石油与天然气地质 ›› 2021, Vol. 42 ›› Issue (5): 1098-1111.doi: 10.11743/ogg20210508

• 油气地质 • 上一篇    下一篇

鄂尔多斯盆地华庆地区延长组6段深水致密砂岩填隙物特征及对储层发育的影响

陈朝兵1,2(), 赵振宇3, 付玲3,*(), 高建荣3, 宋微3, 陈新晶4   

  1. 1. 西安石油大学 地球科学与工程学院, 陕西 西安 710065
    2. 陕西省油气成藏地质学重点实验室, 陕西 西安 710065
    3. 中国石油 勘探开发研究院, 北京 100083
    4. 中国石油 天然气股份有限公司 长庆油田分公司 第六采油厂, 陕西 西安 710200
  • 收稿日期:2020-02-24 出版日期:2021-10-28 发布日期:2021-10-26
  • 通讯作者: 付玲 E-mail:zbchen@xsyu.edu.cn;fuling@petrochina.com.cn
  • 第一作者简介:陈朝兵(1984-), 男, 讲师, 石油地质与储层评价。E-mail: zbchen@xsyu.edu.cn
  • 基金项目:
    国家自然科学基金项目(41802140);国家科技重大专项(2016ZX05050006);陕西省自然科学研究基础计划项目(2019JQ-257);刘宝珺地学科学基金项目(DMSM2019007)

Interstitial matter and its impact on reservoir development in Chang 6 deepwater tight sandstone in Huaqing area, Ordos Basin

Zhaobing Chen1,2(), Zhenyu Zhao3, Ling Fu3,*(), Jianrong Gao3, Wei Song3, Xinjing Chen4   

  1. 1. College of Earth Sciences & Engineering, Xi'an Shiyou University, Xi'an, Shaanxi 710065, China
    2. Provincial Key Lab of Hydrocarbon Accumulation Geology, Xi'an, Shaanxi 710065, China
    3. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China
    4. No. 6 Oil Production Plant of Changqing Oilfield Company Ltd., PetroChina, Xi'an, Shaanxi 710200, China
  • Received:2020-02-24 Online:2021-10-28 Published:2021-10-26
  • Contact: Ling Fu E-mail:zbchen@xsyu.edu.cn;fuling@petrochina.com.cn

摘要:

深水重力流成因的致密砂岩油藏是目前非常规油气勘探开发的新热点。深水环境水动力复杂,填隙物类型及含量变化大,储层微观非均质性强,严重制约了深水沉积储层油气资源的勘探开发进程。通过铸体薄片、扫描电镜、矿物自动识别与分析系统(QEMSCAN)、电子探针和纳米CT等实验分析手段,对鄂尔多斯盆地华庆地区延长组6段(长6段)深水致密砂岩不同填隙物的微观特征进行了精细表征,探讨了不同填隙物对储层孔隙结构及物性的影响。结果表明:杂基并非完全致密,经过成岩改造后的杂基能够产生一定数量的杂基晶间孔和杂基溶孔,孔径介于20~1 000 nm,构成了复杂的杂基次生孔隙网络。当杂基含量≤7%时,杂基次生孔隙发育,对储层产生积极影响。当杂基含量>7%时,杂基次生孔隙发育程度降低,加剧了储层的致密。粘土矿物胶结物的晶间孔在一定程度上缓解了孔隙度的降低,但不同粘土矿物的形态、产状及对储层造成的敏感性又加剧了粘土矿物与渗透率关系的复杂性。伊利石、伊/蒙混层和绿泥石含量的高值区,储层物性通常较差,优质储层多分布在高岭石的发育区;碳酸盐和硅质胶结物是深水致密砂岩储层物性降低的主要因素。综合分析认为,杂基含量≤7%,且高岭石胶结物相对发育的地区是深水致密砂岩油藏勘探开发的重点区域。

关键词: 杂基, 粘土矿物, 填隙物, 深水重力流, 深水致密砂岩, 优质储层, 华庆地区, 鄂尔多斯盆地

Abstract:

Unconventional tight sandstone reservoir resulting from deepwater gravity flow, as a new hotspot for hydrocarbon exploration and development, has attracted much attention.The deepwater depositional environment is characterized by complex hydrodynamics, resulting in large variation in type and content of interstitials, and strong heterogeneity of reservoirs under microscopic observation, thus challenging petroleum E & P.In this study, an integration of casting thin section and SEM observation, Quantitative Evaluation of Materials by Scanning Electron Microscopy (QEMSCAN), electron microprobe and nano CT analysis, is applied to finely characterize the microscopic features of various interstitial matter in the deepwater tight sandstone of the 6th member of Yanchang Formation (Chang 6 Member) in Huaqing area, Ordos Basin, and discuss the effects of interstitials on reservoir pore structure and physical properties.The results show that the matrix is not completely tight, which could, under diagenetic modification, generate a complex secondary pore network consisting of intercrystalline and dissolved pores with a pore size ranging between 20 nm and 1 000 nm.With a matrix content of less than or equal to 7%, the matrix contains well-developed secondary pores, which has a positive impact on reservoir quality; with a matrix content of greater than 7%, the secondary pore development is undermined, exacerbating reservoir compaction.The intercrystalline pores in clay mineral cements, however, could alleviate the reduction of porosity to some extent; on the other hand, the morphology, occurrence of different clay minerals, and their effect on reservoir sensitivity, function to increase the complexity of clay mineral-permeability relationship.In areas with high content of illite, I/S mixed layer and thick chlorite, the reservoirs are commonly poor in physical properties; while high-quality reservoirs are most seen in areas of well-developed kaolinite.Carbonate and siliceous cements are key in undermining the physical properties of deepwater tight sandstone reservoirs.In all, the area with a matrix content of 7% or less and relatively well-developed kaolinite cement is a focus for the exploration and development of tight sandstone reservoirs of deepwater facies.

Key words: matrix, clay mineral, interstitial matter, deepwater gravity flow, tight sandstone of deep water facies, high-quality reservoir, Huaqing area, Ordos Basin

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