从电阻率数据中得到相对渗透率的新方法

相对渗透率是储层评价、油田开发和油藏数值模拟等方面的重要参数,一般通过稳态和非稳态法来获取相对渗透率数据。由于相对渗透率实验所需周期长、成本高,且条件较为苛刻,因此获取相对渗透率数据具有一定难度,而通过现场电阻率测井和室内实验则较为容易获取电阻率数据。本文通过毛细管束模型和阿尔奇电阻率公式,并在引入迂曲度的情况下,推导了一种从电阻率数据中计算相对渗透率数据的新方法。通过文献数据和实验数据对新方法的计算精度进行了验证。结果表明,从电阻率数据得到的水相相对渗透率数据具有很高的精度。在缺少相对渗透率数据的情况下,可以通过新方法从电阻率数据中估算水相相对渗透率。     

基于岩电实验的储层岩石毛管压力与电阻率相关性分析

毛管压力是影响多孔介质中多相流体的重要参数之一,通常采用实验方法测定,但难度大、耗费时间,且准确性难以保证.毛管压力和电阻率指数均为岩石多孔介质中含水饱和度的函数,通过毛管压力与电阻率指数之间函数关系的推导,利用电阻率指数数据直接计算出毛管压力.为了验证两者之间的幂函数模型(Li模型),同时基于更多岩石样品数进行数学模...     

核磁共振测井（CMR）的应用

核磁共振测井具有常规测井无法比拟的优越性。它可以直观，准确地提供储集层的孔隙度，渗透率，区分可动流体和束缚流体，反映储集层的孔隙结构，通过对某CMR核磁孔隙度，渗透率与岩心孔，渗资料的对比分析。建立了两者之间的对应关系，力求精细描述准确的储集层参数；以压汞实验为基础，研究了毛管压力资料与CMR核磁孔径分布曲线的关系，为应用T2谱反演毛管压力曲线奠定了基础；通过求解地层的束缚流体饱和度，结合电阻率测井。采用阿尔奇饱和度解释模型。进行了油（气）层的识别和含油（气）饱和度的计算。从而拓宽了核磁共振测井资料的应用范围，为油（气）层的评价提供了一种新的方法。     

基于微电阻率成像测井的储集层物性及孔隙结构表征——孔隙度谱、渗透率谱及等效毛管压力曲线

基于毛管理论,在构建微电阻率成像测井等效毛管模型的基础上,建立反映储集层非均质性的孔隙度谱(φ_i)、渗透率谱(K_i)和等效毛管压力曲线(pc_i)的理论模型;为扩展理论模型的实际应用,引入阿尔奇公式建立定量表征φ_i、K_i、p_ci的通用模型。对比现有模型表明：(1)现有孔隙度谱模型与φ_i的通用模型相同;(2)相较于普塞尔(Purcell)渗透率模型,K_i模型能计算得到渗透率谱;(3)相较于现有的毛管压力曲线构建经验模型,p_ci模型具有理论基础且克服了现有模型仅基于孔隙度谱分量构建的应用局限。四川盆地川中古隆起TSX井二叠系茅口组实例应用表明,基于孔隙度谱、渗透率谱及等效毛管压力曲线可有效区分储集层类型并计算得到储集层物性及孔隙结构参数,进而有效评价储集层的非均质性。     

核磁共振测井(CMR)的应用(为祝贺新疆油田分公司年产原油一千万吨而作)

核磁共振测井具有常规测井无法比拟的优越性,它可以直观、准确地提供储集层的孔隙度、渗透率,区分可动流体和束缚流体,反映储集层的孔隙结构.通过对某区CMR核磁孔隙度、渗透率与岩心孔、渗资料的对比分析,建立了两者之间的对应关系,力求精细描述准确的储集层参数;以压汞实验为基础,研究了毛管压力资料与CMR核磁孔径分布曲线的关系,为应用T2谱反演毛管压力曲线奠定了基础;通过求解地层的束缚流体饱和度,结合电阻率测井,采用阿尔奇饱和度解释模型,进行了油(气)层的识别和含油(气)饱和度的计算,从而拓宽了核磁共振测井资料的应用范围,为油(气)层的评价提供了一种新的方法.     

用分形几何法预测毛管压力曲线

利用分形几何学的原理和方法,实现了利用常规岩心分析资料如孔隙度和渗透率等反演毛管压力曲线(建立孔喉体积分布预测模型),通过实际资料验证,该方法预测结果精度较高。而毛管压力曲线中包含了大量储集层信息,有一系列的地质应用,包括:计算储集层的相对渗透率;计算任意区间渗透率的贡献值;分析评价储集层的非均质性;确定流动孔喉半径下限值;划分储集层与非储集层并对储集层进行定量评价;对油层流动空间的有效性定量评价;计算储集层原始含油饱和度等,为非取心井段的孔隙结构研究及储集层研究与评价开辟了新途径。     

基于电阻率指数的油水相对渗透率模型

根据多孔介质中骨架和流体并联导电原理建立了基于电阻率指数的水相相对渗透率模型,通过已有研究成果给出了改进的油相相对渗透率模型。对×油田2口检查井12块岩样的电阻率和相对渗透率联测岩石物理实验数据进行了对比验证。提出的基于电阻率指数估算油水两相相对渗透率的方法,其在高孔隙度、高渗透率砂岩中的应用效果较好。     

低孔低压异常气藏储集层参数评价方法

EK气田是中低孔 (平均孔隙度 1 0 .9% )、低渗 (单井渗透率1 0 .1× 1 0 -3μm2 )和低压 (地层压力系数 0 .86 6 )的特殊气藏 ,主力气层受钻井液滤液深侵入 ,测井剖面呈现泥岩为高阻、渗透性砂岩为低阻的异常现象。充分利用岩心实测资料 ,采用非常规的测井解释方法建立了储集层参数解释模型。①孔隙度模型 :统计实测孔隙度和经标准化的声波时差的相关关系 ,再用主力气层分层数据做电阻率 (纵坐标 ,以其平方根的倒数刻度 )与声波时差 (横坐标 ,线性刻度 )的交会图 ,在交会图左上方找出电阻率大幅度降低到相当于水层的气层点做竖直线 ,直线与横坐标轴的交点即为砂岩的骨架声波时差值。②渗透率模型 :EK气田的侧向电阻率可以反映储集层渗透率变化 ,而渗透率与孔隙度之间存在着一定关系 ,因此利用电阻率和声波时差建立渗透率解释模型 ,并用实测渗透率进行检验。③饱和度模型 :根据气水两相密度和二者之间的界面张力关系 ,将毛管压力曲线图的纵坐标换算成气柱高度 ,根据气柱高度对应的岩样实测含水饱和度和孔隙度、渗透率 ,建立了含水饱和度与 3项参数 (气柱高度 ,孔隙度 ,渗透率 )之间的相关关系。经岩心实测资料检验 ,用以上模型解释的储集层参数比较可靠。图 5表 1参 2     

阿尔奇公式在碎屑岩储集层中的应用

岩电实验数据分析表明，阿尔奇公式中的地层电阻率因素都与孔隙度和渗透率呈负相关关系，把渗透率直接引入阿尔奇公式中求地层电阻率因素效果好；而影响含水饱和度指数的主要因素是孔隙度和渗透率的相关性，采用距离校正法可有效地改善地层电阻率指数和含水饱和度的关系，使含水饱和度的计算公式具有一定的稳定性，能把不同沉积环境、不同类型孔隙结构的储集层有效地统一起来。运用修正的阿尔奇公式有效地提高了含水饱和度的计算精度。图５参１（邹冬平摘）     

大庆外围油田润湿性研究

润湿性影响着油水在岩石孔道中的微观分布，决定着毛管压力的大小和方向，因而是油田注水开发中的一项重要参数。对大庆外围油田润湿性进行了研究，润湿性以亲水为主。分析了大庆外围油田润湿性影响因素，随原油中非烃、沥青质含量的增加，亲水性逐渐减弱；随地层水矿化度、束缚水饱和度的增加，亲水性逐渐增强。为了对油层的润湿性有更形象直观的了解，建立了润湿指数和接触角之间的数学模型，该模型可确定油藏的平均接触角，可将依据润湿指数判断润湿性的方法转为依据接触角判断润湿性的方法，可实现压汞法毛管压力曲线和油层条件下油水毛管压力曲线的准确转换，从而为储层微观孔隙结构研究、相对渗透率预测、油藏数值模拟计算提供可靠的数据支持。     

The Validation of Methods to Calculate Gas-Oil Relative Permeability Using Capillary Pressure Data from South Pars Reservoir

Abstract

Gas-oil relative permeability is the most important parameter in the simulation of fluid flow in the gas condensate reservoirs. Experimental measurements of relative permeability need core samples with regular shape, which is costly and time consuming. On the other hand, experimental data of relative permeability may also have significant error and uncertainty in many cases. One source of uncertainty is that the input to numerical simulator is uncertain and inaccurate; it may be reduced if the number of input parameters is decreased, especially if the parameters with the greatest uncertainty are avoided. It is possible to impose only capillary pressure data, because relative permeability can be predicted consistently using specific models. The present methods, which are based on capillary pressure, considered the porous media as a bundle of capillary tubes; they indeed are mercury flow paths that are filled during the mercury injection capillary pressure test at the certain value of capillary pressure. The authors applied the existing capillary models for relative permeability calculations to a gas condensate reservoir. The tested samples have a wide range of liquid permeability from less than 1 to 18 md. The results of this study show that the Purcell model has the best fit with experimental data for wetting phase (oil), and the differences between measured and model data were almost negligible. The predictions of nonwetting phase (gas) relative permeability were a good agreement with experimental data except for Purcell model. Results reveal that the relative permeability could be computed by using accurate capillary pressure data.     

AN APPARATUS FOR SIMULTANEOUS MEASUREMENT OF RELATIVE PERMEABILITY AND DYNAMIC CAPILLARY PRESSURE

The simultaneous measurement of accurate relative permeability and capillary pressure data is essential for studying the phenomena of two-phase flow in porous media. Conventionally, relative permeability and capillary pressure data are measured separately using different equipment and non-identical core samples or sandpacks. It is rather difficult to maintain the same experimental conditions when measurements are made using different equipment and different porous media samples. Moreover, because relative permeability and capillary pressure can be very sensitive to common variables such as saturation and rock/fluid properties, simultaneous measurement of these properties is extremely important to achieve consistency. A relatively new experimental setup has been constructed to obtain dynamic phase pressure and saturation profiles simultaneously during two-phase flow through porous media under steady state and unsteady state conditions. These experimentally measured properties, along with the other needed data, have then been used to calculate the relative permeability and dynamic capillary pressure profiles. Based on the presented experimental results, it has been found that the new experimental setup is reliable and can reproduce stable relative permeability and dynamic capillary pressure profiles with a minimum level of uncertainty.     

裂缝性油藏岩心渗吸实验及其应用

以裂缝性油藏为研究对象,开展了岩心静态渗吸实验,得到了不同物性岩心的渗吸采收率曲线。通过数学推导,建立了圆柱形岩心静态渗吸数学模型,并应用C++语言编程计算,得到了岩心的渗吸采收率数值曲线。通过调整数学模型中的相渗曲线和毛管力曲线参数,进行渗吸采收率数值曲线与物理模拟实验曲线的拟合,应用最小二乘法对拟合结果进行优选。根据拟合最优的渗吸采收率数值曲线,进行岩心相渗曲线和毛管力曲线的确定。     

AN APPARATUS FOR SIMULTANEOUS MEASUREMENT OF RELATIVE PERMEABILITY AND DYNAMIC CAPILLARY PRESSURE

The simultaneous measurement of accurate relative permeability and capillary pressure data is essential for studying the phenomena of two-phase flow in porous media. Conventionally, relative permeability and capillary pressure data are measured separately using different equipment and non-identical core samples or sandpacks. It is rather difficult to maintain the same experimental conditions when measurements are made using different equipment and different porous media samples. Moreover, because relative permeability and capillary pressure can be very sensitive to common variables such as saturation and rock/fluid properties, simultaneous measurement of these properties is extremely important to achieve consistency. A relatively new experimental setup has been constructed to obtain dynamic phase pressure and saturation profiles simultaneously during two-phase flow through porous media under steady state and unsteady state conditions. These experimentally measured properties, along with the other needed data, have then been used to calculate the relative permeability and dynamic capillary pressure profiles. Based on the presented experimental results, it has been found that the new experimental setup is reliable and can reproduce stable relative permeability and dynamic capillary pressure profiles with a minimum level of uncertainty.     

相对渗透率曲线和毛管压力曲线的标准化方法

相对渗透率曲线和毛管压力曲线,是储层的两项重要特性参数,本文提出了两种曲线的标准化方法。相对渗透率曲线和毛管压力曲线,通常是在模拟储层条件下,在实验室的小岩心上直接测量的。两项参数的不同曲线,由本文的标准化方法可以得到无因次关系。该无因次关系可以用于储层特性的对比和得到具有代表性的储层的相对渗透率曲线和毛管压力曲线。      

根据压汞曲线建立砂岩储层渗透率估算模型

岩石的渗透率与孔隙喉道大小及其分布有着直接的关系,而孔隙喉道大小及分布可由毛管压力曲线来确定。根据Purcell提出的渗透率与毛管压力的关系,通过分析研究毛管压力的双曲线特征,建立了一种新的渗透率估算模型。压汞岩心实测数据检验结果表明,模型的参数变化与毛管压力曲线的特征吻合较好,可以较准确地估算出岩石的渗透率。     

The Calculation of Oil-water Relative Permeability From Capillary Pressure Data in an Oil-wet Porous Media: Case Study in a Dolomite Reservoir

Estimating relative permeability curves from capillary pressure data is a well-known technique and the reliability of these techniques for approximation of liquid-gas relative permeability curves had thoroughly investigated. However, there is not enough information to conclude which method is the standard one for calculating oil-water relative permeability curves. The authors utilized various capillary pressure techniques such as the Corey, Brooks-Corey, Li-Purcell, and Li-Burdine methods to calculate oil-water relative permeabilities using the measured oil-water capillary pressure data in drainage process in an oil-wet Dolomite reservoir. Despite wide popularity of Purcell and Burdine methods for calculating relative permeability, the authors used new Li-Purcell and Li-Burdine methods. The calculated results were compared to the experimental data of oil-water relative permeabilities measured in a Dolomite reservoir. The Corey and Brooks-Corey models show an acceptable and nearly exact match with the measured oil relative permeability values. However, the Li-Purcell and Li-Burdine models underestimate the values for wetting phase in most cases. It is also worth mentioning that, except Li-Purcell method, the results of all other methods for calculating nonwetting phase relative permeability are almost the same and they are in good agreement with the measured data. Results of this work reveal that calculation of oil-water relative permeability using the capillary pressure data is also a reliable technique in oil-wet systems.     

Estimation of Fracture–Matrix Transport Properties from Saturation Profiles Using a Multivariate Automatic History Matching Method

Abstract

This study focuses on the development and implementation of a numerical model of multiphase flow in a fractured core sample by describing the capillary pressure–relative permeability characteristics. An automated history matching approach is proposed to determine relative permeability and capillary pressure curves simultaneously for both matrix and fracture consistent with a core flood reservoir model performance, which relies on a commercial reservoir simulator coupled with an optimization protocol. The results indicate that the proposed approach successfully predicts relative permeability and capillary pressure curves of a fractured core sample and provides a foundation for field-scale history matching with simultaneous estimation of transport properties.     

基于岩石电阻率参数研究致密砂岩孔隙结构

低孔低渗致密砂岩储层孔隙结构特征是影响其油气储集能力和采收率的重要因素，故对其孔隙结构特征进行研究具有重要的意义。文章主要探讨了利用电阻率参数开展该类储层孔隙结构特征研究的方法。基于铸体薄片和压汞实验数据反映出的此类储层孔隙结构的特征，选取毛细管束模型推导并建立了致密砂岩储层孔隙结构特征参数计算模型，并结合岩电实验数据对模型进行了验证。结果表明：从电阻率参数计算得到的岩石孔隙结构参数能较好地反映岩石的孔隙结构特征，利用电阻率计算得到的岩石孔隙结构参数是随含水饱和度变化而变化的量，其变化量及变化的速率能够反映出储集层开采过程中油气藏内部流体的分布变化；利用井下不同时刻实测电阻率参数计算得到的岩石的孔喉半径，仅代表测井时刻地层内导电流体所占据的孔隙空间的半径，而计算得到的岩石迂曲度也只反映了当前状态下导电流体的分布状况。