Relationship between Early Permian Taiyuan Transgression and Sandbodies Distribution in the Shenmu Gas Field, Ordos Basin
详细信息
- 责任者：An Wenhong (Exploration and Development Research Institute ; Changqing Oilfield Company ; PetroChina ; Xi’an 710021 ; China) ; Shi Xiaohu
- 刊名：Natural Gas Industry
- 出版年：2013
- 卷期：33(4)
- 关键词：海侵 ; transgression ; 砂体 ; sand bodies ; 陕西 ; Shaanxi Province
- 页码：p.43-47
- 图表：illus., 1 table, 13 refs.
- 分类号：1003
- issnNo：ISSN1000-0976
- isbnNo：CN51-1179/TE
摘要
The Lower Permian Taiyuan Fm is the major pay zone in the Shenmu Gas Field,Ordos Basin.The sandbodies are thick and superimposed,but the distributions of sandbodies formed in each stage are poorly defined.It is believed that the transgression in the Taiyuan period in the study area directly influenced the distribution of sandbodies,thus establishing such relationship is helpful to the identification of favorable intervals for gas development.A sequence stratigraphic classification scheme was established for the Taiyuan Formation by taking the four limestone layers in the 1st and 2nd members of the Taiyuan Formation as secondary sequence boundaries.Based on the study of the stages and directions of transgression in the Early Permian,a map was drawn of the distribution of sandbodies formed in 3 stages(Qiligou,Malan and Qiaotou sandstones) in the sequence stratigraphic framework of the Taiyuan Formation.The following findings were obtained.a.Four times of transgression in southeast direction occurred in the Taiyuan period,and the corresponding four sets of limestones show clear zonation and get more highly developed from the north to the south.b.The scale and stage of transgression directly influenced the distribution area and stage of sandbodies;the distribution area of sandbodies of delta plain facies was getting progressively smaller under the control of transgression,northern uplifting and the change of provenance.Finally,according to the actual drilling data,it was pointed out that the Malan sandbody is the most favorable target interval of development,which was deposited at a time between the two mostly extensive transgression events in the Taiyuan period;due to the impact of transgression,the deposited sand particles are so pure through sea water washing that its reservoir quality is much better than the other two sandbodies.