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1.
在基岩电阻率较高的硬地层中,除去泥质、孔隙和其他矿物等因素的影响后,地层电阻率与致密围岩电阻率的差异就被认为是裂缝以及地层孔隙中储存的流体性质引起的。选择相同岩性含气储层与致密围岩层的电阻率值,利用数值反演的方法确定出计算含气层段消除裂缝以及孔隙中流体性质影响以后的地层真电阻率公式,定义地层真电阻率和深侧向电阻率的差值与地层深侧向电阻率的比值为构造电阻率差比值,该参数主要反映裂缝以及孔隙中的流体性质对电阻率降低幅度的影响。因此,利用差比值法可以识别火山岩裂缝地层的流体性质,进而制作油层、气层和水层的判别图版,并结合其他测井曲线、油藏动态资料以及气测信息综合识别火山岩裂缝地层天然气层。该方法在准噶尔盆地研究区火山岩天然气层的识别中取得了很好的应用效果,解释结论与试油结果基本吻合。 相似文献
2.
鄂尔多斯盆地中部洛河油田长61低渗透油层由于含油饱和度变化大、油层非均质强,再加淡水钻井液侵入,造成油层电阻率径向分布不均且变化大。通过双感应-八侧向测井与阵列感应测井响应特征对比分析,认为水层的径向电阻率均为增阻侵入,油层、油水同层的径向电阻率普遍具有减阻侵入、低阻环带、高阻环带特征或相关趋势。其中,减阻侵入有助于识别高含油饱和度、高电阻率油层和油水同层,低阻环带和高阻环带有助于识别低电阻率油水同层。另外,部分油水同层的双感应-八侧向测井径向电阻率组合具有“增阻侵入”且深感应电阻率低的特征,推测可能是受双感应-八侧向测井探测范围限制,为低阻环带靠近井眼附近遭受淡水钻井液侵入影响的结果,深感应测井反映的是侵入带电阻率而不是油水同层的电阻率,容易被误解释为水层。因此,对于双感应-八侧向测井中具有“增阻侵入”特征且深感应电阻低值的储层,其流体性质有水层、油水同层这两种可能性,需要结合深探测测井资料或油藏地质特征进一步分析,以提高油层、水层的识别率。 相似文献
3.
苏里格气田储层含水特征与测井识别方法 总被引：1，自引：0，他引：1
鄂尔多斯盆地苏里格气田盒8、山1气藏为弹性驱动的河流相低效气藏,储层非均质性强,压裂试气部分井出水。根据测井响应特征及非均质性将气层含水情况分为束缚水、层间水、滞留水3类,分析了3类含水气层特征,并在天然气测井响应机理研究的基础上提出了侵入分析与感应侧向联合解释法、分区图版法及气测综合判识法等气水层判识技术,使该地区气层测井解释符合率从70%左右提高到80%以上。 相似文献
4.
用渭南仪器厂的TYSC-3Q刻度系统对重庆仪器厂的JFS-1B型组合密度探管进行重新刻度，对自然伽玛选用40r刻度环，对密度测井采用400r刻度环，三测向电阻率刻度刚在重新计算回归方程的基础上，消除电阻率负值，通过对探管的重新刻度和计算，保证了测井数据定量解释精度。 相似文献
5.
不同井眼条件下的水平井双侧向测井响应 总被引：1，自引：0，他引：1
为解决油气开发中水平井中井眼对双侧向测井响应的影响,建立了上、中、下三层介质的水平井模型,采用三维有限元方法进行研究。数值计算结果表明,水平井眼处于目的层不同位置、不同井眼尺寸以及泥浆电阻率等都对水平井双侧向测井响应有不同程度的影响,特别是对非厚层影响更加明显。井眼尺寸越大和泥浆电阻率越高,对双侧向测井响应的影响就越严重。当目的层小于6 m时,水平井中的深、浅双侧向测井响应都不同程度地受到层厚围岩的影响;当层厚分别大于36 m和6 m时,深侧向和浅侧向测井几乎不受围岩影响;在15°的范围内,不同的井眼倾角对双侧向测井响应影响不大。 相似文献
6.
A Stanley Raj Y SRINIVAS D Hudson Oliver D Muthuraj 《Journal of Earth System Science》2014,123(2):395-411
The non-linear apparent resistivity problem in the subsurface study of the earth takes into account the model parameters in terms of resistivity and thickness of individual subsurface layers using the trained synthetic data by means of Artificial Neural Networks (ANN). Here we used a single layer feed-forward neural network with fast back propagation learning algorithm. So on proper training of back propagation networks it tends to give the resistivity and thickness of the subsurface layer model of the field resistivity data with reference to the synthetic data trained in the appropriate network. During training, the weights and biases of the network are iteratively adjusted to make network performance function level more efficient. On adequate training, errors are minimized and the best result is obtained using the artificial neural networks. The network is trained with more number of VES data and this trained network is demonstrated by the field data. The accuracy of inversion depends upon the number of data trained. In this novel and specially designed algorithm, the interpretation of the vertical electrical sounding has been done successfully with the more accurate layer model. 相似文献
7.
地堑式断陷盆地储层流体综合识别——以伊通盆地岔路河断陷为例 总被引：2，自引：0，他引：2
伊通盆地岔路河断陷古近系为地堑式断陷盆地沉积,其储层主要为重力流成因的湖泊水下扇,具有物源近、堆积速率快、岩性复杂多变的特征,加之后期成岩作用的影响,造成这类砂体物性变异系数大,非均质程度高。储层内部含流体时,流体性质难以识别,易造成测井解释上油气水层的误判。为了能够应用常规测井资料评价此类油气储层,提高测井解释的成功率,通过综合分析本区储层岩性、物性和含油气性特征,结合试油结果建立了本区岩性、物性及含油气性解释模型。岔路河断陷测井解释参数交汇图版可以明显区分出气层、油层、气水同层、油水同层、水层和干层等不同的地层油气产状。图版显示:岔路河断陷产油气储层含油饱和度下限为20%,并且产气层比产油层具有更高的深浅双侧向电阻率差值;纯水层虽然具有较好的物性条件,但含油饱和度均小于20%;干层泥质体积分数均大于22%,总孔隙度小于10.5%,物性变差,一般为无效储层。 相似文献
8.
井眼压力高于地层压力会导致泥浆侵入,电阻率测井响应受到泥浆侵入的影响而不能真正反映地层的电阻率特性。笔者依据双侧向电阻率测井的基本机理,气-水两相渗流方程及传导对流方程,进行仿真模拟,得到泥浆侵入高矿化度致密气层的二维轴对称模型。研究含水饱和度、地层电阻率以及深浅侧向井壁电场分布随侵入时间的变化规律。研究发现:随着侵入时间的增加,含水饱和度增大,地层电阻率减小;泥浆侵入对致密气层深浅侧向测井响应都产生一定的影响,导致致密气层深浅侧向电阻率幅度差比常规储层深浅侧向电阻率幅度差大,幅度差峰值出现较早。 相似文献
9.
Umar Hamzah Rahman Yaacup Abdul Rahim Samsudin Mohd Shahid Ayub 《Environmental Geology》2006,49(8):1156-1162
A geophysical study was carried out in the Banting area of Malaysia to delineate groundwater aquifer and marine clay layer
of the alluvial Quaternary deposits of Beruas and Gula Formations. The Beruas Formation is formed by peat and clayey materials
as well as silt and sands, whereas the Gula Formation consists of clay, silt, sand and gravels. Both Formations were deposited
on top of the Carboniferous shale of the Kenny Hill Formation. A 2-D geoelectrical resistivity technique was used. Resistivity
measurement was carried out using an ABEM SAS 4000 Terrameter. The 2-D resistivity data of subsurface material for each survey
line was calculated through inverse modelling and then compared with borehole data. The resistivity images of all the subsurface
material below the survey lines show similar pattern of continuous structure of layering or layers with some lenses with resistivity
ranging from 0.1 to 50 Ωm. The upper layer shows resistivity values ranging from 0.1 to 10 Ωm, representing a clay horizon
with a thickness up to 45 m. The second layer with depth varies from 45 to 70 m below surface and has resistivity values ranging
from 10 to 30 Ωm. Borehole data indicate coarse sand with some gravels for this layer, which is also the groundwater aquifer
in the study area. The lowermost layer at a depth of 70 m below ground level shows resistivity values ranging from 30–50 Ωm
and can be correlated with metasedimentary rocks consisting of shale and metaquartzite. 相似文献
10.
裂缝性碳酸盐岩裂缝的双侧向测井响应特征及解释方法 总被引：11，自引：0，他引：11
裂缝评价是裂缝性碳酸盐岩储层评价的关键, 其常规评价方法受到裂缝发育的不均匀性及储层各向异性的影响而存在诸多困难.采用三维数值算法, 利用宏观各向异性地层模型, 研究不同的裂缝参数条件下双侧向测井响应特征, 由此导出一种用于裂缝孔隙度计算的快速算法.分析表明, 裂缝的双侧向响应同裂缝孔隙度与孔隙流体电导率之间存在明显的线性关系, 裂缝的倾角造成双侧向测井曲线幅度差异的变化; 不同倾斜情况下, 将双侧向测井响应近似表示为岩石基岩电阻率、裂缝孔隙度、裂缝流体电导率的函数, 用于裂缝孔隙度的快速计算.实际资料处理表明, 利用双侧向依据该方法确定的裂缝参数同成像测井资料具有良好的对应性. 相似文献
11.
全空间视电阻率公式及全区求解方法是地下瞬变电磁理论的重要组成部分。为探讨全空间全区视电阻率求解方法,笔者将半空间全区视电阻率的平移算法引入至全空间并对其进行了研究。同时,分别采用理论数据、正演模拟数据及实测数据对该方法在全空间资料处理与解释中的有效性和精确性进行了分析。结果显示,平移算法与常规的全区视电阻率解法具有相同的理论基础,但前者避免了传统全区计算方法中的多解性;此外,采用由截距参数绘制的时间剖面图和视电阻率断面图进行联合解释产生了较好的应用效果。 相似文献
12.
Gökhan Göktürkler Çağlayan Balkaya Zülfikar Erhan Ayça Yurdakul 《Environmental Geology》2008,54(6):1283-1290
Near-surface geophysical methods are commonly used to solve a wide class of geological, engineering and environmental problems. In this study, a geoelectrical survey was performed to investigate an alluvial aquifer. The study area is located in the southwest of the Çubukluda? graben, situated in the south of ?zmir, Turkey. The geophysical studies included the electrical resistivity imaging and self-potential (SP) methods. The resistivity data were acquired along eight profiles in the northern part of the study area by a Wenner-Schlumberger electrode configuration and the data processing was achieved by a tomographic inversion technique. The SP data were collected by gradient technique along 16 profiles. Total field values were calculated for each profile by addition of the successive gradient values, then a total field SP map was obtained. The water-saturated zone in the northern part of the study area was clearly revealed by the electrical resistivity imaging and the SP survey yielded useful information on the subsurface fluid movement. 相似文献
13.
地?井瞬变电磁法响应规律复杂,现有解释方法以定性分析和半定量解释应用最为广泛,不能直接获取大地电阻率参数。针对这一问题,提出一种基于瞬变冲激时刻的快速定量解释方法。首先给出均匀半空间地?井瞬变电磁响应的表达式,分析地?井瞬变电磁响应的冲激时刻特征。结果表明,接收点深度越大、大地电导率越高,则瞬变冲激时刻越晚。结合已有的研究成果,推导冲激时刻与大地电导率和深度的函数关系,依据反函数理论进行大地视电阻率定义。以获取真实大地电阻率为目标,研究基于地下电磁场扩散速度的改进大地电阻率恢复算法。采用所提出的算法,根据实际常用工作方式,分别设计均匀半空间、二层模型和三层模型进行模拟计算。模型算例和实测数据试算结果表明:基于冲激时刻的视电阻率定义方法能够较好地反映大地电阻率的变化趋势,但具有较强的体积效应;基于电磁场扩散速度的改进算法能够有效地削弱体积效应的影响,更加准确地恢复大地电阻率值和反映电性界面。该算法无需进行复杂模型的迭代正演计算,具有较高的计算效率,能够定量恢复大地电阻率值,适用于地?井瞬变电磁法的快速初步定量解释。但在实际资料解释应用中,还需考虑视电阻率的“overshoot”和“undershoot”现象,避免造成错误解释。 相似文献
14.
The research site is the whole landmass of the Federal College of Education, Zaria, seated on basement complex of north-central Nigeria. Direct current resistivity geophysical method was employed to characterise parameters such as the basement depth and topography, aquifer depth and thickness, weathered basement distribution as well as mapping of orientations of fractures and faults present in the premises using radial sounding technique. The conventional vertical electrical sounding (VES) Schlumberger array was carried out at 40 stations, and eight of which were radial stations. Radial sounding was used to establish resistivity anisotropy which gives clue for the choice of consistent VES profile direction used throughout the fieldwork. Results from the resistivity interpretation suggest three layers in most parts of the premises with some minor occurrence of two and four layers. The first layer (topsoil) has its thickness ranging between 3.5 and 14.0 m; second layer (weathered basement) thickness ranges between 9.0 and 36.5 m, while the third layer (fresh basement) is deepest (40.1 m) towards the eastern corner of the area. The aquifer depth ranges from 1.5 to 4.0 m with a thickness range of 5.0 to 14.0 m. The thickest aquifer occurs around the centre to the west in the area. Results from radial sounding show presence of resistivity anisotropy, an insight to fracturing and faulting; this is more pronounced around the west-central part of the premises. 相似文献
15.
可控源音频大地电磁(CSAMT)是探测含煤地层富水区及采空区的重要地球物理方法,但其探测深度误差比较大,采用电性标志层进行深度校正,达到精确解释地层的目的。首先,提出基于电场单分量视电阻率计算方法,只需通过平移即可获得全区视电阻率,无需迭代,简单快速。接着,分析视电阻率微分极值与电性标志层的关系,通过测井电阻率曲线识别出电性标志层,然后通过比值计算深度校正系数,在全区进行插值得到任意测点的校正深度。对新元煤矿31004工作面R280测线数据进行深度校正处理,结果表明:校正后的深度和实际地层基本吻合。最后,通过已知充水采空区边界、淋水点以及钻孔揭示的结果进行对比验证,达到了预期效果。该方法为CSAMT在含煤地层进行精细化数据处理和解释提供了新的思路。 相似文献
16.
大地的感应激发极化效应有时会在瞬变电磁晚期响应上产生负值变号现象。常规实电阻率瞬变电磁反演由于没有考虑激发极化效应,对于观测数据负值部分的解释一直存在问题,这影响了反演解释的真实性和可信度。对此,本文首先将Cole-Cole复电阻率模型加入正演计算,并验证了计算的准确性。然后在阻尼最小二乘法的基础上加入Occam平滑约束来构建反演方程,能够同时反演出零频电阻率、充电率、时间常数以及频率相关系数,实现了一维瞬变电磁复电阻率反演算法。最后,建立具有不同程度激发极化效应的典型层状理论模型进行反演试算与结果分析,结果表明,在激发极化效果明显的低阻高极化地层中,复电阻率反演效果更好。与实电阻率反演结果的对比说明,瞬变电磁复电阻率反演既可以达到实电阻率的常规反演效果,也能解决实电阻率无法实现的负值拟合问题。 相似文献
17.
A saltwater intrusion study using electrical resistivity distribution was conducted in a coastal aquifer system in the southeastern part of Busan, Korea. This aquifer system is divided into four layers according to the hydrogeologic characteristics, and the horizontal extent of intruded saltwater is determined at each layer through the geostatistical interpretation of electrical resistivity data. Intrinsic random function of order k (IRF-k) kriging is performed with covariance models to produce the plane of spatial mean resistivities. The kriged estimates are evaluated by cross validation, and they showed a good agreement with the true values. The statistics of cross validation represented low errors for the estimates. In the resistivity contour maps more than 5 m below the surface, a dominant direction of saltwater intrusion was observed beginning from the east side. These results led the authors to conclude that the application of geostatistical technique to electrical resistivity data is useful for assessing saltwater intrusion in a coastal aquifer system. 相似文献
18.
This paper presents a morphological and hydrogeological reconstruction of the Murcia Valley at the location of the great Roman stadium Circus Maximus in Rome. We reconstruct a valley segment using ERT (electrical resistivity tomography) and geoarchaeological drilling data that identified three main layers. The basal layer, with high resistivity values and convex shapes, is correlated to alluvial gravel and lithified silt‐clay sediments. The middle layer shows low‐to‐medium resistivity values extending to concavities between the basal convex shapes. The very low resistivity values of this middle layer characterize elliptical to circular morphologies and have been ascribed to the presence of water‐saturated clay‐silt and peaty sediments. The surface layer is characterized by widespread lateral inhomogeneity interpreted as anthropogenic fill. The data indicate a pre‐Roman anastomosed alluvial plain subsequently modified by human intervention. In an effort to reclaim the valley for construction of the Circus, the Romans utilized the natural topography and created a central embankment, later becoming the Spina, by filling depressions with sand taken from adjacent bars. Our study contributes to (1) knowledge of the pre‐Roman landscape, (2) understanding anthropogenic modification of the Murcia Valley flood plain, and (3) archaeological interpretation of the monument. 相似文献
19.
An evolutionary approach is applied to solve the nonlinear well logging inverse problem. In the framework of the proposed interval inversion method, nuclear, sonic, and laterolog resistivity data measured at an arbitrary depth interval are jointly inverted, where the depth variation of porosity, water saturation, and shale volume is expanded into series using Legendre polynomials as basis functions. In the interval inversion procedure, the series expansion coefficients are estimated by using an adaptive float-encoded genetic algorithm. Since the solution of the inverse problem using traditional linear optimization tools highly depends on the selection of the initial model, a heuristic search is necessary to reduce the initial model dependence of the interval inversion procedure. The genetic inversion strategy used in interval inversion seeks the global extreme of the objective function and provides an estimate of the vertical distribution of petrophysical parameters, even starting the inversion procedure from extremely high distances from the optimum. For a faster computational process, after a couple of thousand generations, the genetic algorithm is replaced by some linear optimization steps. The added advantage of using the Marquardt algorithm is the possibility to characterize the accuracy of the series expansion coefficients and derived petrophysical properties. A Hungarian oil field example demonstrates the feasibility and stability of the improved interval inversion method. As a significance, the genetic inversion method does not require prior knowledge or strong restrictions on the values of petrophysical properties and gives highly reliable estimation results practically independent of the initial model and core information.
相似文献20.
为满足油田薄层及薄互层开发的需求,采用数值模拟与电路仿真联合的交互式仪器仿真设计方法,开发了高分辨率数字聚焦双侧向测井仪器。通过仪器仿真,形成了纵向分辨率为0.2 m、深浅侧向探测深度分别为1.09 m、0.38 m的双侧向测井电极系,并得到了不同地层条件下测量信号的幅度以及视电阻率测量误差。现场应用效果表明,所设计的双侧向测井仪器的纵向分辨率与探测深度达到了理论指标,曲线重复性满足质量要求。仪器仿真方法有效地沟通了理论设计与仪器实现,不仅有助于0.2 m高分辨率双侧向测井仪器开发,同样也适用于电极型测井仪器设计。 相似文献