摘要
大池干井构造带的形成演化可分为四个阶段.其石炭系天然气的聚集主要受背斜及断层控制.早期,当背斜在水平挤压应力作用下两翼出现一对反冲断层组合成倒“八”字形断层-高点圈闭时,因圈闭发育较早、封闭较好而富存天然气;后期,在扭压应力作用下构造带演变为主断高和陡翼潜伏的次断高,前者有时因轴部发育缓冲断层而含气性变差,后者因破坏较小而富存天然气.
Dachiganjing structural zone is one that is quite a typical high-steep anticlinal faultfolded zone.Its subsurface structural pattern has varied obviously,and its concealed faultsand traps are developed well.Hence it has become a favourable Carboniferous gas reser-voir place with fracture and fracture-porous preserving spaces.The structural zone underwent following evolution process:in Himalayan period-1,a wide symmetrical anticline formed;in Himalayan period-2,recoil faults formed on theanticline,and a secondary concealed anticline derived from the footwall of the steep limb;in Himalayan period-3,the steep fault-depressed belt varied and two subrecoil faults de-rived from the secondary concealed anticline;in Himalayan period-4,a overthrust belt de-veloped on the culmination of the main structure and it made the structure disintergrateinto monofault traps or fault-block traps.The migration,acculmulation and distribution of hydrocarbon in the structural zoneare controlled by following two types of strctures.Type-1,the recoil fault assemblage (compressional faults),formed a kind of fault-culmination trap,which make the fillingdegree of Carboniferous gas pools equal or greater than 1.0;type-2,shear-compressionalfaults,usually reformed the primary gas pools,as the result,the gas pool filling degreeof Carboniferous reservoirs in Diaozhongba and Longtou area decreased to less than 1.0.The hydrocarbon pools in the study area are primarily anticline-fault type,and thenfault-block and fracture types.The later ones are generally not controlled by anticlines orculminations.
出处
《石油与天然气地质》
EI
CAS
CSCD
北大核心
1993年第2期126-132,共7页
Oil & Gas Geology
