高矿化度下弱凝胶体系调剖性能研究

通过单因素实验和正交实验考察了聚合物浓度、交联剂浓度、稳定剂浓度及氯化铬/乳酸摩尔比对凝胶性能的影响,研制了一种适用于高矿化度低渗透裂缝性油藏的弱凝胶体系配方,并对弱凝胶体系的驱油效果进行了研究。实验结果表明,在实验温度32℃、地层水矿化度为29 500 mg/L条件下,优选出弱凝胶体系配方为:聚合物质量浓度2 000 mg/L,稳定剂质量浓度800 mg/L,交联剂质量浓度200 mg/L,三氯化铬/乳酸的摩尔比为1∶8;弱凝胶体系注入量越大(0.3～0.6 PV),低渗层采收率提高值越高,对于层间差异大的油层,或对于存在高渗透率的油层,加大注入凝胶量才能调整流量分配,注凝胶后的注入水更多的进入低渗透油层驱油,采收率提高值大于15%。     

复合无机凝胶的研制与性能

使用粘土、硅酸钠及少量PAM和添加剂在一定的反应条件下制成了复合无机凝胶 ,性能评价实验表明 ,该产品耐温 90℃、耐盐 1.6× 10 5mg/l,热稳定性好。与有机凝胶相比 ,价格大幅度降低 ,为中原油田高温高盐恶劣地层条件下的高含水、特高含水区块稳油控水提供了一种耐温抗盐性好、成本低廉的调驱剂。     

低渗透裂缝性油藏的轻质油蒸汽驱

本文是关于低渗透裂缝性油藏轻质油热采热组分模拟的研究。与水驱相比，蒸汽驱的横向和垂向采收率都有提高。采收率增加值的大小与渗透率分布有关，而渗透率的均质分布是最重要的影响因素。     

胶态分散凝胶研究的新进展

本文从胶态分散凝胶的概念,形成过程,评价方法,室内研究和现场应用等方面综述了近十几年来胶态分散凝胶的研究和应用工作,并预示了有关的研究方向。     

预凝胶技术及其在火烧山裂缝性砂岩油藏中的应用

火烧山油田是一个裂缝性特低渗透砂岩油田 ,调堵水技术应用在该油田发挥着重要的作用 ,但是随着堵水次数的增加以及大裂缝的存在 ,使堵水效果越来越差。 1998年在火烧山油田的H 1194井组应用预凝胶技术进行调剖 ,施工 4口井 ,措施后增加的可采储量为 15× 10 4 t,增加的水驱采收率为 5 79%。文中叙述了预凝胶体系性能的主要影响因素以及用于测试其性能指标的流动实验 ,简介了H 1194井组的施工效果。     

CO2响应性增强泡沫体系室内试验研究

为解决低渗透油藏CO₂驱气体窜流影响开发效果的问题,以泡沫综合值为评价指标,通过搅拌法优选发泡剂,建立了CO₂响应性增强泡沫体系,配方为0.1%发泡剂AOS+4.0％小分子胺+水。该体系在接触CO₂前黏度与水接近,与CO₂作用后黏度可升高18倍以上。性能评价结果显示:CO₂响应性增强泡沫体系的泡沫综合值可达到常规泡沫体系的11倍以上;具有明显的剪切稀释特性,流变方程符合幂律流体流变模式;比常规泡沫体系具有更强的黏弹性,可以封堵优势渗流通道,抑制非均质低渗透油藏CO₂驱气体窜流,提高低渗透油藏CO₂驱的采收率。研究结果表明,CO₂响应性增强泡沫体系可以解决低渗透油藏CO₂气体窜流问题,提高CO₂驱的开发效果。      

聚合物驱提高高温高矿化度油藏采收率室内实验研究

对于某高温高矿化度油藏，优选疏水缔合水溶性聚合物NAPs进行驱替实验。研究表明，该聚合物溶液具有良好的耐温、抗盐和抗剪切性能，在高温、高矿化度油藏条件下，可提高采收率7．62％以上，并且具有较强的流度控制能力，能够发挥油层调剖作用，具有广阔的应用前景。     

低渗透裂缝性油藏调剖物理模型研制及实验评价

为提高低渗透裂缝性油藏调剖剂评价物理模型的模拟程度,设计了一种裂缝宽度可调、基质和裂缝流量可分别计量的低渗透裂缝性油藏调剖物理模型。利用该模型开展了弱凝胶、预交联凝胶颗粒以及预交联凝胶颗粒-弱凝胶复合调剖体系对裂缝封堵能力评价实验以及复合调剖体系提高低渗透裂缝性岩心采收率驱油实验。研究结果表明,三种体系在裂缝中的封堵能力均随裂缝宽度的增加而减小,当裂缝宽度大于0.69 mm后,弱凝胶和预交联凝胶颗粒对裂缝基本不起有效封堵作用;随预交联凝胶颗粒浓度的降低,注入压力显著增加时对应的注入量增加、注入时间延长,最佳注入浓度为1000 mg/L;相同裂缝宽度下,复合调剖体系最高封堵压力值高于弱凝胶和预交联凝胶颗粒,且所需预交联凝胶颗粒的量相对较少。当复合调剖体系将裂缝完全封堵后,低渗透裂缝岩心的采收率由5.33%提高至45.58%,提高采收率的效果明显。     

中低渗油藏弱凝胶驱油体系的室内研究

Z35断块聚合物驱中,针对Z145井存在的注入压力不上升,未形成有效流动阻力的问题,在聚合物中加入交联剂及其他添加剂,形成黏度更高的弱凝胶体系。确定了有机铬弱凝胶体系最佳配方:聚丙烯酰胺KY62210浓度为800~1 200 mg/L,Cr(Ⅳ)交联剂浓度为200~400 mg/L,稳定剂硫脲浓度为200 mg/L,体系pH为7~8。KY62210浓度为1 000 mg/L时,成胶后黏度最高可达674.30 mPa·s,油藏温度下热稳定100 d后,黏度仍保持在300.00 mPa·s以上。并联岩心驱油实验表明,该有机铬弱凝胶体系对低渗岩心的提高采收率为13.2%。     

低渗透裂缝性油藏微生物调驱室内研究

低渗透油藏主要开发技术是在强化地质认识基础上,以酸化压裂、完善井网、细分开采、丛式井配套为主的水驱技术,由于天然裂缝发育,在注水开发过程中呈现出油井产水快速上升、产能下降、供液能力差、低产低效的局面.为改变这种局面,对延长油田唐80区从54井组微生物调驱进行室内评价研究.微生物采油是一种经济有效的技术,是油田开发后期一种重要的提高采收率技术.针对井组油藏的特点, 根据微生物驱提高采收率技术路线,对菌种进行筛选及评价,对初步筛选的2种微生物菌种在室内进行了基本性能评价,并进行微生物菌液物理模拟实验,综合评价和研究驱油技术提高采收率的能力.实验结果表明,利用微生物对该类油藏进行调剖驱油,能明显改善注采状况,对区块起到降水增油的作用.为更好地在低渗透性油田应用微生物采油技术,提供了经验和依据.     

The Research on Cross-linking Polymer Gel as In-depth Profile Control Agent

Abstract

Polymer flooding is one of the most important techniques for enhancing petroleum recovery in China. After the polymer is injected into the petroleum formation reservoir, the producing water ratio quickly increases, while some polymer remains in the petroleum reservoir formation. To make use of the residual polymer, the mixture of polymer and cross-linking agent is injected into the petroleum reservoir formation, and then the chemical mixture will change into a gel that can shut off high permeability petroleum formation. The method can enhance the sweep efficiency of the following water. The gel, as the profile control agent, is cross-linked by the polymer compound and cross-linking agent. The gelation time is qualitatively determined, and the gel strength is quantitatively measured by a breakthrough vacuum method. The gelation time is adjustable from 1 to 20 days, and the gel strength is adjustable from 0.030 MPa to 0.060 MPa. Experimental results indicate that the suitable gel is about 0.1 PV (pore volume), for the proper chemical agent will avoid the petroleum reservoir formation being destroyed. The research shows that the gel as in-depth profile control agent is an effective enhanced oil recovery (EOR) method.     

聚合物驱后多元调驱体系提高采收率研究

根据聚合物驱后提高采收率的需要,筛选了多元调驱体系的凝胶颗粒类型、交联剂最优浓度和洗油剂最优浓度,分别考察了单元注入体系(50 mg/L或100 mg/L交联剂、2000 mg/L阳离子凝胶微球,注入体积1 PV),二元注入体系(100 mg/L交联剂+2000 mg/L阳离子凝胶微球,注入体积1 PV)和三元注入体系(0.4 PV×2000mg/L阳离子凝胶微球+0.3 PV×100 mg/L交联剂+0.4 PV×2000 mg/L高效洗油剂)的调剖效果。实验结果表明:二元注入体系转水驱突破压力为3 MPa左右,而且压力整体波动范围和波动幅度都明显高出单元注入体系的,这说明二元注入体系调剖效果比单元注入体系的好;在水驱采收率39.65%、聚合物驱提高采收率18.38%的基础上,三元注入体系提高采收率22.82%;水驱和聚合物驱阶段注入压力较低,凝胶微球注入后压力迅速上升,交联剂的注入保持了压力,高效洗油剂驱使压力进一步上升,转后续水驱后压力下降并稳定在2 MPa左右;与二元注入体系相比,三元注入体系的后续水驱压力明显降低,这保证了在不影响调驱效果的同时还能降低后续水驱压力,因此多元注入体系具有更好的实际应用价值。图5表3参9     

The Study of an Inorganic Gel for Profile Modification in High-Temperature and Low-Permeability Sandstone Reservoirs

Chemical water control technique has been successfully used to improve oil recovery of mature waterflooding reservoirs. However, for high-temperature and low-permeability sandstone reservoirs, not many options are available. An inorganic gel composed of aluminum chloride hexahydrate as gelling agent and urea as an activator was developed. Based on the proper gelation time and degree of syneresis, the optimum mass ratio of aluminum chloride and urea was 1:0.625. According to the gel strength and economical cost, the reasonable concentration of aluminum chloride should range from 3.0% to 6.0%. Gel compatibility with various formation brines showed that the gel could tolerate sodium chloride concentrations up to 80 g·L ^?1 and calcium chloride concentrations up to 40 g·L ^?1. Long-term thermal stability and sandpack flow results showed that after aging for 60 days at 110°C, the gel showed approximately 82% permeability reduction when about 16% syneresis was observed in bulk samples.     

缝洞型碳酸盐岩油藏堵水技术室内研究

为了遏制塔河油田奥陶系缝洞型碳酸盐岩油藏油井含水上升过快的趋势.针对塔河油田储集层条件,对两种有效堵剂(改性栲胶堵剂和柔性堵剂)进行了实验研究.研究结果表明,改性栲胶堵剂高温稳定性好、耐高矿化度盐水侵蚀;柔性堵剂在高温和高矿化度环境中可长期稳定,且易解堵,是封堵塔河油田奥陶系碳酸盐岩油藏出水缝洞的可选材料.利用两种堵剂进行缝洞型碳酸盐岩岩心封堵实验,结果表明:增大堵剂用量的初期主要使封堵层深度变大,突破压力梯度升高;当封堵层达到一定的深度后,堵剂堆积使流动通道变窄小,可大幅度提高残余阻力系数.图5表3参15     

提高裂缝性油藏采收率的综合技术——以火烧山油田为例

火烧山油田为裂缝性特低渗透非均质砂岩油藏,高角度直劈裂缝广泛发育,油田开发过程中水窜、水淹严重,产量递减大。通过4期综合治理,使油田开发效果得到明显提高,实现了油田持续稳产。在治理过程中,以精细注水、精细采油、精细措施作为技术关键,开展了开采配套技术研究,如机械管柱与化学工艺结合,各化学工艺技术相结合等,形成了提高采收率的综合性开采技术,为火烧山油田的稳产奠定了技术基础,取得了良好开发效果。     

大庆油田MD膜驱提高采收率室内实验研究

在大庆主力砂岩油藏岩心上 ,考察了膜驱剂MD 1在不同开发阶段的驱油效果 (4 5℃ )。膜驱剂MD 1为含2 5 %单分子双季铵盐的工业品 ,用矿化度 5 2 10mg/L的油田采出水配制驱替液。注入 0 .5 7PV的 5 0 0mg/LMD 1溶液使未洗油、含束缚水的岩心表面由亲油变弱亲油 ,由弱亲油变中性。在洗油后饱和水 ,再用油驱替至束缚水状态的若干组岩心上 ,膜剂驱的采收率如下 :直接用 5 0 0mg/L溶液间歇驱油 ,采收率 6 0 .8%和 6 4 .1%;水驱后提高采收率 2 .2 3%(5 0 0mg/L× 0 .5PV) ,3.0 9%(10 0 0× 0 .5 ) ,9.10 %(5 0 0× 2 .0 ) ,8.2 0 (5 0 0× 10 .0 ) ,最终采收率略低于直接膜剂驱 ;水驱、聚合物驱 (提高采收率 6 .4 8%～ 8.6 1%)之后提高采收率 1.96 %(5 0 0× 0 .5 ) ,2 .4 4 %(10 0 0×0 .5 ) ,6 .4 8%(5 0 0× 5 .0 ) ,6 .4 6 %(5 0 0× 10 .0 ) ;水驱、三元复合驱 (提高采收率 14 .89%～ 15 .89%)之后提高采收率1.4 5 %(5 0 0× 0 .5 ) ,0 .6 5 %(10 0 0× 0 .5 ) ,5 .98%(5 0 0× 5 .0 ) ,5 .13%(5 0 0× 10 .0 )。在大庆油田 ,聚合物驱和三元复合驱之后采用膜驱技术可进一步提高采收率。表 4参 8     

Surfactant induced reservoir wettability alteration: Recent theoretical and experimental advances in enhanced oil recovery

Reservoir wettability plays an important role in various oil recovery processes.The origin and evolution of reservoir wettability were critically reviewed to better understand the complexity of wettability due to interactions in crude oil-brine-rock system,with introduction of different wetting states and their influence on fluid distribution in pore spaces.The effect of wettability on oil recovery of waterflooding was then summarized from past and recent research to emphasize the importance of wettability in oil displacement by brine.The mechanism of wettability alteration by different surfactants in both carbonate and sandstone reservoirs was analyzed,concerning their distinct surface chemistry,and different interaction patterns of surfactants with components on rock surface.Other concerns such as the combined effect of wettability alteration and interfacial tension (IFT) reduction on the imbibition process was also taken into account.Generally,surfactant induced wettability alteration for enhanced oil recovery is still in the stage of laboratory investigation.The successful application of this technique relies on a comprehensive survey of target reservoir conditions,and could be expected especially in low permeability fractured reservoirs and forced imbibition process.     

适合胜利孤东油田的聚合物/无机铝弱凝胶体系及其试应用

孤东注水开发油田层内、层间矛盾严重 ,注入水和注入聚合物单相锥进 ,注聚井常发生堵塞。为此 ,研制了微凝胶调驱体系 :聚合物 (日本三菱公司的MS35 0 0 ,M =1.9× 10 7,HD =2 6 .4%) 10 0 0mg/L ,交联剂无机铝盐 5 0～2 0 0mg/L ,稳定添加剂 10～ 15mg/L ,用矿化度 390 0mg/L的油田污水配制。铝盐浓度 5 0 ,10 0 ,15 0mg/L的体系(CDG 5 0 , 10 0 , 15 0 ) 6 0℃下的粘度 ,在初配时较相应聚合物溶液 (PS) 6 0℃下的粘度 (4 1mPa·s)略低 ,在 6 0℃反应后均有所降低 ,但相互之间及与PS之间相差不大 ,在 6 0℃反应 5 6天后约在 30mPa·s上下。在 6 0℃下初配制的PS ,CDG 5 0和CDG 10 0流过气测渗透率 4.2～ 4.3μm2 的人造岩心柱时 ,阻力系数相差不大 ,随着 6 0℃下反应时间的延长 (0～ 42天 ) ,PS的阻力系数趋于下降 ,而CDG 5 0特别是CDG 10 0的阻力系数增加的幅度越来越大。在孤东 7 2 9 194井组试用CDG弱凝胶体系进行调驱 ,采用双段塞注入工艺 :10 0 0m3 CDG 10 0 +16 0 0m3 CDG 5 0 ,初步结果良好 ,注水井启动压力由 0 .4上升到 6 .7MPa ,吸水指数由 30下降到 2 8m3 /d·MPa ,对应 6口采油井日产油量由 2 9t上升到 48t,含水由 96 .1%下降到 90 .1%。     

A laboratory study of hot WAG injection into fractured and conventional sand packs

Gas injection is the second largest enhanced oil recovery process,next only to the thermal method used in heavy oil fields.To increase the extent of the reservoir contacted by the injected gas,the gas is generally injected intermittently with water.This mode of injection is called water-alternating-gas(WAG).This study deals with a new immiscible water alternating gas(IWAG) EOR technique,"hot IWAG" which includes combination of thermal,solvent and sweep techniques.In the proposed method CO2 will be superheated above the reservoir temperature and instead of normal temperature water,hot water will be used.Hot CO2 and hot water will be alternatively injected into the sand packs.A laboratory test was conducted on the fractured and conventional sand packs.Slugs of water and CO2 with a low and constant rate were injected into the sand packs alternatively;slug size was 0.05 PV.Recovery from each sand pack was monitored and after that hot water and hot CO2 were injected alternatively under the same conditions and increased oil recovery from each sand pack and breakthrough were measured.Experimental results showed that the injection of hot WAG could significantly recover residual oil after WAG injection in conventional and fractured sand packs.