DY-Ⅱ调剖剂的研制及在大庆杏北区块的应用

大庆油田已进入特高含水开发阶段,层间、平面矛盾突出,浅调剖可作为分层注水技术的重要补充,但目前常用的调剖剂体系存在成本高、毒性大、现场调控难度大等问题,为此,研制了DY-Ⅱ浅调剖剂。该调剖剂聚合物使用浓度为2000~3000mg/L,聚交比为30∶1~40∶1。用TA公司2000EX流变仪,对该体系黏度、储能模量进行评价,发现该体系成胶黏度在17000mPa·s以上,储能模量在10Pa以上,属强凝胶体系。将该体系成胶后的样品在45℃下放置180d,黏度损失率在10%以内,长期热稳定性良好。5次岩心剪切后,该体系黏度和储能模量均没有太大变化,对岩心进行水驱,其突破压力达9.2MPa,后续水驱10PV后压力仍能稳定在7.5MPa,残余阻力系数可达500,具有较好的耐剪切和耐冲刷性能。与常规酚醛浅调剖剂体系相比,DY-Ⅱ浅调剖剂体系综合成本可降低30%。DY-Ⅱ浅调剖剂在大庆杏北油田现场应用68口井,平均单井启动压力升高1.70MPa,平均单井视吸水指数下降10.37m3/(d·MPa)。     

聚驱不同阶段低效井的确定及治理方法探讨

以杏北开发区投产较早的杏四～六面积南、北两个聚驱区块为基础,在确定聚驱不同开发阶段,即初期、中期、后期三个阶段低效井的基础上,根据聚区井的受效时间和受效特点,将低效井分为见效慢型、见效时间短型、见效差型及未见效型四种,并对其形成原因进行分析,提出治理对策:注聚初期阶段,主要通过钻补充井、水驱井利用、转注、对水驱井的聚驱目的层补孔等完善注采关系,并通过调整部分注入井的注入量、调剖、分层注聚等措施缓解平面及层内、层间矛盾;注聚中期阶段,主要通过提高注入井的注入浓度、扩大聚合物溶液的波及体积、实施压裂等改善油层条件:注聚后期阶段,主要通过改变液流方向、井组注采调整相结合、周期注聚等方式治理低效井.同时,举例说明在聚驱不同开发阶段治理低效井的成功做法,这些方法适合聚驱不同开发阶段的开发特点,具有较强的针对性,对提高聚驱开发效果具有指导作用.     

中原油田提高采收率优化技术

中原油田相继开展了CO2吞吐、N2驱、空气驱、合成聚合物驱、交联聚合物驱、微生物采油等项现场试验。鉴于中原油田地层温度高、地层水矿化度高,常规三次采油技术难以适应。对中原油田提高采收率的技术进行优化分析,对油田地质特点、开采特点和不同类型油藏采收率现状进行归纳,并对各技术潜力进行分析,得出结论:从储层条件和原油性质来看,适用中原油田的三次采油方法是CO2混相驱、天然气非混相驱,其次是化学驱。研究预测显示,通过水驱综合调整和气驱,可提高采收率11.1个百分点,达到40.5%,其中水驱综合调整增加可采储量3841×104t,提高采收率7.4个百分点,三次采油提高采收率3.7个百分点。总结出中原油田提高采收率的方向和思路:水驱提高采收率仍是油田当前开发的重点,重组开发层系、强化差层开采、提高油藏水驱采收率,大力发展堵水调剖等配套工艺技术、提高水驱控制程度,气驱仍是今后的主要发展方向。     

Hydrogen: an accommodating fuel

A controlling influence on hydrogen as an energy vector will be the competitive position of electricity. Development of the distribution infrastructure for hydrogen can be expected to complement the electric system, the two together providing an optimum energy network. Hydrogen will be an accommodating fuel: fossil hydrogen helping, in some markets, to extend the use of fossil fuels as primary energy sources; nonfossil hydrogen later providing an alternative to electricity as an energy carrier for some developing nonfossil resources.     

Fabrication of zinc‐loaded hollow glass microspheres (HGMs) for hydrogen storage

The greatest challenge for a feasible hydrogen economy lies on the production of pure hydrogen and the materials for its storage with controlled release at ambient conditions. Hydrogen with its great abundance, high energy density and clean exhaust is a promising candidate to meet the current global challenges of fossil fuel depletion and green house gases emissions. Extensive research on hollow glass microspheres (HGMs) for hydrogen storage is being carried out world‐wide, but the right material for hydrogen storage is yet underway. But many other characteristics, such as the poor thermal conductivity etc. of the HGMs, restrict the hydrogen storage capacity. In this work, we have attempted to increase the thermal conductivity of HGMs by ZnO doping. The HGMs with Zn weight percentage from 0 to 10 were prepared by flame spheroidization of amber‐colored glass powder impregnated with the required amount of zinc acetate. The prepared HGMs samples were characterized using field emission‐scanning electron microscope (FE‐SEM), environmental SEM (ESEM), high‐resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy and X‐ray diffraction (XRD) techniques. The deposition of ZnO on the microsphere walls was observed using FE‐SEM, ESEM and HRTEM which was further confirmed using the XRD and ultraviolet–visible absorption data. The hydrogen storage studies done on these samples at 200 °C and 10‐bar pressure for 5 h showed that the hydrogen storage increased when the Zn percentage in the sample increased from 0 to 2%. The percentage of zinc beyond 2, in the microspheres, showed a decline in the hydrogen storage capacity. The closure of the nanopores due to the ZnO nanocrystal deposition on the microsphere surface reduced the hydrogen storage capacity. The hydrogen storage capacity of HAZn2 was found 3.26 wt% for 10‐bar pressure at 200 °C. Copyright © 2015 John Wiley & Sons, Ltd.     

Fundamentals and recent advances in polymer composites with hydride-forming metals for hydrogen storage applications

Hydrogen has unique properties that make it a promising energy vector to replace fossil fuels. However, it is still required to develop safe and efficient storage methods before being widely implemented. Storing hydrogen in hydride-forming metals (HFM) is an approach that has been extensively studied in the last decades. But only recently the preparation of polymer composites with HFM have been explored. Air resistance, volumetric stability and processability are some of the HFM properties that could be improved by incorporating a polymer phase. This review presents the fundamentals concepts of gas transport in dense polymers, and the evolution and trends of incorporating HFM particles into a polymer matrix. The most recent findings are summarized and discussed. The potential improvement of the most relevant classes of HFM and the mechanisms of how different classes of polymers could be advantageously used are reported.     

多因素模糊综合决策在调剖选井中的应用

调剖是注水开发油田改善开发效果的一项重要措施，也是确保聚合物驱效果的一种有效手段。确立了调剖井筛选指标体系和最佳调剖候选井的多因素综合决策方法。并编制了优化决策程序，该方法和软件应用于孤东二区Ng4—5注聚区注聚前的油藏调整中，取得了明显的效果。为注聚前调剖决策提供了依据。     

蒸汽驱用耐高温堵剂性能研究

注蒸汽稠油开采过程中,高温蒸汽极易在油藏内大孔道和高渗透层形成窜流,导致吸汽剖面不均匀,蒸汽利用率和体积波及系数降低,注汽开发效果变差。提高蒸汽驱波及系数和稠油开采效率的最有效方法是调整蒸汽注入剖面和封堵水窜通道。聚合物耐温性能较差,高温下易降解,严重影响聚合物调整蒸汽注入剖面的效果。用硝基腐殖酸钠作为主剂,甲醛和间苯二酚作为交联剂,制得一种高温堵剂,并对其性能进行评价。结果表明:120℃下高温堵剂的最优配方为硝基腐殖酸钠9%+甲醛2.0%+间苯二酚1.5%,成胶时间为19h;最佳适用pH值为7～9;该堵剂耐盐性能良好,最高可耐NaCl和CaCl2浓度分别为40000mg/L和8000mg/L;该堵剂的初始黏度为10.3mPa.s,泵入性能良好,易于输送和注入;经硝化处理的腐殖酸钠可耐290℃以上的高温,完全满足控制蒸汽驱汽窜的温度要求;该堵剂对不同渗透率的岩心都有良好封堵效果,封堵率在95%以上,并具有堵大不堵小的特性。     

变黏度聚合物驱提高采收率方法

利用室内物理模拟实验方法,采用有效渗透率分别为250×10-3μm2、500×10-3μm2和1000×10-3μm2三管并联岩心模拟非均质油层条件,在聚合物用量相同的情况下,分别采用恒定黏度聚合物和黏度逐渐降低的两种聚合物驱油方案,对比了两种方案提高采收率的效果。同时,利用研制的平面非均质人造可视平板填砂模型,对比了恒定黏度和变黏度聚合物驱油在模型上的波及面积。实验结果表明,在三管并联和填砂模型两种情况下,变黏度聚合物驱效果均好于定黏度聚合物驱,其中三管并联方式聚驱阶段提高采收率幅度增加4.48%,填砂模型波及体积增加了7.7%。结合实验结果,利用五点法平面模型和并联油层模型,探讨了变黏度聚合物驱可以扩大油层纵向和平面上的波及体积,进而提高水驱或聚驱后采收率的原因。分析认为,无论是平面非均质、纵向层内非均质,还是在层间非均质油藏中,变黏度聚合物驱油都可实现不断扩大波及体积的目的。     

不同二类油层水驱及聚驱驱替规律研究

总结萨北开发区二类油层水驱与聚驱规律,为编制开发方案提供依据,进行了室内水驱、聚驱实验。实验按常规驱油实验步骤进行,首先水驱至含水率98%,然后开始转注聚至不出油。实验结果表明,在水驱段,萨尔图组和高台子组二类油层的水驱采收率均与有效渗透率呈正相关关系,其水驱开发指标预测也皆可沿用一类油层的水驱驱替特征曲线方法;相同渗透率下,萨尔图层的水驱采收率要高于高台子层,说明其油层物性更好。在聚驱段,在相同渗透率,以及水驱后注入相同相对分子质量、相同浓度的聚合物溶液的条件下,高台子组的二类油层岩心两端压差变化更加明显,而萨尔图油层注聚量小于高台子层。萨尔图组和高台子组二类油层的采收率在半对数坐标系下均与水油比呈二次函数关系,可以用此关系预测萨尔图组和高台子组二类油层的聚驱开发指标。     

Life cycle cost analysis: A case study of hydrogen energy application on the Orkney Islands

Hydrogen can compensate for the intermittent nature of some renewable energy sources and encompass the options of supplying renewables to offset the use of fossil fuels. The integrating of hydrogen application into the energy system will change the current energy market. Therefore, this paper deploys the life cycle cost analysis of hydrogen production by polymer electrolyte membrane (PEM) electrolysis and applications for electricity and mobility purposes. The hydrogen production process includes electricity generated from wind turbines, PEM electrolyser, hydrogen compression, storage, and distribution by H₂ truck and tube trailer. The hydrogen application process includes PEM fuel cell stacks generating electricity, a H₂ refuelling station supplying hydrogen, and range extender fuel cell electric vehicles (RE-FCEVs). The cost analysis is conducted from a demonstration project of green hydrogen on a remote archipelago. The methodology of life cycle cost is employed to conduct the cost of hydrogen production and application. Five scenarios are developed to compare the cost of hydrogen applications with the conventional energy sources considering CO₂ emission cost. The comparisons show the cost of using hydrogen for energy purposes is still higher than the cost of using fossil fuels. The largest contributor of the cost is the electricity consumption. In the sensitivity analysis, policy supports such as feed-in tariff (FITs) could bring completive of hydrogen with fossil fuels in current energy market.     

The numerical simulation and wellbore modelling of steam injection and stored heat recovery from light oil reservoir

ABSTRACT

Steam injection and thermal recovery of oil from the reservoir are increasing day by day. However, the recovery of the heat remained stored in the steam-flooded oil reservoir is nor in practice neither researched previously. A novel concept of steam injection and energy recovery from a light oil reservoir is presented in this paper. Reservoir numerical model of an actual oil field was generated and simulated with steam injection. Different parameters of thermal properties of geologic formations were discussed and adopted as per actual geology of the study area for more realistic simulation of heat storage, dissipation, and losses. After the optimum oil recovery, water was circulated through the same injection well into the reservoir to extract the energy in the form of heat, stored during the steam injection phase. The effects of different completion schemes of injection well were also simulated, discussed and pointed out for optimum oil recovery. Oil recovery factor is the most important parameter from both research and field development point of views. The comparative analysis was also carried out with the oil production without steam injection and found that steam flooding increased oil recovery factor up to more than 15% by decreasing the production time period up to 40% as compared to without steam injection oil production. The transmission of heat through conduction and convection mechanisms in the porous media, and through advective, dispersive and diffusive processes in the fluid was modeled. To fully investigate the feasibility of the concept presented in this paper, the production wellbore modeling was also carried out and temperature profile of recovered heat energy at the wellhead was obtained by acknowledging the thermal losses and found to be very useful for any direct and indirect utilization of heat throughout the energy recovery period of the reservoir.     

Experimental studies of surfactant-polymer flooding: An application case investigation

A great deal of oil field is currently produced using water flooding and the water cut has reached a high level, which requires enhanced oil recovery (EOR) techniques to improve the recovery. Surfactant-polymer (SP) flooding is the combination of surfactant flooding and polymer flooding. The polymer is added to increase the viscosity and viscoelasticity of the fluid while the surfactant is included to decrease the oil–water interfacial tension and change the wettability. Although the mechanism of SP flooding has been deeply investigated, the application of SP flooding on a specific oil field requires the selection of optimal SP system. Therefore, for the first time, we performed a series of experiments to determine the optimal SP system for high water-cut oil field. In the injection capability experiment, we observe that the SP system is injected into the core with less resistance compared with single polymer solution. In the flooding experiment, regardless of the polymer types, the improvement of recovery becomes significant when the injected PVs increases. SP flooding shows the higher improvement of recovery compared with single polymer flooding or surfactant flooding. Based on the performance of recovery improvement, we recommend the optimal SP system for the studied case is the combination of DQ-TSRP01 polymer and surfactant. The optimal injection parameters of this SP system are 1500 mg/L polymer concentration, 0.3 injection PV and the injection timing of 96% water cut. The finding of this study can help for better understanding of the application of SP flooding in high water-cut oil field production.     

Konys油田调剖体系的研制与室内评价

针对哈萨克斯坦Konys油田地层条件研制了适合的调剖体系,并对调剖凝胶的性能进行室内评价。该调剖体系在现场水源条件下,具有较高强度的封堵作用;在需调剖地层条件下,能够保持长期稳定性;具有较好的可运移性,能够保证进行较大剂量的较深部封堵;调剖成本低,可以大规模推广使用。该调剖体系为相对分子质量为1900×104的聚合物5000mg/L+交联剂(Cr3+)160mg/L+调节剂碳酸钠300mg/L。实验结果表明:该调剖体系初成胶时间为6h,初成胶强度为1354mPa·s,稳定成胶时间为24h,稳定成胶强度大于100000mPa·s,30d后胶体黏度保留率为100%,60d后胶体黏度保留率为88.9%,90d后胶体黏度保留率为74.1%,胶体开始脱水时间为93d,完全脱水时间为120d。该调剖体系抗剪切能力强,稳定性较好,剪切10s,60d后胶体黏度保留率在79%以上;剪切20s,60d后黏度保留率在67%以上。该调剖体系具有较强的封堵能力,封堵率达到90%以上,其抗冲刷能力强,水驱后封堵率达到83%以上。     

An innovative technology of directional propagation of hydraulic fracture guided by radial holes in fossil hydrogen energy development

Conventional hydraulic fracturing fails to develop low permeability reservoirs of fossil hydrogen energy that are not located in the direction of maximum principal in-situ stress. A new technology of fracture propagation guided by radial holes is proposed, which can realize directional propagation of hydraulic fracture along radial holes in fossil hydrogen energy development. In order to verify this new technology, a model of radial holes combined with hydraulic fracturing is established by the ABAQUS extended finite element method. Simulation results show that radial holes play a guiding role in fractures propagation. The influence extent of seven factors on the directional propagation of hydraulic fracture is listed as follows (from strong to weak): azimuth of radial holes > horizontal in-situ stress difference of fossil hydrogen reservoir > injection rate of fracturing fluid > Young's modulus of rock > permeability of fossil hydrogen reservoir > Poisson ratio of rock > viscosity of fracturing fluid. True tri-axial experiment is carried out to verify the accuracy of numerical simulation, and the result is consistent with numerical model, which indicates that numerical simulation is reliable.     

Hydrogen from solar energy,a clean energy carrier from a sustainable source of energy

Solar energy is going to play a crucial role in the future energy scenario of the world that conducts interests to solar-to-hydrogen as a means of achieving a clean energy carrier. Hydrogen is a sustainable energy carrier, capable of substituting fossil fuels and decreasing carbon dioxide (CO₂) emission to save the world from global warming. Hydrogen production from ubiquitous sustainable solar energy and an abundantly available water is an environmentally friendly solution for globally increasing energy demands and ensures long-term energy security. Among various solar hydrogen production routes, this study concentrates on solar thermolysis, solar thermal hydrogen via electrolysis, thermochemical water splitting, fossil fuels decarbonization, and photovoltaic-based hydrogen production with special focus on the concentrated photovoltaic (CPV) system. Energy management and thermodynamic analysis of CPV-based hydrogen production as the near-term sustainable option are developed. The capability of three electrolysis systems including alkaline water electrolysis (AWE), polymer electrolyte membrane electrolysis, and solid oxide electrolysis for coupling to solar systems for H₂ production is discussed. Since the cost of solar hydrogen has a very large range because of the various employed technologies, the challenges, pros and cons of the different methods, and the commercialization processes are also noticed. Among three electrolysis technologies considered for postulated solar hydrogen economy, AWE is found the most mature to integrate with the CPV system. Although substantial progresses have been made in solar hydrogen production technologies, the review indicates that these systems require further maturation to emulate the produced grid-based hydrogen.     

Potential of renewable hydrogen production for energy supply in Hong Kong

Hong Kong is highly vulnerable to energy and economic security due to the heavy dependence on imported fossil fuels. The combustion of fossil fuels also causes serious environmental pollution. Therefore, it is important to explore the opportunities for clean renewable energy for long-term energy supply. Hong Kong has the potential to develop clean renewable hydrogen energy to improve the environmental performance. This paper reviews the recent development of hydrogen production technologies, followed by an overview of the renewable energy sources and a discussion about potential applications for renewable hydrogen production in Hong Kong. The results show that although renewable energy resources cannot entirely satisfy the energy demand in Hong Kong, solar energy, wind power, and biomass are available renewable sources for significant hydrogen production. A system consisting of wind turbines and photovoltaic (PV) panels coupled with electrolyzers is a promising design to produce hydrogen. Biomass, especially organic waste, offers an economical, environmental-friendly way for renewable hydrogen production. The achievable hydrogen energy output would be as much as 40% of the total energy consumption in transportation.     

专家系统模糊识别理论在河南油田聚合物驱整体调剖中的应用

河南油田聚合物驱整体调剖评价是一项复杂且具有多目标元素的工程,由于衡量调剖效果的因素很多。所以必须综合考虑各种因素的影响,对调剖效果利用模糊数学的方法进行综合评价。通过专家系统模糊识别理论在河南油田双河V上层系聚合物驱整体调剖评价中的实践,证明该方法在现有技术条件下能够充分真实反应聚合物驱调剖效果：整体大剂量调剖后,双河油田V上层系12口注水井压力平均上升了3．4MPa,启动压力上升了7．3MPa;对应21口油井,有17口见效,见效率为80．9％,油井见效率较局部调剖提高了15个百分点,累计增油10476t;同时,整体大剂量调剖作为聚合物驱的一项配套措施,可使聚合物防窜能力提高23．6％。     

Comparative life cycle assessment of hydrogen and other selected fuels

A streamlined life cycle assessment (LCA) is reported of a nuclear-based copper–chlorine (Cu–Cl) hydrogen production cycle, including estimates of fossil fuel energy use and greenhouse gas (GHG) emissions. Calculations revealed that the process requires 474 kJ of fossil fuel energy per MJ of hydrogen, which is less than for other hydrogen production processes. Moreover, GHG emissions are estimated to be 27 gCO₂e per MJ of hydrogen, which is only slightly higher than the corresponding value for wind-based hydrogen production. A sensitivity analysis demonstrated that the performance of the system could be further improved at higher yields of hydrogen. Although the system significantly outperformed fossil-based gasoline and hydrogen production pathways, the integrated nuclear and thermochemical cycle still requires significant research and development before commercialization is possible.     

The properties of hydrogen as fuel tomorrow in sustainable energy system for a cleaner planet

The Global energy system transition from fossil fuel to hydrogen utilization is described. Environmental benefits of the combustion of hydrogen are reported. World carbon emissions from fossil fuel are schematized in connection with the opportunities of using hydrogen. The atomic hydrogen/carbon ratio and chemical properties of hydrogen are described. Pollutants of the energy system in our planet and hydrogen production technologies are presented.