Source Rock Distribution and Exploration Prospect of Jilantai Sag in Hetao Basin, China(PDF)
《地球科学与环境学报》[ISSN:1672-6561/CN:61-1423/P]
- Issue:
- 2018年第05期
- Page:
- 612-626
- Research Field:
- 基础地质与矿产地质
- Publishing date:
Info
- Title:
- Source Rock Distribution and Exploration Prospect of Jilantai Sag in Hetao Basin, China
- Author(s):
- SUN Liu-yi; PU Ren-hai; MA Zhan-rong; WANG Fei
- 1. Research Institute of Exploration and Development, Changqing Oilfield Company, PetroChina, Xi’an 710018, Shaanxi, China; 2. Department of Geology, Northwest University, Xi’an 710069, Shaanxi, China
- Keywords:
- source rock; oil source comparison; stratigraphic correlation; Guyang Formation; seismic facies; sedimentary facies; exploration prospect; Hetao Basin
- PACS:
- P618.13
- DOI:
- -
- Abstract:
- In the northwest slope of Jilantai sag, Hetao Basin, the light crude oil display is found in the fractures of Proterozoic metamorphic rocks buried in hundreds of meters. This reveals that there is a certain hydrocarbon generating potential in the area. Using seismic facies analysis to solve sedimentary facies belts and distribution of source rocks of Guyang Formation is an important issue for evaluating the exploration potential of Jilantai sag. According to the outcrops, drilling and seismic data, the stratigraphic correlation, seismic facies and distribution of source rocks were comprehensively studied. The results show that the Lower Cretaceous Guyang Formation in Jilantai sag of Hetao Basin is a rift basin with dry climate proximal fan deposits intercalated by two periods of fan dalta-semi deep acustrine facies; wells TS1, TS2 and JC1 drilled in the sag have a number of thin layers of dark mudstone in Gu1 Member; the acoustic impedance of lacustrine shale and limestone is higher than that of sandstone, and the lacustrine deposition forms strong amplitude reflection on seismic sections; the thickness of dark shale is 20-30 m with the maximum of 45 m, and it distributes along the center of NE sag; the total organic carbon(TOC) of dark shale is 0.31%-2.63% with the type of Ⅱa-Ⅲ; the source rocks in outcrop are overmature, but well ST1 is immature-low mature; the oil from fractures of metamorphic rock at the depth of 540 m in metal exploration well ZK500 belongs to the same source of oil from 4 m oil sand at the depth of 2 270 m in well ST1, and the hydrocarbon generation periods should be the end of Pliocene; the aeromagnetic anomaly and seismic reflection suggest that there is upwarp intrusion near well ZK500, resulting in the fast lateral change of source rock maturity in Jilantai sag; the favorable hydrocarbon generating and exploration areas should be located in a fault convex zone with greater depth, the northern part of Jilantai sag.
Last Update: 2018-10-01