Abstract: Tahe oilfield, located in Akekule swell of south flank of Shaya uplift in northern Tarim basin, is an important base for incremental reserves and production of Sinopec. In 2004, the clue of Cambrian large-scale build-up was found by Northwest Branch during nine-block seismic interpretation. The determination of the geologic attribute of this build-up is of great significance for the nextstep exploration and its long-term deployment. This paper excludes the possibility that the build-up could be salt and volcanic rocks by the analysis of Cambrian reef-building organisms, the case study and the evaluation of sedimentary environment of the build-up, especially by the correlation of geophysical characteristics between the build-up and the volcano and salt body. The analogue from these geophysical characteristics and proved organic reef suggests that this build-up may likely be a bioherm.

Key words: Tahe oilfield, Cambrian, geology, bioherm, attribute