Abstract:

Although most oilfields discovered in the Bohai Sea were controlled by the NEtrending strikeslip fault, their controlling process was still poorly investigated. In this study, we choose the Shaleitian Uplift as one case to investigate the controlling process and mechanism of the NEtrending fault on the hydrocarbon accumulation. The result shows that the NEtrending fault had a longterm impact and cumulative effect on the hydrocarbon migration and accumulation. Two aspects about this impact are suggested: the Mesozoic sinistral motion of the NEtrending fault cut the basement, reworked the structural high of the basement, and consequently, controlled the migration pathways of hydrocarbon; whereas, the Cenozoic dextral motion of the NEtrending fault cut the draping structures and reworked the structural high of the Cenozoic strata, as a result, controlled the favorable site of hydrocarbon accumulation. Such understanding of the controlling process and mechanism of the NEtrending fault on the hydrocarbon accumulation can be widely referred in the hydrocarbon exploration of other areas offshore the Bohai Sea.

Key words: offshore Bohai Sea, strikeslip fault, Mesozoic sinistral motion, Cenozoic dextral motion, hydrocarbon accumulation