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岩性识别是一项重要的地质基础研究内容.以交会图为代表的常规岩性识别工具虽然在构建的二维或三维图版中能够依据手动归类的测井数据点集来明确各种岩性的一系列测井响应判定,但却无法适用于致密砂岩储层,其原因是该类储层的岩性成分不仅复杂,且较多岩性的测井响应特征具有相似性.根据机器学习在数据分析上的强大性能,本文提出利用在模式识别方面能力出众的GBDT模型来解决岩性识别问题.本文以姬塬油田西部长4+5段致密砂岩储层测井资料为基础,通过设计两种实验来验证提出模型的岩性识别能力.为提高验证效果,在实验中加入BP、PNN和KNN三种传统模式识别模型进行对比.实验结果显示,GBDT识别准确率最高,分别为90.14％和90.41％.基于GBDT较传统模式识别模型能够给出更为准确的预测值,实验结果充分证明了提出模型不仅能有效识别致密砂岩储层岩性,在岩性识别研究领域上还具有良好的推广应用前景. 相似文献
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《地球物理学进展》2020,(2)
为判定不同测井系列评价划分储层孔隙结构的能力强弱,进而利用测井资料划分储层孔隙结构类型,筛选储层"甜点"的目的,应用岩芯压汞、物性资料,将鄂尔多斯盆地黄陵油田长6浊积岩储层孔隙结构划分为4种类型.基于此,建立4种孔隙结构样品的岩性、孔隙度与电阻率测井系列响应交汇图,分析不同测井系列识别不同孔隙结构的能力强弱.结果表明,岩性测井系列中,针对Ⅰ、Ⅱ、Ⅲ、Ⅳ类孔隙结构储层,其对应自然伽马分布范围及变化幅度差异明显,反映其识别不同类型孔隙结构最为敏感;钍含量、钾含量及光电吸收截面指数对不同孔隙结构分辨力较强,能够识别四种孔隙结构类型;但铀含量测井对不同孔隙结构分辨力整体较差,自然电位测井识别Ⅱ、Ⅲ类孔隙结构能力较弱.孔隙度测井系列中,声波时差、密度、中子测井识别不同孔隙结构能力相当,鉴于经济实用角度评价,可加强声波时差资料的有效挖掘和应用.电阻率测井系列中,鉴于研究区长6储层致密、孔隙结构复杂及储层油水混储等因素影响,双感应和阵列感应测井难以解释不同孔隙结构储层流体性质及含油性判定.经黄陵油田145口井应用检验,自然伽马、钍含量、钾含量及声波时差等敏感测井系列不仅反映浊积岩储层岩性、物性及含油性特征,且有效提高优质储层识别精度和实用效果. 相似文献
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利用交会图法识别国外M油田岩性与流体类型的研究 总被引：1，自引：0，他引：1
利用测井曲线进行岩性与流体类型的识别是测井解释的重要内容之一,可为油田油气藏的综合评价提供重要的基础依据.基于交会图法和岩心资料,本文分析研究了国外M油田的常规测井曲线特征与岩性和流体类型的关系.首先以岩心资料为基础,选取对岩性和孔隙流体敏感的物理量进行交会图分析识别,在现有测井资料的前提下,综合这些物理量建立了GR-BK、GR-NGR、NGR-BK、PHIE-SW交会图版,然后利用这些图版进行了岩性和流体的识别.其中:岩性主要依据自然伽马、中子伽马、电阻率交会图版来识别,流体类型主要依据饱和度和电阻率交会图版进行识别.在上面工作的基础上确定了该油田不同类型的岩性和流体的识别标准值范围:1)碳酸岩识别标准为GR<70API,NGR>2.5CU,BK<5Ω.m;砂岩识别标准为,70API162API.2)油气层有效孔隙度PHIE>20%,SW<55%,BK>2Ω.m;水层的有效孔隙度PHIE>20%,但是SW>55%,BK<2Ω.m.从上面的结果可看出,在该研究区域,该方法不仅可以区分砂岩和泥岩这样不太复杂的岩性,甚至可以区分砂岩、石灰岩和白云岩这样易混淆的岩性.最后,通过待测试数据对建立的交会图版进行检验,岩性和流体识别的准确率达到了94%和100%.本文的研究结果对中亚地区油田的岩性识别和储层预测具有重要的应用价值. 相似文献
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利用电成像测井图像的直观特征进行岩性识别是目前砂砾岩储层评价的一项主要内容,但是对于电成像的利用研究仅仅停留在定性阶段,缺乏定量的表征,主要成果为基于电成像的图像-岩性识别模式.特别是由于电成像测井资料有限,在缺乏定量数据的前提下,无法将电成像取得的成果推广到常规测井资料,这一难题一直制约着砂砾岩岩性识别的研究.以盐家油田沙四段砂砾岩为例,对其电成像测井图像进行灰度化、盲区充填、图像滤波、图像分割、砾石提取等操作后,电成像图像可转化为连续的岩心砾石信息,进而可以提取纵向的砾石含量、最大粒径、最小粒径、平均粒径等参数.以最大砾石粒径作为砂砾岩储层岩性指示的标志,通过粒径与常规曲线的敏感性分析,建立了砂砾岩岩石粒径与电阻率、自然伽马和密度等常规测井曲线的统计关系,并提出了该地区岩性识别的定量标准. 相似文献
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《地球物理学进展》2020,(2)
位于巴西深J油田的盐下碳酸盐岩岩性及孔隙结构的识别对于区域储层的分布规律十分重要,但由于海外资料的获取量有限,如何最大限度地利用已有资料进行精准有效的岩性识别成为难题.本文在已有的各项地质信息资料的基础上,先利用成像测井资料提取出储层内主要岩性典型的结构标准图版,然后探索各类岩性在常规测井曲线上的响应规律,并提取出识别岩性的敏感参数,建立起常规测井参数的交会图法识别规律.确认其应用在全井段识别中取得效果后,进一步利用数据挖掘软件中的决策树技术,组合成交会图-决策树模型法.将此模型应用于实际井资料的处理,利用薄片资料和成像图像进行验证,得到了更高的岩性识别符合率,证实了模型在仅有常规测井资料中的适用性. 相似文献
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火山岩储层总体属于低孔渗储层评价的范畴,由于测井含气响应远弱于岩石骨架响应,流体识别面临气、水层区别难的问题;由于岩性和孔隙结构复杂引起阿尔奇参数多变,测井解释面临饱和度定量计算精度不高等问题.针对上述问题,提出“定性解释与定量解释相互独立、相互验证”的火山岩测井解释原则.在气层识别方面,从重构孔隙度气层识别组合曲线、研究电阻率相对值、应用核磁测井技术以及分析储层含气丰度与测井响应差异等四个研究方向探索了不同储层的测井识别依据,根据上述研究成果,确定了5类储层的测井判别依据,实现了火山岩定性解释;在火山岩定量解释方面,由于电阻率曲线本身就是岩性和孔隙结构的综合反映,引入基于电阻率测井响应的可变m值阿尔奇计算公式,应用生产测试成果验证,证实该方法定量计算储层含气饱和度精度高.根据上述研究成果,系统建立了松南火山岩测井解释模型.应用新的火山岩储层测井解释方法,多口新井的测井预测结果被生产测试所验证,应用效果良好. 相似文献
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M. N. French R. L. Bras W. F. Krajewski 《Stochastic Environmental Research and Risk Assessment (SERRA)》1992,6(1):27-45
A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities. 相似文献
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Gtz Schroth Luciana Ferreira Da Silva Marc‐Andree Wolf Wenceslau Geraldes Teixeira Wolfgang Zech 《水文研究》1999,13(10):1423-1436
The partitioning of rain water into throughfall, stemflow and interception loss when passing through plant canopies depends on properties of the respective plant species, such as leaf area and branch angles. In heterogeneous vegetation, such as tropical forest or polycultural systems, the presence of different plant species may consequently result in a mosaic of situations with respect to quantity and quality of water inputs into the soil. As these processes influence not only the water availability for the plants, but also water infiltration and nutrient leaching, the understanding of plant effects on the repartitioning of rain water may help in the optimization of land use systems and management practices. We measured throughfall and stemflow in a perennial polyculture (multi‐strata agroforestry), monocultures of peach palm (Bactris gasipaes) for fruit and for palmito, a monoculture of cupuaçu (Theobroma grandiflorum), spontaneous fallow and primary forest during one year in central Amazonia, Brazil. The effect on rain water partitioning was measured separately for four useful tree species in the polyculture and for two tree species in the primary forest. Throughfall at two stem distances, and stemflow, differed significantly between tree species, resulting in pronounced spatial patterns of water input into the soil in the polyculture system. For two tree species, peach palm for fruit (Bactris gasipaes) and Brazil nut trees (Bertholletia excelsa), the water input into the soil near the stem was significantly higher than the open‐area rainfall. This could lead to increased nutrient leaching when fertilizer is applied close to the stem of these trees. In the primary forest, such spatial patterns could also be detected, with significantly higher water input near a palm (Oenocarpus bacaba) than near a dicotyledonous tree species (Eschweilera sp.). Interception losses were 6·4% in the polyculture, 13·9 and 12·3% in the peach palm monocultures for fruit and for palmito, respectively, 0·5% in the cupuaçu monoculture and 3·1% in the fallow. With more than 20% of the open‐area rainfall, the highest stemflow contributions to the water input into the soil were measured in the palm monocultures and in the fallow. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
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M. A. Kahn 《洁净——土壤、空气、水》2000,28(2):95-101
Red tide, a recurrent phenomenon has become conspicuous in several Kashmir lake ecosystems since 1991. The responsible organism (Euglena pedunculata), a rare flagellate rediscovered in the Kashmir Himalaya (Khan 1993) caused first and unprecedented red tide outbreak, constituting a maximum of 96% of resident numerical phytoplankton density in Dal Lake. At present, conflicting hypotheses exist on the generation of causal assemblage(s) imparting redness to waters: Jeeji Bai (1991) linked its origin to acid precipitation – a fallout of burning oil‐fields during the Gulf War – whilst Khan (1993) holds local factor(s) responsible. Field/experimental studies support the latter contention that the influx of untreated sewage, in unison with warm temperatures, high levels of PhAR, iron and interruption to hydrological flow‐pattern together with absence/or reduction in grazing activity created conducive environmental milieu for red tide outbreak. Dal Lake “red tide” drifted the bloom‐inoculum to other waters, including Lake Wular, where additional ecological niches were carved out, threatening the aesthetic value and biological diversity of Kashmir lakes. Ecological monitoring indicates frequent seasonal red tide occurrence in Dal Lake (including summer‐autumn event of 1998) which testifies its unabated eutrophication status. Further studies are needed on ecological adaptability and biogeographic distribution of this rare and unique red tide‐causing flagellate. 相似文献
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