A PRACTICAL APPROACH FOR FIELD SCALE PERFORMANCE ESTIMATION OF WATER INJECTION IN FRACTURED OIL RESERVOIRS

In this study, a practical method is developed to predict the waterflooding performance in naturally fractured reservoirs (NFR) if the production rate is dominated by the capillary imbibition transfer between matrix and fracture. Capillary imbibition transfer rate is defined explicitly as a function of matrix (permeability, wettability, and size), flow (rate or velocity) and reservoir (size) properties. Verification of the formulation is based on previously performed experimental and numerical studies. Then, a correlation between total water injected and total oil produced is developed using the abstract relationship between recovery and time proposed by Aranofsky et al. (1958). A parametric study is performed to obtain a critical (or optimum) injection rate for an efficient recovery of oil. It is shown that a critical injection rate value exists depending on the capillary suction capability of matrix. Beyond the critical rate, the process becomes inefficient as the increasing rate would not yield a faster oil recovery.     

大庆榆树林油田注水井清、防垢剂的研究与应用

根据大庆榆树油田注水井地层,井筒及其配套系统结垢原因,研制了清垢剂（地层解堵剂）YQG和防垢剂YFG;针对该油田储层特点开发了运用暂堵转向技术,能控制处理强度的注水井清垢解堵工艺,应用该工艺和清垢剂YQG在8口注水井进行清垢解堵试验,获得了良好的增注效果;在13口注水井进行连续注入防垢剂YFG的长期（1年）防垢试验中,注入压力上升幅度和视吸水指数下降幅度均显著减小。     

裂缝性储层油气资源评价新方法

本文根据裂缝性储层油气成藏的特殊性,提出一种新的裂缝型油气资源评价模拟系统.它是从裂缝系统控制油气藏出发,基于压降法储量分布和油气藏数分布,通过有序统计和匹配法,预测勘探层的油气藏数及各油气藏的油气量,由此估算勘探层资源总量,并根据未发现油气藏的油气量求得勘探层潜量.     

大庆扶余油层超前注水技术指标界限

应用油藏工程与数值模拟相结合的方法,设计了扶余油层超前注水方案。地层压力保持水平、累计注水量、超前注水强度、超前注水时机的研究表明:超前注水能够建立有效的压力驱替系统,提高地层压力,减小应力敏感损害,改善油田开发效果;扶余油层合理的压力保持水平为120%、超前注水时间约7个月。研究成果为低渗透油田开发提供了技术支持。     

注水油藏大尺度未波及剩余油的三大富集区

我国油田水驱油效率与采收率的差距很大,以河流相储层为例,对应含水率1.0和0.98的平均驱油效率为0.6664和0.5045,而平均采收率仅0.302,说明由于我国油田大都是陆相沉积,非均质性强,使注入水的波及状况仍较差。利用抽象地质模型及相应的典型油层参数加油藏数值模拟加油藏工程加数理统计的研究方法,研究出了“注水多层油藏小层层内与平面波及评价系统”,利用这个系统的计算,确定出了注水多层油藏“大尺度”未波及剩余油的三大富集区:①注水高粘正韵律油层顶部未波及剩余油;②边角影响未波及剩余油;③层系内由于各小层物性差异开采不均衡形成的未波及剩余油。概述了目前确定未波及剩余油的方法及其开采方法,指出这项研究的难度很大,是当前油田开发的核心技术之一,可以称得上是世界级的世纪难题。     

油田注水泵三元叶轮的设计及试验验证

采用叶片机械三元流动理论,对6D100型多级油田注水泵的叶轮进行改型设计,得到的三元叶轮,与原来用一元流动理论设计的叶轮,在同一导叶,同一试验装置的对比试验结果是:单级泵在转速降低50%的条件下,泵效率由64.57%提高到67.17%,相对提高4%.最佳效率点级扬程由33米提高到35.25米,相对提高6.8%.可以肯定,泵在全速工作时,性能改进的幅度会更大.     

OPTIMUM STEAM INJECTION STRATEGIES FOR NATURALLY FRACTURED RESERVOIRS

This study aims to identify the effective parameters on matrix oil recovery and the efficiency of this process while there is a continuous flow of steam in fracture. Single matrix system is studied first. The critical injection rate is defined for laboratory scale simulation for different matrix properties. It is observed that there is a critical injection rate optimizing the process and the critical injection rate for an efficient matrix oil recovery is defined for different matrix sizes and matrix heat transfer coefficients.

In the second part of the study, similar analysis is performed to investigate the effect of injection rate on the oil recovery for field scale. Critical rate concept is evaluated for different number of horizontal fractures and steam qualities. Finally, the economics of steam injection in the field scale is studied. The optimum injection strategies determined by the adjustment of injection rates are discussed based on the fracture properties such as density and permeability. The approach and results can be used in further studies to analyze the efficiency of thermal applications and to obtain correlations for steam injection performances in naturally fractured reservoirs.     

OPTIMUM STEAM INJECTION STRATEGIES FOR NATURALLY FRACTURED RESERVOIRS

ABSTRACT

This study aims to identify the effective parameters on matrix oil recovery and the efficiency of this process while there is a continuous flow of steam in fracture. Single matrix system is studied first. The critical injection rate is defined for laboratory scale simulation for different matrix properties. It is observed that there is a critical injection rate optimizing the process and the critical injection rate for an efficient matrix oil recovery is defined for different matrix sizes and matrix heat transfer coefficients.

In the second part of the study, similar analysis is performed to investigate the effect of injection rate on the oil recovery for field scale. Critical rate concept is evaluated for different number of horizontal fractures and steam qualities. Finally, the economics of steam injection in the field scale is studied. The optimum injection strategies determined by the adjustment of injection rates are discussed based on the fracture properties such as density and permeability. The approach and results can be used in further studies to analyze the efficiency of thermal applications and to obtain correlations for steam injection performances in naturally fractured reservoirs.     

缝洞型油藏孤立溶洞注水替油机理实验

由于缝洞型碳酸盐岩油藏储层的复杂性,研究其注水替油的机理就显得很必要.在注水替油的过程中,溶洞未填充并且充满油时,若将水注入到溶洞内,由于油水的密度差异所产生的重力差异必然导致水下沉,产生油水分离,水逐渐占据了下部油的位置,从而油水进行了置换,达到注水替油的目的.所以,重力分离是注水替油中最主要的理论依据之一,因此有必要对油水两相由于重力作用发生分离的过程进行研究.通过物理模拟实验研究表明:注水过程中注入水在溶洞中发生置换作用、驱替作用和水洗油作用,对于孤立溶洞注水替油,置换作用,是注水替油的决定因素;随着注水替油轮次的增加,油水界面逐渐上升,近井地带的含水饱和度增加,产量递减趋势逐渐加快,井底流压呈指数递减,后期递减速度越来越快.     

裂缝性砂岩油藏周期注水实践

以数值模拟、室内实验为依据 ,论证了对裂缝性砂岩油藏实施周期注水的可行性。同时 ,结合扶余油田西区矿场实例对周期注水的注水方式、周期、注水量及效果进行了探讨。对裂缝性砂岩油藏实施周期注水具有重要的借鉴意义。     

纯化油田薄互层低渗油藏径向水射流矿场实践

纯化油田薄互层低渗油藏处于中高含水开发阶段,由于层多、层薄、非均质性强,"注不进、采不出"的矛盾突出。径向水射流作为一项低成本技术在纯化油田薄互层低渗透油藏开发调整过程中得到较多应用。基于油水井所在区域的物性、动态、径向水射流等数据,研究了径向水射流在薄互层低渗油藏的适应性及开发效果的影响因素,建立了薄互层低渗油藏径向水射流适应性标准。实践表明:径向水射流和井网井距、层系相适配,改善了水驱开发效果,单井注入能力大幅度改善,但增油效果差异较大;径向水射流油水井存在明显的增产、增注有效期及均衡驱替有效期。     

PRODUCING TECHNIQUE BY GRAVITY WATER INJECTION FOR THE OFFSHORE THIN OIL RESERVOIRS

海上油气田开发成本高,多采用天然能量开采.对于弹性驱或弱边水水驱薄油藏,也不能像陆地油田那样实施注水井补充能量开发.而地层自流注水技术是通过分支井把厚储层的大水体与弱边水的含油层系沟通,保持油层压力,增加其驱动能量,以达到有效地开发弱水驱薄油层的效果.研究结果表明,该技术切实可行.实施后,初期效果明显.开发指标与衰竭式开采10 a的开发指标对比,采收率由15％提高到35％.     

注入水缓蚀阻垢剂KL0305A及其应用

在原用双组份双包装缓蚀阻垢剂KL0305的基础上研制了单一包装的性能更好的改进型缓蚀阻垢剂KL00305A。本文介绍了KL0305A的室内性能评价结果及在克拉玛依油田五区南注入水处理中应用的情况。KL0305A在五区南注入水中具有良好的缓蚀阻垢效果，也能适应克拉玛依油田其它各区块注入水的水质。     

陈堡油田回注污水CaCO3结垢预测及实测

应用Ｄａｖｉｓ 和Ｓｔｉｆｆ 等预测ＣａＣＯ３ 结垢趋势和结垢严重程度的公式以及带压力注水系统中ｐＨ 值计算方法，对陈堡油田陈２ 、陈３ 块混合污水进行了ＣａＣＯ３ 结垢理论预测，通过库尔特粒径分析证实了理论预测结果。     

喇嘛甸油田二类油层聚驱油井压裂效果预测方法

喇嘛甸油田二类油层聚驱开发期间,对油井进行压裂是保障聚驱效果的有效方法之一,可减少低效、无效措施井,增加油井经济效益.以影响压裂效果的主要因素为变量,以压裂措施无效时总累计增油量为评价指标,利用多元回归分析原理,建立了压裂效果预测方程.在二类油层聚驱中验证表明,压裂效果预测方程的预测精度可达到90.5％,能够满足油田生产需要,保障了聚驱优势发挥.     

注入水缓蚀阻垢剂KL0305A及其应用

在原用双组份双包装缓蚀阻垢剂ＫＬ０３０５的基础上研制了单一包装的性能更好的改进型缓蚀阻垢剂ＫＬ０３０５Ａ,本文介绍了ＫＬ０３０５Ａ的室内性能评价结果及在克拉玛依油田五区南注入水处理中应用的情况。ＫＬ０３０５Ａ在五区南注水中具有良好的缓蚀阻垢效果,也能适应克拉玛依油田其它各区块注入水的水质。     

SZ36-1油田AI区天然水侵量估算

SZ36-1油田AI区开发3年来产油量、气油比稳定,地层压力下降缓慢,在投有人工注水情况下,综合含水达到18.29％,说明边水起到了驱油作用。根据AI区生产动态数据,将油田假设为直线流系统,应用非稳定流法计算出水侵系数为106×10~4m~3/MPa,油水界面到天然水域外缘的距离约为27km。     

榆树林油田注水井结垢及其机理研究

大庆榆树林油田注水井及其配套系统结垢严重。本文报道了对结垢及其机理进行研究的结果。注入水易结垢，垢主要由ＣａＣＯ３组成（占９２．５％），井筒内结垢量达４６％，其余垢沉积在井底和地层内。讨论了流动状态、温度、压力、地层水等因素对ＣａＣＯ３从注入水结晶析出及沉积的影响。     

XMAC地应力测井资料在油田注水开发中的应用初探

XMAC测井是利用声波原理测得地层或岩石各向异性的一种测井方法。通过南一区地应力测井资料测量出该区最大、最小水平主应力方向与油井动态反映特点，得出最大水平地应力方向往往是地下岩石中裂缝和微裂缝最容易发育的方位，即裂缝及微裂缝的走向主要趋向最大水平地应力方位。最大水平地应力方位是油田注水受效的优势方位。     

裂缝性底水气藏气井水侵模式及见水时间预测

底水供给充足,裂缝系统发育使得裂缝性底水气藏在开采过程中极易形成水窜,造成该类型气藏采收率较低.在前人总结的裂缝性底水气藏气井水侵模式的基础上,针对裂缝性底水气藏非均质性强的特点,提出了该类型气藏见水时间预测方法.在研究过程中,将裂缝性储层抽象成为渗透率突变概念地质模型,定义渗透率突变系数和区域半径比来表征储层裂缝发育...