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海塔盆地复杂岩性储层测井评价方法研究
Research on the Logging Evaluation of Complex Lithology Reservoir of Hai-Tai Basin
【作者】 葛新民;
【导师】 范宜仁;
【作者基本信息】 中国石油大学 , 地球探测与信息技术, 2010, 硕士
【摘要】 测井解释是储层精细评价的重要内容,影响着油气田从勘探初期到后期开发的整个过程,具有重要研究意义。本文针对海拉尔-塔木察格盆地k1t组,k1n1组和k1n2组复杂岩性储层进行了岩性分析和岩石物理实验研究;开展多矿化度岩电实验、岩心核磁共振实验、X矿物衍射实验、自然伽马能谱实验等;分析了影响岩电参数的各种因素、建立了饱和度定量解释模型;应用时间推移测井模拟方法对泥浆侵入地层引起的电阻率变化进行了分析,并结合岩心资料对建立的饱和度模型进行了有效性分析和验证,得到了适应于研究区域的测井精细解释模型和评价方法。泥浆侵入使得地层受到一定程度的污染,进而使得电测井响应不能真正的代表原状地层的电阻率;根据油水两相流理论模拟了地层的侵入特征;针对海塔盆地的特点,分析了孔隙度、渗透率等对泥浆侵入的影响,并对研究区块关键井段进行时间推移测井模拟,综合分析了研究区块的泥浆侵入情况和主控因素,有利于精确计算储层流体饱和度。孔隙度、泥质含量等是测井定量评价和定性解释的重要参数。测井初次解释时常采用三孔隙度交会的方法进行孔隙度计算、并根据已有模型进行渗透率计算。由于缺乏取心和地质资料,解释精度较低。本文根据岩心实验,采用岩心刻度测井的方法,建立了基于岩心实验的孔隙度模型;并根据储层岩石成分特点,采用最优化解释模型定量计算了孔隙度和各种矿物成分,得到了两种不同的计算孔隙度的方法,弥补了初次解释中骨架参数无法准确选取的缺陷。针对研究区域地层水矿化度分布的复杂性,开展了多矿化度电阻率、阳离子交换、核磁共振等岩石物理实验,综合分析了影响岩电参数的主要因素;结合研究区的地质特点,使用了阿尔奇公式、粘土砂岩导电、有效水导电、岩石骨架导电等四种饱和度模型进行储层饱和度计算;并将结果与密闭取心资料进行了分析对比,充分验证了模型的正确性和精度。
【Abstract】 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.
【Key words】 lithology analysis; mud-filtrate invasion; petrophysical experiment; saturation model; comprehensive evaluation;