Contrastive Studies On Reservoir-forming Factors And Enrichment Regularity In The Southeast Of Linqing Depression

Making the contrast of the three depression of geological structure and oil and gasdistribution law as the main line, to discuss the impact of structure on the sedimentary fillingand reservoir forming factors, the differences of reservoir forming and oil and gas enrichmentare studied in this work, applying the theories and methods of basin analysis, structuralgeology and petroleum geology synthetically.This paper does research on the geological structure and its impacting on the depositioncombining with the tectonic setting of the Bohai Bay, using the basin simulation te chniques.In the plane, the form of the three depressions in the study area is long and narrow, and thetectonic framework shows “two sags and one uplift” as a whole. Fault activity is different dueto the different sections. The Paleogene fault activity rate in Dongpu Depression is bigger andact successively. Stretching structural style is main structural style, and salt structural traps,such as graben and rolling anticline developed in the central uplift belt in the north, anddeveloped east and west deep sags successively. Sedimentary environment is not continuousand stable and is unfavorable for developing source rocks, due to Reverse tectonic andsedimentary migration significantly in the eastern part of the Linqing Depression.Accumulation factors in the study are contrastively studied with basic data analysis andthermal modeling imitation. The source rocks of Dongpu depression and the eastern part ofLinqing Depression shows the characteristic of “one large and one small, one thick and onethin, one high and one low”. Self-source-reservoir-sealing and older generating and olderreservoiring are the main assemblages types in the study area, duing to the development ofmultiple sets of salt rock, the reservoir-seal assemblages of Dongpu Depression is better thanthat of Southeast district of Linqing Depression. The combination of types of source rocks,reservoir-seal assemblage and pressure show the characteristic of "North good(high), and South poor (low)".Type and abundance of organic matter of source rocks intergrowth withrock salt in the North is better than that in the Southern District. Multiple salt-sandreservoir-seal assemblage in the vertical developed in the deposition center of Weicheng–Wenliu developed area of the salt rock. Onthe contrary, the abilityof covering oil and gas ofsand-mud reservoir-seal assemblage in the Southern district is weak.Hydrocarbon level is determined by the type of depression, asymmetric structure and oilgeneration condition. Dongpu Depression inherited single off type reaches the standard of therich oil and gas depression according to the total amount of resources and resource abundance,but the eastern part of the Linqing Depression is poor in oil resources. The main controllingfactors of different oil and gas enrichment between northern and southern of DongpuDepression are confirmed. They have the common oil and gas distribution characteristics. Oiland gas is strictly controlled by fault and move up to the west high position from the east sagzone. Of course regularity of distribution of oil and gas also is different due to the betterquality of source rocks and the development of salt rocks and abnormally high pressure in thenorthern part of the Linqing Depression, making the oil and gas reserves of the North severaltimes than that in the Southern.