辽河断陷盆地东部凹陷新生代火山岩裂缝成因探讨

An approach to genesis of Cenozoic volcanic fractures in eastern sag of Liaohe basin

辽河断陷盆地东部凹陷火山活动频繁。新生代时期,受燕山运动、喜山运动Ⅰ、Ⅱ、Ⅲ幕的强烈影响,本区喷发了多期强度不等的火山岩。该区火山岩油藏的裂缝类型具有原生裂缝(包括冷凝收缩缝、收缩节理和构造原生节理、炸裂缝等)和次生裂缝(包括构造裂缝、溶蚀缝和风化缝等)两种。火山岩的岩石类型、喷发形式和所处的构造位置是火山岩裂缝形成的内因;构造运动、溶蚀作用、风化作用是火山岩裂缝形成的主要外因。这种内因和外因的联合作用,形成了本区复杂的裂缝系统。

Volcanic events were active in eastern sag of Liaohe basin. During Cenozoic, volcano of this area had erupted at different strengths in many periods as affected by Yanshan movement, and the Ⅰ , Ⅱ , Ⅲ episode of Himalayan movement. Fracture types in volcanic reservoirs of this area include primary fracture (including condensed constricted fissure, constricted joint and structural primary joint, and explosive fracture) and secondary fracture (including structural fracture, solution and weathered fracture) . The internal causes of forming of volcanic fracture are rock type, eruption form and position in structure; main external causes are structural movement, solution effect and weathering. The combination of internal and external causes resulted in complex fracture system in this area.