酸化助排研究现状与应用进展

综述了上世纪60年代以来酸化液助排剂及酸化液、压裂液及其他水基地层处理液多功能助排剂的发展历程。列表给出了文献报道的、目前国内外应用的12种主要酸化液助排剂的基本组成和技术性能。讨论了酸化液及水基处理液的发展趋势及存在问题。综述了目前国内形成的3种返排技术，即：注液氮层内助排；连续油管液氮气举助排；抽汲助排。参25。     

压裂液助排剂GCY-3的研制及室内评价

针对压裂液返排造成的地层伤害问题,采用季铵盐阳离子表面活性剂及醇复配了一种价格低廉、制作工艺简单的压裂液助排剂GCY-3,确定了其最佳配方。依据行业标准对该助排剂进行室内评价,结果表明,GCY-3具有较高的表面活性和良好的热稳定性,它不仅降低了破胶液的表面张力,还能提高川西常用压裂液的抗剪切能力。     

压裂用高效发泡助排剂JX-YL的性能评价与应用

针对萨南油田南二、三区西块地层压力低,且原油含蜡量高的特点,在压裂施工中应用了JX—YL高效发泡助排剂。对压裂用高效发泡助排剂JX—YL的性能进行了室内评价,介绍了JX—YL的作用原理及现场应用情况。JX—YL释放的热量可以解除高粘油区块由于低温液体的注入所造成的蜡质、胶质的伤害;生成的大量惰性气体,可以有效提高地层返排压力;产生的大量泡沫,可有效降低压裂液的滤失;表面活性减小了毛细管的阻力。室内与现场试验结果表明,JX—YL具有返排快、溶蜡降粘、助排能力强的性能,比普通压裂液初期返排率提高25％左右,有效减小了压裂液对地层的伤害,取得了明显的增产效果及显的经济效益。     

CT5－4压裂酸化工艺助排剂的现场应用效果

在压裂酸化作业中,压入地层的酸液或压裂液．返排是否及时彻底是影响施工效果和油气增产的一个重要因素。在压裂酸化液中加人ＣＴ５－４压裂酸化工艺助排剂,产生极低的表面张力和增大接触角,从而降低毛细管阻力,是促进残液及时彻底返排的有效途径。本文综述了１７口井现场应用情况,结果表明,ＣＴ５－４的加入,促进了残液的返排,返排率达１００％,减轻了因液体滞留地层造成的伤害和污染．缩短了压裂酸化排液周期,提高了试油时效,降低了试油成本,提高了酸化增产效果。     

新型泡沫压裂液研究及应用

针对川西中浅层低温低压低渗及难动用地层面临的压后返排困难、储层伤害大的问题,通过开展降低地层污染、补充地层能量、提高液体返排速度的技术研究--延迟自生热压裂技术,取得了良好的应用效果。该技术利用生热剂体系混合发生化学反应,放出热量和大量的惰性气体,在地层中形成泡沫压裂液,产生自动升温、增压助排、降滤失的作用,相对早期自生热类泡沫压裂液,具有泡沫体积大、稳泡时间长、泡沫携液能力强、析液少、低腐蚀等优点。结合现场试验认为,自生热压裂技术是一种能提高压裂液返排率,减小地层污染,改善储层渗流能力,增加压后产能的高效经济开发手段。     

一种新型复合型超低表面张力助排剂的制备及应用

为解决压裂液在超低渗储层返排过程中产生严重"液阻"效应而引发的储层伤害,采用氟碳表面活性剂与碳氢表面活性剂进行复配试验,研究表面活性剂协同效应、润湿性、热力学铺展作用,评价复合助排剂的助排率,形成了一种表面张力极低、界面张力满足压裂液通用技术要求的超低表面助排剂。室内实验表明,C12与OBS碳氢表面活性剂以0.4∶0.6(摩尔比)比例复配时其水溶液表面张力小于19.00 mN/m,界面张力小于1.50 m N/m,接触角为86.30°,水溶液助排率高达91.51%,同时超低表面张力助排剂与压裂液及其他添加剂均有良好的配伍性。超低表面张力助排剂在长庆超低渗油田的两口水平井进行了应用,返排率为73.19%～78.15%,返排率较之常规的助排剂提高16.30%～18.78%,助排效果较佳。     

CT5—4压裂酸化工艺助排剂的现场应用效果

在压裂酸化作业中,压入地层的酸液或压裂液,返排是否及时彻底是影响施工效果和油气增产的一个重要因素。在压裂酸化液中加入ＣＴ５－４压裂酸化工艺助排剂,产生极低的表面张力和增大接触角,从而降低毛细管阻力,是促进残液及时彻底返排的有效途径。本文综述了１７口井现场应用情况,结果表明,ＣＴ５－４的加入,促进了残液的返排,返排率达１００％,减轻了因液体滞留地层造成的伤害和污染,缩短了压裂酸化排液周期,提高了试油     

压裂助排工艺优化设计研究

如何提高返排率、减少压裂液对地层的伤害,实现人工裂缝高导流能力,已经成为油气藏增产改造技术面临的重要课题。通过分析氮气、CO2的物理化学特性,研究了液氮、CO2的助排机理,建立气体伴注排液模型,编制了气体伴注设计软件,对影响压裂井气体伴注效果的因素进行了研究,并对助排工艺参数进行了优化设计。结果表明,随着井深增加和压力梯度的降低,液氮伴注比和氮气伴注排量略有增大;井深每增加100 m,液氮伴注比增加约0.3%;压力梯度每增加0.01 MPa/m,液氮伴注比降低约0.6%。随着泵注排量的增加,液氮伴注比增大。井底压力的变化幅度与井口注入压力的变化幅度基本相同;井口注入压力每增加5 MPa,井底压力也增加约5 MPa。随注入流量的增加,井筒压力逐渐减小;注入流量每增加0.5 m3/min,井底压力降低约1.75 MPa。对胜利油田某井进行液氮助排参数优化设计,压裂液返排率达到90%,压裂井产量增加了2.7倍,表明所建立的数学模型准确可靠,可以用于指导油田现场施工。     

新型机械助排工艺在青海尕斯油田的应用

针对过热酸助排和液氮助排技术费用高、返排压力低及常规泵返排工艺存在返排不及时和抽油泵腐蚀的问题,提出了新型机械助排工艺。工艺管柱主要由循环阀、助排器、Y241型封隔器、坐封开关、返排专用花管等组成。助排器工作时通过喷嘴将动力液高压势能转变为动能,在喉管内高速动力液与低速地层残液混合进行动量交换。抽汲地层残液进入喉管,在喉管内2种液体混合,扩散管将混合液流速降低,压力增加,通过油管喷射到地面,达到排残酸、残液的目的。应用表明,施工成功率100%,残酸、残液排出彻底率达到80%。     

松辽盆地北部中浅层压裂返排液示踪监测技术

准确监测压裂液返排率和压裂改造后地层的产液状况,是得到压裂后油井实际产能的关键技术.研究了地层水和压裂液组分差异,优选出地层水微量物质溴离子和碘离子,将2种离子作为定性判别地层水存在的指标;探讨了在压裂液中定量加入硫氰酸钠示踪剂,用硫氰酸钠作为定量区分压裂液与地层水的指标;根据示踪监测结果,计算了压裂液返排量和返排率.在松辽盆地北部中浅层3口探井应用该技术,获得了比常规试油试采更为准确的压裂液返排率和压裂改造后地层产液的油水比,解决了压裂返排液地层水与压裂液定性、定量判别难题.     

Predicting the Method of Oil Recovery in the Gas-assisted Gravity Drainage Process

Gas-assisted gravity drainage (GAGD), solving the problem of low volume sweep coefficient for continuous gas injection (CGI) or water-alternating-gas injection (WAG) and increasing the ultimate recovery to a great extent, is a latest method for enhancing oil recovery. However, no effective predicting methods of oil recovery for GAGD exists. The oil recovery is determined by a set of parameters, such as heterogeneity of the formation, wettability, oil and gas density, oil and gas viscosity, viscous force, capillary force, gravity, gas injection rate, and other controllable parameters. Based on the research of producing mechanism of GAGD and dimensional analysis method, the authors analyzed four dimensionless varies, capillary number, bond number, gravity number, and gravity drainage number, and evaluated its influence on oil recovery. Considering the effect of wettability, viscosity ratio, and the difference between oil density and gas density, gravity number and gravity drainage number are modified. Relationship of gravity drainage number with recovery is re-established by experiments and case data. Finally a new predicting method of oil recovery for GAGD is set up. Application shows that this method is far more suitable for GAGD and its predictive result is more reasonable.     

一种新型压裂液纳米助排剂的研制及性能评价

目的解决现有常规助排剂易被储层吸附、难以作用于较深储层孔隙的问题,以及现有纳米助排剂乳液粒径偏大,难以进入致密孔隙储层的问题。 方法通过相转变组分(PIC法)制备了一种新型纳米助排剂,该助排剂乳液粒径较小,表面张力较低且抗地层吸附特性突出。 结果该纳米乳液的粒径在100 nm以下,且长期保持稳定。以纳米乳液作为表面活性剂载体,在被吸附之后,表面张力为44.198 mN/m,接触角为93.08°;而相同配方的非乳液助排剂,在被吸附之后,表面张力为48.123 mN/m,接触角91.24°。计算毛细管阻力均为负数,表现为孔隙对液体的排斥力,纳米乳液的排斥力是非乳液的2.28倍。 结论该纳米乳液中残余的表面活性剂含量更高,更有利于抵抗储层的吸附,能作用于更深的储层孔隙,更利于孔隙排液,有效地解决了常规助排剂作用距离短的问题。      

An Experimental Investigation of Optimum Capillary Number on Vertical Immiscible Gas Injection in Iranian Carbonate and Sandstone Rocks

Abstract

The authors' purpose was twofold: (a) to study optimum capillary number for acquiring maximum oil recovery in vertical gas-oil displacement using carbonate and sandstone cores, and (b) to investigate the influence of capillary end effect on optimum capillary number extracted from experimental data. Two sets of forced gravity drainage experiments were performed on carbonate and sandstone cores. The first set of experiments comprised seven vertical nitrogen injection tests using carbonate core, which had been saturated by kerosene in ambient laboratory condition. The second set consisted of six vertical nitrogen injection tests using sandstone core that had been saturated by live oil under reservoir temperature and pressure conditions. In each set of experiments, in constant bond number, one optimum capillary number (optimum flow rate) was recorded in which the maximum oil recovery was achieved. When capillary end effect was negligible, optimum capillary number was compatible with critical capillary number, which was calculated in critical gravity drainage velocity while in considerable end effect, optimum capillary number was higher than the calculated critical capillary number. In addition, the residual oil saturation in carbonate rock showed a declining trend when capillary number increased, whereas the minimum of residual oil saturation in sandstone core has been observed in optimum capillary number.     

Modeling of oil production by gravity drainage

Gravity drainage is one of the most effective mechanisms of developing an oil field because of high oil recovery yielded. There have been several models to characterize and model the process of gravity drainage. However the existing models do not work well in many cases. In this study, an analytical model was developed to determine the ultimate oil recovery by free-fall gravity drainage. This model demonstrates clearly the effect of capillary pressure on ultimate oil recovery. The ultimate oil recovery increases with the decrease in entry capillary pressure and the increase in pore size distribution index. The model was modified based on the ultimate recovery model to match and predict oil production. The model was tested against experimental, numerical, and field data of oil production by free-fall gravity drainage. The results demonstrated that the modified oil recovery model could work satisfactorily in the oil–gas cases studied. Initial oil production rate, entry capillary pressure, and average residual oil saturation can be estimated using the oil recovery model. An approach was also developed to infer capillary pressure curves from the oil production data by free-fall gravity drainage.     

Static Stability of Liquid Bridges Between Matrix Blocks of a Gas Invaded Zone of Naturally Fractured Reservoirs

A large portion of oil and gas reservoirs in the world are located in naturally fractured reservoirs. Despite such importunity, the production mechanisms of these reservoirs are not completely well defined. Gas–oil gravity drainage that takes place in the gas-invaded zone of this type of reservoirs is one instance of such a weakness. The density difference between gas-filled fractures in contact with oil-saturated matrix blocks brings the oil out of the matrix blocks into the fracture. The drained oil can reach the production well through two different paths: continues fracture network and block-to-block path. These two different paths require different approaches to modeling of gravity drainage. Single-block approaches are used when drained oil only travels through the fracture network, which totally formulated before. But when oil prefers to travel through the matrix blocks, continuum approaches such as Darcy's law may not work in their basic forms any more. Liquid bridges and film that form in the horizontal fracture between matrix blocks usually transfer the wetting phase across the fracture. Stability condition and duration of stability can help better understanding of gravity drainage in stacks of blocks. In this article, the stability of liquid bridges between the matrix blocks studied and a minimum length of stability is predicated. The results show that this stable length of liquid bridges formed between adjacent matrix blocks is 2r₀π, which is a function of the pore throat. This critical length can be used in modeling of capillary continuity and wetting phase transfer across matrix blocks.     

新型高效泡排剂LYB-1的研制及其性能评价

目前,我国多数气田已进入开采中后期,多数气井已出现井底积液的情况,普通泡沫排水剂难以满足现阶段天然气开采的需求。为此,通过正交设计实验法优化得到泡排剂的最佳配比,研制出了一种新型高效气井泡排剂--LYB-1。室内试验主要采用罗氏-迈尔斯评价方法,借助现场取得的地层水和凝析油对该泡排剂的起泡能力、携液能力、耐温能力、抗油能力、抗甲醇能力、缓蚀能力以及与地层水的配伍性等进行了系统的研究与分析。试验结果表明,该泡排剂与地层水具有良好的配伍性能和缓蚀性能,不仅具有优良的耐温能力、抗凝析油能力,而且具有较强的抗甲醇能力,是一种环保型的泡排剂。     

气井泡沫排水采气的动态实验分析

大量现场实验结论证明了泡沫动态实验对于泡沫排水采气非常重要，使地层水、凝析油均可有效地从气井中排出。在改进了RossMile泡沫测定方法的基础上，建立了泡沫动态实验装置，用泡排剂LH和泡排剂UT-11C进行泡沫流动实验。利用两相流理论，开展了气流量和气流速度对气体携液量的影响研究和气液比与携液量的关系研究，定量地分析了气流量和气流速度对气体持液率的影响，对泡沫排水采气动态进行了探索性的研究，从而指导气田经济、高效、合理地开发。     

抗高温泡沫排水用起泡剂的研究与性能评价

以分子结构上含有磺酸基团、主链碳链较长的甜菜碱为主要成分,复配少量具有协同作用的直链烷烃磺酸盐,研制出了一种抗高温起泡剂。该起泡剂能显著降低地层水的表(界)面张力,具有良好的表面活性,利于泡沫产生,且起泡能力、泡沫稳定性以及携液能力均较好,在150℃下具有良好的热稳定性,表现出了较强的抗高温能力。采用高温气井泡沫排水室内模拟实验装置,较真实地模拟了高温气井的泡沫排水过程,评价了该起泡剂在150℃下的泡沫动态性能。模拟实验结果表明:该起泡剂在150℃下仍具有良好的泡沫携液能力。     

苏里格气田气井产水分析及新型泡排剂试验

分析了苏里格气田气井的产水类型,主要有地层水、淡化地层水、凝析水、凝析油及陈发型出水;分析了气井的井底积液特征,通过压力峰值、油套压变化、产气量变化曲线等特征可以判断气井井底积液情况。介绍了三种产水气井排查方法:生产动态分析法、关井恢复压力排查法、井筒压力梯度测试法,这三种方法是苏里格气田产水气井排查常用且有效的方法。介绍了泡沫排水采气的泡排剂优选方法及优选原则,结合试验区所产地层水的水质分析情况,优选了ERD-05起泡剂和ERD-06泡排棒这两种泡排剂;优化了泡排剂的加注制度,进行了泡沫排水采气现场试验,试验井排水、增产效果明显。     

液力驱动无杆泵排采技术在保-平10水平分支井的应用

保-平10水平分支井原采用有杆泵排采工艺,泵挂深度处在水平分支主井眼水平段,在生产中杆管偏磨问题较为突出,排采效率低,能耗高,经济效益差。该井前期生产中,杆管偏磨及煤粉堵塞等导致频繁检泵,检泵周期短,泵效低。经过反复论证,在上下行程换向、井口限压、煤粉自清洁、自携液举升4个方面进行创新设计。采用井口限压产生液力反馈驱动无杆泵下行程,避免水平井杆管偏磨; 推导出不同内层管自喷携液所需最小产气量,在后期产气量上升,产水量下降后实现向自产气携液举升的转换; 充分利用地层能量实现速度管携液自喷,降低能耗,降低生产运行成本,提高煤层气井生产的经济效益。