论文部分内容阅读
四川盆地元坝中部地区须家河组储层属于低孔、低渗透储层,裂缝对其天然气的富集及产量具有重要影响。根据岩心观测、野外露头调查及测井解释等研究成果,综合区域构造演化分析,对元坝中部地区须家河组储层裂缝的发育特征及控制因素进行了系统研究,结果表明,研究区以发育构造成因的低角度剪切裂缝和高角度剪切裂缝为主。裂缝的走向主要为北西西和北东东向,充填程度较低,有效性较好。裂缝的发育受构造应力、构造位置、岩性和岩层厚度等因素控制。随着与断层距离的增大,裂缝密度呈逐渐递减的趋势;中、细砂岩裂缝最为发育,粉砂岩、粗砂岩、砾岩及泥质岩类裂缝发育程度相对较差;随着岩层厚度的增大,裂缝间距变大,发育程度明显降低。研究区裂缝发育区的预测结果表明,裂缝发育区主要位于近南北、北西向展布的大型断裂带附近,主要包括中部元陆1—元陆2井区(不包括元陆2井位置)、元坝5—元陆5—元坝9井区和东部元坝4—花52井区、元陆3井区。
The Xujiahe Formation reservoir in the central part of Yuanba Basin in Sichuan Basin belongs to low-porosity and low-permeability reservoirs, and fractures have an important influence on the enrichment and yield of natural gas. Based on the research results of core observation, field outcrop investigation and logging interpretation, and comprehensive analysis of regional tectonic evolution, the developmental characteristics and controlling factors of the Xujiahe Formation fractures in the central part of Yuanba are systematically studied. The results show that Low-angle shear fractures and high-angle shear fractures dominated the genesis of the tectonic setting. The fractures are mainly North and West and North East-East with low filling degree and good effectiveness. The development of cracks is controlled by tectonic stress, structural position, lithology and rock thickness. With the increase of the distance to the fault, the fracture density gradually decreases. In the medium and fine sandstone, the fractures are the most developed, and the development of siltstone, coarse sandstone, conglomerate and mudstone are relatively poor. With the thickness Increase, the crack spacing becomes larger, the development of significantly reduced. The prediction results of the zone of fracture development in the study area show that the zone of fracture development is mainly located near the major fault zones spreading in the north, south and northwest direction, and mainly includes the Central Yuanlou 1-Yuan Lu 2 well (excluding the location of the Yuanlu-2 well) Yuanba 5-Yuan Lu 5-Yuanba 9 well and the eastern Yuanba 4-Hua 52 well, Yuan Lu 3 well.