Solid-Fluid Action Of Glutenite And Predicton Of Favorable Reservoirs In North Belt Of Dongying Depression

According to systematic study of petrography and diagenesis of deep glutenite in North Dongying Depression, main controlling factors of the reservoir are discussed. Thus reservoir evaluation and classification are studied, and favorable reservoirs are predicted, which is very significant to the exploration and development of Shahejie Formation Member Four in North Belt ,Dongying Depression.Based on the already collected data and core observation, samples are picked out and made into thin sections. After identification of normal slices and cast slices, main rock types of the target layer are listed, with its respective petrography, diagenesis and pore-type characteristics. Combined with collected physical property data such as porosity and permeability, reservoir physical properties are discussed, and analyzed through wellbore logging. Favorable reservoirs are predicted using combined data of sedimentary facies, diagenesis facies, and single well reservoir evaluation. Several main results and conclusions are achieved as follows:Sedimentary facies such as neritic subaqueous fan, deepwater turbidite fan and sublacustrine fan develop in Shahejie Formation Member Four in North Belt. According to core observation, main lithology developed in Shahejie Formation Member Four in the studied area is sandy conglomerate body, with arkose, lithic arkose and feldspathic lithic sandstone being main types of sandstone here. Both compositional maturity and textural maturity are low, interstitial material is mainly made up of argillaceous miscellaneous matrix and cement mixed. The cement is mainly calcareous, kiesel, or argillaceous, with minor minerals such as pyrite and chlorite. Lithoclasts often take a larger proportion in the complex rock composition. Diagenesis imposes more effects on pores.Shahejie Formation Member Four experienced multiple diagenesis processes. acidic or alkaline diagenetic fluids destroyed or improved reservoir rocks for different degrees during different times. Solid - fluid action affects reservoir properties dramatically.Besides solid - fluid action, other factors, like sedimentary facies, tectonic activities, and depth can also influence reservoir properties in the studied area. Those factors are closely related to impacts that solid - fluid action has on reservoir properties.Favorable reservoirs in the studied area are neritic subaqueous fan and deepwater turbidite fan. Physical properties can vary greatly between different subfacies or microfacies in the same sedimentary face. Take neritic subaqueous fan for example, sandy conglomerates of braided channel in middle fan form best reservoirs, main channel microface in inner fan form the second best kind of reservoir, while outer fan form worst reservoirs.Tectonic activities mainly affected this area through faults. From the porosity isopleths map we can see that, porosity is higher near the faults, especially around turning positions where the faults changes there strike directions. Many fault block reservoirs are found around Shengbei Fault, because of faulting processes.