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| 鄂尔多斯盆地NX地区长6段特低-超低渗储层特征及其成因 |
| 黄春梅1,钟红利2,闫凤平1,蒋司淋1,白二林1,张凤奇3,武富礼3,刘伟3 |
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(1. 延长油田股份有限公司南泥湾采油厂, 陕西 延安 716000;
2. 西安科技大学地质与环境学院, 陕西 西安 710054;
3. 西安石油大学地球科学与工程学院, 陕西 西安 710065) |
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| 摘要: |
| 根据物性测试、铸体薄片、扫描电镜、X射线衍射、压汞等资料，对鄂尔多斯盆地NX地区长6段储层特征及成因进行了研究。结果表明，研究区长6段砂岩储层为低孔-特低、超低渗透储层，主要孔隙类型为残余粒间孔和次生溶蚀孔，孔喉组合主要为中孔-细喉型和小孔-细喉型。早期的压实作用、胶结作用是使研究区长6段储层物性变差的两个重要作用。压实作用丧失的孔隙占原始孔隙的45.9%~65.6%，平均为56.5%；胶结作用丧失的孔隙占原始孔隙的21.8%~46.4%，平均为28.3%，粘土矿物、碳酸盐是造成物性降低的主要胶结物类型。长石、浊沸石、岩屑等的溶蚀作用极大改善了储层物性，改善了现今孔隙的22.2%~71.4%，平均44.2%。早白垩世末期，研究区长6储层已基本变为特低~超低渗透，该时期之后，成岩作用对储层物性影响较弱，储层物性基本保持到现今。 |
| 关键词: 低渗透储层 成岩作用 成因 延长组 鄂尔多斯盆地 |
| DOI： |
| 附件 |
| 投稿时间：2019-08-07修订日期：2019-09-26 |
| 基金项目:国家自然科学基金项目（41502137）、陕西省自然科学基础研究计划项目（2017JM4004）、陕西省教育厅重点实验室科研计划项目（17JS110）联合资助 |
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| Characteristics and origins of the Chang-6 reservoir rocks with extra-low and super-low permeability in the NX area, Ordos Basin |
| HUANG Chunmei1, ZHONG Hongli2, YAN Fengping1, JIANG Silin1, BAI Erlin1, ZHANG Fengqi3, WU Fuli3, LIU Wei3 |
(1. Nanniwan Oil Production Plant, Yanchang Oil Field Co., Ltd., Yan'an 716000, Shaanxi, China;
2. College of Geology and Environments, Xi'an University of Science and Technology, Xi'an 710054, Shaanxi, China;
3. School of Earth Sciences and Engineering, Xi'an Shiyou University, Xi'an 710065, Shaanxi, China) |
| Abstract: |
| According to the data of physical properties, cast thin section, SEM, X-ray diffraction analysis, mercury injection test, the present paper deals with the characteristics and origins of the Chang-6 reservoir rocks with extra-low and super-low permeability in the NX area, Ordos Basin. The Chang-6 sandstone reservoirs have low porosity, and extra-low and super-low permeability. The porosity types consist of residual intergranular pores and secondary solution openings. The pore throat types contain mesopore-fine throats and micropore-fine throats. The early diagenetic compaction and cementation are major influencing factors that lead to the formation of poor physical properties of the Chang-6 sandstone reservoirs. The porosity loss caused by mechanical compaction ranges from 45.9% to 65.6%, with an average of 56.5% of the total porosity, and that caused by cementation ranges from 21.8% to 46.4%, with an average of 28.3% of the total porosity. In the cements, clay minerals and carbonate minerals occur as main cements that may reduce the reservoir quality of the sandstones. The dissolution of feldspar, laumonite and lithoclasts may largely improve the physical properties of the Chang-6 sandstone reservoirs, including the increase of the porosity from 22.2% to 71.4%, with an average of 44.2% of present-day porosity. The Chang-6 sandstone reservoirs with extra-low and super-low permeability were developed during the latest Cretaceous, and from that time on, the physical properties cited above remain unchanged. |
| Key words: low-permeability reservoir diagenesis origin Yanchang Formation Ordos basin |