鄂尔多斯盆地奥陶系不同组构碳酸盐岩埋藏溶蚀实验

发布时间：2018-05-28 10:45

  本文选题：碳酸盐岩 + 埋藏溶蚀　； 参考：《沉积学报》2017年02期

【摘要】：鄂尔多斯盆地奥陶系碳酸盐岩储层受埋藏溶蚀作用控制明显,而地层深部复杂的水—岩反应造成埋藏溶蚀研究难度较大,并进而影响了储层的评价与预测。分别利用CO_2溶液和乙酸溶液为流体介质进行溶蚀模拟实验,探讨埋藏条件下温度、压力、流体等因素对不同矿物及组构碳酸盐岩溶蚀作用的影响。结果表明:1)随着温度与压力升高,碳酸盐岩样品在乙酸溶液中的溶解速率均相应提高,在CO_2溶液中的溶解速率则先增加后减小,且在110℃~130℃区间内溶蚀速率最大;深埋藏环境下,各岩类溶蚀速率差异减小,并趋于一致;2)岩石矿物成分和组构,原岩初始孔隙度的大小及其连通关系,以及晶体的产状对成岩后期的埋藏溶蚀作用也具有重要的影响。不溶组分含量低、颗粒/灰泥比高、矿物成分复杂的碳酸盐岩由于组构选择性溶蚀作用而更易被溶蚀;碳酸盐岩的溶蚀速率随方解石含量的增加而增加,但深埋藏环境下,矿物成分含量差异对溶蚀速率的影响作用减弱;硬石膏与白云岩相伴生时,可优先溶蚀形成膏模孔,并促进白云石的溶解,改善储层效果。不同岩性,总体上灰岩较白云岩及过渡岩类更易发生埋藏溶蚀作用。结合研究区实际地质条件分析,砂屑灰岩、膏质白云岩等埋藏溶蚀强度较大,通过对原岩早期组构选择性溶蚀形成孔隙的继承和调整,叠加埋藏期岩溶作用后,可形成规模优质储层。
[Abstract]:Ordovician carbonate reservoirs in Ordos Basin are obviously controlled by buried dissolution, but it is difficult to study buried dissolution due to complex water-rock reactions in the deep strata, which further affects the evaluation and prediction of reservoirs. In this paper, CO_2 solution and acetic acid solution were used as fluid medium to study the effects of temperature, pressure, fluid and other factors on dissolution of different minerals and fabric carbonate rocks. The results show that with the increase of temperature and pressure, the dissolution rate of carbonate rock in acetic acid solution increases and then decreases in CO_2 solution, and the dissolution rate is the highest in the range of 110 鈩，

本文编号：1946407