Abstract

Take the Cambrian Xiaoerblak Formation in the Keping (Kalpin) outcrop area as an example, a 28 km reservoir scale geological model was built based on description of 7 profiles, observation of more than 1000 thin sections, petrophysical analysis of 556 samples and many geochemical tests. The Xiaoerblak Formation, 158–178 m thick, is divided into three members and 5 submembers, and is composed of laminated microbialite dolomite (LMD), thrombolite dolomite (TD), foamy-stromatolite dolomite (FSD), oncolite dolomite (OD), grain dolomite (GD)/crystalline dolomite with grain ghost and micritic dolomite (MD)/argillaceous dolomite. The petrology features show that its sediment sequence is micro-organism layer – microbial mound/shoal – tidal flat in carbonate ramp background from bottom up. The reservoir has 5 types of pores, namely, framework pore, dissolved vug, intergranular and intragranular dissolved pore and intercrystalline dissolved pore, as main reservoir space. It is found that the development of pore has high lithofacies selectivity, FSD has the highest average porosity, TD, OD and GD come second. The reservoir is pore-vug reservoir with medium-high porosity and medium-low permeability. The dolomite of Xiaoerblak Formation was formed in para-syngenetic to early diagenetic stage through dolomitization caused by seawater. The reservoir development is jointly controlled by sedimentary facies, micro-organism type, high frequency sequence interface and early dolomitization. The class I and II reservoirs, with an average thickness of 41.2 m and average reservoir-stratum ratio of about 25.6%, have significant potential. It is predicted that the microbial mounds and shoals in the middle ramp around the ancient uplift are the favorable zones for reservoir development.

中文翻译：

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塔里木盆地柯坪露头区寒武纪小二叠统储层地质模型及其意义

摘要

以柯坪（卡尔平）露头地区的寒武纪肖尔布拉克组为例，根据7个剖面的描述，1000多个薄片的观测，556份样品的岩石物理分析和许多地球化学试验，建立了一个28 km的储层规模地质模型。 。158-178 m厚的肖尔布拉克地层分为3个成员和5个子成员，由层状微白云岩白云岩（LMD），血栓石白云岩（TD），泡沫-叠层石白云岩（FSD），on石白云岩（OD），晶粒白云岩（GD）/结晶白云岩，带有晶粒幻影和微晶白云岩（MD）/泥质白云岩。岩石学特征表明，其沉积层序为微生物层-微生物丘/浅滩-由下而上的碳酸盐斜坡背景下的潮滩。储层有5种孔隙，即骨架孔隙，溶洞，粒间和粒内溶孔以及晶间溶孔为主要储集空间。结果表明，孔隙的发育具有较高的岩相选择性，FSD的平均孔隙度最高，TD，OD和GD位居第二。储层为中高孔隙度，中低渗透率的孔洞型储层。肖尔布拉克组白云岩是由海水引起的白云石化作用在准同生至成岩早期形成的。储集层发育受沉积相，微生物类型，高频层序界面和早期白云石化共同控制。I级和II级储层的平均潜力为41.2 m，平均储层与地层之比约为25.6％。