Quantitative identification of relatively highlevel radioactive sandstone in the Upper Triassic Yanchang Formation of the Ordos Basin, China*
Li Ya-Jun, Zhang Xiao-Li, and Yan Yuan-Zi
1. Department of Geology, Northwest University, Xi’an 710069, China.
2. National & Local Joint Engineering Research Center of Carbon Capture and Storage Technology, Xi’an 710069, China.
Abstract Most relatively high-level radioactive sandstone (HRSS) reservoir has considerable oil (or gas) resource potential. HRSS is often wrongly identified due to its similar logging response characteristics as mudstone, which leads to the omission of effective reservoirs. In this paper, a quantitative identifi cation method for HRSS is proposed after the analyzing of the response characteristics and relationship between spontaneous potential log and natural gamma-ray log in conventional sandstone and mudstone strata. Take the Upper Triassic Yanchang Formation in Ordos Basin as an example: the responses of spontaneous potential log and the responses of natural gamma-ray log are synchronized and positively correlated in conventional sandstone and mudstone strata, but they are not synchronized in HRSS. Quantitative identification of HRSS was realized based on this synchronization feature, and a “virtual compensation” of natural gamma-ray log was performed. At the same time, logging evaluation method about HRSS has been discussed. The fi nal results shows that this identification method work effectively, and can reduce the misjudgment and omission of effective reservoirs.
About author: Li Ya-Jun, a Ph.D. student in Mineral Resource Prospecting and Exploration, Northwest University, China; mainly engaged in well logging data interpretation and unconventional reservoirs evaluation. E-mail: 2602040130@163.com
Cite this article:
. Quantitative identification of relatively highlevel radioactive sandstone in the Upper Triassic Yanchang Formation of the Ordos Basin, China*[J]. APPLIED GEOPHYSICS, 2019, 16(3): 315-321.
2019, Vol. 16 
