松辽盆地北部深层火山岩储层特征

CHARACTERISTICS OF DEEP VOLCANIC RESERVOIRS IN NORTHERN SONGLI AO BASIN

松辽盆地北部深层的火山岩储层主要分布于徐家围子断陷的火石岭组和营城组 ,其爆发相和溢流相火山岩储集性能较好 ,孔隙度一般为 6 3 %～ 10 8% ,渗透率为 0 5 5× 10 - 3～ 12 2 0× 10 - 3μm2 。火山岩的储集性能主要受构造作用、溶蚀作用及流体活动的影响。松辽盆地火山 -断陷期的构造活动致使火山岩产生大量次生裂缝 ,储集性能提高 ;淋滤作用主要改造爆发相凝灰质熔岩 ,使其变得极为疏松 ,孔隙度提高到 15 %以上。流体活动对火山岩储集性的改造具有双重作用 :一方面新矿物的胶结和充填使得储集性能下降 ;另一方面 ,蚀变和溶解作用又可使孔隙度增加。因此 。

Deep volcanic reservoirs of Songliao basin have mainly been found in Huoshiling and Yingcheng Fms..The eruptive and overflow facies have better reservoir capacity , commonly with the porosity of 6.3%～10.8% and permeability of about 0.55×10 -3 ～122.0×10 -3 μm 2.The reservoir capacity of volcanic rocks has largely been affected by tectonism,solution and fluid activity.There are lots of fractures in volcanic rock due to tectonic activity during the volcanic-fault-depression period in Songliao basin,which would enhance the reservoir capacity.The eruptive tuffaceous volcanic has been mainly changed by leaching, and become loose and porous,with the porosity to be increased to over 15%.Fluid flow has double effects on reservoir capacity of volcanic rock, reservoir capacity would be reduced by cementation and filling of new minerals,but on the other hand, porosity would be increased by alteration and solution .These should,therefore, be studied separately by stages and periods.