Research On Burial, Geothermal,Hydrocarbon Generation History In Wangfu Dehui Depression

Rift of Wangfu and Dehui is the secondary structural elements in Songliao depression,faulted strata from the bottom to the top is Huoshiling, Shahezi,and Yingcheng. In this treatise,the abundance of organic matter, organic matter type, maturity of organic matter as the entry point to assess geochemical characteristics of hydrocarbon source rock, combine with the information of geological, geophysical and geochemical, rehabilitate the burial history of the study area with basin modeling technology, discuss the heat thermal history based on the the theory of EASY% Ro model inversion. combined with trigonometric of the study area,combined with the kinetic parameters and geochemical characteristics of hydrocarbon source rocks to calculation the generation history.This paper made the following understanding:1. Two downfaulted achieves very good level of organic matter abundance,Yingcheng is a bit poor. Organic matter is mainly Ⅱ type of Huoshiling Yingcheng and Shahezi is a bit poor. Formation maturity during faulted period Ro are between 1.25% ~ 1.75%, in mature to high mature. Wangfu sag maturity is higher than Dehui, hydrocarbon generation ability better than Dehui.2. Two fault have similair burial history. During Shahezi to Yingcheng stratum buries fast.At the end of Yingcheng, stratum lift obviously. Dehui lifts higher than Wangfu during this stage. Its degree of denudation quantity increased from north to south.3. The history of geothermal gradient of Wangfu fault depression is divided into three stages. The first is the decline stage(Huoshiling ~ Yingcheng) from high geothermal gradient to the low in the fault depression period. Stratum temperature rising rapidly The second is the slowly rising stage(Denglouku to Nenjiang early)of geothermal gradient from distinctive quality period to depression period. Stratum temperature rises fast.At the beginning of Nenjiang stratum reaches maximum depth, corresponding stratum temperature reaching the highest. The third is the stable phase of geothermal gradient in phase inversion.4. Combining before burial history, thermal history, kerogen kinetic parameters and oil pyrolysis activation energy parameters can be worked out: Wangfu and Dehui fault depression hydrocarbon generate mainly of C6+, two periods of hydrocarbon generation is the same,between 105 Ma and75Ma, Corresponds to the period of quantou and nenjiang.Hydrocarbon generate time earlier, time is short.Large of angry period in Shahezi is between115 Ma and 88 Ma, Corresponds to the period of quantou and late yaojia. YINGCHENG between 114 Ma ~ 84 Ma. Corresponds to the early and late Quantou.Yaojia angry between114 Ma ~ 84 Ma. Corresponds to the late Quantou and early Yaojia.The time of oil generation in two rift in Huoshiling is similar,between 90~70Ma. Taking into account the thermal history we know,cracking time surely behind the hydrocarbon complete.In line with the temperature of subsidence history will rise,combine with the hydrocarbon factors,we can obtain the proportion of the generated pyrolysis oil is 70%,oil cracking threshold Ro=1.1%...