鄂尔多斯盆地上古生界煤成气低孔渗储集层次生孔隙形成机理--乙酸溶液对钙长石、铁镁暗色矿物溶蚀的模拟实验  

Secondary porosity formation of Upper Paleozoic low porosity-permeability coal-formed gas reservoirs,Ordos Basin:Simulation on dissolution of anorthite and dark-colored femic minerals in acetic acid solution

作　　者：张文正[1] 杨华[2] 解丽琴[1] 黄思静[3] 杨奕华[1] 

机构地区：[1]中国石油长庆油田公司勘探开发研究院,710018 [2]中国石油长庆油田公司 [3]成都理工大学

出　　处：《石油勘探与开发》2009年第3期383-391,共9页Petroleum Exploration and Development

基　　金：国家自然科学基金项目(40773028);中国石油长庆油田分公司2003-2004年度重点科研项目(3)

摘　　要：通过不同温压条件下乙酸溶液对钙长石、辉石和角闪石的溶蚀模拟实验,探讨成岩过程中长石矿物及长石砂岩的溶蚀特征和次生孔隙、自生矿物的形成机理,进而达到评价和预测有利储集层发育带的目标。实验研究表明,钙长石、辉石和角闪石均表现出较易被溶蚀的特征,主要组成元素中Ca最易被溶出,而Al和Si最难溶出。温度增高可显著提高Ca、Si、Mg的溶出量和矿物的总溶蚀量,总体上表现为正温度效应。Al表现出特殊的溶解特性,在低温阶段(50～75℃)的溶出系数高于Si,呈正温度效应,而在高温阶段(100～125℃)的溶出量为低—很低,并且表现为负温度效应。沉淀析出是造成高温条件下Al溶出量低的主要原因。乙酸的络合作用有助于较低温度成岩阶段铝硅酸盐溶蚀作用过程Al的迁移,但并不能解决高温成岩阶段铝硅酸盐溶解时Al的迁移问题。An experimental device and flowchart were designed to carry out experiments simulating dissolution of anorthites, pyroxenes and amphiboles in acetic acid solution under different temperature and pressure conditions. Anorthites, pyroxenes and amphiboles all show features of erosion and dissolution, with Ca displaying the highest dissolution and Al and Si displaying the lowest dissolution among the major constituent elements. With increase in temperature, the dissolution rates of elements like Ca, Si, and Mg as well as the total dissolution amount of minerals can be remarkably increased, exhibiting a positive temperature effect. However, the dissolution of Al appears to be special, at 50--75 ℃ its dissolution coefficient is higher than that of Si, exhibiting a positive temperature effect, while at 100--125 ℃ its dissolution amount turns out to be low, exhibiting a negative temperature effect. Precipitation can mainly account for the low dissolution of Al at high temperatures. Complexation of acetic acid appears to be favorable for Al migration during the dissolution of alumosilicates at the lower temperature rock forming stage, but cannot account for Al migration at the higher temperature rock-forming stage.

关 键 词：钙长石 铁镁暗色矿物 乙酸溶液 溶蚀作用 上古生界 鄂尔多斯盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]