Study On The Structure Of Concave-Uplift Assemblage And Fault-Rock Assemblage In The Yingzhong-Yingdong Area Of Qaidam Basin

Yingxiongling tectonic belt is a hot spot for onshore oil and gas exploration in China.Since2015,Sh38,Sh205,Sh210,Sh52,Sh58,Shx58 and other high-yielding oil and gas wells have been discovered successively.However,the complex tectonic conditions in this area and disunified understanding of the structure restrict further oil and gas exploration work.Based on the latest three-dimensional seismic data processed by prestack depth migration technology,this paper conducts a preliminary study on the concave-uplift assemblage structure and fault-rock assemblage structure closely relating to accumulation,analyzes their relationship with discovered oil-gas reservoir,and obtains the following main understandings:?1?According to the configuration of trough line,uplift line,valley line and ridge line,T₄seismic reflection layer concave-uplift assemblage structure is divided,and the main type is the central uplift surrounded by concave.the low position of concave-uplift assemblage structure in Yingzhong area is located in the middle of northern border,the low position of concave-uplift assemblage structure in Yingdong area is located in the eastern part of northern border,and the low position of concave-uplift assemblage structure in Yingdongdong area is located in the eastern end of the northern border.?2?The 3D seismic data processed by prestack depth migration technology is used to explain four major faults,including Youshashan fault,XI fault,F_N1 fault and F_N22 fault.According to the fault plane structure,the relationship between fault and rock,the fault activity,and the open horizon,we analyze the fault-rock assemblage structure of the above fault and the extension section of XI,Youshashan,F_N1 fault in Yingxi area?Shibei fault and Shizigou fault?.Among them,the relationship between the fault and rock of Youshashan and XI fault is inversion inclination half ridge-half valley type.Both the faults have continuous activities from N₂¹ to Q₁₊₂ during the sedimentary period.And the relationship between the fault and rock of F_N1 fault is the same inclination half ridge-half valley type and inversion inclination half ridge-half valley type.It has continuous activities from N₂¹ to Q₁₊₂ during the sedimentary period.?3?The deep reservoir E₃¹?lower section of Xiaganchaigou formation?in Gasikule oilfield is located near the ridge line of concave-uplift assemblage structure and at the high position of the strike of XI fault in the Yingzhong area;The shallow reservoir N₁-N₂¹?Shangganchaigou formation-Xiayoushashan formation?in Gasikule oilfield,Youshashan oilfield and Yingdong oilfield are located in the higher position of the ridge in Youshashan fault plane;The oil-gas producing zones of Sh58 well and Shx58 well are located in the high position of the ridge in F_N1 fault plane.?4?Concave-uplift assemblage structure and fault-rock assemblage structure have an important control effect on the formation and distribution of oil and gas reservoirs,There are favorable condition of oil and gas reservoirs at the higher position of the ridge in F_N1 fault plane?between seismic tracks L1100&T500 and L1200&T600,L1350&T700 and L1400&T900,L1800&T800 and L1900&T900?,the high position of the ridge in XI fault plane?between seismic tracks L800&T200 and L900&T400,L900&T500 and L1000&T600,L1700&T1000 and L1800&T1100,L1900&T1000 and L2000&T1100?,and the high position of the ridge in Youshashan fault plane?between seismic tracks L1300&T500 and L1400&T650,L2200&T500 and L2300&T700,L2300&T900 and L2400&T1100?.