库车坳陷克深2区块白垩系巴什基奇克组裂缝分布及建模

发布时间：2018-10-31 06:58

【摘要】：在低孔低渗或致密裂缝型砂岩储层研究中,裂缝无疑是重中之重,裂缝既是油气运移的主要通道也重要的储集空间。库车坳陷克深2区块就是典型的低孔低渗致密性裂缝砂岩气藏,且裂缝发育具有很强的非均质性和不确定性。常规裂缝建模多基于蚂蚁追踪手段来实现裂缝预测,但由于研究区地震资料精度难以满足裂缝预测需求,论文基于象元模拟理论,以成像测井统计裂缝参数为硬数据,通过分析裂缝主控因素进行关键点赋值,选择序贯高斯随机模拟为方法,实现目标区块的裂缝建模。模型直观刻画了研究区内裂缝参数的分布特征及发育趋势,为后期裂缝渗流行为及非均质性研究提供有效地质模型,并且规避了地震资料精度不足带来的限制,丰富了储层地质建模研究方法。通过对前人研究成果调研,以裂缝研究相关理论为指导,本文以库车坳陷克深2区块白垩系巴什基奇克组裂缝为研究对象,通过野外露头、岩心、薄片、成像测井等资料,对研究区的裂缝进行了识别和精细描述,并结合主控因素选取相关算法建立裂缝模型。论文研究取得如下成果： (1)综合运用岩心、成像测井建立了一套完整的裂缝参数识别和计算方法,该方法对裂缝的识别精度达到0.1mm,裂缝拾取率达到80%。通过该方法对研究区22口单井成像测井资料进行了裂缝参数的精细描述和数据库建立。 (2)研究区以小缝发育为主,占89.6%,大、中缝分别只有1.8%、8.6%。裂缝主体走向为SN和近EW向,裂缝倾向主要为NE、SW向,倾角变化范围45°-75°,裂缝密度均值为0.53条/m,裂缝宽度范围0.1-0.5mmm,延伸长度0.1-1m,面缝率区间为0.02%～0.08%。裂缝组合特征多样,其中X共轭缝和网状缝为主要类型。 (3)全区裂缝普遍发育,整体表现出较强的构造控制特征,在近断裂、背斜翼部和核部强烈变形区集中分布。纵向上裂缝主要分布在巴一、巴二段,巴三段整体发育程度低于巴一、巴二段,巴三段上部裂缝发育区的分布与距断裂位置呈相关性；横向裂缝发育延续性差,表现出较强非均质性。 (4)通过对研究区裂缝发育主控因素分析,分背斜区和近断裂区确定主要影响范围并选取控制点,拟合了层厚与裂缝密度、面缝率的关系公式,并依此选取关键井点并赋值,选取序贯高斯随机模拟方法建立了裂缝密度和裂缝面缝率模型,实现了对研究区各层位、任一井点的平面、维裂缝分布预测。使用新井资料完成对模型的相关验证,模型整体准确率达到80%。
[Abstract]:In the study of low porosity and low permeability or tight fractured sandstone reservoirs, fracture is undoubtedly the most important, and fracture is not only the main passage of oil and gas migration, but also an important reservoir space. Kesheng 2 block in Kuqa depression is a typical low porosity and low permeability tight fractured sandstone gas reservoir with strong heterogeneity and uncertainty in fracture development. The conventional fracture modeling is mostly based on ant tracing, but the precision of seismic data in the study area is difficult to meet the requirement of fracture prediction. This paper is based on the theory of pixel simulation and takes the statistical fracture parameters of imaging logging as hard data. By analyzing the main factors of fracture control, the key points are assigned, and sequential Gao Si random simulation is chosen as the method to realize the fracture modeling of the target block. The model intuitively depicts the distribution characteristics and development trend of fracture parameters in the study area, provides an effective geological model for the later study of seepage behavior and heterogeneity of fractures, and avoids the limitation brought by the lack of seismic data accuracy. It enriches the research methods of reservoir geological modeling. Based on the previous research results and the relevant theory of fracture research, this paper takes the Cretaceous Bashiki formation fracture of Kesheng 2 block in Kuqa depression as the research object, through field outcrop, core, thin slice, imaging logging and so on. The cracks in the study area are identified and described in detail, and the fracture model is established by selecting the relevant algorithms combined with the main control factors. The main achievements of this paper are as follows: (1) an integrated method of fracture parameter identification and calculation is established by using the core and imaging logging. The accuracy of the method is 0.1 mm and the pick up rate of fracture is 80 mm. Through this method, the fine description of fracture parameters and the establishment of database are carried out for 22 single well imaging logging data in the study area. (2) the study area was mainly composed of small joints, which accounted for 89.6, and the middle seams were only 1.8 and 8.6, respectively. The main strike of the fracture is SN and near EW, the tendency of fracture is mainly NE,SW, the angle of inclination is 45 掳-75 掳, the mean of fracture density is 0.53 / m, the width of fracture is 0.1-0.5 mm / m, and the extension length is 0.1-1m. The area of face seam is 0.02 and 0.08. The fracture assemblage is diverse, among which X conjugate joint and reticular joint are the main types. (3) the fractures in the whole area are generally developed, and the whole area shows a strong structural control feature, which is concentrated in the strong deformation areas near faults, anticline wings and nuclei. The longitudinal distribution of fractures is mainly in Ba -, Ba-2 and Ba-3 members, which are lower than that of Ba-2, Ba-2 and Ba-3 member. The distribution of fractures in the upper part of Ba-2 and Ba-3 member is correlated with the location of faults. The lateral fracture has poor development continuity, showing strong heterogeneity. (4) through the analysis of the main controlling factors of fracture development in the study area, the main influence area is determined and the control points are selected in the anticline area and the near fault area. The formula of the relationship between layer thickness and fracture density and fracture ratio is fitted, and the key well points are selected and assigned according to this formula. The fracture density and fracture surface fracture rate models are established by using sequential Gao Si random simulation method, and the dimension fracture distribution prediction is realized for the plane of each layer and any well point in the study area. The new well data is used to verify the model, and the overall accuracy of the model is 80%.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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