Characteristics and Distribution of Fractures in Mesozoic Volcanic Rocks in Southern Slope of Laizhou Bay Depression,Bohai Bay Basin
The reservoir fractures of volcanic rock of Kenli 16 structure on the southern slope of Laizhou Bay depression in Bohai Bay Basin are developed,which has a significant effect on reservoir quality.However,its formation period and distribution law are not clear,which restricts the in-depth understanding of the reservoir.Based on core,imaging logging and outcrop data,this paper studies the fracture types,formation stages and distribution of Mesozoic volcanic rocks in Kenli 16 structure.The main results are as follows:Six kinds of cracks are identified,including explosion cracks,crypto-explosion cracks,condensation shrinkage cracks,weathering cracks,structural cracks,and corrosion cracks.The fractures are mainly of middle to high angle.The condensation contraction fractures are mainly of medium scale,and the structural fractures are mainly of large scale.The fracture opening degree descends from pyroclastic rock,pyroclastic lava,and sedimentary pyroclastic rock to lava.The fracture formation period can be divided into five stages,and a large number of structural fractures are formed under the strike-slip stress system.The fracture surface densities of each lithology descend from lava,pyroclastic lava,and pyroclastic rock to sedimentary pyroclastic rock.The fracture surface densities of each facies descend from lava flow subfacies,hot clastic flow subfacies,and hot foundation wave subfacies,to collapse retransported accumulation subfacies.In the outcrop area,the fracture zone width of lava can reach 2 m,the cracks are mostly open,and the fault of the pyroclastic rock develops scratches,forming a decimeter-dense zone,which reduces the permeability of the rock.
fracture genesisdistribution lawvolcanic reservoirMesozoicBohai Bay basinLaizhou Bay depression
万方数据
维普
