CAJ | 학술논문

松辽盆地徐家围子断陷是位于松辽盆地北部深层的半地堑型晚侏罗世早白垩世伸展断陷，火山岩发育。在已有研究成果的基础上，结合野外露头和岩心观测及镜下研究发现：本区火山岩构造裂缝和溶蚀裂缝都比较发育，具有明显的规律性，多数原生缝被后期的构造应力或溶蚀作用改造成次生缝。本区裂缝形成的控制因素较多，主要有应力、构造、岩性和岩相、溶蚀作用、风化淋滤、构造应力场演化等，其中构造应力场演化、岩性和岩相及风化溶蚀作用是控制裂缝形成的主要因素。构造裂缝以高角度的张扭性和张性缝为主，多为半充填和无充填，具有多期、多方向、组合复杂等特点，是晚侏罗世至新近纪各种地质作用相互叠加的结果。构造通过控制不同构造部位的局部应力场分布来控制裂缝发育程度，沿断裂带存在明显的应力集中，形成裂缝发育带，特别在正断层上升盘、断层端部、背斜轴部等应力集中部位容易形成构造裂缝。有效火山岩油气储层为各类原生孔隙与裂缝的有效组合。由于火山喷发多个旋回叠加，加之风化剥蚀及不整合面的存在，造成裂缝在纵向上发育具有旋回性，溶蚀裂缝主要在不整合面附近发育。在平面上，裂缝主要发育在断裂密集区、断裂交汇部位和背形或向形构造发育的地区。本区处于爆发相和溢流相火山岩的发育区，气孔和裂缝最发育，特别是溢流相的流纹岩中，裂缝和气孔均较为发育，是本区的优质储层最发育区，也是天然气富集区。
송료분지서가위자단함시위우송료분지북부심층적반지참형만주라세조백성세신전단함，화산암발육。재이유연구성과적기출상，결합야외로두화암심관측급경하연구발현：본구화산암구조렬봉화용식렬봉도비교발육，구유명현적규률성，다수원생봉피후기적구조응력혹용식작용개조성차생봉。본구렬봉형성적공제인소교다，주요유응력、구조、암성화암상、용식작용、풍화림려、구조응력장연화등，기중구조응력장연화、암성화암상급풍화용식작용시공제렬봉형성적주요인소。구조렬봉이고각도적장뉴성화장성봉위주，다위반충전화무충전，구유다기、다방향、조합복잡등특점，시만주라세지신근기각충지질작용상호첩가적결과。구조통과공제불동구조부위적국부응력장분포래공제렬봉발육정도，연단렬대존재명현적응력집중，형성렬봉발육대，특별재정단층상승반、단층단부、배사축부등응력집중부위용역형성구조렬봉。유효화산암유기저층위각류원생공극여렬봉적유효조합。유우화산분발다개선회첩가，가지풍화박식급불정합면적존재，조성렬봉재종향상발육구유선회성，용식렬봉주요재불정합면부근발육。재평면상，렬봉주요발육재단렬밀집구、단렬교회부위화배형혹향형구조발육적지구。본구처우폭발상화일류상화산암적발육구，기공화렬봉최발육，특별시일류상적류문암중，렬봉화기공균교위발육，시본구적우질저층최발육구，야시천연기부집구。
Xujiaweizi fault depression is a Late Jurassic-Early Cretaceous deep half-graben type extensional fault depression in northern Songliao basin,and volcanic rocks developed.The article is mainly based on macro and micro studies on outcrops,cores and thin sections.Tectonic fractures and corrosion fractures are well developed,and show apparent regularity.Most of primary fractures are transformed into secondary fractures by later tectonic stress or dissolution.Fractures formation are controlled by several factors, for instance, regional tectonic stress and its evolution, structure, lithology,lithofacies,dissolution,weathering.Among these,tectonic stress field evolution,lithology and lithofacies, weathering and dissolution are dominant factors. Most of tectonic fractures are characterized by high angle,tensional and torsional,part filled or unfilled,multi-period,and multi-directional,which is the results of the superposition of various geological and tectonic role from Late Jurassic to Neogene.Local development of fractures are controlled by local stress field distribution.In general,since obvious stress concentration,fault systems are fracture development zone.Local stress are especially concentrated in the hanging wall of normal fault,the end of normal and reverse fault,and anticline axis,where tectonic fractures are abundant.The effective hydrocarbon reservoirs in volcanic rocks are controlled by combination of primary pore spaces and structural fractures.The fracture development shows vertical cyclicity because of multi-eruption,weathering and unconformable surface. The dissolution fractures develop near unconformity.In plane,the fractures mainly developed in fault-concentrated area,faults intersection,anticline and syncline.Pores and fractures is the most developed in explosive and effusive facies,especially in effusive rhyolite.The rhyolite is the most advantageous reservoir and high yield gas production area.