注入水水质对储层的伤害

以胜利油田纯2块储层为研究对象,应用室内岩心模拟试验研究了注入水不同注入速度、悬浮固体颗粒粒径、含油量、含菌浓度、表面活性剂对储层的伤害。研究结果表明,固相颗粒粒径、含油量及含菌浓度是引起纯2块储层伤害的主要因素,建议通过控制注入水中的含油量小于10.6mg/L、细菌含量小于101个/mL、固相颗粒的粒径中值小于1.2μm、加入JOP - 1表面活性剂等方法来减轻对储层的伤害。     

An Experimental Study of the Effect of the Water Injection Process on Rock Structure and Permeability Reduction

Abstract

The estimation and assessment of formation damage on reservoir core samples is an important measurement. Laboratory tests were set up to investigate the effects of injection pressure, flow rate, and induced fracture on the rock sample with respect to formation damage. In this research, selected rock samples from one of Iranian giant oil fields were used as the laboratory physical model. Permeability reduction was observed for unfractured samples: however, it was more interesting that no injection pressure buildup was detected in fractured samples. It appears that fractures in sandstones, especially with weak cementation, can play the role of an agent for particle movement and cause damage far from injection wells over a long period of time.     

注入水中的固相颗粒与储层损害关系的试验研究

通过模拟试验。在低渗透率和中高渗透率的岩样中．研究了注入水中的固相颗粒对岩样渗透率损害率的影响。结果表明．注入水中的固相颗粒直径和含量增加。岩样渗透率损害率增加;注入水中的固相颗粒对低渗透率岩样的损害大干中高渗透率岩样;注水量增加,岩样渗透率损害率增加;对油田注永控制固相颗粒具有重要的意义。     

商河油田注入水结垢趋势及伤害试验分析

对商河油田注入水进行了水质及垢样试验分析；应用溶度积和电离平衡常数理论，建立了5种类型垢的预测模型；应用自行开发的结垢预测软件，对商河油田四净站来水进行了结垢趋势预测；采用岩心驱替试验评价了商河油田注入水结垢对地层的伤害程度。结果表明，商河油田注入水结垢趋势严重，以CaCO3垢为主，对地层存在一定的伤害。     

低渗水敏性储层岩心水驱前防膨处理实验研究

通过静态防膨率测试,筛选出对低渗水敏性储层防膨效果好的防膨剂及其用量.动态防膨效果实验表明,已水驱过的低渗岩心受到伤害后再注防膨剂,伤害的岩心不能恢复;注防膨剂溶液比单纯注水的岩心伤害率小,但停注防膨剂改注水,岩心伤害率迅速上升.提出低渗水敏性储层注水开发前应采取防膨处理措施.     

三塘湖油田牛圈湖区块西山窑组油藏注水开发对策

三塘湖油田牛圈湖区块西山窑组油藏为特低渗、低压、低流度的"三低"砂岩油藏,在开发初期存在注水开发效果差、产量低等问题。为了提高注水开发效果,通过生产动态统计分析、油藏工程和数值模拟方法研究,重新界定了注水技术政策界限,实施超前温和注水,同时论证了合理的井网井距,实施井网加密调整,并刻画出有利建产区,实施滚动建产。通过一系列对策实施,牛圈湖区块西山窑组油藏注水开发状况逐步好转,直井开发区地层压力保持平稳,含水率控制在55%以内,产油量自然递减率下降到10%左右,采油速度最高达1.04%,目前仍保持在0.70%以上,产油量保持稳定,预测牛圈湖区块西山窑组油藏南区和东区的采收率分别为24.5%和18.1%,好于开发方案标定的18.0%。     

刘庄油田超低渗透储集层注水开发的损害研究

对刘庄油田在注水开发过程中储集层敏感性、注入水水质及结垢对储集层的损害进行了研究,结果表明储集层敏感性损害主要有水敏、碱敏及应力敏感性损害。为达到较好的注水开发效果,建议控制注水压差和采油压差,同时要重视和强调注水过程中的储集层保护。     

南梁长4+5低渗透油藏注水伤害机理

针对南梁长₄₊₅低渗透油藏注水开发过程中地层伤害机理认识不清的问题,利用电镜扫描、铸体薄片、共聚焦成像、XRD等实验方法,分析了水驱前后储层岩心的孔隙结构及岩石组成,明确注水开发对储层孔隙特征的影响,通过注入水与地层水矿化度与物质含量对比,分析注水过程的潜在伤害、岩心渗透率的实时变化规律,总结地层结垢堵塞机理。结果认为:南梁长₄₊₅油藏注水地层伤害机理主要为注入水、地层水、储层的不配伍引发的盐敏、结垢,以及注入水水质较差引起的储层机械杂质堵塞。该研究成果为低渗透油藏注水伤害机理认识提供了方法及理论支撑。     

油田注入水引起储层伤害的试验评价

油田注入水与储层不配伍时会导致储层伤害。注入水引起储层伤害的原因是多方面的，既有水质不合格的问题，也有储层敏感性方面的问题。对这二个问题从理论上进行了分析研究，从机理上对各因素引起的储层伤害进行了剖析，设计出了区分各因素所引起的储层伤害的室内试验方法。同时针对室内岩心试验与实际储层注水状况的差别，设计出了评价注入水性能以及注水状况的综合试验方法。     

垦利油田低渗透油藏开发过程中储层伤害与保护

针对垦利油田低渗透砂岩油藏特点及生产现状,根据储层特征及注水、采油和增产措施过程中各种入井流体与地层配伍性的试验资料,研究了注水、采油和措施作业等过程中储层伤害的类型和机理,并据此机理实施了一系列的储层保护和治理措施,取得了明显的效果。     

低渗透油藏残余水形成机理试验研究

采用砂岩微观孔隙模型并模拟实际储层流体条件进行油驱水试验,观察研究了油驱水过程和残余水形成机理,测定了模型渗透率及油驱水入口压力,统计了模型残余水饱和度．并进一步分析了残余水饱和度、油驱水入口压力与渗透率的关系。     

姬塬油田注入水与地层水配伍性研究

姬塬长8储层在采用清水进行注水开发过程中,存在注水压力高、吸水指数低、注水见效慢、注采严重失衡等问题,严重影响油田开发效果。本文在对该区块注入水、地层产出水组成分析的基础上,将结垢趋势预测和室内模拟实验相结合,详细分析评价了注入水与地层水的配伍性。配伍性实验结果表明:姬塬长8储层地层水为CaCl2水型、注入水为Na2SO4水型;地层水与注入水以任意比例混合后,在30℃下均无垢生成,80℃下均产生了碳酸钙结垢而无硫酸钙垢形成。结垢趋势预测结果表明:在30℃下地层水与注入水混合后基本不生成碳酸钙垢;在50℃下,随着地层水比例的增加,碳酸钙结垢趋势增加,当地层水与注入水之比为4∶6 10∶0时,显示会有碳酸钙垢生成;在80℃下,碳酸钙垢趋势明显增加,地层水与注入水以任意比例混合后均会产生碳酸钙垢;在30℃、50℃、80℃下地层水与注入水以任意比例混合后均无硫酸钙垢结垢趋势存在。综上所述,姬塬长8储层注入水与地层水配伍性差、结垢是造成姬塬长8储层注水压力高的主要原因之一。     

疏松砂岩油藏岩石水敏性试验研究

利用渤海地区的A,B,C三个疏松砂岩油蘸的冷冻取心岩样及松散油砂的压实岩样进行了水敏性试验研究。结果表明,冷冻取心岩样和压实岩样具有相同的临界矿化度,压实岩样的水敏性损害程度大于冷冻取心岩样的水敏性损害程度。为疏松砂岩油蘸的临界矿化度和水敏性损害程度的确定提供了合理的方法。     

Velocity-based Formation Damage Characterization Method for Produced Water Re-injection: Application on Masila Block Core Flood Tests

Abstract

With increasing environmental regulations, more and more produced water is being re-injected; however, water injection programs may have low efficiency due to formation damage around the injected wellbore. Traditionally, formation damage was treated as a deep bed filtration (DBF) type of process characterized by laboratory-based damage parameters. These parameters inquire expensive concentration measurement, and lab-scaled results are not usually applicable for field cases. Recent studies on formation damage are more attracted to history-based approaches using an empirical damage equation to capture the uniqueness of each case study. In our previous work, such empirical (velocity based) model was studied and shown to be more practical than (and equivalent to) the DBF model. A robust characterization method was developed to calculate the damage parameters explicitly, and it was successfully tested against offshore field data. In this work, the method has been applied for analysis of a series of core flood tests on cores from the Masila Block field in Yemen and compared with measured damage parameters. Good agreement with lab-measured values validates the characterization method. The accuracy of the method is comparable to the DBF approach, while it is simpler and more suitable for implementing in reservoir simulators.     

Velocity-based Formation Damage Characterization Method for Produced Water Re-injection: Application on Masila Block Core Flood Tests

With increasing environmental regulations, more and more produced water is being re-injected; however, water injection programs may have low efficiency due to formation damage around the injected wellbore. Traditionally, formation damage was treated as a deep bed filtration (DBF) type of process characterized by laboratory-based damage parameters. These parameters inquire expensive concentration measurement, and lab-scaled results are not usually applicable for field cases. Recent studies on formation damage are more attracted to history-based approaches using an empirical damage equation to capture the uniqueness of each case study. In our previous work, such empirical (velocity based) model was studied and shown to be more practical than (and equivalent to) the DBF model. A robust characterization method was developed to calculate the damage parameters explicitly, and it was successfully tested against offshore field data. In this work, the method has been applied for analysis of a series of core flood tests on cores from the Masila Block field in Yemen and compared with measured damage parameters. Good agreement with lab-measured values validates the characterization method. The accuracy of the method is comparable to the DBF approach, while it is simpler and more suitable for implementing in reservoir simulators.     

桩西油田回注污水对储层损害的室内实验研究

桩西油田回注污水水质多项测定值超过行业标准B3级指标。结合桩西油田实际情况讨论了5种因素对地层渗透率的伤害:悬浮固体颗粒;含油量;污水腐蚀;细菌(腐生菌和硫酸盐还原菌)及其代谢和腐蚀产物;污水结垢(预测及注水井油管、地面管线结垢物组成)。在模拟油藏温度(120℃)、压力(30MPa)下,用4组油藏岩心(用2%KCl溶液测定的基准渗透率在0.05×10-3～2.0×10-3μm2范围)分别考察了含不同粒径(<0.45,<0.2,<4.0μm)固体颗粒、不同乳化原油含量(10和20mg/L)、不同铁含量(10和15mg/L,以Fe(OH)3计)的模拟实验污水及现场回注污水对岩心渗透率的伤害程度,结果表明:在本实验条件下,悬浮固体颗粒的伤害程度随渗透率减小和颗粒粒径增大而增大;乳化油滴的伤害十分严重;胶态铁在高浓度(15mg/L)才造成伤害;现场回注污水对基准渗透率～1.0×10-3和～0.05×10-3μm2的2个岩心的伤害程度相当高,渗透率较低时伤害较严重。图11表3参1。     

彩133井区西山窑组油藏储层敏感性特征及注水防膨评价

通过对彩133井区西山窑组储层敏感性实验、注入水与地层水配伍性评价、储层注人水储层伤害评价、防膨稳定剂效果评价的研究发现,该井区储层具有强水敏特征,其临界矿化度为12447.46mg/L;注入水与地层水配伍性良好;当注入达30倍孔隙体积倍数时,储层注入水伤害模拟评价其渗透率损失率平均为41.6%;0.3%的彩-12#防膨稳定剂对储层具较好的防膨稳定效果.     

复杂储层保护技术实验研究

疏松砂岩油气层和裂缝性油气层属于比较复杂的两种油气储层，其油气层损害机理复杂，油气层保护工作难度大，主要原因在于这两种油气藏非均质性严重，代表性实验岩心难以获取，而且缺乏科学实用的实验仪器设备。针对上述问题，详细介绍了笔者在实验岩心的制备仪器、所用实验仪器、以及疏松砂岩油气层和裂缝性油气层的保护技术等方面所取得的成果，部分成果已经进行了推广应用。这些成果对今后复杂储层保护实验研究具有一定的借鉴意义。     

阿南油田低渗油藏储层伤害分析

目前国内外许多油田都在开展储层伤害研究工作,这项研究对于低渗透油田尤为重要。在分析生产动态和岩心分析基础上,对阿南低渗透砂岩油藏开发过程中的储层伤害做了较为深入的研究。认为目前主要的储层伤害因素有：原油中石蜡析出造成油井井底附近地层渗透性下降;注入水水质差引起注水井近井地带的储层伤害;颗粒运移主要造成地层深部伤害及细菌堵塞、地层敏感性伤害等。     

压裂液对低渗砂岩气藏的水敏性伤害实验研究

为了客观准确地评价压裂液对低渗砂岩气藏的水敏性伤害,开展了伤害机理研究。以压裂液"平行液"为实验液体,基于X衍射、扫描电镜及岩心流动实验结果,将核磁共振技术应用于水敏性伤害机理,对胍胶压裂液和酸性压裂液造成的水敏性伤害进行了评价。结果表明:两种压裂液对应"平行液"对岩心造成的水敏性伤害均值分别为12.68%和12.77%;伤害程度大小主要取决于岩心中伊/蒙间层、伊利石的绝对含量以及黏土矿物的总含量,而与压裂液"平行液"类型无严格关系;返排程度与水敏性伤害有一定关系,返排量为0~2倍孔隙体积时,伤害率表现出增大的趋势,返排量为2~10倍孔隙体积时,伤害率趋于稳定;不同孔隙类型岩心由于不同类型压裂液入侵造成水敏性伤害后,表现出不同的核磁共振特征。通过研究,提供了一种定性评价压裂液对油气储层水敏性伤害的新方法。