石油与天然气地质 ›› 2018, Vol. 39 ›› Issue (6): 1213-1224.doi: 10.11743/ogg20180611

• 油气勘探 • 上一篇    下一篇

鄂尔多斯盆地奥陶系马家沟组五段膏盐下白云岩储层形成的主控因素

于洲1,2, 丁振纯1,2, 王利花3, 张道峰4, 罗超5, 魏源4, 郭玮4, 魏柳斌4   

  1. 1. 中国石油 杭州地质研究院, 浙江 杭州 310023;
    2. 中国石油天然气集团公司 碳酸盐岩储层重点实验室, 浙江 杭州 310023;
    3. 中国石油 长庆油田分公司 第五采气厂, 内蒙古自治区 鄂尔多斯 017300;
    4. 中国石油 长庆油田分公司 勘探开发研究院, 陕西 西安 710018;
    5. 重庆科技学院 石油与天然气工程学院, 重庆 401331
  • 收稿日期:2017-06-30 修回日期:2018-06-15 出版日期:2018-12-28 发布日期:2018-10-22
  • 第一作者简介:于洲(1986-),男,工程师,地质工程。E-mail:yuz_hz@petrochina.com.cn。
  • 基金项目:
    国家科技重大专项（2017ZX05008-005）;中国石油股份公司重大专项（2016E-0502）；重庆市教委科学技术研究项目（KJ1713346）。

Main factors controlling formation of dolomite reservoir underlying gypsum-salt layer in the 5th member of Ordovician Majiagou Formation,Ordos Basin

Yu Zhou1,2, Ding Zhenchun1,2, Wang Lihua3, Zhang Daofeng4, Luo Chao5, Wei Yuan4, Guo Wei4, Wei liubin4   

  1. 1. Hangzhou Research Institute of Geology, PetroChina, Hangzhou, Zhejiang 310023, China;
    2. Key Laboratory of Carbonate Reservoirs, CNPC, Hangzhou, Zhejiang 310023, China;
    3. No.5 Gas Production Plant, PetroChina Changqing Oilfield Company, Erdos, Inner Monglia 017300, China;
    4. Exploration and Development Research Institute, PetroChina Changqing Oilfield Company, Xi'an, Shaanxi 710018, China;
    5. School of Petroleum Engineering, Chongqing University of Science & Technology, Chongqing 401331, China
  • Received:2017-06-30 Revised:2018-06-15 Online:2018-12-28 Published:2018-10-22

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摘要： 近期勘探实践表明，鄂尔多斯盆地东部奥陶系马家沟组五段膏盐下白云岩具有良好的天然气勘探开发潜力。为此，综合岩心观察、薄片鉴定、物性分析及地球化学特征等资料，对其岩石学、储集空间和孔渗特征等开展了系统研究。结果表明，鄂尔多斯盆地奥陶系膏盐下储集层为孔隙型白云岩储层，纵向上分布在马五6亚段、马五7亚段和马五9亚段。马五6亚段储集层岩性主要为颗粒白云岩和斑状粉晶白云岩，马五7亚段和马五9亚段储集层岩性主要为颗粒白云岩和粉-细晶白云岩。三个储层段储集空间均以溶蚀孔洞为主，次为残余粒间孔、晶间溶孔、晶间孔和微裂缝，平均孔隙度分别为5.84%、6.81%和7.03%。沉积古地貌、海平面变化和准同生期大气淡水溶蚀作用等因素共同控制膏盐下白云岩储集层的发育与分布。研究认为位于盐岩边界线外侧的中央古隆起带和榆林-横山隆起带地势相对较高，颗粒滩沉积厚度大，在准同生期和浅埋藏期易于发生大气淡水溶蚀作用，其内部赋存的孔隙不易被膏盐岩充填，是盆地内膏盐下有利白云岩储集层的发育区。

关键词: 海平面, 溶蚀作用, 古地貌, 膏盐, 白云岩, 马家沟组, 鄂尔多斯盆地

Abstract: The dolomite underlying gypsum-salt layer in the 5th member of Ordovician Majiagou Formation in the eastern Ordos Basin proves to be of great gas potential by latest exploration practice.Thus we conducted systematic study on its petrological features,reservoir space,porosity and permeability by core observation,thin section identification,physical property analysis and geochemical analysis.The results show that the reservoirs underlying the gypsum-salt layer in the Ordovician are of porous dolomite type in the Ordos Basin,and they occur vertically in O1m65,O1m75 and O1m95.The litho- logies of the O1m65 reservoirs are mainly granular dolomite and porphyritic dolomite with very fine-crystalline,while the lithologies of O71m5 and O1m95 reservoirs are dominated by granular dolomite and dolomite with very fine-to fine-crystalline.The reservoir spaces for the three reservoir intervals are primarily dissolved pores or cavities,with residual intergranular pores,intercrystalline dissolved pores,intercrystalline pores and micro cracks ranked second.The average porosity for each is 5.84%,6.81% and 7.03%.Sedimentary paleo-geomorphology,sea level eustacy and penecontemporaneous meteoric water dissolution collectively control the development and distribution of the dolomite reservoir underlying gypsum-salt layer.It is concluded that the central paleo-uplift belt and Yulin-Hengshan uplift belt,located outside the boundary of the gypsum-salt layer,are relatively higher in topography,and the deposits of grain shoal facies are relatively thicker,so they are prone to undergo meteoric water dissolution during penecontemporaneous and shallow burial stages.Its internal pores are not easily subject to filling of gypsum salt.All in all,they are the favorable areas for the growth of dolomite reservoirs underlying the gypsum-salt layers inside the basin.

Key words: sea level, dissolution, paleo-geomorphology, gypsum-salt layer, dolomite, Majiagou Formation, Ordos Basin

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