Characteristics and main controlling factors of the Ordovician deep dolomite reservoirs in mid-eastern Ordos Basin
YU Zhou1, HU Zijian2, WANG Qianping3, ZHAO Jing4, WU Dongxu1, WU Xingning1, LI Weiling1, LU Huili1, ZHU Wenbo1
1 PetroChina Hangzhou Research Institute of Geology,Hangzhou 310023,China; 2 Exploration Department of PetroChina Changqing Oilfield Company,Xi'an 710018,China; 3 Exploration and Development Research Institute of PetroChina Changqing Oilfield Company,Xi'an 710018,China; 4 Xi'an Changqing Chemical Group Co.,Ltd.,Xi'an 710018,China
Abstract:The deep Ordovician dolomite in the mid-eastern Ordos Basin is an important target for natural gas exploration. There are few studies on this set of dolomite reservoirs,and the reservoir characteristics and genesis are unclear,which restricts the further exploration. Based on outcrops,cores,thin sections,loggings,physical property data and CT scanning data,the dolomite reservoir is systematically studied here. The dolomit reservoir of gypsum-dissolved pore type,granular beach type and bio-turbated type developed in deep Ordovician in the mid-eastern Ordos Basin. The gypsum-dissolved pore type reservoir is characterized by anhydrite nodule bearing micro-crystalline dolomite,and the pore is composed of gypsum molds and micro-fractures with an average porosity of 2.57%. The grain-beach dolomite reservoir is composed of calcarenite-rudite dolomite,oolitic dolomite and crystalline dolomite. The pores include inter-granular pores and micro-fractures,with an average porosity of 4.65%. The bioturbated dolomite reservoir is porphyritic micro-crystalline dolomite and porphyritic calcareous micro-crystall dolomite. The pores are inter-crystalline pores and micro-fractures, and the average porosity is 2.54%. Development of gypsum-solution pore-type and grain-beach type dolomite reservoirs was mainly controlled by sedimentary facies,quasi-synchronous dissolution and rock salt filling. The gypsum bearing dolomitic flat and grain-beach facies provided the basis for development of the two types of dolomite reservoirs. The quasi-synchronous dissolution was the key to development of the reservoir,and the rock salt filling was the main factor for densification of the reservoir. Development of bioturbated dolomite reservoir was mainly controlled by bioturbation and dolomitization. Bioturbation createed basic conditions for development of bio-turbated dolomite reservoir. Quasi-contemporaneous dolomitization was conducive to formation and preservation of inter-crystalline pores. The above results are conducive to the exploration of deep dolomite natural gas in the Ordovician in mid-eastern Ordos Basin,and may provide technical support for the further exploration.
YU Zhou,HU Zijian,WANG Qianping et al. Characteristics and main controlling factors of the Ordovician deep dolomite reservoirs in mid-eastern Ordos Basin[J]. JOPC, 2023, 25(4): 931-944.
[1] 冯增昭,鲍志东,张永生,等. 1998. 鄂尔多斯奥陶纪地层岩石岩相古地理. 北京: 地质出版社,1-144. [Feng Z Z,Bao Z D,Zhang Y S, et al.1998. Stratigraphy and Rocks and Lithofacies Palaeogeography of Ordovician in Ordos Basin. Beijing: Geological Publishing House,1-144] [2] 冯增昭,鲍志东,康祺发,张永生,谭健,李振亚,庞福民,赵学仁. 1999. 鄂尔多斯早古生代古构造. 古地理学报, 1(2): 84-91. [Feng Z Z,Bao Z D,Kang Q F,Zhang Y S,Tan J,Li Z Y,Pang F M,Zhao X R.1999. Palaeotectonics of Ordos in the Early Paleozoic. Journal of Palaeogeography(Chinese Edition), 1(2): 84-91] [3] 付金华,孙六一,冯强汉,包洪平. 2018. 鄂尔多斯盆地下古生界海相碳酸盐岩油气地质与勘探. 北京: 石油工业出版社. [Fu J H,Sun L Y,Feng Q H,Bao H P.2018. Petroleum Geology and Exploration of Lower Paleozoic Marine Carbonate Rocks in Ordos Basin. Beijing: Petroleum Industry Press] [4] 付金华,于洲,李程善,王维斌,黄正良,吴兴宁,王少依. 2021. 鄂尔多斯盆地东部米探1井奥陶系马四段天然气勘探新发现及勘探方向. 天然气工业, 41(12): 17-27. [Fu J H,Yu Z,Li C S,Wang W B,Huang Z L,Wu X N,Wang S Y.2021. New discovery and favorable areas of natural gas exploration in the 4th Member of Ordovician Majiagou Formation by Well Mitan 1 in the eastern Ordos Basin. Natural Gas Industry, 41(12): 17-27] [5] 付玲,李建忠,徐旺林,郭玮,李宁熙,张月巧,宋微,孙远实. 2020. 鄂尔多斯盆地中东部奥陶系盐下深层储层特征及主控因素. 天然气地球科学, 31(11): 1548-1561. [Fu L,Li J Z,Xu W L,Guo W,Li N X,Zhang Y Q,Song W,Sun Y S.2020. Characteristics and main controlling factors of Ordovician deep subsalt reservoir in central and eastern Ordos Basin. Natural Gas Geoscience, 31(11): 1548-1561] [6] 侯方浩,方少仙,何江,杨西燕,傅锁堂,吴正,姚泾利,阎荣辉. 2011. 鄂尔多斯盆地靖边气田区中奥陶统马家沟组五1—五4亚段古岩溶型储层分布特征及综合评价. 海相油气地质, 16(1): 1-13. [Hou F H,Fang S X,He J,Yang X Y,Fu S T,Wu Z,Yao J L,Yan R H.2011. Distribution characters and comprehensive evaluation of Middle Ordovician Majiagou 51-54 submembers reservoirs in Jingbian Gas field area,Ordos Basin. Marine Origin Petroleum Geology, 16(1): 1-13] [7] 李振宏,郑聪斌. 2004. 鄂尔多斯盆地东部奥陶系储层特征及控制因素. 天然气地球科学, 15(6): 604-609. [Li Z H,Zheng C B.2004. The reservoir heterogeneity and controlled factors of Ordovician in the eastern Ordos Basin. Natural Gas Geoscience, 15(6): 604-609] [8] 史基安,邵毅,张顺存,付翠琴,白海峰,马占龙,吴志雄. 2009. 鄂尔多斯盆地东部地区奥陶系马家沟组沉积环境与岩相古地理研究. 天然气地球科学, 20(3): 316-324. [Shi J A,Shao Y,Zhang S C,Fu C Q,Bai H F,Ma Z L,Wu Z X.2009. Lithofacies paleogeography and sedimentary environment in Ordovician Majiagou Formation,eastern Ordos Basin. Natural Gas Geoscience, 20(3): 316-324] [9] 吴汉宁,常承法,刘椿,钟大赉. 1990. 依据古地磁资料探讨华北和华南块体运动及其对秦岭造山带构造演化的影响. 地质科学, 25(3): 201-214. [Wu H N,Chang C F,Liu C,Zhong D L.1990. Evolution of the Qinling Fold Belt and the movement of the North and South China blocks: the evidence of geology and paleomagnetism. Chinese Journal of Geology, 25(3): 201-214] [10] 许杰,肖笛,苏文杰,晏巍,钟寿康,杨鸣一,杨梦颖,谭秀成. 2022. 鄂尔多斯盆地东缘奥陶系马家沟组四段豹斑状云质灰岩特征及成因: 以关家崖剖面为例. 古地理学报, 24(2): 261-277. [Xu J,Xiao D,Su W J,Yan W,Zhong S K,Yang M Y,Yang M Y,Tan X C.2022. Characteristics and genesis of leopard-spotted dolomitic limestone in the Member 4 of Ordovician Majiagou Formation: a case study from Guanjiaya section in eastern margin of Ordos Basin. Journal of Palaeogeography(Chinese Edition), 24(2): 261-277] [11] 杨华,包洪平. 2011. 鄂尔多斯盆地奥陶系中组合成藏特征及勘探启示. 天然气工业, 31(12): 1-10. [Yang H,Bao H P.2011. Characteristics of hydrocarbon accumulation in the middle Ordovician assemblages and their significance for gas exploration in the Ordos Basin. Natural Gas Industry, 31(12): 11-20] [12] 杨振宇,马醒华,孙知明,黄宝春,周烑秀,董金明,朱鸿. 1997. 豫北地区早古生代古地磁研究的初步结果及其意义. 科学通报, 42(4): 401-406. [Yang Z Y,Ma X H,Sun Z M,Huang B C,Zhou Y X,Dong J M,Zhu H.1997. The preliminary results of Early Paleozoic paleomagnetic study in the northern Henan Province and its implications. Chinese Science Bulletin, 42(4): 401-406] [13] 姚泾利,包洪平,任军峰,孙六一,马占荣. 2015. 鄂尔多斯盆地奥陶系盐下天然气勘探. 中国石油勘探, 20(3): 1-12. [Yao J L,Bao H P,Ren J F,Sun L Y,Ma Z R.2015. Exploration of Ordovician subsalt natural gas reservoirs in Ordos Basin. China Petroleum Exploration, 20(3): 1-12] [14] 于洲,丁振纯,吴东旭,董岩,郭婷,刘文. 2017. 鄂尔多斯盆地中东部奥陶系马家沟组沉积相演化模式研究. 海相油气地质, 22(3): 12-22. [Yu Z,Ding Z C,Wu D X,Dong Y,Guo T,Liu W.2017. Sedimentary facies evolution model of Ordovician Majiagou Formation,central-eastern Ordos Basin. Marine Origin Petroleum Geology, 22(3): 12-22] [15] 于洲,周进高,丁振纯,魏柳斌,魏源,吴兴宁,吴东旭,王少依,李维岭. 2020. 鄂尔多斯盆地中东部奥陶系马五 41a储层特征及成因. 天然气地球科学, 31(5): 686-697. [Yu Z,Zhou J G,Ding Z C,Wei L B,Wei Y,Wu X N,Wu D X,Wang S Y,Li W L.2020. Reservoir characteristics and genesis of O1m54-1a in the central and eastern Ordos Basin. Natural Gas Geoscience, 31(5): 686-697] [16] 于洲,牛小兵,张才利,马永威,魏柳斌,董国栋,尹陈,贾佳佳. 2021. 鄂尔多斯盆地米脂地区奥陶系马四段储层成因与分布. 天然气工业, 41(12): 38-48. [Yu Z,Niu X B,Zhang C L,Ma Y W,Wei L B,Dong G D,Yin C,Jia J J.2021. Genesis and distribution of reservoirs of the 4th Member of Ordovician Majiagou Formation in the Mizhi area of the Ordos Basin. Natural Gas Industry, 41(12): 38-48] [17] 周进高,徐春春,姚根顺,杨光,张建勇,郝毅,王芳,潘立银,谷明峰,李文正. 2015. 四川盆地下寒武统龙王庙组储集层形成与演化. 石油勘探与开发, 42(2): 158-166. [Zhou J G,Xu C C,Yao G S,Yang G,Zhang J Y,Hao Y,Wang F,Pan L Y,Gu M F,Li W Z.2015. Genesis and evolution of Lower Cambrian Longwangmiao Formation reservoirs,Sichuan Basin,SW China. Petroleum Exploration and Development, 42(2): 158-166] [18] 周进高,席胜利,邓红婴,于洲,刘新社,丁振纯,李维岭,唐瑾. 2020a. 鄂尔多斯盆地寒武系—奥陶系深层海相碳酸盐岩构造—岩相古地理特征. 天然气工业, 40(2): 41-53. [Zhou J G,Xi S L,Deng H Y,Yu Z,Liu X S,Ding Z C,Li W L,Tang J.2020a. Tectonic-lithofacies paleogeographic characteristics of Cambrian-Ordovician deep marine carbonate rocks in the Ordos Basin. Natural Gas Industry, 40(2): 41-53] [19] 周进高,付金华,于洲,吴东旭,丁振纯,李维岭,唐瑾. 2020b. 鄂尔多斯盆地海相碳酸盐岩主要储层类型及其形成机制. 天然气工业, 40(11): 20-30. [Zhou J G,Fu J H,Yu Z,Wu D X,Ding Z C,Li W L,Tang J.2020b. Main types and formation mechanisms of marine carbonate reservoirs in the Ordos Basin. Natural Gas Industry, 40(11): 20-30] [20] 周进高,尹陈,曾联波,胡琮,吴东旭,于洲,李维岭,唐瑾,刘雨昕,贾佳佳. 2022a. 鄂尔多斯盆地奥陶系马家沟组四段颗粒滩发育特征及天然气勘探有利区. 天然气工业, 42(7): 17-30. [Zhou J G,Yin C,Zeng L B,Hu C,Wu D X,Yu Z,Li W L,Tang J,Liu Y X,Jia J J.2022a. Development characteristics of grain shoals and favorable gas exploration areas in the 4th Member of Ordovician Majiagou Formation in the Ordos Basin. Natural Gas Industry, 42(7): 17-30] [21] 周进高,于洲,吴东旭,任军峰,张道锋,王少依,尹陈,刘雨昕. 2022b. 基于激光U-Pb定年技术的白云岩储集层形成过程恢复: 以鄂尔多斯盆地奥陶系马家沟组为例. 石油勘探与开发, 49(2): 285-295. [Zhou J G,Yu Z,Wu D X,Ren J F,Zhang D F,Wang S Y,Yin C,Liu Y X.2022b. Restoration of formation processes of dolomite reservoirs based on laser U-Pb dating: a case study of Ordovician Majiagou Formation,Ordos Basin,NW China. Petroleum Exploration and Development, 49(2): 285-295] [22] Veizer J,Ala D,Azmy K,Bruckschen P,Buhl D,Bruhn F,Carden G A F,Diener A,Ebneth S,Godderis Y,Jasper T,Korte C,Pawellek F,Podlaha O G,Strauss H.1999. 87Sr/86Sr,δ13C and δ18O evolution of Phanerozoic seawater. Chemical Geology, 161(1): 59-88.