Abstract:

Binnan Oilfield is situated at the northwest margin of the Dongying Sag in the Jiyang Depression. The reservoir is an assemblage of andesiticbasalt lava and breccia with vesicles and fractures as reservoir spaces.The block trap consists of overlying source rocks and tensil faults. Thepool is a complex massive fault-block one composed of several amall blockswith similar oil-water boundary, its buried depth is 1700-1800m, andthe overlying thick dark beds and the neighbouring Lijin oil-generating sagserve as its oil source. The volcanic rock in this area is a composite volcanic massif composedof seven craters. It was formed by multi-eruption and multi-overflowduring the Oligocene,covering an area of about 20 km² and overlying on Bin-338 horst in beded pattern with a thickness of 2-63m. To study the reservoir rock, the volcanic rock can be divided into 4facies such as low vesicle lava, vesicular lava (A¹, A²), welded and unwel-ded volcanic breccia (B¹, B²) according to vesicle content, breccia struc-ture and welded feature. Among them, A², B² are fine vesicle-fracture re-servoir rock facies. The lava-clastic cone are divided into 3 facies zones due to the distribu-tion of lithofacies for the need of hydrocarbon exploration: crater facieszone (Ⅰ), middle distance volcanic slope facies zone (Ⅱ) and distancevolcanic slope facies zon(Ⅲ). It has teen shown by physical property analysis of lithofacies assemblage and well testing data that the type-Ⅱfacies zone is a favourable reservoir facies zone. Volcanic facies and structural position are controlling factors for theenrichment and productivity of fault-block massive volcanic oil pool theposition near the fault in the middle-distance volcanic slope facies zone isthe very place of hydrocarbon enrichment and productivity.