Gaoqing Fault Zone, Possession Of More Than Coexistence Mechanism

GaoQing big fault which has been regarded as a bounding fault of DongYing sag and QingCheng uplift, is a long term inheritable actival big fault of basement, whose evolution controls the formation and evolution of QingCheng uplift and BoXing sag, and also has profound effection on hydrocarbon accumulation; Especially these reservoirs of three kind(oil reservoir,methane reservoir and carbon dioxide gas pool) ,which distribute along the GaoQing fault zone, coexist within the fault zone and each has it's unique character. According to the research of the factors during reservoir formation (fault seal research,oil-source correlation,Genetic Analysis Gas Pool,Unconformity research) and many aspects such as rule of multi-reservoirs coexistence etc, we have conducted systematic research on this special phenomenon of reservoir formation, and reached following results:At the base of fault's vertical and crossrange blockage theory, it regards that GaoQing big fault has obvious character of episodic transporting, it also a fault with character of both normal faults and torquing. Taking Gao 17 oil reservoir for example, the research has analysised the crossrange blockage of GaoQing zone fault belt, according to the lithological ordonnance in two sides of fault.By oil-source correlation, it is clear that the Qinggao oil field's main oil-source comes from source rock of S4 section of BoXing sag; The geochemical index of hydrocarbon gas inflects it has the character of petroliferous gas and has suffered from different extent of biology degradation. The character of carbon isotopes in nonhydrocarbon gas layer has proved its inorganic origin, mainly of magma-mantle cause. He,N₂ have also come from mantle.In the process of oil-gas accumulation in Gao-qing fracture belt, unconformity surface and connected sand body make an important chrous. Not only fracture surface is the migration channel, but also the mudstone upon it, has plugging effect. Since the sand body is the main channel for the oil-gas's lateral migration, accordingly many reservoirs of different types has formed such as : unconformity oil-gas pool, fault block oil-gas pool, lithological oil-gas pool, composite pool and so on.Reservoir formation of Gaoqing fractural belt has character of multi-periods,multi-accumulation, the enriching sections distribute along the bilateral of GaoQing fault. Each layer that contains oil-gas has obvious regionalization. Fault,sand body,unconformity has controlled the distribution of oil-gas and GaoQing fault is the main control factor among them. The oil source of oil reservoir is the hydrocarbon source rock of sag; hydrocarbon gas reservoir is regarded as petroliferous gas; Dioxide carbon reservoir is formed mainly by the movement of upper mantle caused by the emerge of deep part material: the deep part volatile matter and actival compound made up-migration with magma intrusion and fractural movement, then trapped within multi-traps located at the structural belt. At the same time, the non-hydrocarbon gas in Hua 501 gas reservoir which mainly contains He,N₂ and CO₂,and CH₄ petroliferous gas assembled separately, this mean that there were at least two period for reservoir formation.