【作者】 李维彦；

【导师】 郭海敏； 章成广；

【作者基本信息】 长江大学 ， 地球探测与信息技术， 2014， 博士

【摘要】 评价裂缝性储层一直是测井解释的难题,是测井解释方法研究的前沿论文,其关键是裂缝的识别和定量评价。井壁成像测井(FMI、EMI、STAR-Ⅱ)可提供高分辨率的井壁地层图像,从图像上可直观地识别出裂缝、孔洞等储层特征,目前已广泛应用于碳酸盐岩、火山岩等缝洞性复杂储层的识别与评价中。近年来国内外一些油田在裂缝识别和定量评价(主要是有效裂缝)以及相关应用上做了一些创造性工作,取得的成果已广泛应用于生产。但研究的重点在裂缝的开放有效性上,在充填裂缝充填性质和定量评价方面研究较少,裂缝和溶洞的充填特征与裂缝和溶洞的期次有直接关系,与古构造运动和古应力场也有一定关系,而古构造运动和古应力场确定裂缝的裂缝的延伸方位等重要参数,同时成像测井对裂缝和溶洞的充填特征也有一定的响应。开展该论文的研究对寻找裂缝性储层以及油田的勘探开发具有重要的意义。本文通过对研究区域岩心的详细观察,对研究区域内的裂缝、溶洞的类型和特征进行分析,该区域的裂缝为构造缝和溶蚀缝、充填裂缝和张开缝(半充填和未充填缝),充填裂缝充填物主要为泥质、黄铁矿和方解石。经过深度归位,对比分析成像测井资料和常规测井资料,总结古裂缝成像测井和常规测井响应特征,在此基础上对研究区域的成像测井资料进行处理,整理分析出该区域不同层位不同类型充填裂缝的纵、横向规律,结合区域地质规律和地层演化历史,对充填裂缝和溶洞的期次进行划分,并总结提出不同期次裂缝的测井响应特征。根据成像测井得到溶洞的处理结果,进而探索古裂缝与各个期次溶洞以及充填缝和古应力场的关系；最后根据岩石力学和地质力学原理研究探索现今应力场和古应力场研究方法。为了研究古应力场,进行岩石力学参数实验,在岩石力学实验数据分析基础上,提出研究区域岩石力学参数动、静转换模型和计算方法,处理计算出该区域岩石力学参数和主应力大小及方向,并总结奥陶系地层岩石力学特征和变化规律,探索现今现今应力场特征和变化规律,并根据充填缝的特征(充填类型、方向、充填物等)、充填缝的期次,结合该井区地层古地理运动规律和地质、地震研究成果以及研究区域人员地区经验,研究探索出古应力场特征和变化规律。通过研究,取得的成果为：1)研究区域的裂缝有构造缝和溶蚀缝、充填裂缝和张开缝(半充填和未充填缝),充填裂缝的充填物类型主要为泥质、方解石和黄铁矿充填(主要以泥质充填为主,其次是方解石充填)。裂缝的产状主要为垂直、斜交和水平三类。在这些发育的裂缝中。充填缝占78.6%,半充填和未充填的仅占14.9%和9.9%。裂缝宽度在0-1mm和1-2mm之间的裂缝最多。2)不同类型裂缝在电成像测井上有不同的响应;一般泥质充填裂缝和黄铁矿充填裂缝在图像上表现为暗色高导特征,与未充填裂缝相似,而方解石充填裂缝(方解石脉)则呈白色高阻特征。3)研究区域古裂缝大致由四种不同的构造运动在不同时期产生,古裂缝除成岩早期形成外大致分成三个期次：加里东晚期-早海西期、晚海西-印支期、燕山-喜山期,这说明裂缝的分布发育程度主要受构造作用控制。4)研究区域奥陶系碳酸盐岩地层中溶洞的表现形式复杂多样,既有未充填溶洞,也有充填溶洞。未充填溶洞的规模较小,洞径毫米～厘米级。充填溶洞从毫米～米级均有分布。大型溶洞多数为充填洞。充填溶洞充填物的成分变化很大,主要有泥质或砂泥质沉积、岩溶角砾岩及与洞穴水化学沉淀作用有关的层状或晶洞式碳酸盐岩。溶洞在形态上主要有斑点-斑块状中小型溶洞、片状缝洞、网状缝洞、层状大洞四大基本类型。5)研究区域奥陶系地层裂缝与溶蚀孔洞具有相互伴生的特点,在裂缝发育的地层溶洞也较发育。不同类型的裂缝经溶蚀可以形成不同类型的溶洞。单条裂缝经溶蚀可以形成沿裂缝面发育的串珠状小溶洞；多条裂缝交叉发育经溶蚀扩大可形成层状大溶洞。断裂发育带附近,尤其是多组断裂交汇的地带,往往能够形成缝洞共生的较好的储集层。第一期裂缝易经溶蚀形成片状溶洞；第二期共轭剪切缝相交处易形成溶洞；第三期裂缝易经溶蚀形成串珠状溶洞。6)研究区域弹性模量、剪切模量、体积模量整体上变化范围不大,分别为14.23-29.563GPa、5.759-12.483GPa、13.278-23.008GPa；三模量在纵向上,从良一至良四段依次增大,但在良二段其值变小,不同于整体的变化趋势；抗剪强度从良一至良四段依次减小,而抗剪强度整体变化不大,规律性不明显；因岩心岩性均为灰岩,泊松比在数值上变化不大,其值均出现在0.247～0.361范围内；从良一至良四段,泊松比整体变小的趋势,但在良三段出现最大值；同一口井岩石力学参数表现出明显的非均质性,各向异性明显,这反应出了工区地层的各向异性；7)根据古裂缝的期次和现今应力场的分析,井区古应力场的变化为：第一期裂缝多为泥质充填的微小缝,多为不规则,常见切割穿插现象。第二期裂缝对应的构造运动受昆仑地体和中天山地体的挤压作用,主要产生的NEE-SWW向张剪性裂缝指示了这期古应力的方向；第三期裂缝受南天山向南逆冲作用影响,裂缝走向说明该期次应力为NNW-SSE方向；第四期裂缝因塔里木地块先被挤压后被拉伸的复杂构造过程,因挤压不对称,形成旋区域应力场,裂缝反应出的古应力方向为NNE-SSW方向,同时裂缝的剪性力学特征也印证了右旋应力场。更多还原

【Abstract】 Fractured reservoir logging evaluation, the frontier subject of well logging, has always been a serious problem in log interpretation. The key is identification and quantitative evaluation of crackBorehole face imaging logging(FMI,EMI,STAR-Ⅱ) can provide borehole wall formation image with high resolution. We can directly identify reservoir characteristics such as cracks and holes. At present it has been widely used in the recognition and evaluation of the complex fracture-vuggy type reservoir like carbonate rock and volcanic rock. In recent years at home and abroad some oil fields have done creative work in the fracture identification and quantitative evaluation (mainly in effective crack) and related applications. Achievements has been widely used in production. But compared with fracture filling properties and quantitative evaluation, the focus of the study is on the cracks open effectiveness.Filling characteristics and the issues of crack and karst cave are directly related, as well as ancient tectonic movement and palaeostress field. And ancient tectonic movement and palaeostress field decide the extension azimuth of fracture and other important parameters.At the same time imaging logging has certain response to the filling characteristic of karst cave and cracks.Research on the subject has the vital significance on looking for fractured reservoir and the exploration and development of oil field.Based on detailed observations of the core and the analysis on crack, types and characteristics of karst cave of the area, the fissures of the area are structural fractures, dissolution fractures, filling cracks and open fissure (half filling and no filling). Fracture fillings are mainly clay, pyrite and calcite. After depth migration and contrast with imaging logging data and conventional log data, summarizing the different filling fracture imaging logging and conventional logging response characteristics, process the imaging logging data of the area, analysis the different layers in the region of different types of fracture law of vertical and horizontal.Combining with regional geological regularity and stratigraphic evolution history, dividing the filling fracture and cavity through issues, and summarizing the characteristics of logging response of fractures in different periods. According to the processing results of imaging logging, and then explore the relationship between ancient cracks, the karst cave in each issues,the filled fracture and palaeostress field; At last according to the principle of rock mechanics and geomechanics study the methods to explore the current stress field and palaeostress field.In order to study the palaeostress field, rock mechanics parameters experiments are conducted. Based on the analysis of the experimental data of rock mechanics, dynamic and static conversion model of the rock mechanics parameters in the research area and calculation methods are proposed. Processing the rock mechanics parameters and the principal stress magnitude as well as direction and then summarizing the Ordovician strata of rock mechanics characteristics and change laws. To explore the present stress field characteristics and change rules, and according to the characteristics of filled fracture (filling type, direction, fillings) and filled fracture issue, combined with the ancient geographical law of motion and the geological, seismic research and the personnel experience of the area, we can explore the characteristics of the palaeostress field and the change rule.The following achievements are obtained by the research:1) The cracks of the research area include structural fractures dissolution fissure, filling cracks and open fracture (half filling and no filling), type of fracture fillings are mainly argillaceous, calcite and pyrite (mainly argillaceous filling, followed by calcite filling). Crack occurrence are mainly vertical, diagonal and horizontal. In the development of the cracks, filling seam for78.6%, half filling and no filling for only14.9%and9.9%. Crack width is most in from0-1mm to1-2mm.2) Different types of cracks on the electric imaging logging have different response:Generally, argillaceous filling and pyrite filling cracks on the images show the dark high conductivity characteristics, similar to no filling crack. While calcite (calcite vein) filling cracks have a white high resistance characteristics.3) The ancient crack in research area roughly made up of four different tectonic movement in different periods, the cracks in addition to the early diagenetic formation are roughly divided into four periods:the early diagenesis, late caledonian to early hercynian, late hercynianindosinian period, yanshan and Himalayan period, it shows that the distribution of fracture development degree is mainly controlled by tectonic action.4)The ordovician carbonate formation of the reaearch area contains both unfilled caves and filled ones, and the manifestations of the caves are complex and diverse. The scale of unfilled caves whose diameter is on the level of millimetre to centimetre are small, while the diameter of filled ones fluctuates from millimetre to meter. Most of the large caves are filled. The ingredients of filled caves change significantly, which mainly are argillaceous or arenaceouspelitic sediments, karst breccia and miarolitic or layered carbonate rocks which are related to chemical precipitation of the cavern water. In the form of caves, there are mainly four basic types---mottled-patchy small and medium sized cave, flaky fracture cave, mesh fracture cave and layered large cave.5)The Ordovician cracks and solution cave are mutually associated in the area. Solution cave is developed in the fissure strata and different types of caves can be formed by the erosion of different types of fissures. Single crack can develop the beadlike caves by erosion along the fracture surface; more cracks’cross development can form layered caverns by corrosion expansion. Near the fracture zone, especially the Multiple sets of fault zone, often can form better reservoir with both fissures and caves. The schistose cave can be easily formed by the first phase’s fractures through corrosion. The second phase of the conjugate shear joints can form caves while The third crack can easily develop string of beads shaped caves by the corrosion.6)Elasticity modulus, Shear modulus and bulk modulus of the study area on the whole range is not big, respectively is14.23～29.563GPa,5.759～12.483GPa,13.278～23.008GPa; Three modules in the longitudinal from the Liang one to the Liang four section increased in turn, but it becomes smaller in the Liang two section which is different in the whole change tendency; The shear strength from the Liang one to the Liang four section reduced in turn, but the shearing strength on the whole range is not big and the regularity is not obvious; Because the core sample is limestone, the Poisson’s ratio changes not in a big way in the value, its value appears in0.247～0.361scope; From the Liang one to the Liang four section, the Poisson’s ratio has a small tendency on the whole, but appears the maximum value in the Liang three section; With a well rock mechanics parameters shows obvious heterogeneity and anisotropy, which reflects work area formation anisotropy 7) According to the issue of old fracture and the analysis of the current stress field, the change of ancient stress field in wellblock are as follows:the first phase of the cracks are tiny seam, argillaceous filling is irregular, more common cutting phenomenon. Squeezing action of the Kunlun Mountain terrane and transit body corresponding second stage fracture by tectonic movements, mainly resulting NEE-SWW to Zhang shear fractures which indicates the direction of the ancient stress; Phase three crack affected by the south tianshan mountain to the south thrust action, fracture trend shows that the issue of stress is NNW-SSE direction; Fourth crack due to the complexity of the Tarim block was first constructed extrusion process after stretching, due to compression asymmetry, spin regional stress field was formed, the ancient stress direction which fracture reflects is NNE-SSW direction, shear mechanical properties of the cracks at the same time also verified the right-lateral stress field.更多还原