Analysis Of The Relationship Between Low-high Tectonic Pattern And Faults In Linhe Depression And Its Evolution And Petroleum Entrapment Favorable Area

Linhe depression in Hetao Basin is an important area for oil and gas exploration,The structural characteristics are the basis of studying the distribution law of oil and gas reservoir in Linhe depression.Previous studies have done a lot of research on the regional tectonic characteristics,fracture characteristics,local structural features and tectonic evolution of the area,however,the study on the the low-high structural pattern and its relationship with the fault and the fault related structures which closely related to the petroleum entrapment is relatively weak.In this paper,on the basis of a large number of seismic data and geological data,the Linhe depression low-high tectonic pattern and its relationship with fault and fault structure are studied,and based on it,the characteristics of petroleum entrapment were studied.Made the following understanding:1.The low-high structural patterns of the main hydrocarbon source rock series Te(Lower Cretaceous roof)and Tnl(Oligocene roof)in the Linhe depression are both semi concave-side apophysis,the trough-line is located in the north of the basin and deep depression in the Northwest,the uplift-line is located in the southeast of the basin boundary.The overlying strata Tn2(Miocene roof)and Tq(Pliocene roof)low-high structural pattern and Te,Tnl seismic reflection layer is similar to that of the same as the semi concave-side apophysis,the trough-line,the trough-line is located in the north of the basin near the Langshan fault.The Te layer low-high structural pattern is similar to that the Te layer at the end of-Paleogene,Miocene and Pliocene,which are both semi concave-side apophysis.The Tnl layer low-high structural pattern at the end of the Miocene,Pliocene and the low-high structural pattern of Tnl current is also similar,both semi concave-side apophysis.2.In the low-high tectonic units of the Te and Tnl layer development Hanghou and Hangwu fracture,they belond to fault parallel to the slope.The two fracture is in the intersection,extended longer,they segmentation of low-high tectonic units from the middle part.The two fracture are formed in Paleogene,which are continuous fault,during the Miocene and Pliocene epoch,the activity is more severe.The Hanghou fracture is a northwest normal fault,the Hangwu fracture is a northward normal fault,the two fault sections have the characteristics of steep and slow.The combined conformati of the terrane on both sides of the fault are in accordance with the distribution of half-ridge-half-valley of the same tendency and the valley shape,fracture hanging wall development of rollover anticline structure.3?The hydrocarbon migration in the source rocks of the Linhe Depression is mainly between the trough line and the Hangwu and Hanghou fault zones.The vertical permeability of Hanghou and Hangwu fracture is obvious,Oil and gas migration along faults,and migrate to the the shallow zone of fault and fracture related structure.The Cretaceous has two oil and gas enrichment zones,Paleogene has three favorable areas,it is mainly located in the intersection area of the hanging wall of the Hanghou,Hangwu fault and the tectonic ridge in the north of the fault.Neighbors of the favorable area mainly around the Hangwu,Hanghou fracture related structural area.