伊拉克哈勒法耶油田白垩系Mishrif组碳酸盐岩储层成因及分布评价

发布时间：2018-08-08 11:21

【摘要】：伊拉克哈勒法耶油田是以生物碎屑灰岩为主的巨型油田,Mishrif组是最主要的产油层位,沉积厚度大,发育滩相和非滩相两类储层,两类储层成因不同,储集性能有明显差异。综合利用岩石薄片观察、扫描电镜、阴极发光、碳氧同位素、物性测试等技术资料对岩石学特征、沉积特征、成岩作用及储层特征进行研究,明确储层发育控制因素,在此基础上开展滩相和非滩相储层成因类型研究,提出Mishrif组储层成因类型划分方案。根据不同成因类型储层物性和孔隙结构特征的差异开展不同成因类型储层分类评价研究,将滩相储层划分为四类,非滩相储层划分为三类。同时,在单井储层分布基础上,综合考虑沉积微相类型、储层成因类型和有效储层厚度等地质因素,开展Mishrif组优质储层平面分布评价研究。Mishrif组发育在一个二级层序内,可进一步划分为2个三级层序和4个四级层序,Mishrif组层序地层发育主要受海平面变化控制,横向层序对比性好、展布稳定,该组含油层在海侵体系域和高位体系域均有发育。研究区碳酸盐岩时代较新、生物繁盛,根据邓哈姆分类的支撑类型分为颗粒灰岩和泥晶灰岩两大类,依据沉积水动力条件的差异将颗粒灰岩分为生屑/砂屑灰岩和有孔虫灰岩,以生屑/砂屑、有孔虫骨架和泥晶基质为三个端元将研究区岩石类型分为生屑/砂屑灰岩、有孔虫灰岩和泥晶灰岩三大类,进一步结合颗粒含量的多少细分为6小类,共计9种岩石类型,并对不同岩石特征进行了研究,同时在岩性测井识别的基础上开展不同岩性的分布特征,其中生屑/砂屑灰岩类在Mishrif组分布广泛,其中MB2段是整个Mishrif组生屑/砂屑灰岩分布最为集中的层段,厚度约50m;泥晶灰岩主要分布在MB1段,以薄层状分布在生屑/砂屑灰岩之间。Mishrif组发育在碳酸盐台地背景下,通过对沉积特征的研究表明发育局限台地、开阔台地和台地边缘三种沉积亚相。局限台地发育生屑滩和台内洼地两类微相,生屑滩与灰泥呈频繁互层状分布,局部可见少量搬运改造后的生物碎屑,台内洼地和缓坡相以泥晶灰岩沉积为主,优质储层不发育。开阔台地发育滩间和台内生屑滩沉积,沉积水动力条件比局限台地生屑滩强。台地边缘发育多种沉积微相及其组合,其中介屑滩+滩间+厚壳蛤碎屑滩+生屑滩+厚壳蛤碎屑滩组合储集性能最好。Mishrif组发育滩相和非滩相两类储层,滩相储层主要发育在台地边缘和开阔台地相,储集岩类包括介屑灰岩、厚壳蛤碎屑灰岩、砂屑灰岩、生屑泥粒灰岩、生屑粒泥灰岩等。储集空间以粒间孔和铸模孔为主,发育多种孔隙组合类型,其中生物格架孔仅在厚壳蛤碎屑滩储层段发育。滩相储层孔隙度、渗透率较高,属高孔、中-高渗储层。孔隙结构发育大喉道与小喉道两类,大喉道占比少但却对渗透率起控制作用,渗透率最高达到765×10-3μm2。非滩相储层主要发育在局限台地相,储集岩颗粒较细,孔隙类型组合以体腔孔、溶孔和铸模孔为主,孔隙度1.67%~25.35%,平均15%,渗透率0.01×10-3μm2~72.14×10-3μm2,平均8.47×10-3μm2,为中高孔、中低渗储层,孔喉分布以中等喉道为主,约占比65%。Mishrif组层间隔夹层厚度较大、横向分布较稳定、区域连续性好;层内隔夹层普遍厚度较小,连续性差。总的来说,Mishrif组储层表现出层内较弱、层间稍强的非均质性特征。通过对Mishrif组储层特征的研究,认为沉积相是控制研究区碳酸盐储层的根本因素(成岩作用主要为同生期的溶蚀作用和少量的胶结作用,其也受控于沉积相)。在储层特征及主控因素研究基础上,提出Mishrif组不同储层成因类型划分方案:根据沉积微相、岩石类型和优势孔隙类型组合的差异,将研究区滩相储层分为台缘滩储层和台内滩储层,其中台缘滩储层包括砂屑灰岩储层、似球粒灰岩储层、介屑灰岩储层、厚壳蛤碎屑灰岩储层及生屑灰岩储层;台内滩主要为生屑颗粒成分复合的灰岩储层,共计2大类、4小类成因类型;通过对非滩相储层特征研究及成因分析,结合岩石类型及优势孔隙类型将非滩相储层划分为2类、3小类成因类型,其中台缘斜坡、滩间(洼)地的生屑有孔虫粒泥灰岩相、缓坡及台洼中的有孔虫灰岩相和有孔虫泥晶灰岩相为较好的储层。在储层成因类型研究基础之上,结合不同成因类型储层物性和孔隙结构特征,将滩相储层划分为Ⅰ、Ⅱ类,其中Ⅰ类储层为台缘滩相发育带,在MB2段最为发育,特别是在介屑滩、厚壳蛤碎屑滩和砂屑滩发育部位;滩相Ⅱ类储层为似球粒滩、台内滩,在MA、MB2和MC1段均有发育,分布最广;将非滩相储层划分为Ⅱ、Ⅲ类,其中Ⅱ类储层主要发育在MB1下段局部生屑滩和台缘斜坡、滩间(洼)地的生屑有孔虫粒泥灰岩相发育部位;Ⅲ类储层主要为缓坡及台洼中的有孔虫灰岩相和有孔虫泥晶灰岩相发育部位,非滩相Ⅳ类为非储层,主要发育在缓坡、台洼相,整体厚度较薄,岩性以泥晶灰岩为主,含少量致密粒泥灰岩。通过单井储层分布和储层平面分布研究认为优质储层为滩相I+II类储层和非滩相II类储层,主要发育在生屑滩、粒屑滩相灰岩及有孔虫发育的非滩相灰岩区。
[Abstract]:The Hale Faye oilfield in Iraq is a giant oil field mainly with bioclastic limestone. The Mishrif group is the most important oil producing layer, with large thickness of deposit and two types of reservoirs with developed beach and non shoal facies. The formation of two types of reservoirs is different and the reservoir performance is different. On the basis of the study of petrological characteristics, sedimentary characteristics, diagenesis and reservoir characteristics, the control factors of reservoir development are clearly defined. On this basis, the genetic types of the shoal and non shoal facies are studied, and the classification scheme of the formation types of the Mishrif formation is put forward. The differences in the characteristics of reservoir physical properties and pore structure of different genetic types are also proposed. In the study of different types of reservoir classification and evaluation, the shoal facies are divided into four types, and the non shoal reservoirs are divided into three types. At the same time, on the basis of the distribution of single well reservoir, the type of sedimentary microfacies, the reservoir genesis type and the effective reservoir thickness are considered, and the evaluation of the.Mishrif group of the high quality reservoir plane distribution in the Mishrif group is carried out. It is developed in a two order sequence, which can be further divided into 2 three order sequences and 4 four order sequences. The sequence stratigraphic development of group Mishrif is mainly controlled by sea level change, the transversal sequence contrast is good and the distribution is stable. According to Dunham classification, the support types are divided into two major categories: granular limestone and muddy limestone. According to the difference of the hydrodynamic conditions, the grained limestone is divided into raw chip / sand clastic limestone and foraminifera limestone, and three endpoints, including the raw debris / sand debris, the foraminifera skeleton and the mud crystal matrix, are divided into the raw debris / sand clastic limestone and the foraminifera limestone. Three types of muddy limestone, which are further combined with the number of particles in 6 small categories, are divided into 9 types of rock, and the characteristics of different rocks are studied. At the same time, the distribution characteristics of different lithology are carried out on the basis of lithologic logging recognition. Among them, the debris / dust limestone is widely distributed in the Mishrif group, and the MB2 section is the whole Mishrif group. The most concentrated layer of clump / clastic limestone is about 50m, and the muddy limestone is mainly distributed in the MB1 section, and the.Mishrif group between the clump and the clastic limestone is developed under the background of the carbonate platform. By the study of the sedimentary characteristics, three sedimentary subfacies in the limited platform, the open platform and the edge of the platform are found. There are two types of microfacies in the developmental and platform depressions, and the slime and plaster are frequently interbedded, and a small amount of reformed bioclasts can be seen, and the low-lying and gentle slope facies are mainly composed of muddy limestone deposits, and the high quality reservoirs are not developed. A variety of sedimentary microfacies and their assemblages are developed on the edge of the platform. Among them, the combination of the chip beach + interbank + thick shell clam clastic beach + raw clam clam clam clam flats is the best.Mishrif formation and non shoal facies, and the beach facies reservoirs are mainly developed at the edge of the platform and the open platform facies, and the reservoir rocks include the mesoporous limestone and the thick clam. Clastic limestone, sand clastic rock, bioclastic limestones and bioclastic marl, and so on. The reservoir space is mainly composed of intergranular pore and mold hole, and many kinds of pore combination are developed. Among them, the biogrid hole is developed only in the clam clam reservoir section of thick clam. The porosity and permeability of the reservoir are high, and the pore structure is high and medium high permeability reservoir. The pore structure develops large throat and the pore structure is developed with large throat and large throat. There are two types of small larynx. The large throat is less than the permeability, but the permeability is controlled by the permeability. The permeability is up to 765 x 10-3 mu m2., the reservoir is mainly developed in the limited platform facies, the reservoir rock particles are fine, the pore type is composed of the body cavity, the porosity and the mold hole are mainly, the porosity is 1.67%~ 25.35%, the average is 15%, and the permeability is 0.01 * 10-3, m2~72.14 * 10-3 Mu m2, The average 8.47 x 10-3 Mu M2 is medium and low permeability reservoir, and the pore throat distribution is mainly medium throat. The thickness of the interval interlayer of the 65%.Mishrif group is larger, the transverse distribution is more stable, the continuity of the region is good, the thickness of the interlayer is small and the continuity is poor. In general, the reservoir of the Mishrif group shows a weak layer in the layer and a slight heterogeneity between the layers. Through the study of the reservoir characteristics of the Mishrif group, it is considered that the sedimentary facies are the fundamental factors to control the carbonate reservoirs in the study area (the Cheng Yan action is mainly the dissolution of the same period and a small amount of cementation, and it is also controlled by the sedimentary facies). On the basis of the reservoir characteristics and the main controlling factors, the genetic types of different reservoirs in the Mishrif group are put forward. Division scheme: according to the difference of sedimentary microfacies, rock types and the combination of dominant pore types, the study area is divided into the platform margin reservoir and the platform inner beach reservoir, in which the platform margin reservoir includes the sand clastic reservoir, the pellet limestone reservoir, the mesoporous limestone reservoir, the clam clastic limestone reservoir and the clastic limestone reservoir, and the main platform of the platform is the flat beach. There are 2 types of limestone reservoirs composed of the composition of raw debris particles, and 4 small types of genetic types. Through the study on the characteristics of the non shoal facies and the genetic analysis, the non shoal facies are divided into 2 types and 3 types of genetic types, including the rock types and the dominant pore types, including the platform margin slope and the interbank (depression) area of the grain marl facies, the gentle slope and the platform depression. The foraminifera limestone and foraminifera mudstone facies are good reservoirs. On the basis of the genetic types of reservoir formation and the characteristics of reservoir physical properties and pore structure of different genetic types, the shoal facies are divided into type I and class II, among which, the type I reservoir is the platform margin Development Zone, and the most developed in the MB2 section, especially in the mesoporous beach and thick clam. The formation of clastic beach and sand flats; the type II reservoir of the shoal facies is like pellet beach, and the inner beach is developed and distributed most widely in MA, MB2 and MC1 segments; the non Shoal Reservoir is divided into II and III, of which the second kind of reservoir is mainly developed in the local crumb and edge slope of the lower MB1 segment, and the development part of the pellet marl facies in the interbank (depression); The reservoir is mainly the foraminifera limestone and the foraminifera muddy facies development parts in the gentle slope and the platform, the non shoal type IV is non reservoir, which mainly develops in the gentle slope, the platform depression is thin, the lithology is mainly composed of muddy limestone and contains a small amount of dense grained marl. It is a type I+II reservoir of beach facies and a type II reservoir of non-beach facies, mainly developed in the non-beach facies limestone areas of bioclastic beach, granular beach facies limestone and foraminifera.
【学位授予单位】：成都理工大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：P618.13

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