玄武岩发育区砂岩储层特征及控制因素:渤海南部BZ34-9区与KL6区块对比

渤海南部BZ34-9区与KL6区块位于莱北低凸起南北两侧，均发育新生代玄武岩并得到钻井证实，但储层特征差异明显.以三维地震、薄片、SEM以及X衍射等技术手段对两个区块玄武岩时空展布，沉积体系以及储层特征进行对比.研究表明，BZ34-9区构造位于缓坡带，供源速率中等.渐新世玄武岩为沉积期及准同生期喷发且位于砂体主体部位，优质层段形成白云石包壳、沸石胶结溶蚀、混层粘土包膜等成岩响应，整体对储层发育发挥积极作用；KL6区构造近物源，供源强烈，渐新世玄武岩发育在凹陷内部，对砂体影响有限，储层以高岭石及碳酸盐胶结充填为特征，在成岩期受郯庐断裂带岩浆热液影响，绢云母、菱铁矿重结晶等现象普遍.对比分析表明玄武岩对储层的影响受控于火山喷发时机、物源供给速率、砂体及火山岩配置关系等因素. 

Characterization and Controlling Factors of Sandstone Reservoirs in Basalt Development Areas: An Example from Comparison between BZ34-9 and KL6 Areas in South of Bohai Sea

BZ34-9 area and KL6 area are located in the north and south of Laibei low uplift, respectively in south of Bohai Sea. The characteristics of the sandstone reservoirs in the two areas are of great differences in spite of the similar background of Cenozoic basalt development which has been proven by drilling. The contrastive studies on structural background, temporal-spacial distribution of basalt, sedimentary system and reservoir development have been taken combined with the analytical methods of 3-D seismic data, well log, casting thin section observation, SEM, BSE and X-ray diffraction. For the BZ34-9 area, braided river deltas were deposited on a gentle slope at low depositional rates. Syndepositional basalt flows occur in the upper and lower parts of the sand body and high-quality sandstone reservoirs are characterized by dolomite coats, zeolite cementation and dissolution, and mixed-layer clay coats, which collectively had a positive impact on the reservoir quality.By contrast, the KL6 area was situated on a steep slope and fan delta deposition occurred at a high rate. The Neogene basalt focused on the middle of the basin and had limited influence on the sandstone reservoirs which is characterized by abundant kaolinite and carbonate cementation. The Oligocene strata of KL6 area which situated near Tan-Lu fault zone has been greatly influenced by the Neogene basalt activities during the diagenesis stages. The magma and hydrothermal activity caused recrystallization of siderite, sericitization and prevailing precipitation of ferrodolomite. The basalt influence on the sandstone reservoirs are controlled by the time of eruption, source supply and the configuration of sandbody and basalt.