预测聚合物驱油田产量的两种方法的对比

在分析大量油田动态指标预测方法及聚合物驱影响因素的基础上,对适合于聚合物驱油田开发指标的预测方法进行了深入研究,并结合大庆油田杏四~六面积北部区块注聚合物驱的实际资料,应用物质平衡法和预测模型法对该区块的产油量进行了预测.结果表明:物质平衡法可以对聚合物驱整个过程进行预测,其优点是计算速度快、精度高,缺点是需要的参数多,对后续水驱阶段预测有一些偏差;在聚合物驱开发初期,两种预测模型法的误差偏大,达到最高月产油量后,预测误差较小,表明在含水稳定阶段和含水回升阶段预测模型法的应用效果较好;物质平衡法优于模型法,其平均误差为2.05%,而两种模型法预测的平均误差分别为4.61%、3.73%.总体来说,两种方法都满足生产的需要.     

砂砾岩油藏聚合物驱试验效果评价及作用机理探讨——以呼和诺仁油田贝301区块南屯组油层为例

砂砾岩油藏储层通常具有孔隙结构复杂、非均质性强等特征,高含水期砂砾岩油藏层内、层间及平面间矛盾突出,而常规技术难以有效控制含水上升速度,无法提高差油层的动用程度,油田开发效果逐年变差。为此,以呼和诺仁油田贝301区块南屯组高含水油层为主要研究对象,优化设计聚合物驱试验方案,开展为期3年聚合物驱现场试验。研究结果表明,试验油层综合含水下降大于10.0%,自然递减连续3年小于5.0%,阶段增油达3.75×104 t,与水驱对比,阶段采收率提高8.5%以上,聚合物驱试验取得了良好的增油降水开发效果。     

一种预测聚合物驱开发动态的模型

在分析聚合物驱与水驱驱替机理差异的基础上,对水驱预测的经验公式进行改进,建立了适用于聚合物驱的预测模型。预测模型可考虑聚合物溶液黏度、注入PV数及最大残余阻力系数等参数对聚合物驱效果的影响。预测模型预测大庆喇南和喇北东块的聚合物驱含水率曲线与实际含水动态吻合,预测提高采收率误差小于8%,结果可靠。预测模型所需参数简单、计算简便,可用于聚合物驱动态预测、效果评价及潜力分析。     

大庆油田二类油层聚合物驱油井含水率变化特征

大庆油田利用主力油层聚合物驱成熟配套技术,在室内研究的基础上,进行了二类油层聚合物驱矿场试验.总结试验区的动态开发特点,分析存在的问题,形成了以聚合物驱控制程度为核心,以限制聚合物驱对象、细分层系、缩小井距、优化聚合物驱方案为主要内容的二类油层聚合物驱总体开发原则,通过工业化应用,深入研究了二类油层聚合物驱含水率变化特征,通过研究含水率曲线形态,将二类油层含水变化特征分为5种类型,其中圆底锅型含水率下降幅度较大,含水率下降了22.9个百分点,阶段提高采收率为7.4%,聚合物驱效果好.     

海上稠油油田聚驱后二元复合驱注入时机与注入方式优选

模拟海上绥中36-1油田油层条件,进行了聚合物驱后二元复合驱注入时机、注入方式的优化实验研究。聚合物驱后在不同注入时机(直接转注、含水最低点、含水70%和含水95%时)转注二元复合体系,最终采收率分别为75.36%、73.32%、71.22%和68.61%,直接转注二元驱的采收率最高(42.61%)。在相同水驱条件下,以不同注入方式注入二元复合体系后发现,注入0.3 PV二元复合体系的驱油效果优于注入0.05 PV聚合物+0.2 PV二元复合体系+0.05 PV聚合物和0.1 PV聚合物+0.2 PV二元复合体系。但注入方式的改变对最终采收率的影响较小,以聚合物做保护段塞更有利于控制工业化成本。在相同段塞聚合物用量条件下,用前后保护段塞的效果好于单一前置段塞。在等经济的条件下,聚合物驱后进行0.3 PV二元复合驱可提高原油采收率19.05%,比等价的0.7 PV聚合物驱采收率高1.61%,使油田开发的整体效益最大化。     

萨中开发区高台子油层聚合物驱合理注入参数优选

为了进一步扩大聚合物驱在不同类型油层上的应用,参考"两三结合"先导性试验区的资料,针对萨中开发区高台子油层进行了聚合物驱数值模拟合理注入参数的优选,并对聚合物驱提高采收率指标进行了预测.优选聚合物注入参数为:注入聚合物分子量为800×104,浓度为800 mg/L,年注入速度为0.10 PV,聚合物驱油时间为7 a,聚合物用量为560 mg/L·PV,总注入孔隙体积为0.70 PV.萨中开发区高台子油层聚合物驱提高采收率为4.29%.     

大庆油田聚合物驱分注措施效果分析

分注措施效果的确定是聚合物驱开发指标预测的重要内容。针对目前确定分注效果的方法较少,指标预测过程中操作难度较大的问题,数值模拟了不同含水阶段实施分注对最终采收率的影响,并定量计算了分注过程中低渗透层最佳溶液注入量比例;系统分析了大庆油田聚合物驱分层注聚实施效果,得到了分注对综合含水和提高采收率的影响特征,为聚合物驱油田开发规划中措施效果的预测提供了依据。     

水驱含水98%以后采出程度的计算与讨论

应用多种方法对大庆主力油田主力油层水驱含水98％以后的采出程度进行了计算。结果表明,含水98％以后含水上升非常缓慢．因而采出程度增加很多;水驱含水从98％到99％的采出程度平均增加5．36％,含水98％到100%的采出程度平均增加16．78％。虽然大庆油田主力油层聚合物驱比水驱提高采收率10％～12％。三元复合驱比水驱提高采收率20％．但聚合物驱在油田应用中不可能提高驱油效率。而三元复合驱提高驱油效率也不超过5％。     

聚合物驱不同注入方式对比评价

对油田实际的注水结果统计分析表明,油田进入高含水期以后,厚油层内90%以上的注入水进入层内高渗透及强水洗段,致使厚油层内存在严重的无效注采循环。因此,为了解决纵向非均质层内开发矛盾,改变无效注采循环现状,提高开发效益,进行了室内物理驱油实验,对强水洗油层转注高相对分子量聚合物的情况进行了模拟,分析了不同流度控制条件对提高采收率的影响规律。实验结果表明,采用高相对分子质量聚合物驱是一种较好的提高原油采收率的方法。综合对比采收率提高幅度和注入压力,聚合物溶液质量浓度由高到低的三阶梯式段塞驱油效果最好,能够在水驱基础上将采收率提高27.97%。     

聚合物驱组合段塞分注实验研究

萨尔图油田南二区东部140号断层以东地区葡I1-4油层,以多段多韵律和正韵律沉积为主,平均孔隙度30.0%,平均空气渗透率1 980×10-3μm2。水驱结束时该油层平均含水92%,采出程度39.5%。计划对该区块实施聚合物驱开采。以往经验认为,组合段塞调整注聚技术能够有效改善流度控制作用。然而对组合注入情况下如何进一步提高驱油效果、注入井分注时机、层段注入强度对开发效果有何影响却很少探讨。通过室内驱油实验,在聚驱的组合段塞注入不同时机(水驱空白阶段、含水下降阶段、含水稳定阶段、含水回升阶段)下调整注入强度实施分注以及在含水回升分注基础上进一步调整注入强度,同时对比不分注实验,评价各方案驱油效果。实验表明:不实施分注时聚驱采收率在水驱基础上提高了19.07个百分点,而组合段塞注入时实施分注均能够在不分注基础上进一步提高驱油效果;空白水驱时实施分注采收率提高幅度最大,为26.55个百分点;随着分注时机的滞后采收率提高幅度增加值依次递减,分注时机越早越好。     

The Characterization of Natural Surfactant and Polymer and Their Use in Enhanced Recovery of Oil

Abstract

Studies have been done to examine the applicability of natural surfactant and polymer for enhanced oil recovery. A detailed investigation has been made on interfacial and rheological properties of natural guar gum polymer and surfactant obtained from extracted soapnut shell. Based on the physicochemical properties of the surfactant and polymer solutions, optimum compositions were designed for flooding experiments. Three sets of experiments were performed to study enhanced oil recovery by injecting the same pore volume of polymer, surfactant–polymer, and alkaline–surfactant–polymer slug after brine flooding. Significantly higher additional recovery (~24% original oil in place) was obtained by alkaline–surfactant–polymer flooding compared to the other two methods over waterflooding (~50% original oil in place).     

预交联体增效聚合物驱研究

利用预交联体良好的耐温抗盐能力、在地层中具有变形特性和选择性进入等特点,首次开发建立了适合高温高盐和聚合物驱后提高采收率的预交联体增效聚合物驱油方法。室内高温高盐条件下双管驱油试验结果表明：预交联体增效聚合物驱油体系具有极好的液流转向、扩大波及体积能力,能够同时改善层内、层间矛盾;0．3PV聚合物驱比水驱提高采收率6．7％,而同等段塞尺寸的预交联体增效聚合物驱段塞提高采收率可达23．8％,聚合物驱后0．2PV预交联体增效聚合物驱段塞可进一步提高采收率11．8％。预交联体增效聚合物驱在高温高盐、聚合物驱后具有极好的提高采收率效果,是复杂苛刻油藏进一步提高采收率的潜力技术。     

聚合物驱控制程度的计算方法及应用

在总结水驱控制程度计算方法的基础上,提出了运用体积法计算聚合物驱控制程度的方法。该方法既考虑了油层平面上的连通状况,又考虑了聚合物分子能够进入的孔隙体积大小。对于聚驱开发油层来说,使用聚驱控制程度方法要比沿用传统的水驱控制程度方法更能体现油层地质条件对聚驱效果的影响程度。     

Experimental Study on Polymer-enhanced Nitrogen Foam Flooding

In order to improve the traditional foam stability, a kind of polymer enhanced foam was proposed to enhance oil recovery in Gan’guyi oilfield. Based on experiments, the polymer concentration of 1,500 ppm was firstly determined by measuring the foam volume and half-life time. The investigation of the effect of polymer on foam plugging ability proved that polymer enhanced foam has excellent plugging capacity both with and without oil. The oil displacement experiments showed that polymer enhanced foam flooding increased oil recovery by 40.6% after waterflooding and the total recovery could reach 79.2%, which was 20.7% higher than that of traditional foam flooding, indicating polymer enhanced foam has excellent oil displacement performance.     

Mathematical model for prediction of oil recovery of core-flood tests in process of viscoelastic polymer flooding

In this study a new mathematical model was developed that considers thermal effects, dispersion, effective concentration, elastic behavior of viscoelastic polymers, polymer retention, permeability reduction of aqueous phase, salt effects, inaccessible pore volume, and equivalent shear rate in porous media to predict oil recovery of core-flood experiments in process of viscoelastic polymer flooding as a tertiary stage of enhanced oil recovery. The model was found highly reliable when compared to material balance and experimental data. Displacement performance of core-flood tests could be predicted by presented model, therefore, experimental costs will be decreased significantly.     

Low gas-liquid ratio foam flooding for conventional heavy oil

The recovery of heavy oil by water flooding is 10% lower than that of conventional crude oil,so enhanced oil recovery (EOR) is of great significance for heavy oil.In this paper,foam flooding with a gas-liquid ratio (GLR) of 0.2:1 for the Zhuangxi heavy oil (325 mPa·s at 55 °C) was performed on cores,sand packs and plate model.In sand pack tests,polymer enhanced foam flooding increased oil recovery by 39.8%,which was 11.4% higher than that for alkali/surfactant/polymer (ASP) flooding under the same conditions.Polymer enhanced foam flooding in plate models shows that the low GLR foam flooding increased oil recovery by about 30%,even when the extended water flooding was finished at 90% water cut.Moreover,it was discovered by microscopy that foam was more stable in heavy oil than in light oil.These results confirm that low GLR foam flooding is a promising technology for displacing conventional heavy oil.     

自发乳化驱油方法Ⅱ:自发乳化驱油试验研究

研究了模拟油在岩心中的自发乳化驱油效果及提高采收率机理。不同渗透率岩心中,自发乳化驱油效果好于表面活性剂驱及聚合物驱。碱聚合物自发乳化驱替后采收率在水驱基础上还可提高23.7%,远远高于单独碱自发乳化驱、聚合物驱和表面活性剂驱,说明这一自发乳化驱油体系具有良好的驱替能力,能够大幅度提高采收率。模拟油在岩心中的自发乳化驱采收率和总采收率分别为24.5%和71.8%,与超低界面张力聚合物表面活性剂驱相近。高于三元复合驱、高浓聚合物驱。微观驱油试验证实光刻模型中发生了自发乳化现象。残余油自发乳化成小油滴,很容易穿过孔喉,以水包油型乳化状态开采出来。     

Application of nano-fumed silica in heavy oil recovery

The resources of heavy oil in the world are more than twice those of conventional light crude oil and the technology utilized for the recovery of heavy oil has steadily increased recovery rates. Polymer flooding is the most commonly applied chemical enhanced heavy oil recovery technique. However, still there is a need for a large amount of polymer, leading to high operational costs, presenting a big challenge in technologies. This challenge can be addressed by considering the newly emerging nanomaterials especially those made from silica. In this work, the author focuses on roles of silica nanoparticles on polymer viscosity and improvement of recovery in heavy oil recovery. The author presents the results obtained from a coreflood experiment with polymer injection in heavy oil at 1320 mPa.sec viscosity. The results indicate that polymer flooding with higher viscosity can significantly improve oil recovery. These laboratory results will be helpful for the planning of nano silica polymer flooding for heavy oil reservoirs. Also flooding test showed a 8.3% increase in oil recovery for nanosilica polymer solution in comparison with polymer solution after one pore volume fluid injection.     

交联聚合物封堵平面非均质油藏物理模拟

利用平面非均质填砂模型进行了有机交联聚合物封堵的油藏物理模拟实验,对比研究了水驱、聚合物驱和交联聚合物封堵对开采效果的影响.通过布置49个高精度的压差传感器测量交联聚合物封堵过程中油藏压力场的动态变化,用数码相机照相定性地观察了油藏流体变化情况.实验中发现,交联聚合物封堵最终采收率比水驱提高33%,比聚合物驱提高14%.交联聚合物能有效地封堵高渗条区,形成"段塞",改变了油藏内流体流动方向,扩大了波及范围,驱替出低渗区的油,提高了采收率.     

Effect of nano titanium dioxide on heavy oil recovery during polymer flooding

In recent years, polymer flood of heavy oil has been extensively studied in laboratories and successfully applied in several fields. Polymer flooding is the most successful chemical enhanced oil recovery method. However, still, the need for a large amount of polymer, leading to high operational costs, presents a big challenge in technologies. This challenge can be addressed by considering the newly emerging nanomaterials. In this work, the author focuses on roles of TiO₂ nanoparticles on polymer viscosity and improve recovery in heavy oil recovery. He present the results obtained from a coreflood experiment with polymer injection in heavy oil at 1320 mPa.sec viscosity. Nanopolymer exhibits an outstanding flow behavior and enhanced oil recovery performance in coreflood displacement tests compared to base polymers. The results indicate that polymer flooding with higher viscosity can significantly improve oil recovery. Flooding test showed about 4% increase in oil recovery for nanopolymer solution in comparison with polymer solution after one pore volume fluid injection.