共查询到16条相似文献，搜索用时 125 毫秒
1.
脉冲中子伽马能谱测井是利用多探测器获取非弹性散射伽马、热中子俘获伽马能谱及伽马时间谱,通过C/O和地层宏观吸收截面来确定饱和度,但俘获伽马能谱的信息没有得到很好利用,在地层水矿化度较高的情况下,由于俘获伽马能谱的Si,Ca和H的能窗内总的伽马计数与Fe能窗内的伽马计数比值与含氯量有关,因此由俘获伽马能谱确定含水饱和度是可行的,利用MCNP(蒙特卡罗方法)模拟研究了三能窗计数与Fe能窗计数比值与饱和度、岩性、孔隙度、泥质含量、井眼持水率、地层水矿化度以及井眼套管等条件下的关系,为在高矿化度地区利用俘获伽马能谱确定饱和度的可行性在理论上提供了支持. 相似文献
2.
随着注水开发方式的进行,跃进二号油田水淹已经非常严重,主产层含水率已超80%.经过多轮的注水开发和措施调整,常规测井资料不能满足水淹层评价的要求.因此,油田在2007年,引入PNN生产测井技术,但是在应用过程中发现,PNN测井资料受井中流体及矿化度影响较大,使得测井响应变化复杂,难以反映储层水淹程度.为了更加准确地解释水淹层,利用PNN测井宏观俘获截面和泥质含量、孔隙度,建立了评价水淹层的定量模型.首先,为了降低井眼和井中流体对PNN测井的影响,本文利用中子衰变公式模拟热中子俘获后,剩余热中子百分比与时间的关系曲线,研究发现:在0～100μs之间时,该曲线成线性反比关系,且斜率较大,表明该时间段热中子寿命小,热中子被快速俘获;在大于100μs的时间段,曲线变缓,斜率减小,热中子寿命明显增大;结果表明,0～100μs之间PNN测井受井眼影响,导致热中子被快速俘获,即PNN测井在大于100μs时开始计数可以降低井眼对测井的影响,测量地层真实宏观俘获截面.其次,通过岩心资料对泥质中的黏土矿物类型进行分析,发现泥质中的黏土矿物主要是高岭石、蒙脱石、绿泥石和伊利石四种;进一步分析泥质中的黏土矿物含量,发现该区块黏土矿物含量变化稳定,并利用泥质含量对各黏土矿物含量进行表征.将降低井眼影响后的宏观俘获截面和泥质含量引入传统的碳氢比、碳氧比计算模型,对该模型进行优化,提高了该模型对水淹层的解释精度.最后,综合射孔、注水及吸水层资料对不同水淹级别的响应特征进行分析,发现碳氢比、碳氧比优化模型不仅可以解释油层和水淹层,建立水淹层定量解释标准和划分水淹级别,同时可对储层进行更为精细的流体类型刻画.油田采用碳氢比、碳氧比优化模型对储层进行解释,深入挖掘剩余油潜力,实现增产的目的. 相似文献
3.
脉冲中子双伽马谱饱和度测井方法是利用特定的脉冲和测量时序设计,采用远、近伽马探测器记录非弹性散射和俘获伽马能谱以及伽马射线时间谱,通过获取C/O和地层宏观俘获截面等信息来确定地层含油饱和度.采用大直径仪器和BGO晶体探测器时,其采集的非弹性散射和俘获伽马能谱计数统计性优于国外仪器,重复脉冲发射中子后伽马射线时间谱仍满足指数衰减规律,且能使伽马射线时间谱的道计数累积,计数统计性好于常规中子寿命测井,得到的地层宏观俘获截面与单脉冲发射近似相同.在地层孔隙度未知的情况下,利用C/O和地层宏观俘获截面交会技术可以定量确定含油饱和度. 相似文献
4.
地层水矿化度检测的地球物理测井方法 总被引：1，自引：1，他引：1
传统的水文地质研究方法在进行地下水的矿化度评价时，是通过地层水的取样进行室内分析化验，确定含水岩组中地层水的矿化度，目前，在利用已有的地质、地球物理资料进行西部地下水资源评价的研究中，鉴于大多数石油井不含有浅层地层水的水样化验资料，因而本文介绍一种利用石油测井数据（主要为自然电位曲线）计算地层水矿化度的方法，并将之应用于鄂尔多斯白垩系自流水盆地地层水的矿化度估算，方法研究和应用实例证明这种方法是较为可靠的，虽然求取的地层水的矿化度的数值存在一定的误差，但完全可以满足地层水矿化度分级评价的需求，从而开发了石油测井数据在水文地质中的应用，也降低了单纯利用水文取样，由于样点少，矿化度预测精度低的缺点。 相似文献
5.
套管井剩余油饱和度监测技术是研究剩余油分布最重要的测井方法.针对研究区块中-低孔隙度、中-低渗透率、高矿化度地层水的油藏特点与饱和度监测的现状,对比研究了现有监测技术与仪器装备的性能指标,同时考虑脉冲中子、非弹性散射与地层中元素的相互作用的特性,提出了适用于这种不同油藏地质特点的剩余油饱和度监测系列优化方案.针对某区块编制了整体监测方案,并且对监测资料进行精细处理与解释.多口井实施和应用表明,该方案与应用效果良好. 相似文献
6.
《地球物理学进展》2020,(3)
GS油田E■油藏水淹程度严重,已处于中高含水期,平均含水高达77.97%.由于注水开发过程中,先注入淡水后注入污水导致注入水变化性质复杂,致使储集层水淹后地下流体性质、岩石物理性质等发生复杂变化,导致测井响应变化复杂,通过常规的测井技术与解释方法难以精确解释水淹层.为了能精确划分GS E■油田水淹级别,本文结合PNN测井技术,以宏观俘获截面、电阻率曲线和GR_(PNN)的变化定性识别水淹层,当油层被水淹后,GR_(PNN)曲线多呈现异常增大现象,与GR曲线变化出现差异,宏观俘获截面曲线值随着水淹程度的增加而增加.利用宏观俘获截面计算含水饱和度,通过岩石物理实验得出孔隙度、渗透率等参数计算产水率,通过建立产水率和含水饱和度的计算模型定量判断水淹级别,建立了一套适用于GS油田E■油藏的水淹层划分标准.与实际生产吻合,有很好的应用效果,为GS油田E■油藏水淹层划分提供了新的标准. 相似文献
7.
为了进一步认识泥质对岩石宏观电性的影响规律,本文利用非规整三维逾渗网络模型,通过数值模拟研究了不同矿化度下泥质对岩石电性影响的规律. 模拟结果表明：在中低矿化度下,泥质对岩石导电整体上呈现减阻作用,随着泥质含量的增加,电阻率降低的速度减慢;中等矿化度下泥质的减阻效果明显弱于低矿化度下的减阻效果;在高矿化度下泥质对岩石导电整体上呈现增阻作用. 在高矿化度、高含水饱和度下泥质对岩石电性的影响较小. 泥质起减阻、增阻作用的具体矿化度范围取决于储层的孔隙度、连通性以及地层温度等特性. 相似文献
8.
《地球物理学进展》2017,(5)
过钻杆存储测井是评价水平井、大斜度井地层参数的一种重要的测井方式.本文针对过钻杆中子孔隙度测井中源和探测器相对钻杆的位置开展研究,并与电缆、随钻中子孔隙度测井响应进行了对比.利用蒙特卡罗方法建立了过钻杆、电缆及随钻中子孔隙度三种仪器模型,模拟研究了热中子分布及近、远探测器计数比值与孔隙度的响应关系,分析了孔隙度测量精度和相对灵敏度以及井眼尺寸的影响.结果表明:源在钻杆内探测器在钻杆外的测量方式近探测器计数率和孔隙度测量精度高;且低孔隙度时相对灵敏度高,同时防止测量过程中放射源的脱落.随着孔隙度增大,随钻仪器近探测器计数率增加,而电缆与过钻杆仪器计数率降低;随着井眼尺寸增加,近、远热中子计数率比值率增大,过钻杆和电缆近探测器计数率降低,随钻近探测器计数率增加.源在钻杆内探测器在钻杆外的测量方式在保证孔隙度测量精度及灵敏度的同时,提高了放射性源测井的安全性. 相似文献
9.
地层孔隙水含量的计算主要受地层孔隙度与孔隙含水饱和度的影响.通过实验室煤层及其顶底板岩芯物理测试与孔隙度测量,可以获得煤系地层岩芯的孔隙度与岩芯纵、横波速度的经验公式;结合三分量地震勘探获得的纵波与横波速度,能够计算出煤系地层的孔隙度;含水饱和度的计算通过实验室岩电参数测试和阿尔奇公式可以计算得到.结合淮南某矿区三维三分量地震勘探和地球物理测井及岩样的岩电试验,实现了三维空间煤系地层孔隙含水体积百分比的精确计算.该预测方法与传统的、钻孔控制的地下水评价方法相比可以提供相对精细的、三维空间的、定量化的煤系地层孔隙相对含水量,对煤炭与煤层气资源开采中所涉及的地下水分布规律预测有一定的参考意义. 相似文献
10.
研究各种地层和井眼环境因素对碳氧比C/O测井长、短源距探测器的影响规律，可以为C/O测井仪器的刻度方法提供指导，为解释模型的建立和数据处理提供依据.本文用Monte Carlo方法，计算了C/O值随井眼直径、水泥环厚度、套管直径、孔隙度、含油饱和度、地层岩性和油密度的变化规律.从中看出，当井内流体为油时，井径或套管直径增大，C/O值增大，井眼影响增大；当井内流体为水时，井径或套管直径的增大，C/O值减小；水泥环厚度增加时C/O值减小；当井眼条件不变时，地层孔隙度越大，含油饱和度越大，C/O值越大，对测井越有利；反之，地层孔隙度越小，含油饱和度越小，C/O值越小，对测井不利；地层岩性对C/O值的影响显著，相同条件下，碳酸盐岩比砂岩的C/O值高；油密度越大，C/O值越大.文中还提出了一种消除这些因素影响的数据处理方法 相似文献
11.
Invasion of mud filtrate from the borehole into the surrounding formation can significantly alter the response of logging tools.In this paper the neutron tool response was calculated for a gas-bearing rock crossed by the borehole.The invaded zone is characterized by variable fluid and gas saturation and is defined by a specific hyperbolic function. The saturation function is based on the characteristics of Polish Carpathian Foredeep Miocene formations reached in gas-bearing rocks. The whole system including neutron tool equipped with Am-Be neutron source and a set of neutron detectors, borehole, invaded zone, and virgin zone, was numerically modeled and used as the input to the Monte-Carlo neutron transport code. The response of each detector was calculated for different combinations of porosity and saturation of invaded zone and virgin zone. 相似文献
12.
Laura Carmine Elsa Aristodemou Christopher Pain Ann Muggeridge Cassiano de Oliveira 《Geophysical Prospecting》2008,56(1):115-140
The purpose of this work was to investigate a new and fast inversion methodology for the prediction of subsurface formation properties such as porosity, salinity and oil saturation, using time‐dependent nuclear well logging data. Although the ultimate aim is to apply the technique to real‐field data, an initial investigation as described in this paper, was first required; this has been carried out using simulation results from the time‐dependent radiation transport problem within a borehole. Simulated neutron and γ‐ray fluxes at two sodium iodide (NaI) detectors, one near and one far from a pulsed neutron source emitting at ～14 MeV, were used for the investigation. A total of 67 energy groups from the BUGLE96 cross section library together with 567 property combinations were employed for the original flux response generation, achieved by solving numerically the time‐dependent Boltzmann radiation transport equation in its even parity form. Material property combinations (scenarios) and their correspondent teaching outputs (flux response at detectors) are used to train the Artificial Neural Networks (ANNs) and test data is used to assess the accuracy of the ANNs. The trained networks are then used to produce a surrogate model of the expensive, in terms of computational time and resources, forward model with which a simple inversion method is applied to calculate material properties from the time evolution of flux responses at the two detectors. The inversion technique uses a fast surrogate model comprising 8026 artificial neural networks, which consist of an input layer with three input units (neurons) for porosity, salinity and oil saturation; and two hidden layers and one output neuron representing the scalar photon or neutron flux prediction at the detector. This is the first time this technique has been applied to invert pulsed neutron logging tool information and the results produced are very promising. The next step in the procedure is to apply the methodology to real data. 相似文献
13.
Inversion of nuclear well-logging data using neural networks 总被引：1，自引：1，他引：1
Elsa Aristodemou Christopher Pain Cassiano de Oliveira Tony Goddard Christopher Harris 《Geophysical Prospecting》2005,53(1):103-120
This work looks at the application of neural networks in geophysical well‐logging problems and specifically their utilization for inversion of nuclear downhole data. Simulated neutron and γ‐ray fluxes at a given detector location within a neutron logging tool were inverted to obtain formation properties such as porosity, salinity and oil/water saturation. To achieve this, the forward particle‐radiation transport problem was first solved for different energy groups (47 neutron groups and 20 γ‐ray groups) using the multigroup code EVENT. A neural network for each of the neutron and γ‐ray energy groups was trained to re‐produce the detector fluxes using the forward modelling results from 504 scenarios. The networks were subsequently tested on unseen data sets and the unseen input parameters (formation properties) were then predicted using a global search procedure. The results obtained are very encouraging with formation properties being predicted to within 10% average relative error. The examples presented show that neural networks can be applied successfully to nuclear well‐logging problems. This enables the implementation of a fast inversion procedure, yielding quick and reliable values for unknown subsurface properties such as porosity, salinity and oil saturation. 相似文献
14.
《中国科学D辑(英文版)》2008,(Z2)
Studying the response differences between neutron and density logging of gas reservoir for well-balanced and under-balanced logging will be of significance in evaluation of gas reservoir under the under-balanced condition and application of logging data. With Monte Carlo simulation technique,the paper obtains the relationship between neutron and density logging measurement and borehole di-ameter,porosity or gas saturation for well-balanced and under-balanced logging. The conclusions show that the response trend of under-balanced logging to gas reservoirs agrees with that of well-balanced logging with small borehole,and under-balanced logging data can be used usually as well-balanced logging data. When borehole diameter is large,under-balanced logging data should be corrected for the influences of borehole. 相似文献
15.
The phenomenon of acoustic waves inducing electric fields in porous media is called the seismoelectric effect. Earlier investigators proposed the usage of seismoelectric effect for well logging. Soil texture has a strong influence on the coupled wave fields during shallow surface explorations. In this article, we study the borehole pure shear‐horizontal wave and the coupling transverse‐electric field (acoustic–electrical coupling wave fields) in the partially saturated soil. Combined with related theories, we expand the formation parameters to partially saturated forms and discuss the influence of soil texture conditions on the seismoelectric wave fields. The results show that the elastic and electrical properties of porous media are sensitive to water saturation. The compositions of the acoustic and electric fields for different soil textures do not change, but the waveforms differ. We also use the secant integral method to simulate the interface‐converted electromagnetic waves. The results show that interface response strength is greatly influenced by soil texture. In addition, considering the sensitivity of the inducing electric field to fluid salinity, we also simulate the time‐domain waveforms of electric field for different pore fluid salinity levels. The results show that as the salinity increases, the electric field amplitude decreases monotonically. The above conclusions have certain significance for the application of borehole shear wave and its coupled electric fields for resource exploration, saturation assessment and groundwater pollution monitoring. 相似文献
16.
震电测井的现场试验中测得电磁首波幅值大于伴随电场幅值,这种情况在前人的理论模拟和模型井测量中从未出现.本文研究矿化度界面对震电测井波场的影响,基于Pride方程和边界连续条件模拟了震电测井波场,其中井外孔隙地层可以视为均匀的或者是径向分层的.计算结果表明:对于均匀孔隙地层,当井内流体矿化度大于井外地层孔隙流体矿化度时,电磁首波幅值可以比伴随斯通利波的电场幅值还大;井内流体矿化度与井外地层孔隙流体矿化度的比值越大,电磁首波相对伴随斯通利波的电场的幅值越大.对于径向分层地层,当井内流体矿化度大于内层地层的孔隙流体矿化度时,电磁首波幅值可以比伴随斯通利波的电场幅值还大;当外层地层矿化度小于内层地层矿化度时,电磁首波幅值可以比伴随斯通利波的电场幅值还大;增加内层地层厚度,电场全波幅值减小,电磁首波相对伴随电场的幅值减小.本文的模拟结果表明,震电测井中确实会出现电磁首波幅值比伴随电场幅值还大的情况,这对于解释震电测井的测量结果具有指导意义. 相似文献