华庆地区延长组长8砂岩储层沉积与成岩作用

针对华庆地区储层物性普遍偏低、邻近井区物性差异较大等特点,从沉积作用和成岩作用这2个方面综合探讨了该区储层物性差异的原因。通过岩心观察、铸体薄片、扫描电镜等,深入研究了华庆地区长8储层的沉积与成岩作用。结果表明：多物源沉积是华庆地区长8储层物性平面差异明显的重要起因;北东物源的沉积储层特征整体好于西南物源;成岩作用对储层物性的影响参差不一。最后,根据成岩作用类型对储层孔隙结构的影响,将成岩作用划分为3种组合：绿泥石薄膜胶结及溶蚀组合是研究区的优势组合,具有相对较高的孔渗特征;强压实及碳酸盐胶结组合严重破坏了储层的物性;高岭石/伊利石胶结及溶蚀组合对储层物性的影响介于前两者之间。

Sedimentation and diagenesis of Chang 8 sandstone reservoir of Yanchang Formation in Huaqing area

The reservoir in Huaqing area is characterized by poor properties and large differences of properties between adjacent wells. This paper analyzed the major factors of resulting in differences of reservoir properties from the two aspects of sedimentation and diagenesis. By using core observation, cast thin section and scanning electron microscope, this paper studied the sedimentation and diagenesis of Chang 8 reservoir in Huaqing area. The result shows that multi-source of deposition is an important cause of obvious differences of Chang 8 reservoir properties in Huaqing area, the sedimentary quality from the northeast is better than that from the southwest in respect for sorting coefficient and average pore size, and the effect of diagenesis on reservoir properties is different. Based on the effect of diagenesis on reservoir properties, three combinations of diagenesis are divided as follows： dissolution and chlorite rim cementation is the best combination with relatively high porosity and permeability, the combination of strong compaction and carbonate cementation severely damaged the reservoir properties, and the effect of the combination of kaolinite or illite cementation and dissolution is moderate.