Fault Structural Characteristics And The Controling Function Of Hydrocarbon Accumulation Process In Wuerxun Sag

Wuerxun sag is the internal level 2 sag of Haita basin, is the most potential exploration areas. This paper mainly fault accused of Tibetan accentuation, caught in Wuerxun sag fault development and hydrocarbon accumulation the core problems, according to the regional geological research achievements, further system research in Wuerxun sag structure, construction characteristics and the formation and evolution process, and analyses fault of the influence of petroleum geologic conditions. Through this research thinks:Hang up in Wuerxun sag is bounded by T2-2 reflection can be divided into two sets of fault system, the upper fault system is mainly distributed in the K₁d, grinding turn K₁y group broken bend so as to breakstubborn strata and K₂q flexed, bottom stuck strata within fault system is mainly distributed in K₁t, south of K₁n within the faulted strata.In Wuerxun sag of rupture of evolutionary times was divided into six stages respectively, corresponding to the K₁t, K₁n₁,K₁n₂,K₁d1～K₁y1,K₁y₂₃,K₁y～K₂q period. Among the strong activity period in fault K₁t, K₁n₁,K₁n₂,K₁y₂₃,K₁y～K₂q period. In different periods of activity intensity of deformation and fault characteristics different.Will be in Wuerxun sag development of fault is divided into four sets of fault system: namely early stretch fault system, mid zhang twist fault systems, early stretch medium-term zhang twist fault systems and early stretch medium-term zhang twist late reverse fault systems. Fault evolution process for early put in twist night reverse polyphasic deformation stack.In Wuerxun sag freshman section plastic layer make fault vertical upward piecewise growth. When a fault fault distance to increase, will cut plastic layer, communication nether. Think in Wuerxun sag early stretch medium-term zhang twist fault system is formed the wrong without breaking mudstone daub, to keep out fault, and early stretch mid to late twist zhang against real cut freshman segment of the fault, it is to make big grinding turn of the oil accumulation in the oil source of fault. We value calculation, think through SSF when early stretch medium-term zhang twist late reverse fault SSF values greater than 7.1, fault fault put on regional cap rock overburden, in other conditions suitable conditions, can be formed in sophomore year section secondary hydrocarbon reservoirs.In only consider docking closed, keep out fault is besides reversal period in the trunk of large fault activities outside the reverse faults and fault distance part of larger whetherisolated faults.In Wuerxun sag fault accused of hydrocarbon mode have 4 kinds: that is, oil primary migration whetherisolated reverse faults common occluded K₁n subsags transform parts assembled mode, oil and gas vertical migration reverse fault conducting K₁d turn of the reverse tectonic gathered mode, gas vertical migration south K₁n gas reservoir deep fault handover parts assembled mode, rupture segmentation fan body gathered mode.