富县探区长8段致密油藏特征及主控因素

1.陕西延长石油集团,陕西 西安 710075; 2.西北大学 地质学系,陕西 西安 710069; 3.大陆动力学教育部 重点实验室,陕西 西安 710069; 4.陕西延长石油集团有限责任公司 研究院,陕西 西安 716000

长8段; 致密油藏; 主控因素; 富县探区; 鄂尔多斯盆地

Chang 8 Section tight oil reservoir characteristics and distributional controlling factors in Fuxian exploration area
HE Yong-hong1,4,REN Zhan-li2,3,CHEN Zhan-jun2,3,DENG Ya-ren2,3,GE Yun-jin1,4,

(1.Yanchang Petroleum Group,Xi'an 710075,China; 2.Department of Geology,Northwest University,Xi'an 710069,China; 3.Key Laboratory of continental dynamics in the Ministry of Education,Xi'an 710069,China; 4.Research Institute of Shaanxi Yanchang Petroleum Group,Xi'an 716000,China)

Chang 8 section; tight oil reservoir; distributional controlling factors; Fuxian exploration area; Ordos Basin

DOI: 10.13800/j.cnki.xakjdxxb.2016.0316

备注

富县探区位于鄂尔多斯盆地中部,近年来的勘探成果表明,长8段油藏的储层以细砂岩为主、储层孔隙度介于5%~15%,渗透率一般小于0.5×10-3 μm2,主要发育致密储层,且非均质性明显; 长8段油藏没有明显的油藏边界,油水亦无统一的分异界面,开发的主要对象为物性较好、产油量相对较高的“甜点”油藏,生产需经过压裂,上述特征表明长8段油藏为致密型油藏。根据富县探区长8段的地质背景及油藏特征分析,研究认为该区长8段油藏是近源充注的结果,其分布主要受长7段优质烃源岩的展布以及长8段物性较好的“甜点”型储层共同控制; 由于区域性地史演化较为稳定,油藏在成藏之后没有发生大的破坏,所以油藏保存条件普遍较好,该因素对油藏的分布不起主要控制作用。根据上述油藏控制因素分析认为,富县探区中南部2个区块不但砂体发育,而且西邻长7段烃源岩发育区,应是长8段成藏的有利区带。

Fuxian area locates in the center of Ordos Basin.The exploration results of these years indicates that Chang 8 Member of the Triassic YanChang Formation is mainly fine sandstone,the porosity is between 5% and 15%,and the permeability generally less than 0.5×10-3 μm2.The Chang 8 Member of the Triassic YanChang Formation in Fuxian area is mainly tight reservoir with intensive heterogeneity.The hydrocarbon reservoir of Chang 8 has no apparent boundaries,there has no unified oil and water differentiate boundary.The main development target is preferable physical property and higher crude output “sweet point” hydrocarbon pool.The hydrocarbon pool needs fracture treatment.All the features can illustrate Chang 8 reservoir is tight reservoir.According to the geological background and reservoir features,the Chang 8 deposit is the result of close to source filling; its distribution is controlled by the distribution of high-quality source rock of Chang 7 Member and controlled by the preferable physical property reservoir of Chang 8 Member.For the stable geologic history,the deposit has no major damage; there has generally good preservation conditions,so preservation conditions are not the main controlling factors.According to the above mentioned factors,the two south central areas of Fuxian not only has beneficial sand body but also near the western source rock of Chang 7 Member,the two areas are the favorable zones of Chang 8 Member.