基于埋藏溶蚀模拟实验的白云岩储层孔隙效应研究——以塔里木盆地下寒武统肖尔布拉克组为例

发布时间：2018-01-29 12:30

本文关键词： 埋藏溶蚀模拟实验孔隙效应白云岩储层肖尔布拉克组塔里木盆地　出处：《石油实验地质》2017年05期 　论文类型：期刊论文

【摘要】：埋藏溶蚀作用是白云岩储层发育的控制因素之一,但其对储层的孔隙效应不清,从而制约埋藏溶蚀型白云岩储层的评价与勘探。以塔里木盆地下寒武统肖尔布拉克组白云岩为例,优选藻砂屑白云岩、叠层石白云岩和凝块石白云岩3种最常见的岩相为样品,用0.2%的乙酸溶液代表埋藏环境中的有机酸,开展高温高压条件下、开放连续流动体系中的储层溶蚀模拟实验。实验结果显示,不同温压条件、不同岩相特征样品的孔隙度都有所增大,但渗透率呈指数级增大;藻砂屑白云岩的储集空间类型从孔隙型演变为孔隙—孔洞型,叠层石白云岩和凝块石白云岩的储集空间类型从孔隙型演变为溶孔—溶缝型。由此说明在埋藏环境中,有机酸对白云岩具有较强的溶蚀性,白云岩储层的初始孔隙结构控制着最终储集空间类型;埋藏溶蚀作用从开始相对均匀溶蚀逐渐转变为非均匀溶蚀,导致溶孔、溶缝非均质发育,局部孔隙间连通性变好。因此埋藏溶蚀作用对改善白云岩储层渗透率的贡献更大。
[Abstract]:Buried dissolution is one of the controlling factors for the development of dolomite reservoir, but its pore effect on the reservoir is unclear. Therefore, the evaluation and exploration of buried solution dolomite reservoir are restricted. Taking the dolomite of Lower Cambrian Sholburak formation in Tarim Basin as an example, the algae-sand dolomite is selected. The three most common lithofacies of stromatolite dolomite and condensed dolomite are used as samples and 0.2% acetic acid solution is used to represent the organic acids in the buried environment under the conditions of high temperature and high pressure. Simulation experiment of reservoir corrosion in open continuous flow system. The results show that the porosity of samples with different lithofacies characteristics increases under different temperature and pressure conditions, but the permeability increases exponentially. The reservoir space type of algae-sand dolomite evolves from pore type to pore-pore type. The reservoir space types of stromatolite dolomite and condensed dolomite have changed from pore type to dissolving porosity type, which shows that organic acid has strong dissolution to dolomite in buried environment. The initial pore structure of dolomite reservoir controls the final reservoir space type. The buried dissolution gradually changed from relatively homogeneous dissolution to heterogeneous dissolution, resulting in the development of dissolution pore and dissolving joint heterogeneity. Therefore, buried dissolution contributes more to the improvement of dolomite reservoir permeability.
【作者单位】：中国石油集团碳酸盐岩储层重点实验室;中国石油杭州地质研究院;中国石油塔里木油田分公司;
【基金】：国家重大科技专项(2016ZX05004002) 中国石油天然气股份有限公司科技部项目(2016B-04)资助
【分类号】：P618.13
【正文快照】： 3.中国石油塔里木油田分公司,新疆库尔勒841000)目前对于白云岩储层的成因,主要认为沉积相、层序界面和埋藏(热液)溶蚀作用是储层发育的主控因素[1-9]。其中优势相带控制基质孔规模发育,层序界面控制暴露面之下洞穴、溶孔和溶缝规模发育的机理明确。对于埋藏(热液)溶蚀作用,勘

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