科技支撑。随着油气勘探难度越来越大,全世界都越来越重视对非常规油气藏的勘探开发。由于储层非均质性极强及裂缝发育的难以预测性,为此类油藏的勘探开发带来很大困难。本次研究尝试进行基底变质岩裂缝性储层特征及储层描述方面的研究,为探索此类油藏勘探开发的关键——储层预测技术奠定了一定基础。更多还原

【Abstract】 In the worldwide,with the continuous deepening of exploration and sdudy extent to the oil and gas,the complex and unconventional hydrocrabon reservoirs are being paid much more attention and researched increasingly high.Bedrock reservoir is one of them.A few bedrock reservoirs has been found and confirmed containing high-yileld industrial oil flow in Qaidam Basin.mainly the northern margin of the and the west,most of them are tiththe rractured metamorphic rocks asreservoir. Because of the strong heterogeneity of the fractured metamorphic rock reservoir as well as the difficulty of prediction,the exploration and development is blind and passive.A few Fractured hydrocarbon reservoirs have been found in domestic, however, at present one of the key Technologies that has not been solved and positively being researched and developed in petroleum industry is how to recognize the fractured reservoir and describe fractured spatial distribution and orient from well logging and seismic data.In this paper, we taken the basement rock reservoir of oil field in Qaidam Basin as example to characterize and peidict reservoir,after researched tectonic setting in this region and basin revolution. we chose to study the basement metamorphic rocks fractured reservoir which is quite challengely,a comprehensive analysis of research combined with core, conventional logging and imaging well logging data, and adopted to advanced three-dimensional pre-stack seismic data inversion techniques, explored the basement metamorphic fractured reservoir of the Qaidam Basin description and prediction methods,at first.The studies of fractured reservoir is difficult, especially the fractured reservoir of base rock in Ma Bei oil fields. Because the depth of bedrock is relatively shallow and the width of fracture is small and the fractures extend a short distance, it increases the difficulty of forecasting. It is still lack of methods and means to research and forecast the fractured reservoir of basement metamorphic rocks. It is necessary to carry out the research of fracture, and identify accurately and predict the spatial distribution and law of the development of the fracture, which plays a decisive role and has a great significance in the exploration and development of oil and gas of determining the net of well, projecting the points of wells, and choosing the distance of wells and the technical measure. This paper has carried out mainly in the following research work:(1)The reservoir rock of basement of Ma Bei oil field are the segment of metamorphic rocks of the fracture prolifically and the wall of the well which are seriously avalanche. The types of the reservoir space are mainly including cracks, holes and caverns dissolved. Cracks in the formation plays an important role and development of dissolution porosity has provided preconditions for improving the storage reservoir rock permeability conditions.The cracks mainly developed in the metamorphic section, who generally can be divided into low-angle joints, high-angle joints, and fine irregular mesh. Cracks tend to edge direction is NNE and SSW in both directions. The crack inclination angle of the main low, mostly in 30°-40.The caving of drilling bedrock wall of MaBei3 well is common, The avalanche edge of direction is NW-SE, reflecting the present maximum horizontal principal stress direction to the NE-SW.(2)The main base rock reservoir in Mabei Oilfield is metamorphic rock,with little deep buried depth,but need high requirements on three-dimensional seismic data processing. Analysing the azimuth and offset distribution of seismic data,which plays an important part in extracting the azimuth of seismic data volume, and is also the most important first step in fracture detection.Due to the different tuning frequencies caused by the differences of the reservoir acoustic wave characteristics and the thickness, we can use spectral imaging technology. Using the changes in space of amplitude and phase in different frequencies, we can identify reservoir, describe the discontinuous change of geological body, and establish a space geological model of reservoir. Combining with other attribute profiles, we establish the vertical reservoir geological model and understand the geological characteristics of the reservoir. Establishing correct geological model of reservoir is the base to study the reservoir characteristics of fracture distribution.We simulate the changes in amplitude of the oil, water fractured reservoir with azimuth changes, and establish the relationship between seismic reflection amplitude with azimuth elliptical and fracture orientation, though rock physics model of Mabei 3 well. The results show that the long axis of the amplitude ellipse represents the strike direction of fracture, and the short axis represents the normal direction of fracture in bedrock fracture segment. Fracture orientation is related to the distribution of reservoir fracture systems.(3)The developmental characteristics of the planar transverse crack:there are lot of fractures, the matrix storage capacitu is well.. The fractures are more appear at Mabei No3 well and the neighborhood slope of Mabei No3 well southern, the fractures are little at the neighborhood of Mabei 302 well. The anisotropic characteristics have great change in horizontal. Especially, the propped fractures are well in the tectonic slope and the trending tectonics.By the developmental degree of the propped fractures, the local structural position and lithologic character are main control factors in the matrix, Mabei oil field. The structural faults have little effect in the degree of fractures. The study of pre-stack detected fractures shows that the relation between the fracture-developed zone and the great fault should be reconsideration. In fact, The results show that fault strike and the direction of main fracture set are consistent. For example, north north-east.(4)The fracture reservoir characteristics is well reflected by seismic attribution preprocessing, for example, intrinsic attenuation, AVO/FVO, prestack elastic wave impedance inversion, and so on. The analsis results of its is consistent with the analsis results of azimuthal amplitude and bearing-frequency(5)there are two sets of fractures in basement metamorphic rock, Mabei oil field. One is north north-east and the other is west northwest. They are controlled by the Indo-china movement and the Himalayan movement. The stage of fracture formation is a important information to impove resevoirs physical property.The successful results of well testing in MaBei No.3 prove that, the 3D basement rock fracture bearing area is profitable for exploring fracture reservoir. Using preexisting data of geology logging seismic and various advanced technology this thesis, multidisciplinary analyze and study the basement rock fracture in this block, ascertain the distribution characteristics and variation in thickness of regularity of the basement rock reservoir in MaBei No.3, to provide technical evidence for the successor exploring and development.Owning to the exploration activity is becoming more and more difficult, unconventional hydrocarbon reservoirs have been given more and more significances all over the word. Because of the heterogeneous reservoir sands and the difficulty of predicting of fracture bearing, so it is becoming difficulty for the exploratory development of this style hydrocarbon reservoir. In this paper, we try to study the characteristics of basement metamorphic rock fracture reservoir and the reservoir description, to provide some references for the exploring the key factor—predicting reservoirs technology.更多还原