Optimization of Injection Parameters for Profile Control and Flooding in an Oilfield during High Water Cut Period

In order to improve the effect of water control and oil stabilization during high water cut period, a mathematical model of five point method well group was established with the high water cut well group of an Oilfield as the target area, the variation law of water cut and recovery factor of different injection parameters was analyzed, and the optimization research of injection parameters of polymer enhanced foam flooding was carried out. The results show that the higher the injection rate, the lower the water content curve, and the higher the oil recovery rate. As the foam defoamed when encountering oil, when the injection time was earlier than 80% of water cut, the later the injection time was, the better the oil displacement effect would be. When the injection time was later than 80% of water cut, the later the injection time was, the worse the oil displacement effect would be. The larger the injection volume, the lower the water content curve and the higher the recovery rate. After the injection volume exceeded 0.2 PV, the amplitude of changes in water content and recovery rate slowed down. The optimal injection parameters of profile control agent for high water content well group in Oilfield A were: injection rate of 15 m3/d, injection timing of 80% water content, and injection volume of 0.2 PV.

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.

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.

Simulation and Experiment Research on the Proportional Pressure Control of Water-assisted Injection Molding

Water-assisted injection molding（WAIM）,a newly developed fluid-assisted injection molding technology has drawn more and more attentions for the energy saving,short cooling circle time and high quality of products.Existing research for the process of WAIM has shown that the pressure control of the injecting water is mostly important for the WAIM.However,the proportional pressure control for the WAIM system is quite complex due to the existence of nonlinearities in the water hydraulic system.In order to achieve better pressure control performance of the injecting water to meet the requirements of the WAIM,the proportional pressure control of the WAIM system is investigated both numerically and experimentally.A newly designed water hydraulic system for WAIM is first modeled in AMEsim environment,the load characteristics and the nonlinearities of water hydraulic system are both considered,then the main factors affecting the injecting pressure and load flow rate are extensively studied.Meanwhile,an open-loop model-based compensation control strategy is employed to regulate the water injection pressure and a feedback proportional integrator controller is further adopted to achieve better control performance.In order to verify the AMEsim simulation results WAIM experiment for particular Acrylonitrile Butadiene Styrene（ABS） parts is implemented and the measured experimental data including injecting pressure and flow rate results are compared with the simulation.The good coincidence between experiment and simulation shows that the AMEsim model is accurate,and the tracking performance of the load pressure indicates that the proposed control strategy is effective for the proportional pressure control of the nonlinear WAIM system.The proposed proportional pressure control strategy and the conclusions drawn from simulation and experiment contribute to the application of water hydraulic proportional control and WAIM technology.

The Effect of the Sinking of Isotope Grains in Water Injection Profile Logging

In the process of oil field exploitation, radioactive isotope tracer water injection profile logging is a main method to determine the water-intake capacity of the target intervals. For those general water injection wells, whose perforated intervals are beyond the tubing shoe, the sinking speed of isotope grains is related to the density and salinity of the injection water and the tubing dimension. We studied the motion of the isotope grains in the water injection wells by both theoretical calculation and field experiment. The result shows that if the water injection quantity is over 20 m＆3/d, and the density of the isotope grains, whose diameter is 100-600 μm, is 1.06 g/cm^3, then the logging technique for this kind of water injection wells will be appropriate. Whether water injection profile logging is successful in the well, whose perforated intervals are beyond the tubing shoe, depends on the sinking speed of the tracer grains.

Study of Water Treatment Residue Used as a Profile Control Agent

A large amount of residue from the water treatment process has gradually accumulated and thus caused serious environmental pollution in waterflood oilfields. The water treatment residue is a grey suspension, with a density of 1.08 g/cm^3, and mainly contains over 65% of light CaCO3, MgCO3, CaSO4, Fe2S3 and Ca（OH）2. This paper ascertains the effect of water treatment residue on core permeability and its application in oilfields. Coreflooding tests in laboratory were conducted in two artificial cores and one natural core. Core changes were evaluated by cast model image analysis, mercury injection method and scanning electron microscopy （SEM）. Fresh water was injected into another natural core, which was plugged with water treatment residue, to determine the effective life. The results indicate that the water treatment residue has a strongly plugging capability, a resistance to erosion and a long effective life, and thus it can be used as a cheap raw material for profile control. In the past 8 years, a total of 60,164 m^3 of water treatment residue has been used for profile control of 151 well treatments, with a success ratio of 98% and an effective ratio of 83.2%. In the field tests, the profile control agent increased both starting pressure and injection pressure of injectors, and decreased the apparent water injectivity coefficient, significantly improving intake profiles and lengthening average service life of injectors. 28,381 tons of additional oil were recovered from these corresponding oil wells, with economic benefits of ￥3,069.55×10^4 （RMB） and a remarkable input-output ratio of 8.6：1.

Water-Assisted Injection Molding System Based on Water Hydraulic Proportional Control Technique

Water-assisted injection molding（WAIM）, an innovative process to mold plastic parts with hollow sections, is characterized with intermittent, periodic process and large pressure and flow rate variation. Energy savings and injection pressure control can not be .attained based on conventional valve control system. Moreover, the injection water can not be supplied directly by water hydraulic proportional control system. Poor efficiency and control performance are presented by current trial systems, which pressurize injection water by compressed air. In this paper, a novel water hydraulic system is developed applying an accumulator for energy saving. And a new differential pressure control method is proposed by using pressure cylinder and water hydraulic proportional pressure relief valve for back pressure control. Aiming at design of linear controller for injection water pressure regulation, a linear load model is approximately built through computational fluid dynamics（CFD） simulation on two-phase flow cavity filling process with variable temperature and viscosity, and a linear model of pressure control system is built with the load model and linearization of water hydraulic components. According to the simulation, model based feedback is brought forward to compensate the pressure decrease during accumulator discharge and eliminate the derivative element of the system. Meanwhile, the steady-state error can be reduced and the capacity of resisting disturbance can be enhanced, by closed-loop control of load pressure with integral compensation. Through the developed experimental system in the State Key Lab of Fluid Power Transmission and Control, Zhejiang University, China, the static characteristic of the water hydraulic proportional relief valve was tested and output pressure control of the system in Acrylonitrile Butadiene Styrene（ABS） parts molding experiments was also studied. The experiment results show that the dead band and hysteresis of the water hydraulic proportional pressure relief valve are large, but the control precision and linearity can be improved with feed-forward compensation. With the experimental results of injection water pressure control, the applicability of this WAIM system and the effect of its linear controller are verified. The novel proposed process of WAIM pressure control and study on characteristics of control system contribute to the application of water hydraulic proportional control and WAIM technology.

Study on Dust-Control WaterInjection in Fully-Mchanized Top-Coal Caving Longwall Faces

Based on the analysis of the top-coal movement, the appropriate position of holes through which dustcoutrol water is injected is confirmed. And a practical test has been carried out, which has achieved good reuslts both in dust control and in the flow rate of water injected into coal.

Research progress and application prospect of functional adhesive materials in the field of oil and gas drilling and production

By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,mechanical interlocking,and electrostatic adsorption,are expounded.The research status of these materials in oil and gas drilling and production engineering field such as lost circulation prevention/control,wellbore stabilization,hydraulic fracturing,and profile control and water plugging,and their application challenges and prospects in oil and gas drilling and production are introduced comprehensively.According to the applications of functional adhesive materials in the field of oil and gas drilling and production at this stage,the key research directions of functional adhesive materials in the area of oil and gas drilling and production are proposed:(1)blending and modifying thermoplastic resins or designing curable thermoplastic resins to improve the bonding performance and pressure bearing capacity of adhesive lost circulation materials;(2)introducing low-cost adhesive groups and positive charge structures into polymers to reduce the cost of wellbore strengthening agents and improve their adhesion performance on the wellbore;(3)introducing thermally reversible covalent bond into thermosetting resin to prevent backflow of proppant and improve the compressive strength of adhesive proppant;(4)introducing thermally reversible covalent bonds into thermoplastic polymers to improve the temperature resistance,salt-resistance and water shutoff performance of adhesive water shutoff agents.

乳化沥青提高原油采收率研究进展

乳化沥青具有注入性能好、封堵强度高等优点,作为一种选择性堵剂在油田提高采收率领域比其他化学剂体系更具应用潜力。本文总结了国内乳化沥青堵水体系的开发历程及现场选择性堵水的应用效果。通过调研近年来国内外文献,概述了乳化沥青堵水的作用机理,一种是作为乳液的作用机理,主要是乳液颗粒被变形捕获产生贾敏效应和乳液液滴的机械滞留使水的流动阻力增大;另一种是其分散相也就是乳液破乳后沥青的作用机理,主要是沥青黏附在岩壁上起到的堵水作用。同时,总结了乳化沥青稳定的主要影响因素,包括温度、水相中的电解质浓度和pH值以及分散相中的沥青质,并且论述了各因素影响乳化沥青稳定性的作用机理。最后,详细叙述了乳化沥青应用于油田调剖堵水领域的最新研究进展,研究表明乳化沥青不仅具有优异的封堵效果,还具有独特的封堵选择性。此外,乳化沥青还能与CO_(2)吞吐、泡沫调驱组成复合增产技术进行现场应用,并且指出了乳化沥青应用于调剖堵水领域存在的问题与未来展望。

水侵气藏型储气库全周期高效建设微观模拟实验

借助微观可视化模型与微流控技术,开展了水侵气藏型储气库初期建库阶段注气驱水及循环储采阶段采气底水上侵、储气排驱水体的模拟实验,分析气液界面稳定机制、气液渗流与赋存规律,探索储气库全周期高效运行的优化调控方式。研究表明:储气库初期建库阶段应调控注气速度,充分发挥重力作用保证气液界面宏观稳定运移,大幅度提高气体的波及能力,为储气库后续循环储采阶段提供更大的储气孔隙空间。储气库循环储采阶段,恒定的储采气速度导致孔隙空间利用率低,逐渐提高储采气速度,从“小吞小吐”逐渐过渡到“大吞大吐”,可以持续打破孔喉内流体的平衡受力状态,扩大储气孔隙空间与流动通道,有利于储气库扩容增效和调峰保供。

同位素注入剖面测井解释智能化批量处理技术的实现与应用

同位素注入剖面测井是水驱油田了解各小层吸水状况的主要监测手段,该测井方法在中国油田的年测井工作量在3万井次左右,在注水油藏动态监测中占主导地位。传统的同位素注水剖面测井结果依赖人工解释,工作效率低、工作量大且多解性强,容易受到不同分析员人为因素影响,已经无法满足日益增长的生产需求。运用大数据监测和机器学习等技术,解决了基础数据录入、原始数据解编、深度匹配、工具识别、曲线叠合、综合评价等关键环节技术难题,形成了智能化批量处理技术。通过在CIFLog测井解释平台上的集成运行,单井处理时间从30~60min缩短到30s,人工干预率低于12%,验证了该处理流程及算法的有效性。

吴A区侏罗系油藏黏弹自调剂调驱效果分析

吴A区延9、延10底水油藏于2017年开始水驱动用程度大幅度下降,只有38.0%,受重力影响,吸水段逐渐下移,受地层平面非均质性和层间非均质性强、前期注入强度和采液强度大的影响,底水过早锥进导致油井见水,甚至见注入水发生水淹,常规堵水调剖措施无法完成地层深部地带封堵。为延缓注入水沿大孔道和微裂缝等地层深部高渗通道突进,提高注入水的波及体积,改善吸水剖面,吴A区延9、延10油藏于2022年8月开展黏弹自调剂调驱矿场试验。试验结果表明,2022年8月-2023年10月注入黏弹自调剂后,调驱效果较好,深入地层后能有效滞留于孔喉,平均单井日注水量下降,注入压力由7.20MPa上升到7.80MPa;整体吸水指数由38.1m^(3)/(d·MPa)下降到25.1m^(3)/(d·MPa);黏弹自调剂在地层中形成有效封堵,有效改善油水流度比以及提高洗油效率,注入黏弹自调剂后月度递减率由0.10%下降到-0.40%,月度含水率上升幅度由0.03%下降到0.02%。

耐高温水基微球调驱剂性能评价

评价了一种耐高温水基微球调驱剂性能。实验结果表明:不同浓度耐温水基微球调驱剂注入不同渗透率岩心的阻力系数均小于等于5,注入性好;浓度为4 000 mg/L的耐温水基微球调驱剂在岩心中的有效封堵渗透率范围最大,封堵率最高超过90%;该水基微球调驱剂在150℃下有效封堵时间45 d左右,耐温性良好;该耐温水基微球调驱剂可提高渤海油田非均质储层原油采收率15.41%~17.92%。

水淹水窜油藏的数值模拟开发方案对比分析

随着开发的深入,大多数油田已经进入高含水阶段。以新疆某水淹水窜油藏为研究对象,该区水淹严重,开发效果差。针对上述问题,利用油藏数值模拟手段,对改善开发效果的4种技术方案进行研究。研究结果表明,深层调剖方案增产效果明显,可有效提高日产油量、降低含水率;浅层调剖方案作用范围、受效时间有限,措施效果较差;井网调整方案含水率明显下降,产油量上升,增油效果介于深层调剖与浅层调剖之间;周期注水增油效果最差,呈负增长趋势。经方案对比分析,建议对研究区水窜严重的井实施深层调剖。该研究为同类水淹水窜油藏改善开发效果提供了重要理论指导和借鉴。

黏弹剂调剖在姬塬油田侏罗系油藏中的应用

姬塬油田侏罗系油藏位于鄂尔多斯盆地中西部,属于低渗透砂岩油藏,油藏油水运移以孔隙型渗流为主。进入开发中后期,油井水淹现象严重。姬塬油田先后应用“交联聚合物冻胶+体膨颗粒”、“PEG单相凝胶调驱剂”、“纳米级微球”等调剖体系对侏罗系油藏注水井开展调剖,虽然在降低油藏递减、控制含水率上升幅度等方面取得了一定效果,但对于水淹井降含水率方面效果不明显。近年来,姬塬油田通过开展侏罗系油藏油井水淹机理研究,优化调剖体系,筛选了一种新型黏弹剂进行调剖,室内评价及现场实施均证明该黏弹剂性能可靠。2021—2022年,通过在姬塬油田56个侏罗系油藏水淹井组采用黏弹剂调剖后,井组月度递减率由2.59%下降至1.01%,月度含水率上升幅度由0.61%下降至0.08%。同时,大部分水淹井含水率下降明显,平均有效期内单井组增油达226 t。按照油价45美元/桶计算,投入产出比1.00∶2.11,实施效益较好。

闭式注水油藏自分散型耐高温高盐调驱剂

南海东部高温高盐油藏闭式注水井无地面注水流程,常规调驱剂无法在地面混配后注入地层,且由于自分散性差,难以直接注入地层。以南海东部A油田为目标,从快速自分散和耐高温高盐两个角度出发,以2-丙烯酰胺-2-甲基丙磺酸(AMPS)含量为40%的耐温耐盐聚合物为基础,辅以多酚类复合交联剂、多支链醇聚醚类分散剂等,通过反应成胶、机械研磨,制得自分散型耐高温高盐调驱剂。采用激光粒度仪、电子显微镜、动态光散射仪等,对调驱剂的粒径、微观形貌和表面电性进行了表征,评价了调驱剂的自分散性能、注入性能和剖面调整性能,并在南海东部A油田X井组进行了现场应用。结果表明,自分散型耐高温高盐调驱剂呈球形,初始粒径D50(粒径中值)为1.09~11.63μm,通过调整配方、研磨条件或加热时间可调节调驱剂的粒径。调驱剂颗粒表面呈负电,Zeta电位值为-19.30~-26.1 mV。与常规油分散型颗粒调驱剂相比,该调驱剂自分散性好,遇水后能快速均匀分散,在注入水中的自分散率为90.0%,岩心注入压力仅为油分散型颗粒调驱剂的53.13%。调驱后,高渗透岩心的分流量由92.6%降至20.5%,低渗透岩心的分流量由7.4%增至79.5%,吸水剖面明显“反转”。现场实施效果良好,调驱剂施工爬坡压力为0.5 MPa,施工后最高日增油106 m3,阶段增油8900 m3。该调驱剂满足目标油田高温高盐条件,注入性好,增油效果明显,适合闭式注水油藏调驱。

堵水调剖在低效水驱油藏中的发展与应用

目前油田存在含水较高的现象,为了保障石油开发开采能力,加快对油田化学堵水调剖技术的研究十分重要。首先调研了国内油田应用的堵水调剖技术与各类堵水调剖剂的性能、作用机理研究以及在油田的应用现状,重点介绍了化学堵水调剖剂,然后进行实际应用。通过油藏的地质特征、高渗透层的窜流特征,开展井组筛选标准、堵剂优选、方案优化的深入研究,在现场试验取得良好增油效果,能够有效提高水驱控制程度和采出程度,为低效注水开发区块提供了重要的借鉴意义。