Reservoirs Characteristics And Evaluation Of Cretaceous In Xianlaga Depression, Erlian Basin

Xianlaga depression in Erlian basin affected by multiphase structure and magmatic activity, sedimentary microfacies and composition characteristics of the Cretaceous Aershan and the Tenggeer Formation reservoirs is complex, this paper mainly based on the well core of hao1, logging and outcrop lithology analytical data, According to sedimentology, petroleum geology and reservoir geology theory as a guide, on the basis of previous studies, with emphasis on the background of the depression reservoir deposition, distribution and occurrence, microfacies types, lithological composition, pore structure as well as the main controlling factors has been systematically studied.Study found that the main reservoir in the Lower Cretaceous reservoir Xianlaga depression is sandstone reservoir, the maturity of the textural maturity and composition of the ingredients are low, the main pore type is secondary porosity, the main reservoir space types are feldspar dissolution pores, clastic debris dissolved pore and micro-cracks, the main reservoir influencing factors are the structure, sedimentary facies and diagenesis.On this basis, the Erlian Basin Cretaceous sandstone reservoir properties criteria as a standard, classification and evaluation of the Cretaceous reservoir depression of the Xianlaga, that the Xianlaga depression Lower Cretaceous reservoir is mainly divided into three categories, Class I reservoir:porosity greater than18%, permeability greater than10×10-3μm2, the main pore type is secondary porosity, apparent control by the microfacies; class Ⅱ reservoir:porosity of18to10%, permeability1～10×10-3μm2, the main Pore type is secondary porosity, class Ⅲ reservoir:porosity＜10%, permeability＜1×10-3μm, is the most common type of reservoir in the area, the pore type is secondary porosity or primary porosity which was compaction, cementation reduced.