Fine Characterization Of Pre Jurassic Paleogeomorphology In The Yanwu Area Selection Of Favorable Production Areas

Over the years,the Jurassic Yan10 oil layer formation in the Yanwu area has been the main oil layer with great exploration potential and is an important exploration horizon in the basin.The Indosinian movement occurred during the Late Triassic,eroding the upper strata of the Yan’an Formation,comprehensively uplifting the Ordos Basin,and then accepting the sedimentation of the Jurassic Yan’an Formation.Therefore,the paleogeomorphology and sedimentary environment control the distribution of oil reservoirs in the Yan’an Formation.This article finely characterizes the pre Jurassic paleogeomorphic morphology,clarifies the sedimentary microfacies types,sand body distribution,and microstructure characteristics of the Yan 10 oil layer group,analyzes the geological conditions and main controlling factors of the formation of the Yan 10 oil layer,and constructs the paleogeomorphology and oil and gas enrichment laws.On this basis,it is recommended to establish a favorable target area.Research has gained some understanding in the following areas:1.On the basis of structural background and previous research,through comprehensive research of various data,the Yan10 oil layer formation in the Yanwu area is finely divided into three sub layers and compared.2.The ancient geomorphic units were restored and depicted by the impression method,well seismic combination method,erosion surface contour map analysis method,etc.The shape of branch river valleys in the north of Yanwu area was more refined,and three new branch river valleys were identified in the south of the mining right.3.According to the research on sedimentary microfacies,single well facies,well connected facies and sand body distribution of Yan10 member in Yanwu area,the core beach and flood plain sedimentary microfacies of braided river are identified.Micro nose uplift structure is locally developed,and the top structure of each sub stratum has good inheritance on the whole.The reservoir lithology is dominated by lithic arkose,with strong diagenesis;The dissolution of super large pores with good scale connectivity improves the physical properties of the reservoir,making it a low porosity medium permeability reservoir.4.Conduct research on reservoirs in the Yanwu area,and explore the rules of oil and gas enrichment and analyze the main controlling factors for reservoir formation.Research has shown that the morphology of ancient landforms controls the development of favorable facies zones,and the high parts of ancient structures are favorable areas for oil and gas accumulation.And based on this,predict and optimize the benefit area.