Performance Analysis of a Profile Control Agent for Waste Drilling Fluid Treatment

A method for the treatment of hazardous waste drilling fluids,potentially leading to environmental pollution,is considered.The waste drilling fluid is treated with an inorganic flocculant,an organic flocculant,and a pH regulator.The profile control agent consists of partially hydrolyzed polyacrylamide,formaldehyde,hexamethylenetetramine,resorcinol,phenol,and the treated waste drilling fluid itself.For a waste drilling fluid concentration of 2500 mg/L,the gelling time of the profile control agent is 25 h,and the gelling strength is 32,000 mPa.s.Compared with the profile control agent prepared by recirculated water under the same conditions,the present profile control agent displays better stability,salt-resistance,and performance.

Research on Optimization Design of Deep Profile Control Injection Scheme in Block S

In view of the rapid decline rate of oil production and gradual increase of water cut in oil wells in Block S, based on the determination of the formula of foam profile control agent, the optimization study of foam profile control injection scheme was carried out. Petrel software is used to establish a facies controlled geological model based on stochastic modeling method in Block S, and CMG software is used for numerical simulation to design 7 sets of foam profile control prediction schemes. Dynamic data and numerical simulation methods are used to optimize foam injection mode and injection cycle. By simulating and calculating, the optimal injection method of alternating gas and liquid injection and the optimal plan with an injection period of 2 months were selected. Through the calculation results of various research plans, it can be seen that the water content of the optimal plan has decreased significantly, and the oil production rate has increased significantly, in order to slow down production decline, control water content rise, extend the economic recovery period of the oilfield, and achieve the goal of improving oil recovery.

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.

Researches on the PAM／Cr^3＋ Gel for Deep Profile Control

The profile control hard-gel is composed of polyarylamide (5-6g/L), whose molecular weight is 4,000,000 - 7,000,000 and hydrolysis degree is 17.6%, and cross-linking oxidation-reduction agent (Na2Cr2O7 + NH4Cl), with an delayed organic acid crosslinker which contains lactic acid/propionic acid/ethanoic acid and ethylene glycol. After research of the influence factors, such as pH, temperature, salinity and the dosage of delayed crosslinker, the optimum condition(pH 5.2, temperature 55℃, salinity < 7g/L) was found. Gelation time (12-144h) can be controlled by adjusting the dosage of the delayed crosslinker. Deep profile control experiments are carried out on heterogeneous models, which contains three serial high permeable and low permeable cores arranged in a parallel. After water flooding (total recovery, 24.3%), the first, second and third high-permeable cores each are sealed in turn by the profile control agent, and the total displacement recovery increases to 46.8%, 62.2% and 69.1% respectively. So, the greater the sealed depth, the larger the enhancing recovery will be. Finally, the oil displacement mechanisms of deep profile control are discussed.

Injection Scheme Optimization of Foam Profile Control on Block S103

Facing problems with oil production decreasing quickly and water content increasing gradually in S103 well area, the Foam Profile Control was studied on the basis of its confirmed agent formula. The facies-controlled geological model of S103 well area was generated using random model based on Petrel software and using numerical simulation based on CMG software. Gas liquid alternating injection pattern was optimized as the optimal solution through the simulation optimization. Two months are optimized as the optimal solution through the simulation optimization. The cumulative oil production is 0.933 × 107 kg which is higher than the value of subsequent water flooding and the other three. Finally, it reaches the goals of slowing down the production decline and controlling the water rising.

Performance Evaluation of a New Type of Polymer Profile Control Agent

The low-permeability oil and gas resources of our country are quite common and abundant. Their reserve has accounted for one-fifth of total oil reserves of our country, and their yield has constituted the important part of national petroleum annual yield, but its development is very difficult. Polymer gel technology is a technical method of improving sweep efficiency in recent years which substantially increases the viscosity of the polymer solution by adding a crosslinking agent to the polymer produced by intramolecular or intermolecular crosslinking.

油田含聚废液处理及再利用技术研究

近年来虽然对聚合物驱油藏油水井洗井、作业及站内管线清洗产生的含聚废液开展了回收再利用技术研究,但缺乏聚合物胶块废液的有效处理技术。为此,结合注聚区废液的特点,研究相应的处理技术,确定注聚区废液的调剖用配方,并针对不同废液改进调剖注入工艺,形成注聚区废液调剖再利用技术。研究结果表明:研制的橇装式含聚废液地面分离及处理装置能够有效分离废液中的胶块,对其进行粉碎处理后,形成颗粒调剖剂,进而实现单井直接注入;结合含聚废液特点,研发了相应的复配调剖剂配方,形成了调剖剂系列,达到了封堵高渗透油藏堵剂要求;现场实施调剖21口井,累计处理废液51 978 m^(3),油压平均上升了1.5 MPa,累计增油达8 036.2 t。研究结果可为油田清洁环保开发生产提供技术依据。

两性离子表面活性剂和纳米颗粒为起泡剂的高稳定性超临界二氧化碳泡沫封窜体系

胜利油田低渗透油藏具有埋藏深(>3000 m)、温度高(>120℃)、非均质性强等特点,针对低渗透油藏CO_(2)驱波及效率低、常规泡沫高温调驱性能变差等问题,构建了由两性离子表面活性剂(HSD)和改性SiO_(2)纳米颗粒为起泡剂的高稳定性超临界CO_(2)泡沫体系。研究了该体系在高温下的起泡性能和耐温性能;分别评价了纳米SiO_(2)对超临界CO_(2)泡沫体系流变特性、封堵特性以及调驱性能的影响;最后探讨了纳米颗粒强化超临界CO_(2)泡沫的稳定机理。结果表明,高稳定性超临界CO_(2)泡沫体系表现出良好的起泡性能和耐高温特性,随着体系中纳米颗粒浓度的增加,泡沫半衰期先增加后降低。在110℃下,0.5%的纳米颗粒可使泡沫析液半衰期由17 min提高到40 min,稳定性提高了近1.5倍。在相同的剪切速率下,体系的表观黏度随纳米颗粒浓度的增加而增加,稠度系数由0.073增至1.220。在岩心封堵实验中,泡沫在多孔介质中的稳态表观黏度随纳米颗粒浓度的增加而增加,封堵强度逐渐增强;超临界CO_(2)泡沫呈“颗粒状”堆叠排放,泡沫直径为10~20μm。超临界CO_(2)泡沫具有较好的调驱性能,能封堵高渗透通道,迫使后续注入的CO_(2)进入低渗透基质中,从而提高采收率。表面活性剂分子吸附在纳米SiO_(2)表面使其具有了界面活性,进而纳米SiO_(2)吸附到气液界面上,提高了泡沫稳定性。

渤海S油田在线调驱乳液聚合物凝胶体系筛选与性能评价

随着海上油田在线调驱调剖技术的应用和逐步推广,针对海上平台在线调驱调剖体系的研究成为一个重点。研发了一种适用于海上平台在线调驱的乳液聚合物凝胶体系,它是由高含量的油包水型乳液聚合物和交联剂组成。研究了乳液聚合物含量、交联剂含量、温度、钠离子和二价离子对其体系性能的影响,并通过室内物理模拟实验对体系进行了驱油性能评价。结果表明:乳液聚合物凝胶体系最佳体系配方为0.2%~0.5%EM533+0.2%~0.5%SLPF,成胶时间2~5 d可调,成胶黏度在185~5 893 mPa·s可控。乳液聚合物凝胶体系具有较好的耐温、耐盐和耐二价离子的能力,并且具有良好的驱油性能,措施后,注入压力上升,含水率下降,采收率增加20.34%。

低渗透裂缝型油田调剖用弱凝胶体系室内评价

通过实验室模拟与现场应用分析,详细考察了弱凝胶体系的性能以及在油田中的实际应用效果。实验结果显示,弱凝胶体系的成胶时间从20℃的115.2 min显著减少至70℃的14.9 min,黏度从1560.5 m Pa·s降至1047.2 m Pa·s,体现了温度提高加速化学交联反应的效果。在老化稳定性实验中,凝胶黏度在室温条件下经过3个月从初始的1200 m Pa·s缓慢降至1149 m Pa·s,而在80℃的高温条件下,从1013 m Pa·s降至970 m Pa·s,表明温度的升高加速了老化过程,但整体上凝胶展示了良好的稳定性。剪切稳定性测试中,凝胶黏度从500 r·min^(-1)的1198 m Pa·s降至5000 r·min^(-1)的987 m Pa·s,显示出良好的剪切稳定性。大洼油田采用弱凝胶调驱技术后,油井的日产油量平均提升了50%,同时减少了水窜现象,优化了油水分层,显著提高了油田的整体采收效率。

大庆油田聚驱后油层无碱中相自适应堵调驱实验

大庆油田聚驱后弱碱复合驱扩大现场试验取得了聚驱后进一步提高采收率13.5百分点的较好效果,但体系中碱的存在导致管线、泵产生腐蚀、结垢和采出液出现严重乳化破乳难等问题。同时,由于优势渗流通道的存在,流度控制难,致使体系中聚合物质量浓度高达2500 mg/L。为解决上述问题并实现更大幅度提高采收率,需研发出适用于大庆油田聚驱后油层的高效中相微乳液驱油体系。通过对表面活性剂溶液的界面张力进行测量,初步筛选出能够达到超低界面张力的表面活性剂产品,然后进行中相微乳液体系水溶性评价,并开展了较为完善的油水相态评价,进一步确定中相微乳液体系的最佳盐度(盐的质量分数)及其与油水比的关系,从而研发出无碱中相微乳液配方,并加入预交联颗粒凝胶(PPG)组成无碱中相自适应堵调驱体系。岩心驱替实验结果表明,该体系聚驱后可进一步提高采收率23.3百分点,比常规弱碱复合驱多提高采收率10.1百分点,降低聚合物用量28%。研究成果为大幅提高大庆油田聚驱后油层的采收率提供了理论及实验支撑。

高盐低渗透油藏CO_(2)泡沫微观尺度耐盐性及调驱效果

针对高盐低渗透油藏CO_(2)驱存在的气窜问题,以长庆油田H3区块为研究对象,构建SiO_(2)纳米颗粒强化CO_(2)泡沫体系,从泡沫流变性、气液界面张力、气泡液膜厚度与渗透性、泡沫微观结构4个方面评价泡沫体系耐盐性;通过开展SiO_(2)纳米颗粒强化CO_(2)泡沫体系并联岩心调驱实验,研究该体系调驱效果。根据实验结果,在油藏条件下,构建出配方为质量分数0.20%(OW-1)+0.30%(OW-4)+0.05%(SiO_(2))纳米颗粒强化CO_(2)泡沫体系,该泡沫体系的综合指数为36834 mL·min;该泡沫体系的微观尺度耐盐性评价结果表明,矿化度46357 mg/L与矿化度500 mg/L的配液相比,泡沫流变性更好,气液界面张力在10 MPa时仅增加1 mN/m,液膜渗透性增加了0.14 cm/s,但仍具有良好的泡沫骨架结构,该泡沫体系具有良好的耐盐性。此外,在并联岩心渗透率级差为15.55的条件下,该SiO_(2)纳米颗粒强化CO_(2)泡沫体系对岩心剖面改善率达到了97.28%,采收率显著提升,展现出良好的调驱能力。

渤海油田中低渗油藏“凝胶+微球”组合调剖体系研究与应用

针对渤海Z油田6井区中低渗储层注入水窜流严重、水驱效率低的问题,开发了乳液聚合物凝胶+水基微球组合调剖体系。实验结果表明,乳液聚合物凝胶体系成胶稳定时间为7 d左右,成胶黏度大于20000 mPa·s;水基微球粒径14 d左右膨胀到最大。乳液聚合物凝胶+水基微球组合体系在双管并联岩心实验中具有较好的改善剖面能力,可有效启动低渗岩心,两根岩心提高采收率分别为12.57%和15.33%。组合体系在6井区边部4井组现场试验,实施措施后3口油井全部受效,井组高峰期日增油45.79 m^(3),单井最高含水下降20.47%,9个月内累计增油1.5×10^(4)m^(3)。

海上特超稠油油藏小井距蒸汽吞吐汽窜堵调工艺

渤海某大规模热采开发的特超稠油油藏在一轮次注热期间井间汽窜率超70%,严重影响油田产能。针对该情况,基于探井、测井认识,先后开展药剂性能评价、单/双管驱替实验及现场堵调应用,对高含水层物性得到了进一步认识,随后开展泡沫调剖、井组同注数值模拟及现场试验,井间汽窜得到有效控制。研究结果表明,局部高含水低渗储层经蒸汽冲刷后平均渗透率或高于探井阶段测量值,对于已汽窜井开展井组同注措施,对于未汽窜井及井组边部井采用强化泡沫调剖,该措施不仅可以有效控制和预防汽窜,同时可均匀动用储层,优势层段吸汽剖面级差降低46.8%。泡沫调剖辅助井组同注的工艺策略实施后单井产能提高12%~33%,对海上特超稠油高效开发具有指导意义。

涠洲高渗油藏冻胶泡沫体系优选及室内评价

为找到耐温抗盐性能优秀、调剖控水能力优良且成冻时间可控的冻胶泡沫体系,进而应用于涠洲高渗高含水油藏,采用Waring Blender法、Sydansk代码法以及物理模拟实验以起泡体积、半衰期、成冻强度、阻力系数及分流量为评价指标,优选出0.2%阴离子型聚合物(KY-6)+0.6%有机铬交联剂(YG107)+0.6%十二烷基苯磺酸钠(BHSN12)+1%缓速剂乳酸钠的冻胶泡沫体系。结果表明:该体系耐温耐盐性能优秀;加入缓速剂后可实现成冻可控(约15 h成冻,强度为G级),稳定时间长;在目标油藏渗透率范围内封堵率大于99%,具有很好的封堵控水作用;渗透率级差为3.2~15.8,能有效注入并封堵强水窜通道,具有优秀的调剖控水能力,其中渗透率级差为7左右调剖效果最优。

基于低渗油藏裂缝型水淹泡沫复合调驱技术研究

针对裂缝型油藏水窜水淹以及传统的泡沫体系调控效果受限的问题,提出凝胶-泡沫复合调驱技术,并对其注入工艺进行优化研究。通过室内驱替实验对封堵增油效果进行评价,在此基础上,通过实验设计分别对体系的注入量、注入浓度、注入速度和注入方式进行优化,并进行矿场实践应用。实验结果表明,与单纯水驱相比,凝胶-泡沫体系最终采收率提高幅度达到19.7%。参数优化结果表明,当气液比为3∶1,起泡效果最好;注入量为0.3 PV、注入浓度为900 mg·L^(-1)·PV-1时,驱替效果最优;同时采取小排量、多段塞交替注入方式,驱油效率增幅比笼统注入方式下高6.79%。井场实践结果表明,措施后单井平均日增油1.59 t,含水率降低24.74%,增油率达到56.58%,降水增油效果显著。凝胶-泡沫协同调驱技术能够显著实现高含水井以及低效井降水增油的目的,针对裂缝型油藏注水开发中后期出现水淹水窜问题具有较好的治理效果。

层内自生低界面张力泡沫调驱技术研究与应用——以渤海KL油田A20井组为例

针对渤海KL油田A20井组平面注水突进、纵向吸水不均及常规调剖体系难以注入等问题,开展了层内自生低界面张力泡沫调驱性能评价实验。采用界面流变仪、泡沫扫描仪和泡沫调驱动静态评价装置等设备,筛选优化了层内自生低界面张力泡沫体系的组成药剂及最佳复配浓度比,并采用多功能物理模拟驱替装置考察了该体系的动态调驱性能。结果表明:优选组成药剂及配比为10%生气药剂A+10%生气药剂B+2%释气药剂C+0.5%起泡剂PA-5+0.3%稳泡剂PJ(质量浓度),该复配体系可在可视化填砂管中稳定生泡;一维填砂管驱油效率可在水驱的基础上提高19.1%;非均质填砂管并联驱油时,注入复配体系可进一步驱洗高渗填砂管残余油并有效封堵高渗通道,扩大低渗填砂管的波及系数,分液率从0增至34%。从矿场实践来看,A20井组实施层内自生低界面张力泡沫调驱作业后,生产曲线呈含水下降、产油上升的形态,3个月内累计增油2007.29 m3,初步说明层内自生低界面张力泡沫调驱技术在海上油田具有广阔的推广应用前景。

一种高温高矿化度复合冻胶的研制与应用

为了解决高温高矿化度油藏深部调驱问题,以丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)和N,N-二甲基丙烯酰胺(DMAA)为原料合成共聚物PASD,并以酚醛树脂作为交联剂、硫脲作为稳定剂,添加增强剂MZQ制备得到复合冻胶体系。通过红外光谱仪、扫描电镜、岩心流变仪等对冻胶体系进行应用研究,考察了共聚物PASD、交联剂、稳定剂、增强剂加量的影响,确定复合冻胶体系的最佳配方;在150℃、矿化度为25.198×10^(4) mg·L^(-1)下条件下应用,其冻胶强度为Ⅰ级,抗老化脱水性能良好,有效耐温脱水时间超过180d;冻胶封堵能力超过93%,具有良好的封堵性能以及抗盐耐温性能。

水平注水井双低乳液丙烯酰胺冻胶调剖体系研制与应用

针对水平注水井调剖过程中注入压力高,措施效果差的问题,以渤海X油田为目标,建立了低相对分子质量、低初黏的双低乳液丙烯酰胺冻胶调剖体系.室内性能评价实验表明:物模试验注入压力仅为常规冻胶调剖体系的5833%,调剖后,当水平段的趾部是高渗时,高渗岩心管分流量由调剖前的925%下降至583%,调剖效果较好.当水平段跟部为高渗时,高渗岩心管分流量由调剖前的912%下降至439%,高、低渗透管的分流量出现反转;调剖效果进一步好转.该体系在渤海X油田E井组进行了现场应用,措施后含水率最高下降52%,累计增油13786m^(3).