Research On The Logging Evaluation Of Complex Lithology Reservoir Of Hai-Tai Basin

Logging reservoir evaluation, as the main content of fine reservoir evaluation, affects the whole process in oilfield from the initial exploration to the later production, thus having great research significance. This paper proceeds lithological analysis and petrophysical experiments for reservoirs with complicated lithology in Tongbomiao Formation and the one and two sections of Nantun Formation. Experiments, such as multi-salinity rock-electricity experiment, core NMR experiment, mineral X ray diffraction experiment, and natural gamma ray spectrometry experiment, are implemented. All kinds of factors which influence rock-electricity parameters are analyzed, and quantitative interpretation model of saturation is established. The resistivity log respond is simulated and analysised with time-lapse logging method Then, by combining core data, effectiveness of the established model is analyzed and validated, and fine logging interpretation model and evaluation method suitable for this region are obtained.The formation is polluted by the mud-filtrate invasion in some degree, making the resistivity acquired by well logging different from the virgin one. The invasion was simulated based on Two-phase Fluid Flow Theory. Combined with the characters of Haita basin, we analyzed the effect of mud-filtrate invasion on porosity and permeability and so forth. In addition, the simulation of time-lapse logging was carried out on the key well of the study area, the invasion and the controllable factors are analyzed comprehensively. All of these works are beneficial to compute the reservoir fluid saturation.Porosity and shale volume are important parameters for quantitative logging evaluation and qualitative interpretation. During the initial logging interpretation, the cross plot technique of three porosities is commonly adopted for porosity computation, and permeability is calculated according to the existing model. Due to the lack of coring and geological data, the interpretation accuracy is doubtable. In this paper, with method of core calibrating log, a porosity model based on core experiments is established. On the basis of the characteristic of rock compositions, porosity and all kinds of mineral compositions are quantitatively computed by optimum interpretation model, thus two different ways of computing porosity obtained, which compensates the shortage of uncertainty in choosing matrix parameters during the initial interpretation.Due to the complex salinity distribution of the study area, we carried out many petrophysical experiments including multi-salinity resistivity, cation exchange, NMR and so on, comprehensively analyzed the main factors on rock-electric parameters. Combined with the geological properties, the saturation is computed with several saturation models including Archie equation, malm rock electric conduction, effective water electric conduction and rock matrix electric conduction. The comparison with sealed coring approves the model.