泥质白云岩储层裂缝系统定量表征及建模

发布时间：2018-02-02 01:33

本文关键词： 塘沽地区泥质白云岩裂缝成因控制因素地质建模裂缝模型　出处：《中国地质大学》2015年博士论文　论文类型：学位论文

【摘要】：塘沽地区的沙河街组三段下部发现一套泥质白云岩和白云岩组合的裂缝性储层,其内受到构造作用形成复杂的断块,孔缝作为其主要的渗流、储集空间,具有重要的研究意义。此油藏属于非常规类储层,且埋藏较深,达到3500m左右。分析研究区的可采储量,认为达到经济开发要求,然而这类储层对于勘探而言是个重大挑战。从基本岩石矿物含量到储层沉积、裂缝、油藏类型及特征,湖相白云岩同以往研究的海相白云岩相比,各个方面均存在差异性,对基础地质到开发开采的各方面研究都是一种新的尝试,需要新的理论及思路进行指导。对于泥质白云岩储层中各岩石矿物的组成复杂,裂缝测井响应模式精度不足,区域内裂缝成因、分布特征和控制分布的缺乏准确的认识,本文基于区域构造分析、地层沉积、岩心、常规/特殊测井、实验分析、试油/生产等资料,以精细描述裂缝空间分布为目标,从裂缝识别和特征参数描述两大根本内容入手,对裂缝主要特征及控制因素进行解析,并建立三维化储层裂缝模型,主要包括六部分：区域构造演化、裂缝发育特征与测井评价、裂缝成因及成缝主控因素、物性与含油性评价、建立裂缝控制因素三维约束体、储层裂缝三维化地质建模。区域构造演化分析。研究重在基于地震剖面解释下分析塘沽凸起的沙三段地层构造演化。整个沙三段的的演化概括为三幕断裂活动、一幕反转隆升和二期广泛暴露剥蚀的过程。最早的沙三5亚段沉积时期,区域主要的断层相互作用,在整个研究区的中部区域产生一个地垒构造；地垒构造的西北方向形成了一个半地堑的构造。随后在沙三4亚段沉积时期,区域内的主要活动断层-塘北断裂活动由强变弱。通过地震剖面可以识别出多个似花状构造,其周围多见密集的次级断裂,这些对于区域内白云岩储层的裂缝产生有积极的意义。其上部沉积的沙一段时期,区域断裂方向指示应力场发生重大变化,方向由左旋转变为右旋。整个研究区此地层沉积厚度较薄,主要分布在西北部,部分地层出现不整合接触。沙河街组上部的东营组,在研究区大部分与下部地层接触关系为角度不整合接触,研究区中间地震剖面见明显的同相轴削截现象,不难看出此区域内由早期的地层沉降中心→反转隆升→长期暴露剥蚀的过程。沙二段的地层在研究区全部缺失,其上的沙一段沉积厚度薄,东营组地层与底面角度不整合接触。裂缝发育特征与测井评价。研究重在通过多方面资料识别研究区的裂缝发育特征及利用测井响应模型计算裂缝发育。从裂缝特征参数角度统计,取心段裂缝倾角形态主要为高角度斜交(44.03%)和垂直(43.88%)；裂缝开度大部分小于1mm(84.32%),且多为网状微裂缝(开度小于100～150μm)；裂缝长度多分布于0～10cm(67.05%)；裂缝填充物主要为未充填(35.68%,主要为裂缝闭合)、方沸石及沥青质充填(31.65%)。常规/特殊测井对裂缝的响应,可能表现为AC增加、DEN降低、CAL异常变大或者变小,也可受到一些非裂缝的因素影响：岩性变化面、溶蚀孔隙、沉积团块等。所以需建立适合本区的裂缝测井解释模型。首先通过筛选各岩性的裂缝与相应的测井曲线敏感程度,最终确定常规测井曲线声波时差、密度、井径、声波时差/密度、声波时差/自然伽马,依据岩心中观察的数据点制作各自岩性的裂缝发育程度的测井曲线蜘蛛网图,描述裂缝发育的特征,利用多元统计分析由裂缝线密度值、5种测井及组合参数组成的矩阵,求解储层裂缝测井响应的数学模型。保留部分岩心观察的数据点验证建立的数学模型,最终得到71.43%的识别准确率,认为此模型可靠。裂缝成因与成缝主控因素。观察、分析取心井塘12C的岩心段裂缝的特征,按照裂缝的应力状态的不同,对成因进行分类,发现研究区以构造缝为主,层理缝、溶蚀缝比例较少,渗流能力依次减弱。根据方沸石、沥青质充填情况以及溶蚀发育情况,认为研究区共发育四期裂缝：平行层面的层理缝；倾角45°的共轭斜交缝、倾角60°的高角度斜交缝；倾角75°-90°的高角度/垂直张性裂缝;倾角70°-85°的高角度/垂直缝。对于成缝控制因素,从岩性、构造、成岩、超压方面分析。认为上述因素均对裂缝有控制作用,而断裂和应力场的作用尤为明显。各因素具体表现：岩性方面,在构造运动较弱的区域,岩性对裂缝分布有控制作用,裂缝发育程度随白云石、方沸石含量的升高而增大；构造方面,地应力集中的区域,断层延伸方向改变处、结束端,以及多条断层拼合、交错的断块等区域,裂缝比较发育；成岩方面,破裂和溶蚀为研究区控制裂缝的主要成岩作用；超压与裂缝发育程度呈正相关性。物性及含油性评价。对于复杂的泥质白云岩储层,物性模型尤其重要,是建立裂缝模型的基础,如何考虑多方面因素对模型的影响,建立适合本区、精度达标的模型显得尤为重要。由于白云岩储层中孔渗相互关系比较复杂,受泥质含量、裂缝影响不能忽视,所以决定按照基质、裂缝、总体的三部分,分别建立孔隙度、渗透率、含油饱和度的模型。孔隙度模型中基质部分的求取,采用以三孔隙度计算模型为基础,通过确定不同岩性的泥质含量和岩石骨架参数,最终于实验测试结果拟合修正,建立基质孔隙度的模型。裂缝部分的孔隙度采用双侧向电阻模型,通过岩心测量获取裂缝面孔率代替实验测试的裂缝孔隙度,拟合修正建立裂缝孔隙度模型。渗透率模型中基质部分的求取,利用谭延栋经验公式,以实验数据修正,裂缝部分的渗透率采取经验公式。含油饱和度的基质模型,通过对比经典的阿尔奇公式和考虑泥质、裂缝影响因素的并联模型,选取跟实验结果吻合的前者进行计算。通过计算研究区的孔隙度、渗透率和含油饱和度,认为塘沽地区沙河街三段下部的泥质白云岩储层孔隙度值主体范围为7%-18%,渗透率均值多低于1mD,主要为中-低孔,特低渗储层,岩性与含油性具有相关性,白云岩含油饱和度相对最高(45.61%),其次为泥质白云岩(33.81%)。建立裂缝控制因素三维约束体。建立裂缝模型时需要考虑如何把控制裂缝分布的地质因素作为约束条件,不能仅仅通过数学模型计算裂缝。本次研究先利用各个层面的构造起伏计算相应最大曲率面,并在还原本区裂缝产生期构造的地质模型基础上,利用Ansys有限元软件对古应力场进行模拟,计算裂缝发育时期的应力值。依据计算结果,计算岩石破裂值和能量值,综合考虑多个裂缝属性参数,将其与岩心观察的裂缝线密度进行多元回归关系拟合标定,建立一个适合本区的裂缝体预测模型,对整个研究区进行裂缝分布预测。建立的裂缝体预测模型,不同于单井的岩心、测井资料,在井间未知区域利用地质统计方法插值,而是综合了岩性、构造等因素的体数据,并通过岩心、测井校正,具有高可信度,可以作为下一步储层裂缝建模的约束体存在。储层裂缝三维化地质建模。在资料综合处理、岩相综合研究、物性含油性模型以及大量人工制图分析的基础上,建立塘沽地区沙三5亚段泥质白云岩储层裂缝地质模型,其中包括构造、岩性、物性、净毛比、原始含油饱和度和裂缝分布等六个三维定量化模型。岩性建模采用岩性趋势面约束的序贯指示模拟的方法；孔隙度建模主要采用了岩石物理相单元控制的方法。该种多级次的地质建模方法使得岩性、孔隙度和渗透率模型分布更加合理,准确程度提高。净毛比模型利用研究储层物性下限：孔隙度≥6.6%、渗透率≥12.5×10-3μm2。裂缝采用DFN随机裂缝模型,通过输入统计得到的裂缝特征参数及裂缝建模约束体控制,保证了其符合地质认识。储量计算结果显示：塘沽地区地质储量的模拟结果与实际地质储量相当,建立的地质模型可靠。根据以上六部分的研究,分析了研究区构造演化特征,建立了研究区泥质白云岩致密储层的裂缝评价、物性及含油性评价的测井模型,分析了裂缝成因及成缝主控因素,建立了多种控制因素三维约束体下精细的储层裂缝模型,认为本区裂缝发育优势区主要集中在距离中部断垒近的2组近NW和NE向断裂交叉地带,油气勘探中应综合研究寻找上述裂缝发育区与高压地层配合的“甜点”区。
[Abstract]:Tanggu District Shahe Street Group three part found a set of argillaceous dolomite and dolomite combination of fractured reservoir, the formation of fault block tectonics is complex, the slot as its main seepage, reservoir space, and has important significance. This reservoir belongs to the unconventional reservoir. And deeply buried up to about 3500m. The study area of recoverable reserves, that meet the requirement of economic development. However, this kind of reservoir for exploration is a major challenge. The cracks from the basic rock mineral contents to reservoir sedimentation, reservoir types and characteristics, compared with the previous study of lacustrine dolomite facies white dolomite, various aspects. There are differences on the basis of geological research exploitation in all aspects is a new attempt, need theory and new ideas for guidance. For the composition of the rock mineral mud dolomite reservoir in complex fracture test Well response model of low accuracy, area of crack formation, distribution and control of distribution of the lack of accurate knowledge, based on the analysis of regional tectonic, sedimentary, core, conventional / special logging, experimental analysis, test oil / production data, the distribution of fine description of fracture space for the purpose of describing the two fundamental contents from crack identification and analysis of the characteristic parameters of the main features of cracks and control factors, and establish the three-dimensional reservoir model, mainly includes six parts: regional tectonic evolution, fracture characteristics and log evaluation, crack formation and crack controlling factors, physical property and oil bearing evaluation, establish crack control factors of three-dimensional constraint body, reservoir 3D geological modeling. The analysis of tectonic evolution. The study focuses on three strata tectonic evolution of Tanggu uplift seismic interpretation under the sand. The sand based on the three section of the evolution Summary for the three act fault activity, a reverse uplifting and two wide exposure erosion process. The earliest sand three 5 submember sedimentary period, the main fault zone, the interaction of the central region in the study area have a Horst structure; Northwest Horst formed 1.5 tectonic graben. Then in the deposition period of the three 4 sub section of sand, the main activities within the area of fault - Tangbei fault activity from strong to weak. The seismic section can identify multiple flower like structure around the common faults in the area of dense, the dolomite reservoir cracks are of positive significance. The upper part of the sand deposition period, regional fault direction stress field change, the direction of change from sinistral dextral. The whole study area here is thin layer deposition thickness, mainly distributed in the northwest part of formation is not the whole joint Dongying Shahe Street group. Touch the upper part of the group, in most of the research area and the lower strata contact relations for angular unconformity, the study area between seismic events see obvious truncation phenomenon, is not difficult to see in this area by the early formation of subsidence center, reverse uplifting, long-term exposure and erosion process. Sand two the strata in the study area are missing, the sand on the sedimentary thickness, Dongying formation and the bottom surface of angular unconformity. Fracture characteristics and log evaluation. The research focuses on the fracture development characteristics of various aspects of recognition in the study area and the logging response model to calculate the fracture development. Statistics from the crack parameters coring section angle, fracture dip configuration was mainly high angle oblique (44.03%) and vertical (43.88%); most of the crack opening is less than 1mm (84.32%), and many micro cracks (mesh opening is less than 100~150 m); crack Slot length distributed in 0 ~ 10cm (67.05%); the main filler for filling cracks (35.68%, mainly for the crack closure), analcime and bitumen filling (31.65%). The routine / special logging on the fracture response may be manifested as AC increased, DEN decreased, CAL anomaly becomes smaller or larger. Can also be affected by some non fracture factors: lithology, porosity, mass deposition. So need to establish suitable for fracture logging interpretation model. Firstly, by screening each crack and the corresponding lithologic logging curve sensitivity, and ultimately determine the conventional logging curve sonic, density, hole diameter, acoustic time / / sonic density, natural gamma logging curve, according to their respective lithology making Yan Xinzhong spider diagram crack observation data point of the degree of development, describe the characteristics of fracture development, using multivariate statistical analysis by the line density, 5 kinds of logging and Matrix parameters the mathematical model for solving the reservoir logging response. Keep mathematical models of core observation data points to verify the establishment, finally obtained 71.43% recognition accuracy, that this model is reliable. The causes of cracks and crack controlling factors. Analysis of the characteristics of the coring observation, Tang 12C core fracture the cracks, according to the different stress state, the classification of causes, the research area mainly by structural fracture bedding fractures, karst seam less proportion, seepage ability weakened. According to Fang Feishi, asphaltene and filling karst, that the study area has developed four stages: crack layer parallel bedding fractures; conjugate oblique angle of 45 degrees seam, high angle oblique angle of 60 DEG seam; high angle / angle of 75 degrees -90 degrees vertical tension crack; high angle / vertical angle of 70 DEG -85 DEG seam. For crack control factors from lithology, Structure, diagenesis, analysis of overpressure. That the above factors have effect on crack, fracture and stress field effect is particularly obvious. The factors of the specific performance: lithology, tectonic movement in the area of weak, lithologic control effect on fracture distribution, fracture development degree with the increase of analcime dolomite. The increasing of the content; the construction aspect, the stress concentrated area, fault extending direction change at the end, and a plurality of fault elements, staggered fault block area, fractures; diagenesis, diagenesis fracture and dissolution as the research area of crack control; overpressure is positively correlated with the degree of development crack evaluation. Property and oil content. The argillaceous dolomite reservoir complex, physical model is especially important, is the foundation of crack model, how to consider the influence of various factors on the model, the establishment of this area, precision The standard model is very important. Because the dolomite reservoir porosity and permeability relationship is more complex, the shale content, the cracks cannot be ignored, so the decision in accordance with the matrix crack, the three part of the overall, established porosity, permeability, oil saturation model. Calculate the matrix porosity model, used for on the basis of three porosity calculation model, by determining the shale content of different lithology and rock skeleton parameters, the final test results in fitting correction, establish matrix porosity model. Crack porosity using dual laterolog resistance model for fracture porosity crack face test rate instead of through the core measurement, fitting and correction to establish fracture porosity model calculate the matrix permeability model. The use of the Tan Yandong formula, the experimental data correction, part of the permeability to crack Formula. Matrix model of oil saturation, by contrast to the classical Archie formula and considering the mud, the influence factors of crack parallel model, selected with experimental results. The former is calculated by studying the calculation of porosity, permeability and oil saturation, that Tanggu area three Shahe Street section of the lower part of the argillaceous dolomite reservoir porosity the main value is in the range of 7%-18%, the mean permeability below 1mD, mainly for low porosity, low permeability reservoir, lithology has correlation with the oil-bearing dolomite oil saturation is relatively high (45.61%), followed by argillaceous dolomite (33.81%). The establishment of crack control factors of 3D constrained crack model establishment. Need to consider how to control the crack distribution of geological factors as constraints, not just through the mathematical model for calculating the crack. This study first constructed using all levels of ups and downs to calculate the Large curvature surface, basic geological model and produce tectonic fractures in the area in the reduction on the stress field was simulated by using the finite element software Ansys on the ancient stage, calculating the crack stress value. According to the calculation results, the calculated value and energy value of rock rupture, considering multiple fracture parameters, with the the observation of core fracture linear density calibration multivariate regression fitting, establish a suitable area of the body crack prediction model for prediction of fracture distribution of the studied area. Prediction model of crack model is established, different from the single well core, logging data between wells in the unknown region using geostatistical interpolation method, but a comprehensive the lithology, data structure and other factors, and through the core, log correction, which has high reliability, can exist as a constraint reservoir modeling step. Reservoir fracture three-dimensional geological modeling. In the comprehensive data Combined treatment, comprehensive study of lithofacies, physical properties analysis model and drawing a lot of artificial oil, the establishment of Tanggu area three 5 sand sub section of argillaceous dolomite reservoir geological model, including the structure, lithology, physical property, net to gross, original oil saturation and crack distribution of six dimensional quantitative model methods. Lithology modeling using sequential indicator simulation lithology trend surface constraint; porosity modeling method was used to control the petrophysical facies unit. Geological modeling method of the multilevel model makes the lithology, porosity and permeability distribution is more reasonable, improve the accuracy of the research. The reservoir porosity lower limit model using the net to gross more than 6.6%, the permeability is greater than or equal to 12.5 * 10-3 m2. crack by DFN random crack model, fracture parameters and fracture modeling constrained control body obtained by the input statistics, which accord with the Geological knowledge. Reserves calculation results show that the simulation results of the Tanggu area geological reserves and actual geological reserves, geological model is established and reliable. Based on the above six parts of the study, the analysis of the characteristics of tectonic evolution, a fracture evaluation study area argillaceous dolomite reservoir, logging evaluation model of physical property and water oily, analysis of cracks and crack controlling factors, establish various control factors under three-dimensional constraint fine reservoir model, considers the advantage of development in this area is mainly concentrated in the central region of crack distance off base near 2 group near NW and NE faults cross areas, should be comprehensive study for the development of cracks with high pressure formation with the "dessert" area of oil and gas exploration.

【学位授予单位】：中国地质大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：P618.13

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