China Petroleum Exploration ›› 2021, Vol. 26 ›› Issue (3): 68-78.DOI: 10.3969/j.issn.1672-7703.2021.03.006

Previous Articles     Next Articles

Exploration breakthrough of Upper Paleozoic of Well Changtan 1 in southern Ordos Basin and its significance

Qi Rong, He Faqi, Wang Fubin, Jia Huichong, Wang Wei   

  1. Sinopec North China Oil and Gas Company
  • Online:2021-05-14 Published:2021-05-15

Abstract: Binchang Block in the southwestern margin of Ordos Basin is with complex structural features, In 2020, Well Changtan 1, a risk exploration well drilled by Sinopec, tested commercial gas flow in the Upper Shihezi Formation, marking the natural gas breakthrough in Upper Paleozoic in the southern margin of Ordos Basin. Subsequently, several wells tested commercial gas flow or penetrated good gas shows in Upper Shihezi Formation, Lower Shihezi Formation and Shanxi Formation, showing multiple gas bearing layers of Upper Paleozoic in the complex structural zone of southern basin, which is different from the Longdong area inside basin. In order to find out gas accumulation pattern and improve understanding of the provenance system in the southern margin of the basin, in this paper, the gas accumulation conditions of Upper Paleozoic in Binchang block were systematically studied, including the regional tectonic evolution, fault activities, characteristics of coal measures source rocks, sedimentary facies, reservoir distribution, regional preservation conditions, and natural gas transportation characteristics by means of lithologic logging, formation test, chromatography-mass spectrometry analysis, logging interpretation, seismic interpretation and attribute analysis, and regional geological analogy, etc. The study results show that there are favorable geological conditions for natural gas accumulation of Upper Paleozoic in the southern basin, which is characterized by “multi-layer superposition, fault transportation, lower generation and upper storage, and stereoscopic gas accumulation”. The gas enrichment is jointly determined by the distribution of high-quality reservoirs and high angle fault transportation. The areas where large-scale delta sand bodies are developed with large thickness and good physical properties, as well as high angle faults for gas migration and accumulation are favorable targets for gas exploration.

Key words: gas accumulation pattern, Upper Paleozoic, southern provenance area, Ordos Basin

CLC Number: