Song R.,Chengdu University of Technology |
Xiao J.,Chengdu University of Technology |
Xiao J.,China National Offshore Oil Corporation |
Li M.,Exploration and Exploitation Institute of Tarim Oilfield |
And 4 more authors.
Scientia Geologica Sinica | Year: 2015
On the basis of previous research, an uncomformable surface between the 1st sub-member of upper member of Kepingtage Formation in Tazhong area and the 2nd was discerned by the log information, the drilling core and the seismic profile. Then the rationality of the existence of the uncomformable surface was confirmed by some microscopic means, such as the thin section, the data of geochemistry, and so on, which could play a part in dividing the sequence of strata and the late oil and gas exploration in the area. There are several results as follows: 1) The ferritization of pyrite in the 1st and 2nd sub-member of upper member of Kepingtage Formation in Tazhong area is widthwise traceable. 2) The asphalt with shrink fractures in the 3rd sub-member of upper member of Kepingtage Formation formed because of the oxidation of the low maturity hydrocarbon during the migration of the oil and gas from the low tectonic position to the high. 3) Carbonate cement in the 3rd and 2nd sub-member of upper member of Kepingtage Formation mainly formed in fresh water or admixing water, and carbonate cement in the 1st and carboniferous mainly formed in sea water. These microscopic evidence confirms there is a phenomenon of the stratigraphic unconformity at the top boundary of the 2nd sub- member of upper member of Kepingtage Formation. ©, 2015, Science Press. All right reserved.