临兴地区山西组致密砂岩储层特征及成因探讨

发布时间：2018-11-13 14:46

【摘要】：鄂尔多斯盆地临兴地区具有巨大的天然气勘探开发潜力,是我国重要的致密砂岩气接替区,但其致密砂岩储层物性较差,储层致密化成因复杂,制约了该区致密砂岩气的产业化发展。根据X射线衍射、扫描电镜、阴极发光、铸体薄片、流体包裹体及分析化验等资料,对研究区山西组致密砂岩储层特征及成因进行了系统研究。结果表明:该区砂岩储层岩性主要为岩屑砂岩和次岩屑砂岩,储集空间以剩余原生粒间孔和次生溶蚀孔为主;砂岩储层物性较差,平均孔隙度为5.9%,平均渗透率为0.073 m D,排驱压力和饱和度中值压力均较高,孔喉半径小且分选性较差,孔隙结构参数总体较差。对致密砂岩储层成岩序列的划分表明,该区砂岩储层具有4个世代的黏土充填,多期次的黏土充填使储层逐渐致密化。孔隙度演化定量分析表明,该区储层质量主要受压实作用和胶结作用的影响,早成岩阶段压实作用造成17.1%的孔隙度损失,中成岩阶段压实作用和胶结作用造成22.9%的孔隙度损失,其中,胶结作用中的黏土矿物大量充填孔隙并堵塞喉道,不仅导致原生粒间孔隙变成了微小的晶间孔隙,而且使孔隙表面变得粗糙,迂回度增加,导致储层孔隙度和渗透率大大降低。
[Abstract]:Linxing area of Ordos Basin has great potential for natural gas exploration and development. It is an important tight sandstone gas replacement area in China, but its physical properties of tight sandstone reservoir is poor, and the formation of tight sandstone reservoir is complex. The industrial development of tight sandstone gas in this area is restricted. Based on the data of X-ray diffraction, scanning electron microscope, cathodoluminescence, thin sheet casting, fluid inclusion and analytical analysis, the characteristics and genesis of tight sandstone reservoir of Shanxi formation in the study area were systematically studied. The results show that the lithology of sandstone reservoir in this area is mainly lithic sandstone and secondary lithic sandstone, and the remaining primary intergranular pore and secondary dissolution pore are the main reservoir space. The sandstone reservoir has poor physical properties, average porosity of 5.9%, average permeability of 0.073 m D, high displacement pressure and saturation median pressure, small pore throat radius and poor sorting, and poor pore structure parameters. The diagenetic sequence of tight sandstone reservoir shows that the sandstone reservoir in this area has four generations of clay filling, and the multi-stage clay filling gradually densifies the reservoir. The quantitative analysis of porosity evolution shows that the reservoir quality in this area is mainly affected by compaction and cementation, and the porosity loss of 17.1% is caused by compaction during early diagenesis. Compaction and cementation in the middle diagenesis stage caused 22. 9% porosity loss. Among them, the clay minerals in the cementation process filled the pores and blocked the throat, which not only caused the primary intergranular pores to become tiny intergranular pores, Moreover, the pore surface becomes rough and the roundness increases, which results in the decrease of reservoir porosity and permeability.
【作者单位】：中国地质大学(北京)海相储层演化与油气富集机理教育部重点实验室;中国地质大学(北京)页岩气勘查与评价国土资源部重点实验室;中石化勘探分公司;中联煤层气有限责任公司;
【基金】：国家科技重大专项“大型油气田及煤层气开发”子课题“鄂尔多斯盆地石炭—二叠系煤层气勘探开发示范工程”(编号:2011ZX05062-001)
【分类号】：P618.13

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