Seismic Characterization And Gas-bearing Analysis Of Deep Metamorphic Buried Hill Reservoir

The large-scale condensate gas field discovered in the BZ area of Bohai Sea is a deep-seated metamorphic buried hill oil and gas reservoir,which was controlled by the development of the main structural styles of the Indosinian and Yanshan Movements which caused the NW and NW faults zones.The top interface and the inner structure of Archean buried hill are complex and various.The interaction of Wedge Thrust,double thrust and fault depression causes a three-dimensional network of fault-fracture system.The deep and strong heterogeneity of buried hill Reservoir,rapid lateral change of lithology,high degree of deformation,and poor quality of seismic data in the target area bring many challenges to the technology of seismic reservoir prediction.This paper is based on requirement of fracture and gas-bearing reservoir characterization in the seismic data interpretation of deep metamorphic buried hill reservoirs in the BZ area of Bohai Sea.The main research contents are fracture prediction and gas-bearing property analysis.For fracture prediction,some seismic attribute analysis methods which can reflect the characteristics of different scales and different orientations are adopted in the study,which mainly includes high precision coherence analysis,directional weighted enhanced coherence analysis(AFE),maximum Likelihood method and fracture prediction based on the different azimuth,and is combined with seismic forward modeling,well logging fracture evaluation and analysis of geological tectonic movement.And the distribution of fracture zone and the time of fracture development at the top of the reservoir in the Archean Buried Hill are concluded.It is pointed out that the NE strike-slip faults and associated high-angle fracture system were formed in the Yanshan movement period,while the north-west fault and associated high-angle fracture system were formed in the Indosinian period.For the gas-bearing analysis,AVO response characteristics and attribute analysis,wave impedance inversion and other methods are used to predict the gas-bearing favorable areas.The above results of methods research and their application to the area provide scientific basis for exploration and deployment in the study area,and also provide references of seismic methods selection for the further exploration and development in BZ and similar areas.