Water shutoff and conformance improvement: an introduction

This paper provides an introduction to the topic of water shutoff and conformance improvement. After indicating the volumes of water produced during oilfield operations, a strategy is provided for attacking excess water production problems. Problem types are categorized, typical methods of problem diagnosis are mentioned, and the range of solutions is introduced for each problem type. In the third section of the paper, the concept of disproportionate permeability reduction is introduced—where polymers and gels may reduce permeability to water more than to oil or gas. When and where this property is of value is discussed. The fourth section describes the properties of formed gels as they extrude through fractures and how those properties can be of value when treating conformance problems caused by fractures. Section 5 covers the efficiency with which gels block fractures after gel placement—especially, the impact of fluids injected subsequent to the gel treatment.

Water shutoff model test in water-rich sandy stratum by phosphoric acid-water glass grout

The rheological behavior of phosphoric acid-water glass grout in different mixing ratios was studied. Grout made of water glass with Baume degree of 20° and 13.4% phosphoric acid by 1:1 volume ratio is found to be more effective in stopping water. Laboratory model test of water shutoff by grouting was conducted. Test results show that the diffusion length and water cutoff effect of the grout are significantly improved as the grout head is raised, due to the dilution of underground water, and it takes the grout longer than its gel time to cut off water.

Evaluation of polyacrylamide gels with accelerator ammonium salts for water shutoff in ultralow temperature reservoirs:Gelation performance and application recommendations

Water shutoff in ultralow temperature reservoirs has received great attention in recent years.In previous study,we reported a phenol-formaldehyde-based gel formula with ammonium salt which can provide a gelation time between 2 hrs and 2 days at 25
C.However,systematic evaluation and field recommendations of this gel formula when encountering complex reservoirs environment are not addressed.In this paper,how and why such practical considerations as water composition,temperature,pH,weight ratio of formaldehyde to resorcinol and contaminant Fe3t to affect the gelation performance are examined.Brookfield DV-III and scanning electron microscopy(SEM)are employed respectively for viscosity measurement and microstructure analysis.SEM results further illustrate the mechanism of the effect of salinity on gelation performance.It reveals that crosslinking done by covalent bond has great advantage for gel stability under high salinity environment.The target gel formula can provide desirable gelation time below 60
C,perfect for 15e45
C,while it is unfeasible to use high salinity to delay gelation at 60
C.We summarized the effect of salinity on gelation performance of different gel formulas from the present study and published literature.The summarized data can provide important guideline for gel formula design before conducting any kinds of experiments.The variation of gelation performance at different salinity may be dominated by the interaction between crosslinker-salt-polymer,not only limited to“chargescreening effect”and“ion association”proposed by several authors.We hope the analysis encouraging further investigations.Some recommendations for field application of this gel are given in the end of this paper.

Composite polymer networks of polyacrylamide and modified amino resin-polyurethane for oil field water shutoff

SINCE water emitting in oil wells is a general problem in developing oil fields, the workers inthe world put quite an emphasis on water shutoff. In recent years, the study on develop-ing a novel and highly effective water plugging agent has become an important technical mea-sure for controlling water emitting in the middle and later periods of an oil field. A highly ef-fective water plugging agent can form gel, gradually swell in water and shut off water, but oilcan get through. It also has suitable resistance to pressure and high temperature and a longservice life. Only when the water shutoff agent can form a composite polymer network (CPN)

Intelligent responsive self-assembled micro-nanocapsules:Used to delay gel gelation time

In the application of polymer gels to profile control and water shutoff,the gelation time will directly determine whether the gel can"go further"in the formation,but the most of the methods for delaying gel gelation time are complicated or have low responsiveness.There is an urgent need for an effective method for delaying gel gelation time with intelligent response.Inspired by the slow-release effect of drug capsules,this paper uses the self-assembly effect of gas-phase hydrophobic SiO_(2) in aqueous solution as a capsule to prepare an intelligent responsive self-assembled micro-nanocapsules.The capsule slowly releases the cross-linking agent under the stimulation of external conditions such as temperature and pH value,thus delaying gel gelation time.When the pH value is 2 and the concentration of gas-phase hydrophobic SiO_(2) particles is 10%,the gelation time of the capsule gel system at 30,60,90,and 120℃is12.5,13.2,15.2,and 21.1 times longer than that of the gel system without containing capsule,respectively.Compared with other methods,the yield stress of the gel without containing capsules was 78 Pa,and the yield stress after the addition of capsules was 322 Pa.The intelligent responsive self-assembled micronanocapsules prepared by gas-phase hydrophobic silica nanoparticles can not only delay the gel gelation time,but also increase the gel strength.The slow release of cross-linking agent from capsule provides an effective method for prolongating the gelation time of polymer gels.

水驱油藏聚乙烯亚胺交联聚合物凝胶体系研究进展

聚乙烯亚胺(PEI)是一种低毒性环保材料,它与聚合物交联的凝胶体系具有适用温度范围广、成胶时间可控、成胶后强度大、高温稳定时间长、几乎不受储层岩石矿物影响等优点。本文回顾了以PEI作为交联剂的各类凝胶体系的研究动态,阐明了PEI与各类聚合物的交联反应机理及其凝胶体系特点,分析了各类因素对凝胶性能的影响,并列举了改善凝胶性能的方法和成功的矿场应用实例,重点分析了提高凝胶体系交联活性的方法研究。最后,提出聚丙烯酰胺(PAM)/PEI凝胶体系作为环保型调驱体系在中低温油藏深部调控方面具有非常大的应用前景,应继续深入研究提高PAM/PEI凝胶体系交联效率的方法及其作用机理,以降低聚合物与交联剂用量,为这一体系的推广应用提供理论依据与实验基础。

海上油田深部堵水用乳液增黏复合凝胶体系研究

针对海上油藏作业空间有限的特点以及传统的在线配注堵剂体系存在成胶强度低和封堵能力弱的问题,研制了一种由AMPS耐温抗盐乳液聚合物、聚乙烯亚胺(PEI)交联剂和无机纳米增强剂所组成的复合凝胶体系。通过成胶实验研究了组分质量分数、温度和矿化度对复合凝胶体系成胶性能的影响,优选了合理的配方并评价了注入和运移性能、热稳定性能和选择性封堵性能。结果表明:随着聚合物、交联剂和无机纳米增强剂组分质量分数的增加,成胶时间缩短和成胶强度增加。相比单一凝胶体系,复合凝胶体系的成胶时间缩短和强度增强。岩心注入和运移性能评价结果表明,复合凝胶体系待成胶液黏度低,能够在多孔介质中实现注入和深部运移,达到深部封堵目的。在模拟油藏温度80℃条件下,复合凝胶体系老化90 d后,脱水率仍然低于10%。该体系对不同渗透率的地层均具有良好的选择性封堵性能。

多重复合网络增韧凝胶在裂缝油藏中的封堵行为研究

采用水溶液聚合法,研究了在聚丙烯酰胺凝胶中同时引入共价键交联、氢键交联、缠结交联和疏水微区交联四种交联结构的复合交联凝胶的力学性能,结果表明,含有疏水单体和聚乙烯醇(PVA)的多重复合交联结构的凝胶可以有效提高凝胶颗粒的变形能力,断裂伸长率高达800%,可以作为一种裂缝油藏用颗粒堵剂,对裂缝产生有效的封堵,颗粒与裂缝宽度的配伍最低临界值为1.25,封堵强度大于0.034 MPa/cm,应用中推荐使用与裂缝宽度比值为1.25~1.87粒径的颗粒作为封堵剂。

化学堵水调剖剂DX-9研制及应用

在水平井开采中,边水或底水水窜问题严重,为穏油控水,提高采收率,介绍了一种可应用于水平井选择性堵水的化学堵水剂DX-9,研究该堵剂体系的性能以及影响因素。结果表明,选择性堵水剂DX-9具有固化时间可控、固化强度高且韧性强,最高突破压力梯度可达41.2 MPa/m,岩心封堵率可达99.23%,能够满足延长油田水平井选择性堵水应用。

某高水头抽水蓄能电站球阀动水关闭试验分析

球阀作为抽水蓄能电站机组的重要辅助设备,安装在压力钢管与蜗壳之间,是防止调速系统故障导致导叶无法关闭引发机组事故扩大的最后保障。为检验某高水头抽水蓄能电站球阀动水关闭能力,分别在空转、50%额定负荷、100%额定负荷工况下进行球阀动水关闭试验,对机组振摆、球阀振动、接力器油压、球阀前和蜗壳压力等参数指标进行测取分析。试验结果表明,试验球阀在导叶不关闭的情况下能够可靠关闭切断水流,球阀及相关设备未产生有害变形和损坏。

煤矿堵水用高分子材料渗透系数测试装置的研究

为了解决煤矿堵水用高分子材料渗透系数测试设备短缺的问题,分析研究渗透系数测试方法,采用理论计算、校核,选型设计出试件夹持器、受力架、液压缸、液压泵、压力传感器等主要机械机构部件。基于VB语言开发了测控系统,实现轴向载荷、围压、渗水压力、流量的闭环控制,实时自动采集参数,并计算及输出结果。以煤矿堵水用高分子材料为测试对象,对自然含水状态、干燥状态和水饱和状态的试样进行了测试验证。结果表明,研制的煤矿堵水用高分子材料渗透系数测试装置全面满足标准要求,运行稳定,噪声小,具有广阔的应用前景。

塔山煤矿副平硐中部出水段注浆治理方案设计

针对中煤集团塔山矿副平硐中部花岗岩-泥岩-灰岩的岩性变化交界区域(1 470~1 850 m)存在的涌水现象,进行注浆堵水治理。通过深、浅孔组合的方式,浅孔及跑浆区域以水泥-水玻璃双液浆为主,深孔以单液水泥浆为主,并选用高分子堵水材料进行补充注浆,结束后进行导流排水。结果表明:涌水量由治理前的46.2 m^(3)/h降至3.4 m^(3)/h左右,降幅达92.6%。有效封堵了涌水裂隙,加固了井壁,堵水效果良好。

风机后循环对卫浴停水后非正常过热保护的影响

本文主要研究在关闭供暖出、回水口处阀门的非正常情况下,风机后循环对板换式燃气采暖热水炉(以下简称壁挂炉)在卫浴停水以后出现过热保护的影响。试验表明按照原风机后循环控制逻辑运行的壁挂炉在卫浴停水以后,极限温控器的温度持续升高并触发机器过热保护。本文通过调整风机后循环的控制逻辑,有效降低卫浴停水以后极限温控器的最高温度,并通过试验验证了方法的可行性。

Research progress and application prospect of functional adhesive materials in the field of oil and gas drilling and production

By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,mechanical interlocking,and electrostatic adsorption,are expounded.The research status of these materials in oil and gas drilling and production engineering field such as lost circulation prevention/control,wellbore stabilization,hydraulic fracturing,and profile control and water plugging,and their application challenges and prospects in oil and gas drilling and production are introduced comprehensively.According to the applications of functional adhesive materials in the field of oil and gas drilling and production at this stage,the key research directions of functional adhesive materials in the area of oil and gas drilling and production are proposed:(1)blending and modifying thermoplastic resins or designing curable thermoplastic resins to improve the bonding performance and pressure bearing capacity of adhesive lost circulation materials;(2)introducing low-cost adhesive groups and positive charge structures into polymers to reduce the cost of wellbore strengthening agents and improve their adhesion performance on the wellbore;(3)introducing thermally reversible covalent bond into thermosetting resin to prevent backflow of proppant and improve the compressive strength of adhesive proppant;(4)introducing thermally reversible covalent bonds into thermoplastic polymers to improve the temperature resistance,salt-resistance and water shutoff performance of adhesive water shutoff agents.

油气钻采领域功能胶黏材料研究进展及前景

通过概述功能胶黏材料的组成、分类及性能表征,阐述了功能胶黏材料的吸附/界面反应、扩散、机械互锁和静电吸附等黏结作用机理,综述了其在防漏堵漏、井壁稳定、水力压裂和调剖堵水等油气钻采工程领域的研究现状、应用挑战及应用展望。依据现阶段功能胶黏材料在油气钻采领域的应用,提出了功能胶黏材料在油气钻采领域的重点研究方向:(1)对热塑性树脂进行共混改性或设计可固化热塑性树脂,提高黏结堵漏剂的黏结性能和承压能力;(2)在聚合物中引入低成本黏附性基团和正电荷结构,降低黏结固壁剂成本,提高其在井壁的黏附性能;(3)在热固性树脂中引入热可逆共价键,预防支撑剂回流,提高黏结支撑剂抗压强度;(4)在热塑性聚合物中引入热可逆共价键,提高黏结堵水剂的抗温抗盐能力和堵水性能。

海上高含水大液量水平井凝胶堵水数值模拟

复杂条件下的水平井化学堵水不可控因素多,施工条件苛刻,堵水成功率低。针对这些问题,文中采用物理实验及数值模拟,开展岩心尺度纳米酚醛凝胶堵水效果研究,建立了考虑交联反应、吸附理论的凝胶堵水机理模型,通过实验数据拟合,获取了Langmuir等温吸附系数、岩石最大吸附量和残余阻力系数等关键参数。以文昌19-1油田典型大液量(大于1000 m^(3))、高含水率(大于90%)水平井——A8H1井为例,通过近井地带网格加密建立单井堵水数值模型,开展水平井凝胶堵水效果影响因素研究。结果表明:堵剂用量受实际油藏岩石的吸附水平限制,A8H1井最优堵剂用量为250 m^(3);油井含水率越低,生产压差和地层渗透率级差越小,水平井凝胶堵水效果越好。研究成果可为类似复杂水平井凝胶堵水选井及工艺方案设计提供参考。

新型延迟交联堵水剂体系的制备及性能评价

针对目前常规堵水剂普遍存在“要么注不进,要么堵不住,不能深部调驱,增油降水效果差”等问题,采用丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)、N-(3-二甲氨基丙基)甲基丙烯酰胺(DMAPMA)制备新型三元共聚物,同时制备多重乳液将交联剂进行包裹实现延迟交联。结果表明,多重乳液体系交联时间可延迟1倍以上,达到5~15 d,实现了延迟交联的目的;最佳凝胶体系具有良好的耐温耐盐性能,适用于矿化度<100000 mg/L和温度70~90℃范围内的油藏。该凝胶体系具有初始黏度小,易注入低渗透地层,且交联时间可控,成胶强度大等特点,可对高渗通道形成有效封堵。

地下成胶堵水体系在海上油田的适应性及先导性试验

为了控制海上油田油井过量产水,评价了地下成胶堵水体系(1%功能微球+3%功能单体+0.8%促胶剂)在海上油田的注入性、封堵性、选择性、耐水冲刷性等性能,并进行了堵水先导性试验。研究表明,地下成胶堵水体系从A级到I级强度的成胶时间长达134 h,能满足现场施工对成胶时间的要求;体系具有良好的注入性,在渗透率为1020×10^(-3)μm^(2)的填砂管中,注入压力仅为0.28 MPa,且随渗透率的增加而降低;体系具有良好的选择性、封堵性及耐水冲刷性,能优先进入高渗窜流区域,成胶后对高渗窜流区域的封堵率达90%以上,连续用水冲刷100PV,封堵率仅下降约5.0%;体系成胶后具有良好的耐候性,在65℃下浸泡60 d后强度损失率仅为4.1%。现场先导性试验结果表明,地下成胶堵水体系堵水效果明显,能有效控制目标井复杂来水,实现目标井的“降水增油”。

纳米二氧化硅微乳液的制备及其控水性能研究

以纳米二氧化硅、水溶性非离子表面活性剂(NSW)、油溶性非离子表面活性剂(NSO)、矿物油和去离子水等为原料,通过机械乳化法研制了一种具备优良油水选择性的水包油型微乳液。借助扫描电子显微镜、透射电子显微镜、低温液氮吸附-脱附分析、热重-差热分析、激光粒度分析、冷冻环境扫描电镜及接触角测试等表征技术分析纳米二氧化硅微观结构、织构以及微乳液微观结构,并进行岩心驱替封堵性能评价。结果表明,该微乳液初始粒径D_(50)=3.343μm,当岩心渗透率达4 700 mD时,水相封堵率为88%,无油相封堵率;当岩心渗透率为1 200 mD时,水相封堵率达92%,油相封堵率为12%。该微乳液具有非常好的选择性封堵作用,可应用于油田稳油控水领域。