二项式产能试井拟合图版

本文通过对产能方程的分析,在无因次二项式产能方程的基础上,绘制二项式产能方程拟凳图版,分析了其多解性,并利用该图版求取ＩＰＲ曲线特征参数、地层压力、绝对无阻流量。     

高压气井产能评价方法对比分析

结合松南气田腰平3井的试气测试,通过对气井多种无阻流量计算方法的对比,得出了对于气藏,尤其是高压气藏,只要能得到相关系数较高的二项式产能方程,由此得到的无阻流量是最为准确的。在计算高压气井的产能时,各种方法的优先级是：二项式压力法,指数式压力法,一点压力法。     

龙凤山凝析气藏气井合理配产研究

龙凤山凝析气藏为一受岩性物性控制的特低渗凝析气藏,储层属特低孔、特低渗储层;孔喉结构复杂,属中孔、微-细喉道。地露压差小,凝析油含量高,极易发生反凝析伤害及井筒积液。如何科学、合理的确定单井合理产量,既满足天然气开发需求,又有效防止井筒积液显得十分重要。本文综合运用无阻流量、采气指数法、临界携液流量法和数值模拟法确定单井合理产量。通过优化气井配产,延长气井稳产期,提高单井开发效益。     

塔里木盆地牙哈凝析气田地质特征与开发机理研究

塔里木盆地牙哈凝析气田具有地层压力高、凝析油含量高和露点压力高等显著特点。在分析其主要地质特征的基础上建立了地质模型来准确地预测储层中影响注气效果的高渗透层的分布规律。通过对凝析气田地质特征和开发机理的深入研究,发现对于高渗、高含油的凝析气藏,由于凝析油临界流动饱和度较低,可以采用衰竭式开发方式;而对于储层物性较差的高含油凝析气藏,则适合保持压力开发。据此不仅建成了我国凝析油产能规模最大的凝析气田--牙哈凝析气田,还在多个气田开发前期评价及柯克亚凝析气田综合调整中得到广泛应用,在开发实践中形成了一套适合于塔里木盆地超深高压凝析气藏的开发技术系列。     

数值试井技术在凝析气藏边界识别中的应用

做为一种新兴试井解释技术,数值试井技术在油、气藏复杂边界形态描述方面发挥了重要作用,具有处理非均质、复杂边界油气藏问题的优点.通过对塔中某区块凝析气藏测试资料综合分析评价,探讨了综合运用解析试井及数值试井进行联合分析方法,将测试动态成果和地质静态成果进行对比,相互验证、补充,实现了对油、气藏外部复杂边界形态的精细描述,落实该气藏边界情况,为该区块凝析气藏下一步开发提供可靠依据.     

新疆牙哈凝析气田产能变化试井解释

牙哈凝析气田是目前国内已投入开发的规模最大的整装凝析气田,投产以来开发效果很好。但目前牙哈凝析气田全面进入反凝析生产阶段,提气稳产的效果受到很大的影响,生产过程中的矛盾逐渐暴露。使用现代试井解释方法,应用KAPPA公司的Saphir试井解释软件对牙哈凝析气田9口生产井历次压力恢复试井、产能试井进行了试井解释,分析了牙哈凝析气田产能变化规律及反凝析现象对产能变化的影响,得出以下结论:(1)一般储层渗透率为20×10-3μm2,测试点测试产量在25万m3时,为产能测试曲线出现负斜率的分界线;(2)反凝析现象的存在造成试井解释模型多采用径向复合油藏模型。这些对正确认识气藏开发动态及生产特征、加强动态监测技术研究、获得良好的注气效果和显著经济效益起着重要的指导作用。     

利用测井资料进行天然气储层产能的评价与预测

以鄂尔多斯某区块石盒子组第一段为主要研究层段,以测井数据体为实际利用资料,通过对测井数据资料的聚类分析,建立了对应产层的评价参数,以多参数聚类分析方法建立了天然气储层产能评价和预测的标准模式,从而达到从定性到定量对天然气储层的产能进行评价和预测的目的.分析结果表明,该区块目的层段的产能级别可分为两类,一类的产能级别较差,其无阻流量小于5 000 m3/d,达不到国家工业气流标准,无开采价值;而另一类的产能级别较好,其无阻流量大于5 000 m3/d,多在10 000 m3/d以上,具备一定的开采价值.研究验证该方法是一种行之有效的方法.     

裂隙—岩石格架系统中二相流的耦合模型

针对某些地质条件导出了离散双重介质二维二相流耦合微分方程,对方程中的渗透率和裂隙宽度进行了Ｋａｒｈｕｎｅｎ－Ｌｏｅｖｅ级数展开,对其他参数进行了多项式随机函数的级数展开,同时对截取级数前有限项所产生的误差作了分析,在求解基本未知量的同时也能求解随机变量的特征数。     

裂隙-岩石格架系统中二相流的耦合模型

针对某些地质条件导出了离散双重介质二维二相流耦合微分方程,对方程中的渗透率和裂隙宽度进行了Karhunen－Loeve级数展开,对其他参数进行了多项式随机函数的级数展开,同时对截取级数前有限项所产生的误差作了分析．在求解基本未知量的同时也能求解随机变量的特征数。     

复杂岩性储层渗透率-应力敏感性及其对气井产能的影响

采用变流压定围压试验方式,在高温、高压条件下模拟了气藏开发过程,研究了复杂火山岩气藏储层渗透率应力敏感性,对比了变流压定围压与常规的定流压变围压方式评价储层应力敏感性的异同。试验结果表明,火山岩储层渗透率随着孔隙压力的减小而减小,渗透率减小主要发生在孔隙压力从40 MPa下降至25 MPa的变化区间,渗透率损失率与其初始渗透率之间的相关性较差,这与常规沉积砂岩储层具有一定的差别。变流压定围压试验评价的应力敏感性强于定流压变围压评价结果,气藏储层有效应力变化范围内两种试验评价的应力敏感性结果差异更大。基于渗流力学理论,推导得到考虑应力敏感性的气井产能方程。计算结果表明,考虑应力敏感性时气井无阻流量约为不考虑应力敏感性时的63.28%,应力敏感性对气井产能的影响随着生产压差的增大而增大。     

具有补给气的异常高压有水凝析气藏物质平衡方程建立及应用

物质平衡法是计算气藏地质储量、水侵量、补给气量的有效方法之一.具有补给气的异常高压有水凝析气藏是气藏开发中最复杂的类型之一, 兼具异常高压气藏、凝析气藏和补给气的边底水气藏的特性.综合考虑开发过程中的凝析油析出, 岩石、束缚水和凝析油弹性膨胀, 水相挥发, 凝析气相中水蒸气增多, 水溶气溢出, 边底水的推进及外来气补给等复杂物理现象, 根据物质平衡原理, 推导了具有补给气的异常高压有水凝析气藏物质平衡方程, 并运用相对海明距离及关联度理论, 以驱动指数均方差、比拟压力与采出程度偏差指数和综合目标函数为分析因素, 分析了各组合方案贴近程度及相似程度, 挑选最佳组合方案并确定出地质储量、补给气量及水侵量, 同时计算了水体倍数.实例计算表明: 中国西北某凝析气藏地质储量为66.80×108 m3, 如果忽略凝析油, 计算地质储量偏大, 误差高达91.77%, 其次是水侵、弹性膨胀和气侵的影响, 误差分别为75.75%、23.95%和12.87%, 而溢出水溶气为2.69%与水蒸气为1.65%, 影响较小, 但也不可忽略.      

天然气的加速式二次运移过程研究

在静水条件下,游离相天然气运移的主要动力是浮力,阻力是毛细管力。根据前人的实验数据,通过理论计算发现,浮力和毛细管力均受地层温度和压力的影响,气体在储层中上浮的临界高度随地层温度和压力的降低而增大。根据气体状态方程及天然气运移的动力学理论,推导出温度和压力降低前、后气体流速比方程,用其计算了不同储层中临界气体长度并分析不同储层中相同长度的气体在运移途中的变化规律。由此发现,在运载层物性不变的情况下,天然气沿上倾地层向上倾方向运移的过程,是随地层温度和压力不断降低、其运移速度逐渐增大的过程,如果有后续气体的加入,会使气体长度增大,致使运移速度增加得更快。     

塔里木盆地和田河气田碳酸盐岩储层的多期次多来源油气聚集特征

高成熟度演化地区的海相碳酸盐岩储层易受到油气演化的影响 ,油气的聚集在储层中都留下了踪迹 ,既有对储层储集性能的改善有利的一面 ,也有对储层形成伤害的一面。对和田河气田的碳酸盐岩储层薄片观察、凝析油气的地球化学分析和储层沥青分析表明 ,主要有 3期油气运移 ,分别为 :晚加里东期—早海西期、晚海西期和喜山期。前两期都是寒武系来源的油气 ,均被生物降解或散失 ,喜山期是天然气的关键聚集时期。第一期以油相运聚的油气被降解 ,形成的沥青对储层造成了伤害 ,第二期以气相运移的油气多散失 ,仅在储层中留下凝析油 ,第三期油相运移的石炭系来源的油受到后期转移上来的寒武系干气的气侵 ,产生沥青质沉淀 ,使得寒武系凝析油被封堵 ,储层产出的凝析油的地球化学特征更接近石炭系源岩。     

Control Factors and Diversities of Phase State of Oil and Gas Pools in the Kuqa Petroleum System

Based on the analysis of the hydrocarbon geochemical characteristics in the Kuqa petroleum system of the Tarim Basin, this study discusses the causes and controlling factors of the phase diversities and their differences in geochemical features. According to the characteristics and differences in oil and gas phase, the petroleum system can be divided into five categories: oil reservoir, wet gas reservoir, condensate gas-rich reservoir, condensate gas-poor reservoir and dry gas reservoir. The causes for the diversities in oil and gas phases include diversities of the sources of parent material, maturity of natural gas and the process of hydrocarbon accumulation of different hydrocarbon phases. On the whole, the Jurassic and Triassic terrestrial source rocks are the main sources for the hydrocarbon in the Kuqa Depression. The small differences in parent material may cause diversities in oil and gas amount, but the impact is small. The differences in oil and gas phase are mainly affected by maturity and the accumulation process, which closely relates with each other. Oil and gas at different thermal evolution stage can be captured in different accumulation process.     

东海盆地西湖凹陷凝析气藏成藏特征及分布控制因素

实际勘探证实西湖凹陷油气藏具有上油下气的特征,油气资源分布表现为南多北少。通过西湖凹陷凝析油和凝析气地球化学参数的分析,认为西湖凹陷的凝析油和凝析气具有相同的成因类型和成熟度,均为平湖组煤系源岩生成的油气。根据西部斜坡带和中央反转带油气藏类型、油气成藏期次及圈闭形成时间研究成果,认为：西部斜坡带油气首先充注在平湖组中,后期由于断层开启调整至花港组中,因压力降低油气分离和天然气散失而在花港组中形成凝析油藏;在中央反转带,由于圈闭定型时间晚,油气主要经历一期成藏再通过断层运移至花港组,花港组上部压力低,使油气分离、天然气散失而形成纯凝析油藏。通过对油气成藏和分布特征的研究,认为生烃中心的分布控制着油气藏的分布,断层分布和断穿层位控制着油气藏丰度,超压控制着西部斜坡带凝析油和凝析气藏的分布界面。     

基于物质平衡反演法的致密砂岩气藏地层压力计算

压力是气藏的“灵魂”,地层压力是评价气井产能,分析气藏潜力的基础。然而,受到资料完整程度、方法适用条件等因素的限制,大部分气井无法准确获取地层压力。为了评价致密砂岩气藏地层压力,基于少量压力监测资料,采用数学反演思维,提出物质平衡反演法。首先,利用拟稳定流动状态下气井生产数据,拟合Blasingame图版,计算气井动态储量。而后,通过动态储量及一个测压数据进行反演,建立物质平衡方程,代入累产气量,评价地层压力,最后,以大宁–吉县区块致密砂岩气井为例,进行地层压力计算。结果表明:(1) 物质平衡反演法仅需一个测压点,可以评价气井的地层压力变化。(2) 气井原始地层压力差异大,单井地层压力变化复杂,存在多个压力系统。(3) 压力系统不一致与储层非均质性强有关。研究结果对于致密气单井压力计算和致密气藏压力评价提供了可靠的方法,为致密气藏开发方案调整和效益开发奠定了基础。      

Using vorticity to quantify the relative importance of heterogeneity, viscosity ratio, gravity and diffusion on oil recovery

The vorticity of the displacement velocity is used to derive dimensionless numbers that can be used to quantify the relative importance of viscosity ratio, gravity, diffusion/dispersion and permeability heterogeneity on secondary hydrocarbon recovery. Using this approach, a new objective measure of the impact of permeability and porosity heterogeneity on reservoir performance is obtained. This is used, in conjunction with other dimensionless numbers, to analyse the relative impact of heterogeneity, buoyancy effects, mobility ratio and dispersion on breakthrough time and recovery at 1 pore volume injected during first contact miscible gas injection. This is achieved using results obtained from detailed simulation of miscible displacements through a range of geologically realistic reservoir models. This study goes some way towards developing a unified mathematical framework to determine under which flow conditions reservoir heterogeneity becomes more important than other physical processes. We propose that comparison of these dimensionless numbers can be used to identify the key factors controlling recovery and thus assist the engineer in determining appropriate enhanced oil recovery techniques to improve recovery.     

基于Copula函数的入库洪水与坝址洪水关系研究

采用频率分析法计算入库设计洪水时,需要通过相关分析将坝址洪水系列插补得到对应的入库洪水系列。常用的线性回归法假设两者满足线性关系且入库洪水系列服从正态分布,可能与实际情况并不相符。引入Copula函数构建坝址洪水与入库洪水的联合概率分布和条件概率分布,计算给定坝址洪水时入库洪水的条件最可能值和置信区间,提出了一种基于Copula函数的入库洪水插补新方法。三峡水库的应用实例表明:线性回归法得到的入库洪水值在坝址洪水量级较大时明显偏小,甚至稀遇洪水时不在90%置信区间内。所提方法能较好地反映坝址洪水与入库洪水的内在关系,不仅可以计算入库洪水的各种点估计值,而且能够定量评价估计的不确定性。     

Distribution of the Ordovician Fluid in the Tahe Oilfield and Dynamic Response of Cave System $48 to Exploitation

The Tahe Oilfield is a complex petroleum reservoir of Ordovician carbonate formation and made up of spatially overlapping fracture-cavity units. The oilfield is controlled by a cave system resulting from structure-karst cyclic sedimentation. Due to significant heterogeneity of the reservoir, the distribution of oil and water is complicated. Horizontally, a fresh water zone due to meteoric water can be found in the north part of the Akekule uplift. A marginal freshening zone caused by water released from mudstone compaction is found at the bottom of the southern slope. Located in a cross- formationai flow discharge zone caused by centripetal and the centrifugal fows, the main part of the Tahe Oilfield, featuring high salinity and concentrations of CI- and K Na , is favorable for accumulation of hydrocarbon. Three types of formation water in the Tahe Ordovician reservoir are identified: (1) residual water at the bottom of the cave after oil and gas displacement, (2) residual water in fractures/pores around the cave after oil and gas displacement, and (3) interlayer water below reservoirs. The cave system is the main reservoir space, which consists of the main cave, branch caves and depressions between caves. Taking Cave System $48 in the Ordovician reservoir as an example, the paper analyzes the fluid distribution and exploitation performance in the cave system. Owing to evaporation of groundwater during cross-formational flow, the central part of the main cave, where oil layers are thick and there is a high degree of displacement, is characterized by high salinity and Brconcentration. With high potential and a long stable production period, most wells in the central part of the main cave have a long water-free oil production period. Even after water breakthrough, the water content has a slow or stepwise increase and the hydrochemistral characteristics of the produced water in the central part of the main cave are uniform. From the center to the edge of the main cave, displacement and enrichment of oil/gas become weaker, residual water increases, and the salinity and concentration of Br- decrease. At the edge of the main cave, although the wells have a high deliverability at the beginning with a short stable production period and water-free production period. After water breakthrough, the pressure and deliverability drop quickly, and the water content rises quickly. The hydrochemistrai characteristics of the produced water are relatively uniform. Wells in the branch caves have a relatively low deliverability at the beginning, with a short stable production period. Water breakthrough appears quickly and then the pressure and deliverability drop quickly. The salinity and concentrations of CI-and K Na are usually fluctuant or descend slowly in the produced water. Wells in low areas of ancient karst have a low deliverability and a short stable production period. The yield drops quickly and the water content is high, while the characteristics of the produced water may vary significantly well to well. The salinity and concentrations of CI- and K, Na in the produced water are usually fluctuant with a precipitous decline.