鄂尔多斯盆地西缘古峰庄地区低级序断层封闭性及其控藏作用
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摘要
鄂尔多斯盆地西缘古峰庄地区低级序断层发育,断层性质及其封闭性与油藏密切相关,明确该区低级序断层特征及其封闭性对于复杂构造条件下的石油勘探具有重要意义。基于井震结合分析了低级序断层特征,根据断层与成藏匹配关系以及延长组岩性组合特征,运用断—储排替压差法定量评价了断层封闭性。结果表明,低级序断层主要为晚侏罗世—早白垩世末期形成的逆断层,断距小,倾角陡,延伸短,以北西—南东向呈雁行式分带展布。研究区延长组总体为砂泥岩薄互层段,受断层作用易形成断层岩,断层封闭与否取决于断层岩与所对置储层的排替压差。该区断层岩泥质含量为20%～60%,排替压力一般小于1.5MPa,普遍小于对置储层的排替压力,断层以开启为主,仅少数为封闭断层。早白垩世末期,开启断层为石油输导提供了运移通道,受围岩及封闭断层封堵影响,断层附近的低幅度圈闭及相对高渗储集区为石油聚集的有利目标。
Low-grade faults are relatively developed in the Gufengzhuang area on the western margin of the Ordos Basin. Their characteristics and sealing capabilities are closely related to hydrocarbon accumulation. It is significant to analyze the characteristics and sealing capacities of the faults for petroleum exploration under the complex tectonic conditions. The characteristics of the low-grade faults was analyzed based on seismic and well data, and the sealing capabilities of the faults were evaluated using the displacement pressure difference between reservoirs and faults, according to the matching relationship between faults and hydrocarbon accumulation and the lithology of the Yanchang Formation.The result indicates that the faults are mainly reversed Late Jurassic to Early Cretaceous faults characterized by small fault throw, large dip and short extension, and in echelon distribution from NW to SE. The Yanchang Formation in the study area is thin interbeds of sandstone and mudstone, which are easy to develop fault rocks, so the sealing capability depends on the displacement pressure difference between the fault rock and related reservoir. The mudstone in the fault rock accounts for 20% to 60%, and the displacement pressure is generally less than 1.5 MPa,which is generally smaller than the displacement pressure in the reservoir. Most faults are open, and less are close. During the early time of the Early Cretaceous, the open faults acted as transport systems for hydrocarbon migration, and hydrocarbon accumulated in low-relief traps and high-permeability reservoirs near the faults, controlled by the surrounding rock and sealing faults.
Low-grade faults are relatively developed in the Gufengzhuang area on the western margin of the Ordos Basin. Their characteristics and sealing capabilities are closely related to hydrocarbon accumulation. It is significant to analyze the characteristics and sealing capacities of the faults for petroleum exploration under the complex tectonic conditions. The characteristics of the low-grade faults was analyzed based on seismic and well data, and the sealing capabilities of the faults were evaluated using the displacement pressure difference between reservoirs and faults, according to the matching relationship between faults and hydrocarbon accumulation and the lithology of the Yanchang Formation.The result indicates that the faults are mainly reversed Late Jurassic to Early Cretaceous faults characterized by small fault throw, large dip and short extension, and in echelon distribution from NW to SE. The Yanchang Formation in the study area is thin interbeds of sandstone and mudstone, which are easy to develop fault rocks, so the sealing capability depends on the displacement pressure difference between the fault rock and related reservoir. The mudstone in the fault rock accounts for 20% to 60%, and the displacement pressure is generally less than 1.5 MPa,which is generally smaller than the displacement pressure in the reservoir. Most faults are open, and less are close. During the early time of the Early Cretaceous, the open faults acted as transport systems for hydrocarbon migration, and hydrocarbon accumulated in low-relief traps and high-permeability reservoirs near the faults, controlled by the surrounding rock and sealing faults.
引文
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[2]罗群.鄂尔多斯盆地西缘马家滩地区冲断带断裂特征及其控藏模式[J].地球学报,2008,29(5):619-627.Luo Qun.Characteristics of faults in Majiatan area of west Ordos basin and their petroleum reservoir controlling model[J].Acta Geoscientica Sinica,2008,29(5):619-627.
[3]Smith D A.Theoretical consideration of sealing and nonsealing faults[J].AAPG,1966,50:363-374.
[4]Speksnijder A.The structural configuration of Cormorant Block IV in context of the northern Viking graben structural framework[J].Geologists Bulletin,1989,73:1397-1414.
[5]Lindsay N g,Murphy F C,Walsh J J.Outcrop studies of shale mear on fault surface[J].International Association of Sedimentologists Special Publication,1993,15:113-123.
[6]Yielding G,Freeman B,Needham D T.Quantitative fault seal prediction[J].AAPG,1997,81:897-917.
[7]Watts N L.Theoretical aspects of cap-rock and fault seals for single and two phase hydrocarbon columns[J].Marine and Petroleum Geology,1987,4:274-307.
[8]吕延防,王伟,胡欣蕾,付广,史集建,王超,等.断层侧向封闭性定量评价方法[J].石油勘探与开发,2016,43(2):310-316.Lv Yanfang,Wang Wei,Hu Xinlei,Fu Guang,Shi Jijian,Wang Chao,et al.Quantitative evaluation method of fault lateral sealing[J].Petroleum Exploration and Development,2016,43(2):310-316.
[9]吕延防,沙子萱,付晓飞,付广.断层垂向封闭性定量评价方法及其应用[J].石油学报,2007,28(5):34-38.Lv Yanfang,Sha Zixuan,Fu Xiaofei,Fu Guang.Quantitative evaluation method for fault vertical sealing ability and its application[J].Acta Petrolei Sinica,2007,28(5):34-38.
[10]梁全胜,刘震,何小胡,王德杰,王晓东.断层垂向封闭性定量研究方法及其在准噶尔盆地白家海凸起东道海子断裂带应用[J].现代地质,2008,22(5):803-809.Liang Quansheng,Liu Zhen,He Xiaohu,Wang Dejie,Wang Xiaodong.The quantitative study method and its application to Dongdaohaizi fracture belt in Baijiahai uplift,Junggar Basin[J].Geoscience,2008,22(5):803-809.
[11]童亨茂.断层开启与封闭的定量分析[J].石油与天然气地质,1998,19(3):215-220.Tong Hengmao.Quantitative analysis of fault opening and sealing[J].Oil&Gas Geology,1998,19(3):215-220.
[12]张立宽,罗晓容,廖前进,袁淑琴,苏俊青,肖敦清,等.断层连通概率法定量评价断层的启闭性[J].石油与天然气地质,2007,28(2):181-190.Zhang Likuan,Luo Xiaorong,Liao Qianjin,Yuan Shuqin,Su Junqing,Xiao Dunqing,et al.Quantitative evaluation of fault sealing property with fault connectivity probabilistic method[J].Oil&Gas Geology,2007,28(2):181-190.
[13]付广,于丹.苏仁诺尔断裂垂向封闭性时空分布及其与油气聚集的关系[J].石油学报,2005,26(6):40-45.Fu Guang,Yu Dan.Time space distribution of vertical seal in Shurennouer fault and its relation with oil-gas accumulation[J].Acta Petrolei Sinica,2005,26(6):40-45.
[14]吕延防,黄劲松,付广,付晓飞.砂泥岩薄互层段中断层封闭性的定量研究[J].石油学报,2009,30(6):824-829.Lv Yanfang,Huang Jinsong,Fu Guang,Fu Xiaofei.Quantitative study on fault sealing ability in sandstone and mudstone thin interbed[J].Acta Petrolei Sinica,2009,30(6):824-829.
[15]张春林,高先志,李潍莲,马达德.柴达木盆地尕斯断陷断层封闭性及其对油气运聚的作用[J].石油与天然气地质,2004,25(6):659-665.Zhang Chunlin,Gao Xianzhi,Li Weilian,Ma Dade.Sealing capacity of faults and its control on hydrocarbon migration and accumulation in Gas fault depression in Qaidam Basin[J].Oil&Gas Geology,2004,25(6):659-665.
[16]万天丰,王明明,殷秀兰,晋香兰.渤海湾地区不同方向断裂带的封闭性[J].现代地质,2004,18(2):157-163.Wan Tianfeng,Wang Mingming,Yin Xiulan,Jin Xianglan.Sealing properties of different direction faults in the Bohai Bay aera[J].Geoscience,2004,18(2):157-163.
[17]王珂,戴俊生.地应力与断层封闭性之间的定量关系[J].石油学报,2012,33(1):74-81.Wang Ke,Dai Junsheng.A quantitative relationship between the crustal stress and fault sealing ability[J].Acta Petrolei Sinica,2012,33(1):74-81.
[18]吴李泉,曹代勇,郝银全,张立勤.东营凹陷北部陡坡带断层应力封闭研究[J].中国矿业大学学报,2006,35(3):414-418.Wu Liquan,Cao Daiyong,Hao Yinquan,Zhang Liqin.Characteristics of stress sealing of fault in north zone of Dongying Basin[J].Journal of China University of Mining&Technology,2006,35(3):414-418.
[19]朱轶,蔡正旗,李延钧,姜中卫,华徐发.利用地球化学方法判断断层封闭性--以四川黄泥堂构造为例[J].中国石油勘探,2007,12(1):67-71.Zhu Yi,Cai Zhengqi,Li Yanjun,Jiang Zhongwei,Hua Xufa.Judging fault sealing property with geochemical method[J].China Petroleum Exploration,2007,12(1):67-71.
[20]吕延防,陈章明,陈发景.非线性映射分析判断断层封闭性[J].石油学报,1995,16(2):36-41.Lv Yanfang,Chen Zhangming,Chen Fajing.Evaluation of sealing ability of faults using nonlinear mapping analysis[J].Acta Petrolei Sinica,1995,16(2):36-41.
[21]孙皓,徐田武,樊尚武,宋海强,李静,雷燕.MQ地区断层封闭性模糊综合研究[J].石油天然气学报,2010,32(2):200-204.Sun Hao,Xu Tianwu,Fan Shangwu,Song Haiqiang,Li Jing,Lei Yan.Synthetic fuzzy judgment of fault sealing in MQ area[J].Journal of Oil and Gas Technology,2010,32(2):200-204.
[22]万旸.断层垂向封闭性物理模拟实验研究[D].大庆:东北石油大学,2014:1-59.Wan Yang.The physical simulation experiment research on vertical sealing of fault[D].Da qing:Northeast Petroleum University,2014:1-59.
[23]张东涛,童亨茂,赵海涛,吕雪,张昊.砂泥岩地层地应力纵向分布特征与规律[J].地质力学学报,2014,20(4):352-362.Zhang Dongtao,Tong Hengmao,Zhao Haitao,Lv Xue,Zhang Hao.Characteristics and regularity of longitudinal geostress distribution in sand-mudstone strata[J].Journal of Geomechanics,2014,20(4):352-362.
[24]孟令东.塔南凹陷断层封闭性综合定量评价[D].大庆:东北石油大学,2012:1-84.Meng Lingdong.Integrated evaluation of fault seal in Tanan depression[D].Daqing:Northeast Petroleum University,2012:1-84.
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