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.%Burial dissolution is one of the important factors which control the development of dolomite reservoirs, but its effect on porosity is still not clear, which restricts the evaluation and exploration of burial dissolution dolomite reservoirs. This study took arene dolomites, stromatolite dolomites and thrombolite dolomites of the Lower Cambrian Xiaoerbulake Formation in the Tarim Basin as an example, used 0.2%acetic acid solution instead of organic acids of burial environment, carried out dissolution simulation experiments of dolomite reservoirs in the condition of high tem?perature and high pressure. The results showed three different samples' porosity was improved in different tempera?tures and pressures, but their permeability increased exponentially. The reservoir space of arene dolomites changed from pores to pores and vugs, while the reservoir space of stromatolite dolomites and thrombolite dolomites changed from pores to pores and solution fractures. It implied that organic acid had a strong solubility to dolomites, and the initial pore structure controlled the final reservoir space type. With the dissolution from homogeneous to heterogeneous, the vugs and solution fractures developed heterogeneously, and reservoir connectivity was partly improved. So, burial dissolution is of great importance in reforming the permeability of dolomite reservoirs.
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