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凝胶体系成胶效果评价方法研究

Study on the Property Evaluation Methods Used for Oilfield Cross-linked Polymer Gel System

【作者】 赵劲毅

【导师】 杨柏;

【作者基本信息】 吉林大学 , 高分子化学与物理, 2004, 硕士

【摘要】 我国油田主要以陆相沉积为主,大多数油藏往往由多个油层组成,由于油层沉积环境的差异,油层存在平面、层内和层间等多种矛盾,导致注水开发油层注入水沿高渗透层突进,造成油井过早水淹,特别是油田进入高含水期,这种现象日趋严重,极大地影响油田整体开发效果。因此,采取合理有效的调整注水井吸液剖面措施,对于改善水驱和聚合物驱油效果、促进油田长期高产稳产具有十分重要的现实意义。 本文全面阐述了国内外油田使用过的调剖、堵水剂种类和类型,归纳了6类大约70种调剖、堵水剂的性能及其特征。本文还描述了国内油田调剖、堵水发展状况,归纳如下,我国油田从50年代开始研究和应用堵水调剖技术,至今大体经历了三个发展阶段,即机械式为主阶段(50年代至70年代),化学剂为主阶段(80年代初期开始),单井调剖与区块整体综合治理阶段(80年代中期开始)。自 1979年至 1996年,国内油田共进行了 2×104多井次的现场试验和应用作业,改善了注水开发效果,增加了原油可采储量和产油量,减少了产水量,取得了明显的经济效益和社会效益。本文针对油田交联聚合物凝胶体系性质评价方法方面存在的问题,利用室内实验方法,对铝交联聚合物凝胶体系、铬交联聚合物凝胶体系和复合离子交联聚合物凝胶体系的性质进行了全面、系统研究。对于铝交联聚合物凝胶体系,交联聚合物溶液粘度、阻力系数、残余阻力系数和流变特性测试结果表明,聚合物分子间或内部发生了交联反应,交联聚合物溶液具有粘度低、残余阻力系数大且大于阻力系数等性质特征;交联聚合物溶液在多孔介质内可以流动,但与普通聚合物溶液相比,其流动能力较差;交联聚合物溶液流动阻力大,进入高渗透层后可以实现后续液流转变进入中、低渗透层,进而扩大波及体积,提高采收率;粘度、阻力系数、残余阻力系数和流变特性可以作为交联聚合物溶液配方筛选的基本指标。对于铬交联聚合物凝胶体系,本文研究结果表明,在大庆油田二厂污水条件下,铬(Cr3+)和有机交联剂都可以使聚丙烯酰胺分子发生交联反应,形成一定程度的聚合物交联微凝胶;铬(Cr3+)交联剂的交联反应速度快、交联后聚合物溶液的粘度增幅大; 有机交联剂与聚合物间的交联反应速度<WP=63>较慢、交联后聚合物溶液的粘度增幅大,建议改善交联剂的水溶解性和耐氧性,以增强该技术对矿场实际条件的适应性;在聚合物交联微凝胶内,单个聚合物分子链内部或多个聚合物分子链间发生交联反应,形成局部或区域性网状分子结构,使得聚合物在多孔介质内滞留量增加,进而使得流动阻力显著增加;聚合物交联微凝胶在多孔介质中的滞留可以有效地封堵高渗透层,促使后续液体进入中、低渗透层,进而达到调整吸液剖面的目的;并联(层间)非均质模型驱油实验结果表明,由于不同层间渗透率级差的影响,水驱时注入水绝大部分进入了高渗透层,使其采出程度较高;注聚合物或聚合物交联微凝胶不仅可以在较大程度上改善吸液剖面,增加中、低渗透层尤其是中渗层的吸液量,而且还可以进一步扩大高渗透层的波及范围。近年来,复合离子型调剖技术是大庆油田使用较多、效果较好的一种改善水驱和聚合物驱油技术。但由于现行复合离子调剖剂中主剂浓度较高,加之主剂为复合离子型聚合物,生产工艺复杂且售价高于普通阴离子型聚合物,使得该项技术的推广应用受到一定程度限制。本文采用普通阴离子型聚合物作为主剂,有机和无机化学剂为交联剂,形成复合离子型调剖剂。研究结果表明,利用有机和无机化学试剂组合而成的复合型交联剂,可以使普通阴离子聚合物分子间或分子内部发生交联反应,形成具有较高强度的聚合物凝胶;复合离子交联聚合物凝胶体系成胶后稳定性较好,60天剩余粘度保持在104mPa.s以上;聚合物相对分子质量、浓度、水型和温度等因素将影响复合离子型聚合物凝胶的成胶时间和强度。本文针对交联聚合物凝胶体系性质的差异,建立了一套与之匹配的评价系统。当聚合物凝胶体系为区域性网状分子构型时,粘度或传统的转变压力是可以替代阻力系数和残余阻力系数的简单、快捷和有效的评价指标;当聚合物凝胶体系为局部性网状分子构型时, 粘度或传统的转变压力指标都很难反映聚合物分子构型特征;在矿场对聚合物凝胶体系成胶效果进行监测时,对于污水配制Cr3+和复合离子交联凝胶体系和清水配制Al3+交联凝胶体系,建议采用粘度或传统转变压力指标进行评价; 对于污水配制Al3+交联凝胶体系,建议采用阻力系数和残余阻力系数或本课题提出的转变压力指标进行评价。

【Abstract】 There is mostly continental sediment in domestic oilfields, and the majority of oil reservoirs are composed of several oil-bearing sands. Because of the discrepancy in reservoir sedimentary environment, there are some contradictions in stratification plane, inlayer and interlayer. The injected water goes ahead abruptly along in high permeable reservoir during water flooding, which will lead to the water out happen too early. The phenomenon is especially severe when the reservoir enters into the high water cut period, it will affect holistic development effect. So, we take some effective and reasonable measures to adjust water injection profile, it has important realistic significance to improve water flooding, polymer flooding effect and promote a long term high yield and stable production.This paper entirely expatiates upon the categories and types of the profile control agents and the water shutoff agents that are used oilfields in home and abroad, and concludes the performances and characteristics of six categories (about 70 kinds) profile control agent and the water shutoff agent. This paper also depicts the development situation of domestic oilfield’s profile control agents and the water shutoff agents. It is concluded as follows: domestic oilfields began to research and apply water plugging and profile control techniques in the 1950s, up to the present, it generally experienced three development stages, that is to say, the stage mainly composed of machinery (1950s-1970s), the stage mainly composed of chemical agents (started from the early 1980s), profile control of single well and block integral comprehensive treatment stage (started from the mid of 1980s). From 1979 to 1996, there are 2×104 times field trials and application operations in domestic oilfields, which improve the water flooding development effect, and increase the recoverable reserves of crude oil and oil producing capacity and decrease the water production rate, at the same time , there are an obvious economic benefit and social benefit.This paper aims at the problem that exists in the property evaluation methods aspect of oilfield cross-linked polymer gel system. We proceed all sided and systemic research into the property of Al3+ cross-linked polymer gel, Cr3+ cross-linked polymer gel and composite ion cross-linked polymer gel making use of the indoor experiment method.For the polymer gel cross-linked by trivalent aluminium (Al3+), the testing results of the cross-linked polymer solution viscosity, resistance factor, residual resistance <WP=65>factor and rheological behaviors show that the cross-linked polymer solution made by produced water has low viscosity, property characteristics of high residual resistance factor and is larger than resistance factor after cross-linking reaction happened between the polymer molecules or inside the polymer molecule. The cross-linked polymer solution can flow in the porous medium, but compared with common polymer solution, the flow ability of cross-linked polymer solution is worse. The cross-linked polymer solution’s flow resistance is big, it enters into the high permeability zone, which makes the sequent liquid enters into middle and low permeability zone, thus, sweep volume is enlarged and recovery efficiency is enhanced. The resistance factor, residual resistance factor and rheological behaviors can be act as the basic sieving indexes of directions for producing cross-linked polymer solution.For the trivalent chromium (Cr3+) cross-linked polymer gel, the research results of this paper show that under the produced water of the No. 2 oil production plant of Daqing oilfield, trivalent chromium(Cr3+)and organic cross-linking agent both can make cross-linking reaction of polyacrylamide molecules happen, and polymer cross-linking micro-gel forms. The cross-linking reaction speed of trivalent chromium(Cr3+)cross-linking agent is fast, the incremental value of viscosity of polymer solution is big after cross-linking. The crossing reaction speed between organic cross-linking agent and polymer is

  • 【网络出版投稿人】 吉林大学
  • 【网络出版年期】2004年 04期
  • 【分类号】TE39
  • 【被引频次】2
  • 【下载频次】871
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