Lithofacies identification and favorable reservoir prediction of volcanic rocks in BZ8-A structure

The development of high-quality volcanic reservoirs is dominated by lithofacies.In order to figure out the distribution of favorable reservoirs in BZ8-A structure, we identified 16 ring and nearly-ring volcanic craters which are distributed linearly along fault development zones according to the lithofacies distribution mode and volcanic eruption mechanism of other central volcanic rocks that had been drilled in the Bohai Sea, based on the inner reflection characteristic and geometric shape of volcanic rocks, combined with seismic attributes, time and coherence slice.And around the volcanic craters, columnar and mushroom shaped volcanic channel facies, weak-amplitude, discontinuous and lenticular near crater facies (including eruption facies and overflow facies) and strong-amplitude and continuous far crater facies are identified.Among them, near crater facies is the most favorable facies for the development of high-quality reservoirs.In the main part of BZ8-A structure, it is the neutral-acidic eruption facies and overflow facies, and faults are developed.And favorable reservoirs are distributed near the unconformity of the main part and the short-period erosion surface, and their hydrocarbon potential is promising.