Bedding-parallel fractures in ultradeep tight sandstone reservoirs in Jurassic and Cretaceous of Yongjin Oil Field, Junggar Basin, China
Bedding-parallel fractures in ultradeep tight sandstone reservoirs in Jurassic and Cretaceous of Yongjin Oil Field, Junggar Basin, China
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准噶尔盆地永进油田侏罗系、白垩系超深层致密砂岩储层层理平行裂缝
DOI：
10.1007/s11707-022-0999-9
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发表时间：
2022-10
影响因子：
2
通讯作者：
Yang Luo
中科院分区：
文献类型：
--
作者：
Hongping Liu;Changmin Zhang;Li Zhang;Yang Luo
层理平行裂缝是指与岩层层理构造面平行的裂缝，是致密砂岩和页岩储层油气生产的关键因素，已被广泛认可。然而，这些平行层理裂缝的形成机制仍存在争议。本文采用岩心、显微观察、元素地球化学、碳氧同位素等方法对永锦油田层理平行裂缝进行了分析。研究了其成因及其与储层质量、断层和岩石力学性质的关系。上侏罗统和下白垩统组均发现层理平行裂缝，表明其形成时间晚于早白垩统。不含沥青和碳酸盐胶结的顺层平行裂缝充填状态表明它们是经过石油充注和碳酸盐胶结后形成的。岩心和薄片观察的张性裂缝特征以及覆盖层应力超过孔隙压力的事实表明，层理平行裂缝既不是由构造压缩产生的，也不是由超压产生的。最可能的产生机制是在高地应力条件下岩心钻探过程中的应力释放。高地应力和低抗拉强度导致裂缝间距变细。存在高的顺层平行裂缝密度是储层质量良好的标志，可导致高的油气产量。
Bedding-parallel fractures are fractures that are parallel to rock bedding structure planes and have been widely accepted as a key factor for oil and gas production in tight sandstone and shale reservoirs. However, the formation mechanisms of these parallel-bedding fractures are still under debate. In this study, bedding-parallel fractures in Yongjin Oil Field were analyzed using methods including core and microscopic observations, element geochemistry, and carbon and oxygen isotope analysis. Their origin and relations to reservoir quality, faults, and rock mechanical properties were examined. The discovery of bedding-parallel fractures in both the Upper Jurassic and Lower Cretaceous formations indicates that the BPFs are generated later than the early Cretaceous. The filling state of bedding-parallel fractures that with no bitumen and carbonate cement indicate that they formed after oil charging and carbonate cementation. The tensile fracture characteristics in core and thin section observations, and the fact that overburden stress exceeds the pore pressure indicate that the bedding-parallel fractures were neither generated from tectonic compression nor overpressure. The most likely generation mechanism is stress relief during core drilling under high in situ stress conditions. High in situ stress and low tensile strength lead to thinner fracture spacing. The existence of high bedding-parallel fracture density is an indicator of good reservoir quality and result in high oil/gas production.
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DOI：
--
发表时间：
2009
期刊：
Xinjiang Petroleum Geology
影响因子：
--
作者：
Z. Ning
通讯作者：
Z. Ning
DOI：
--
发表时间：
2011
期刊：
Journal of China University of Petroleum
影响因子：
--
作者：
Zhang Pei-zhi
通讯作者：
Zhang Pei-zhi
影响因子：
1.7
作者：
P. Cobbold;N. Rodrigues
通讯作者：
P. Cobbold;N. Rodrigues
影响因子：
5.6
作者：
Lai, Jin;Liu, Bing-Chang;Wang, Gui-Wen
通讯作者：
Wang, Gui-Wen
影响因子：
0.8
作者：
N. I. Belov;V. Ivanov
通讯作者：
N. I. Belov;V. Ivanov