鄂尔多斯盆地镇北地区延长组长7古地貌与砂体分布特征
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摘要
镇北地区延长组是油气挖潜的主要目的层,其砂体类型和分布受古地貌控制。以精细等时地层格架为基础的古地貌恢复可以为砂体的成因和分布提供依据。结合岩心、测井和地震资料,以高分辨率层序地层学为指导建立研究区精细地层格架,将长7划分为1个中期旋回和5个短期旋回;以短期基准面旋回为单元,采用优化后的回剥法定量恢复研究区古地貌。结果表明:镇北地区主要发育坡折带,长73时期湖侵范围最大,坡折带较陡,东部深湖区发育浊积扇砂体;长73至长71时期,基准面下降,坡折带和沿湖岸线分布的河口坝砂体逐渐向湖区推进,坡折带逐渐变宽缓,其下的滑塌岩较发育;长71末期,基准面上升,坡折带和砂体逐渐向陆退缩。基准面旋回的变化导致沉积地貌发生改变,坡折带随之发生迁移,砂体成因和分布规律发生了明显变化。该研究对寻找有利油气目标区具有借鉴作用。
Chang 7 member of Yanchang Formation in Zhenbei area is one of the main targets of oil and gas exploration.The type and distribution of sand body are controlled by palaeogeomorphology.The recontructed palaeogeomorphology based on precise isochronous stratigraphic framework can provide basis for analyzing the genesis type and distribution of the sand body.Based on core,logging and sesmic data,this paper established fine stratigraphic framwork under the guadence of high resolution sequence stratigraphy,and divided Chang 7 reservoir into one middle-term base-level cycle and five short-term base-level cycles.An optimized backstripping method was used to restore the deposited terrain,and the palaeogeomorphology map of the study area was drawn by short-term base level unit.The result shows that there mainly developed slope break in Zhenbei area,Chang 73 is the maximum transgression,and turbidite fans appear in the deep lake in the northeastern part of the study area.From Chang 73 to Chang 71 stage,the base level decreases,the mouth bar and the slope break zone gradually advance to the lake,the angle of the break zone begins to decrease,and fluxoturbidite forms consequently;from late Chang 71 stage,the base level begins to rise,the slope break and the sand body gradually retreat to the shore.Base level cycle change leads to geomorphic change,the origin and distribution of the sand bodies changes regularly,and it has an important significance in searching for oil and gas.
Chang 7 member of Yanchang Formation in Zhenbei area is one of the main targets of oil and gas exploration.The type and distribution of sand body are controlled by palaeogeomorphology.The recontructed palaeogeomorphology based on precise isochronous stratigraphic framework can provide basis for analyzing the genesis type and distribution of the sand body.Based on core,logging and sesmic data,this paper established fine stratigraphic framwork under the guadence of high resolution sequence stratigraphy,and divided Chang 7 reservoir into one middle-term base-level cycle and five short-term base-level cycles.An optimized backstripping method was used to restore the deposited terrain,and the palaeogeomorphology map of the study area was drawn by short-term base level unit.The result shows that there mainly developed slope break in Zhenbei area,Chang 73 is the maximum transgression,and turbidite fans appear in the deep lake in the northeastern part of the study area.From Chang 73 to Chang 71 stage,the base level decreases,the mouth bar and the slope break zone gradually advance to the lake,the angle of the break zone begins to decrease,and fluxoturbidite forms consequently;from late Chang 71 stage,the base level begins to rise,the slope break and the sand body gradually retreat to the shore.Base level cycle change leads to geomorphic change,the origin and distribution of the sand bodies changes regularly,and it has an important significance in searching for oil and gas.
引文
[1]杨华,刘显阳,张才利,等.鄂尔多斯盆地三叠系延长组低渗透油藏主控因素及其分布规律[J].岩性油气藏,2007,19(3):1-6.
[2]刘化清,袁剑英,李相博,等.鄂尔多斯盆地延长期湖盆演化及其成因分析[J].岩性油气藏,2007,19(1):52-56.
[3]李树同,张海峰,王多云,等.聚油古地貌成因类型及其有利成藏条件分析——以鄂尔多斯盆地上里塬地区前侏罗纪古地貌为例[J].沉积学报,2011,29(5):962-969.
[4]李相博,刘化清,完颜容,等.鄂尔多斯盆地三叠系延长组砂质碎屑流储集体的首次发现[J].岩性油气藏,2009,21(4):19-21.
[5]庞军刚,卢涛,国吉安,等.鄂尔多斯盆地延长期原型湖盆恢复及中部砂体成因[J].岩性油气藏,2012,24(4):56-63.
[6]李树同,王多云,陶辉飞,等.鄂尔多斯盆地延长组坡折带对岩性油藏的控制[J].新疆石油地质,2009,30(1):53-56.
[7]邓宏文,王洪亮,宁宁.沉积物体积分配原理——高分辨率层序地层学的理论基础[J].地学前缘,2000,7(4):305-313.
[8]邓宏文.美国层序地层研究中的新学派——高分辨率层序地层学[J].石油与天然气地质,1995,16(2):87-97.
[9]陈永峤,李伟华,汪凌霞,等.鄂尔多斯盆地合水地区延长组—延安组地层分布特征[J].地层学杂志,2011,35(1):41-47.
[10]姜正龙,邓宏文.古地貌恢复方法及应用——以济阳坳陷桩西地区沙二段为例[J].现代地质,2009,23(5):865-870.
[11]Sciunnach D,Garzanti E.Subsidence history of the Tethys Himalaya[J].Earth Science Reviews,2012,111(1):179-198.
[12]Yin J R,Wan Z Q.Jurassic ammonite morphotypes as water-depthindicator of Tethys-Himalaya sea[J].Acta of Palaeontological Si-nica,1996,35(6):734-751.
[13]张世奇,任延广.松辽盆地中生代沉积基准面变化研究[J].长安大学学报:地球科学版,2003,25(2):1-5.
[14]郭少斌,孙绍寒.周家湾地区前侏罗纪古地貌恢复及油气富集规律[J].地球科学——中国地质大学学报,2006,31(3):372-377.
[15]邓秀芹,蔺昉晓,刘显阳,等.鄂尔多斯盆地三叠系延长组沉积演化及其与早印支运动关系的探讨[J].古地理学报,2008,10(2):159-166.
[2]刘化清,袁剑英,李相博,等.鄂尔多斯盆地延长期湖盆演化及其成因分析[J].岩性油气藏,2007,19(1):52-56.
[3]李树同,张海峰,王多云,等.聚油古地貌成因类型及其有利成藏条件分析——以鄂尔多斯盆地上里塬地区前侏罗纪古地貌为例[J].沉积学报,2011,29(5):962-969.
[4]李相博,刘化清,完颜容,等.鄂尔多斯盆地三叠系延长组砂质碎屑流储集体的首次发现[J].岩性油气藏,2009,21(4):19-21.
[5]庞军刚,卢涛,国吉安,等.鄂尔多斯盆地延长期原型湖盆恢复及中部砂体成因[J].岩性油气藏,2012,24(4):56-63.
[6]李树同,王多云,陶辉飞,等.鄂尔多斯盆地延长组坡折带对岩性油藏的控制[J].新疆石油地质,2009,30(1):53-56.
[7]邓宏文,王洪亮,宁宁.沉积物体积分配原理——高分辨率层序地层学的理论基础[J].地学前缘,2000,7(4):305-313.
[8]邓宏文.美国层序地层研究中的新学派——高分辨率层序地层学[J].石油与天然气地质,1995,16(2):87-97.
[9]陈永峤,李伟华,汪凌霞,等.鄂尔多斯盆地合水地区延长组—延安组地层分布特征[J].地层学杂志,2011,35(1):41-47.
[10]姜正龙,邓宏文.古地貌恢复方法及应用——以济阳坳陷桩西地区沙二段为例[J].现代地质,2009,23(5):865-870.
[11]Sciunnach D,Garzanti E.Subsidence history of the Tethys Himalaya[J].Earth Science Reviews,2012,111(1):179-198.
[12]Yin J R,Wan Z Q.Jurassic ammonite morphotypes as water-depthindicator of Tethys-Himalaya sea[J].Acta of Palaeontological Si-nica,1996,35(6):734-751.
[13]张世奇,任延广.松辽盆地中生代沉积基准面变化研究[J].长安大学学报:地球科学版,2003,25(2):1-5.
[14]郭少斌,孙绍寒.周家湾地区前侏罗纪古地貌恢复及油气富集规律[J].地球科学——中国地质大学学报,2006,31(3):372-377.
[15]邓秀芹,蔺昉晓,刘显阳,等.鄂尔多斯盆地三叠系延长组沉积演化及其与早印支运动关系的探讨[J].古地理学报,2008,10(2):159-166.
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