Bedding parallel fractures in fine-grained sedimentary rocks: Recognition, formation mechanisms, and prediction using well log
Bedding parallel fractures in fine-grained sedimentary rocks: Recognition, formation mechanisms, and prediction using well log
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DOI：
10.1016/j.petsci.2021.10.017
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发表时间：
2022-04-01
影响因子：
5.6
通讯作者：
Wang, Gui-Wen
中科院分区：
文献类型：
--
作者：
Lai, Jin;Liu, Bing-Chang;Wang, Gui-Wen
利用岩心、薄片、常规和成像测井资料，对吉木萨尔凹陷二叠系芦草沟组细粒沉积岩裂缝分布进行了研究。顺层平行裂缝是细粒沉积岩中常见的裂缝类型，具有层状结构特征。岩心和薄片分析表明，芦草沟组裂缝主要有构造斜裂缝、顺层平行裂缝和异常高压裂缝。顺层平行裂缝非常丰富，但只有少量裂缝保持开放，其中大部分裂缝被碳酸盐矿物（方解石）和沥青部分或完全封闭。顺层平行裂缝导致电阻率迅速降低，在成像测井上，它们被识别为沿沿着层面延伸，并且由于部分-完全填充的电阻性碳酸盐矿物以及晚期溶解而具有不连续表面。对顺层平行裂缝的分布进行了综合解释，绿色线表示层面，红线表示诱导裂缝，黄线表示阻力裂缝，蓝线表示开放（顺层和倾斜）裂缝。顺层平行断裂的走向与层面一致。顺层裂缝与层面数量密切相关，层面密度高有利于顺层裂缝的形成。成像测井曲线上，明暗相间的层间平行裂缝最多，且平行裂缝常与低阻带伴生。上述研究结果有助于优化细粒沉积岩的最佳压裂点，为今后的压裂设计和井距优化提供参考。?? 2021作者Elsevier B.V.代表KeAi Communications Co. Ltd.提供的出版服务。这是一篇在CC BY许可证下开放获取的文章（http：//creativecommons.org/licenses/by/4.0/）。
Core, thin section, conventional and image logs are used to provide insights into distribution of fractures in fine grained sedimentary rocks of Permian Lucaogou Formation in Jimusar Sag. Bedding parallel fractures are common in fine grained sedimentary rocks which are characterized by layered structures. Core and thin section analysis reveal that fractures in Lucaogou Formation include tectonic inclined fracture, bedding parallel fracture, and abnormal high pressure fracture. Bedding parallel fractures are abundant, but only minor amounts of them remain open, and most of them are partly to fully sealed by carbonate minerals (calcite) and bitumen. Bedding parallel fractures result in a rapid decrease in resistivity, and they are recognized on image logs to extend along bedding planes and have discontinuous surfaces due to partly-fully filled resistive carbonate minerals as well as late stage dissolution. A comprehensive interpretation of distribution of bedding parallel fractures is performed with green line, red line, yellow line and blue line representing bedding planes, induced fractures, resistive fractures, and open (bedding and inclined) fractures, respectively. The strike of bedding parallel fractures is coinciding with bedding planes. Bedding parallel fractures are closely associated with the amounts of bedding planes, and high density of bedding planes favor the formation of bedding parallel fractures. Alternating dark and bright layers have the most abundant bedding parallel fractures on the image logs, and the bedding parallel fractures are always associated with low resistivity zones. The results above may help optimize sweet spots in fine grained sedimentary rocks, and improve future fracturing design and optimize well spacing. ?? 2021 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).