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本文针对脉冲中子多循环发射过程中测量的非弹伽马能谱受俘获能谱干扰,引起的油水区分度小的问题,提出了利用时间谱和能谱结合获取纯净非弹伽马能谱的方法.通过蒙特卡罗方法建立C/O仪器数值计算模型,模拟不同井眼和地层条件下的伽马时间谱,分析了井眼和地层对伽马能谱的贡献,对比了俘获伽马时间谱理论计算结果和模拟结果,同时利用某油田刻度井实测数据,验证该方法在评价含油饱和度的可靠性.结果 表明:井眼条件是影响伽马能谱的主控因素;利用理论计算的脉冲区内俘获密度和数值模拟结果一致;采用该方法处理某油田刻度井实测数据,C/O对油、水差异反应更加灵敏度,油水动态范围提高;最终实测井数据也验证了该方法的准确性. 相似文献
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构造油藏开发中后期含水上升快,稳产技术措施必须进行合理调整,开展好精细地质研究,尤其是充分利用现有常规测井资料开展油水界面识别和油藏剖面特征研究十分重要.本文基于文献调研,结合研究区(Z区)地质资料、测井资料和动态生产资料,开展了油水界面识别方法研究,并对现有测井资料按照测井时间进行合理分段研究,提出基于时间推移的油水界面确定方法和油藏剖面动态特征研究方法,得到了工区油水界面动态变化特征.研究表明,基于自然伽马、自然电位和感应测井方法可以较好地识别工区目的层油水界面,按照测井时间合理分段可以更准确地实现对油水界面变化的动态分析,基于时间推移的油水界面研究方法简单有效.本文研究成果对邻区具有一定的参考作用. 相似文献
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地层油藏是一种复杂的油藏类型,在地震描述中根据地震反射特征追踪的尖灭线与实际地层油藏的尖灭线常常存在较大的误差,因此精确落实地层超剥线的位置是地层油藏勘探成功的关键,本文通过大量的正演模型和地质统计方法,发现地层油藏超剥尖灭线的误差与地层和不整合面的夹角有关,从而提出了地层油藏超剥尖灭线夹角定量外推这种新方法,通过实际资料的应用,较好地解决了地层油藏超剥尖灭线不准的问题,取得了良好地质效果. 相似文献
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地层水电阻率是水淹层精确识别的重要参数之一,对储层的定量评价起着关键性作用.在油田实际开发过程中,随着注入水一直在变化,地层水矿化度也随之发生改变,导致混合地层水电阻率与原始地层电阻率不一致,利用传统方法求取混合地层水电阻率结果误差较大,目前尚没有一个通用合理的广泛应用的方法,如何准确求取混合地层水电阻率成为国内各大高含水阶段油田面临的关键问题.从地层水的动态混合过程出发,提出一种基于离子交换的动态分析方法,其实质就是忽略注入水矿化度的变化性,将混合地层水分为无离子交换、离子交换完全以及离子交换未充分完成三个阶段,利用物质平衡方程和并联电阻关系式推导出计算模型,最终计算出混合地层水电阻率.利用该方法在大港油田G区块进行实际应用,将计算出的结果与利用自然电位资料计算方法的结果进行对比分析,结果表明:基于离子交换的水淹层地层水电阻率计算方法误差较小,有效的提高了计算精度,证实该方法的有效性,为实现水淹层的定量评价奠定了良好基础. 相似文献
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本文给出一种双感应资料快速近似迭代反演技术. 首先建立Fréchet导数的快速算法,保证在反演过程中能够同时获得测井响应相对于地层电阻率和层界面的偏导数,并给出用规范化处理与奇异值分解技术进行迭代反演的具体过程. 为了对理论模拟和井场实际资料进行反演,利用综合分层技术从双感应曲线中提取层界面初始位置和地层电阻率初值,通过单独迭代反演中感应资料,修改层界面和地层电阻率实现中感应资料的最佳拟合,得到探测深度相对较浅的地层电阻率,然后固定层界面位置,再迭代反演深感应资料,得到另一组探测深度相对较深的地层电阻率. 理论和实际资料处理结果证明,两个不同探测深度的电阻率反演结果的相对大小能够准确地反映地层真实的侵入特征.此外,由于深感应仪器具有较深的探测深度,不论在高侵或低侵地层上,深感应反演结果与地层原状电阻率的差异大大小于视电阻率的差异,所以利用反演结果也能得到更好的地层原状电阻率的估计值. 相似文献
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K油田位于哈萨克斯坦南图尔盖盆地阿克赛隆起带上,主要产层为白垩系底砂岩及侏罗系河道砂。油田区南北跨度较大,油藏类型多样,砂体边界识别困难。该油田在2000年之后逐步投入开发,但在开发过程中发现相邻井的出油情况差异较大,油水关系复杂,油田需要提高对油藏的识别精度来应对新一轮增储上产及井网调整问题。利用敏感属性分析、3D可视化模块、地质统计反演等技术,重新认识和评价了K区油藏特征,识别区内多个独立油藏,厘清油藏间的油水关系,总结该区不同油藏类型的含油气规律,就目前困扰K油田勘探开发工作的问题给出解答。 相似文献
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由于南苏丹P区块没有可用于确定油层水淹程度的密闭取心新井资料,且单层生产及试油数据非常少,开采与完井时间间隔较长,地层水性质相同导致底水水淹与油水同层难以识别,因此,水淹层解释难度较大.本文首先根据区块地质特征与开发特征及水淹层水源和水进方向,归纳总结出研究区油层的水淹类型为边水与注入水推进水淹型和底水推进水淹型,注水水淹和边底水水淹在电阻率测井响应特征上均表现为电阻率值的明显降低.其次,采用新老井相同层位测井信息对比方法,结合相邻老井生产动态测试结果,确定出新井典型水淹层,分析水淹层测井响应特征,优选出深侧向电阻率、浅侧向电阻率、深浅侧向电阻率幅度差、深侧向电阻率与冲洗带电阻率幅度差等4个水淹敏感参数,其中深侧向电阻率和深浅侧向电阻率幅度差为最有效的水淹识别参数.利用深侧向电阻率值与深浅侧向幅度差交会,建立了水淹层定性识别图版,利用该图版可有效地区分水淹层与水层和油层.基于储层岩性物性测井响应特征分析,采用岩心刻度测井方法,建立了水淹层泥质含量、孔隙度、渗透率、饱和度等参数定量解释模型,利用计算的驱油效率值可有效地划分弱水淹、中水淹、强水淹.综合水淹层定性识别图版法以及定量解释方法,结合邻井生产动态,建立了水淹层综合测井评价方法,经实际井验证证明该方法结合了静态测井解释与动态生产数据在水淹层评价中优势,提高了水淹级别测井综合评价准确性.采用开发初期井连井剖面对比方法,确定出油水同层顶界面海拔深度,再结合邻井开发动态,寻找出新井水源,判断出新井水淹类型.对于底水水淹类型,新井不存在油水同层,只能为水淹层;对于边水水淹类型,将解释油水同层或水淹层海拔深度高于最高油水同层顶界面海拔深度的储层判定为水淹层,而海拔深度低于最高油水同层顶界面海拔深度的储层判定为油水同层,经实际井验证证明该方法可有效地区分底水水淹层与油水同层. 相似文献
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重力位场的界面反演是位场处理解释中的重要问题.本文将基于快速傅里叶变换的频率域界面反演方法Parker-Oldenburg公式推广到物性可随深度变化的三维情况,得出了密度可以横向、纵向任意变化的重力界面正反演公式.该方法在计算时可以合理地选取地面下某一深度作为基准面以减小界面起伏,使迭代易于收敛.理论模型试验表明该方法反演精度高,收敛速度快,在密度界面反演中具有广泛的实用价值.最后利用该方法反演华北地区莫霍面的深度,反演结果得到了地震测深数据的验证. 相似文献
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V.B. Piip 《Geophysical Prospecting》2001,49(4):461-482
A method using simple inversion of refraction traveltimes for the determination of 2D velocity and interface structure is presented. The method is applicable to data obtained from engineering seismics and from deep seismic investigations. The advantage of simple inversion, as opposed to ray‐tracing methods, is that it enables direct calculation of a 2D velocity distribution, including information about interfaces, thus eliminating the calculation of seismic rays at every step of the iteration process. The inversion method is based on a local approximation of the real velocity cross‐section by homogeneous functions of two coordinates. Homogeneous functions are very useful for the approximation of real geological media. Homogeneous velocity functions can include straight‐line seismic boundaries. The contour lines of homogeneous functions are arbitrary curves that are similar to one another. The traveltime curves recorded at the surface of media with homogeneous velocity functions are also similar to one another. This is true for both refraction and reflection traveltime curves. For two reverse traveltime curves, non‐linear transformations exist which continuously convert the direct traveltime curve to the reverse one and vice versa. This fact has enabled us to develop an automatic procedure for the identification of waves refracted at different seismic boundaries using reverse traveltime curves. Homogeneous functions of two coordinates can describe media where the velocity depends significantly on two coordinates. However, the rays and the traveltime fields corresponding to these velocity functions can be transformed to those for media where the velocity depends on one coordinate. The 2D inverse kinematic problem, i.e. the computation of an approximate homogeneous velocity function using the data from two reverse traveltime curves of the refracted first arrival, is thus resolved. Since the solution algorithm is stable, in the case of complex shooting geometry, the common‐velocity cross‐section can be constructed by applying a local approximation. This method enables the reconstruction of practically any arbitrary velocity function of two coordinates. The computer program, known as godograf , which is based on this theory, is a universal program for the interpretation of any system of refraction traveltime curves for any refraction method for both shallow and deep seismic studies of crust and mantle. Examples using synthetic data demonstrate the accuracy of the algorithm and its sensitivity to realistic noise levels. Inversions of the refraction traveltimes from the Salair ore deposit, the Moscow region and the Kamchatka volcano seismic profiles illustrate the methodology, practical considerations and capability of seismic imaging with the inversion method. 相似文献
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在电缆地层测试器的测量过程中，油水两相共渗的情况普遍存在，此时其测量过程的数学模型是非线性的耦合场问题，无法用解析方法求解.加上测量中存在抽吸探针与地层、井筒接触面几何形状复杂、探针与地层尺寸相差悬殊等问题，使得应用渗流力学中较为成熟的有限差分方法求解数学模型也不能获得理想的结果.本文应用适合于处理复杂几何形状计算的有限元方法，根据地层测试器测试过程中油水两相渗流的数学模型，首次建立了地层测试器测量油水两相渗流的有限元模型，给出了验证和求解的实例.运用本文所建立的计算模型可以更准确地模拟测试过程中压力和饱和度随时间和空间变化的情况,为正确使用地层测试器提供指导. 相似文献
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岩芯核磁共振（NMR）T2分布和毛管压力分析数据均在一定程度上反映了岩石的孔隙结构,理论分析表明,这两组数据具有相关性.应用NMR T2分布研究岩石孔径分布，关键是在分析两者的相关性的基础上，从T2分布构造出可靠的毛管压力曲线.但以前用饱和水T2分布构造的毛管压力曲线的方法与实际毛管压力曲线匹配性差.事实上，薄膜束缚水部分的存在引起T2分布反映的孔隙空间与毛管压力曲线反映的孔隙空间有差异.本文提出一种改进方法，在消除薄膜束缚水对T2分布的贡献后，用自由水T2分布构造毛管压力曲线.应用本文方法,对24块岩芯数据自由水T2分布构造的毛管力曲线及其孔喉半径分布与隔板毛管压力分析结果进行了对比.结果表明，改进方法对于毛管压力曲线的构造精度有明显改进，从而为NMR T2分布研究孔隙结构提供了可靠的理论和方法上的支持. 相似文献
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利用核磁共振测井资料构造储层毛管压力曲线的新方法及其应用 总被引：3，自引：1，他引：2
By analyzing hundreds of capillary pressure curves, the controlling factors of shape and type of capillary pressure curves are found and a novel method is presented to construct capillary pressure curves by using reservoir permeability and a synthesized index. The accuracy of this new method is verified by mercury-injection experiments. Considering the limited quantity of capillary pressure data, a new method is developed to extract the Swanson parameter from the NMR T2 distribution and estimate reservoir permeability. Integrating with NMR total porosity, reservoir capillary pressure curves can be constructed to evaluate reservoir pore structure in the intervals with NMR log data. An in-situ example of evaluating reservoir pore structure using the capillary pressure curves by this new method is presented. The result shows that it accurately detects the change in reservoir pore structure as a function of depth. 相似文献
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The formation of oil-water emulsion often occurs when oil is spilled into the ocean. Oil weighting factor of oil-water emulsion is one of the most important parameters for emergent oil-spill microwave monitoring. A new method is proposed here to evaluate the oil weighting factor based on fractional Weierstrass scattering model. By using the proposed method, we analyze the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR) L-band fully polarimetric data acquired during 2010 Deepwater Horizon oil spill disaster event in the Gulf of Mexico. The result shows that our method performs well in evaluating oil weighting factor of oil-covered area. 相似文献
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Oil reservoirs with low permeability and porosity that are in the middle and late exploitation periods in China’s onshore oil fields are mostly in the high-water-cut production stage. This stage is associated with severely non-uniform local-velocity flow profiles and dispersed-phase concentration (of oil droplets) in oil-water two-phase flow, which makes it difficult to measure water holdup in oil wells. In this study, we use an ultrasonic method based on a transmission-type sensor in oil-water two-phase flow to measure water holdup in low-velocity and high water-cut conditions. First, we optimize the excitation frequency of the ultrasonic sensor by calculating the sensitivity of the ultrasonic field using the finite element method for multiphysics coupling. Then we calculate the change trend of sound pressure level attenuation ratio with the increase in oil holdup to verify the feasibility of the employed diameter for the ultrasonic sensor. Based on the results, we then investigate the effects of oil-droplet diameter and distribution on the ultrasonic field. To further understand the measurement characteristics of the ultrasonic sensor, we perform a flow loop test on vertical upward oil-water two-phase flow and measure the responses of the optimized ultrasonic sensor. The results show that the ultrasonic sensor yields poor resolution for a dispersed oil slug in water flow (D OS/W flow), but the resolution is favorable for dispersed oil in water flow (D O/W flow) and very fine dispersed oil in water flow (VFD O/W flow). This research demonstrates the potential application of a pulsed-transmission ultrasonic method for measuring the fraction of individual components in oil-water two-phase flow with a low mixture velocity and high water cut. 相似文献
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K. DEPPERMANN 《Geophysical Prospecting》1973,21(3):424-463
For the two and three layer cases geo-electrical sounding graphs can be rapidly and accurately evaluated by comparing them with an adequate set of standard model graphs. The variety of model graphs required is reasonably limited and the use of a computer is unnecessary for this type of interpretation. For more than three layers a compilation of model graphs is not possible, because the variety of curves required in practice increases immensely. To evaluate a measured graph under these conditions, a model graph is calculated by computer for an approximately calculated resistivity profile which is determined, for example, by means of the auxiliary point methods. This model graph is then compared with the measured curve, and from the deviation between the curves a new resistivity profile is derived, the model graph of which is calculated for another comparison procedure, etc. This type of interpretation, although exact, is very inconvenient and time-consuming, because there is no simple method by which an improved resistivity profile can be derived from the deviations between a model graph and a measured graph. The aim of this paper is, on the one hand, to give a simple interpretation method, suitable for use during field work, for multi-layer geo-electrical sounding graphs, and, on the other hand, to indicate an automatic evaluation procedure based on these principles, suitable for use by digital computer. This interpretation system is based on the resolution of the kernel function of Stefanescu's integral into partial fractions. The system consists of a calculation method for an arbitrary multi-layer case and a highly accurate approximation method for determining those partial fractions which are important for interpretation. The partial fractions are found by fitting three-layer graphs to a measured curve. Using the roots and coefficients of these partial fractions and simple equations derived from the kernel function of Stefanescu's integral, the thicknesses and resistivities of layers may be directly calculated for successively increasing depths. The system also provides a simple method for the approximative construction of model graphs. 相似文献