任务驱动数据挖掘方法的提出及在低阻油层识别中的应用

为了解决数据挖掘算法的高效性、工具智能性与所获取知识无效性之间的矛盾,同时使所获取知识能有效地解决地层评价领域中的各种疑难问题,提出任务驱动数据挖掘方法。结合数据挖掘的概念和技术,阐述了任务驱动数据挖掘的概念和基本原理,分为建立数据仓库、数据预处理、选择特征子集、形成模型、模型评估、模型修正和模型发布等7个部分,是一个循环迭代的过程,直到构建能有效解决目标任务的预测模型为止。并以低阻油层的识别为例,详述整个分析处理过程,结合决策树形成的白盒模型和支持向量机构建的黑盒模型综合识别目标区的低阻油层,获得了准确率大于90%的识别效果。     

一种基于安全因子判据的坝肩裂隙岩体动力抗滑稳定分析方法

基于某混凝土拱坝,结合现行拱坝设计规范,研究提出了一种基于安全因子判据的坝肩岩体动力抗滑稳定安全度分析方法。该方法综合利用有限元和（刚体）极限平衡两种方法的优点,考虑了凝聚力和摩擦力是不同的抗力,其不确定性具有较大差异性,定义了抗滑稳定安全因子,据此来判别坝肩岩体的抗滑稳定安全度,安全因子随着凝聚力与摩擦力所占权重不同而变化,这种方法既考虑了坝肩岩体与坝体的联动作用,又能够反映拱坝体系真实的工作性态。通过某混凝土高拱坝工程实例,分析了坝肩裂隙岩体的抗震稳定性,结果表明,该方法具有较高的实用价值。     

鄂尔多斯盆地姬塬地区上三叠统长6段储层成岩非均质性

通过对57口钻井的岩心观察,结合岩石薄片、岩石铸体薄片和扫描电镜观测,以及岩石常规物性、X衍射及流体包裹体分析等多种分析测试的综合研究,在明确姬塬地区长6段储层岩石学、物性及成岩作用特征的基础上,探讨了该地区储层成岩非均质的成因及演化过程。研究表明：姬塬地区长6段是以长石砂岩为主的低孔超低渗储层;沉积伊始,受机械分异作用控制,形成原始沉积的孔隙非均质,使不同原始孔隙条件的储层在成岩演化过程中发生差异演化,并经历早期压实、早期酸性水注入、碳酸盐胶结受阻、有机酸及油气注入4个演化阶段,导致储层的成岩非均质性。     

裂隙岩体流-热耦合传热的三维数值模拟分析

通过对潘西煤矿水文地质条件的分析,基于裂隙岩体的流-热耦合数学模型,描述了裂隙岩体渗流场分布和水流及岩体的温度场分布,并结合边界条件及计算参数对裂隙岩体的流-热耦合传热进行了数值模拟和分析。数值模拟结果表明,岩体内裂隙水流所引发的热量迁移,对裂隙岩体的温度场分布有重要影响。断裂带及地下水流的存在改变了岩体的原有温度场分布。在渗流初期,温度梯度矢量沿渗流方向向两侧岩体方向流动,由于两侧岩体的渗透性系数低于断裂带处的渗透性系数,右侧等温线及温度梯度矢量方向逐渐向渗流方向移动,改变了两侧岩体的温度场分布。通过对断裂带内裂隙水流渗透性系数的折减,分析渗透性系数发生变化时对岩体温度场分布的影响,渗透性系数越大,伴随的热量迁移增大,对岩体的温度场分布的影响也越大。     

Evaluation of volcanic reservoirs with the “QAPM mineral model” using a genetic algorithm

Gas-bearing volcanic reservoirs have been found in the deep Songliao Basin, China. Choosing proper interpretation parameters for log evaluation is difficult due to complicated mineral compositions and variable mineral contents. Based on the QAPF classification scheme given by IUGS, we propose a method to determine the mineral contents of volcanic rocks using log data and a genetic algorithm. According to the QAPF scheme, minerals in volcanic rocks are divided into five groups： Q（quartz）, A （Alkaline feldspar）, P （plagioclase）, M （mafic） and F （feldspathoid）. We propose a model called QAPM including porosity for the volumetric analysis of reservoirs. The log response equations for density, apparent neutron porosity, transit time, gamma ray and volume photoelectrical cross section index were first established with the mineral parameters obtained from the Schlumberger handbook of log mineral parameters. Then the volumes of the four minerals in the matrix were calculated using the genetic algorithm （GA）. The calculated porosity, based on the interpretation parameters, can be compared with core porosity, and the rock names given in the paper based on QAPF classification according to the four mineral contents are compatible with those from the chemical analysis of the core samples.     

基于QAPM矿物模型遗传算法评价火成岩储层

在松辽盆地深层发现了含气火成岩储层。由于火成岩矿物组成复杂和含量的变化,使得选择用于测井评价的解释参数很困难。基于IUGS提出的QAPF分类方案,本文提出了采用遗传算法,利用测井数据确定火成岩矿物含量的方法。根据QAPF分类方案,将火成岩中的矿物分为五类:Q-石英;A-碱性长石;P-斜长石和方柱石;F-副长石(研究区未出现);M-铁镁矿物。本文提出用包括孔隙度在内的QAPM模型对储层进行分析。建立密度、视中子孔隙度、声波时差、自然伽玛和体积光电吸收截面指数的测井响应方程,各矿物参数从斯伦贝谢的矿物参数手册中得到。用遗传算法计算骨架中四种矿物的体积,根据四种矿物的体积含量,依据QAPF分类对火成岩命名。基于解释参数计算的孔隙度可与岩心分析的孔隙度相比,本文给出的火成岩命名与岩心化学分析的命名相一致。     

碳酸盐岩储层多角度弹性阻抗流体识别方法

碳酸盐岩储层的AVO响应要比碎屑岩储层响应微弱,因此,弹性阻抗（EI）即使在确定了最佳入射角的情况下,要判断碳酸盐岩储层中的流体性质,依然十分困难.本文提出了一种多角度扩展弹性阻抗（MEEI）反演进行碳酸盐岩储层流体识别方法.利用已有钻井的测井数据,通过计算目的层段的MEEI,建立相应的含流体模式,进而建立了碳酸盐岩储层流体检测中的有效气水判据.通过不同入射角下EEI随入射角变化的不同趋势,可以有效识别储层中含气或含水情况,判别储层好坏.本文方法的有效性在四川盆地某地区实际资料应用中取得了良好的流体检测效果.     

Seismic imaging of the geothermal field at Krafla,Iceland using shear-wave splitting

Shear-wave splitting is emerging as a useful exploration method for geothermal reservoirs as it can detect the geometry of the fracture system, the intensity of cracking and possibly, changes in fluid pressure within the reservoir. The method is based on the analyses of polarizations and time delays of shear-waves that have been distorted by the anisotropy of the medium through which the seismic waves have propagated. Observations of shear-wave splitting within the Krafla–Leirhnúkur geothermal field, Iceland, using a 20-station 3-component portable seismic array have provided evidence for at least two major crack systems of microfractures, oriented approximately N–S and E–W. Located microearthquakes align roughly along the E–W direction of the geothermal field, with shallow focal depths mostly around the injection well, probably related to the ongoing injection. This unexpected direction is however consistent with results from a simultaneous MT (magnetotelluric) survey.     

特低渗岩性油藏间连通性表征研究 ——以鄂尔多斯盆地马岭地区长8油藏为例

分析各岩性油藏之间的连通性,可为油藏之间区域寻找新的油气富集区提供依据。以鄂尔多斯盆地马岭地区长8油藏为研究对象,根据砂体发育规模及夹层发育状况分析储层砂体连通性,通过原油全烃色谱分析判断油藏间流体连通性。运用动静结合的方法探讨了马岭地区长8段各个小油藏间的连通性,结果表明:研究区长8段储层砂体叠置样式包括:孤立式、接触式、切叠式,其中切叠式储层砂体间连通性较好;建立了基于夹层的发育状况下砂体连通概率公式,并计算了研究区长8段储层砂体连通概率;通过原油全烃色谱分析可将研究区长8油藏分为三个流体连通系统,每个系统内的小油藏之间相互连通,不同系统内的小油藏间连通性差;根据马岭地区最新的勘探评价成果验证了该方法的有效性,该方法对特低渗岩性油藏间的连通性分析及油气勘探部署具有一定的指导意义。     

Controlling factors of reservoir quality in low-permeability reservoir within a sequence stratigraphic framework: a case study of the lower Jurassic sandstones in the Northern margin of the Qaidam Basin,China

The Qaidam Basin, one of China’s most prolific petroliferous basins, is located in the northeastern corner of the Qinghai-Tibet Plateau. Using analytical data from cores, thin-sections and seismic data, and combined with the previous sequence stratigraphy research results, research on the reservoir characteristics was undertaken. The main controlling factors of reservoir quality in the sequence stratigraphy framework in the Lenghu area are discussed. The Lower Jurassic includes lowstand system tract (LST) and transitional systems tract (TST); the highstand systems tract are missing owing to tectonic uplift. The Lower Jurassic sandstones are composed of moderately to poorly sorted, subrounded sandstone representing several representative environments, including fan-delta and lacustrine facies. The main types of the Lower Jurassic sandstones are mostly feldspathic litharenite and lithic sandstone. The pore types of the Lower Jurassic sandstones are mainly secondary dissolution pores with few fracture types. The Lower Jurassic sandstones have experienced strong compaction that resulted in the loss of primary porosity. Carbonate cementation of the LST sandstones is greater than in the TST sandstones. Dissolution, which has an important role in reservoir development, is mainly caused by acidic fluids from the matured source rocks in the LST and meteoric water ingression from the top sequence boundary in the TST. Distributary channel sandstones adjacent to coal and mudstones are favourable reservoirs with turbidite sandstones adjacent to the sequence boundary less favourable reservoirs.