Black Oil and Compositional Reservoir Simulation for Increasing the Recovery Performance of an Iranian Fractured Carbonate Reservoir

Abstract

Naturally fractured reservoirs contain a significant amount of world oil reserves. Accurate and efficient reservoir simulation of naturally fractured reservoirs is one of the most important, challenging, and computationally intensive problems in reservoir engineering. Black oil and compositional reservoir simulators have been used to determine the reservoir management and production strategies to increase the oil recovery from a low-porosity, low-permeability fractured carbonate reservoir, with an average matrix permeability of 0.8 md, average fracture permeability of 500 md, and an average matrix porosity of 10%. This reservoir is a candidate for an enhanced oil recovery (EOR) process, because the reservoir production rate has been declined due to increasing the water cut as a result of rising the water oil contact. The injection techniques that have been considered in this study for black oil model include (a) gas injection, (b) water injection, and (c) simultaneous water alternating gas injection and for the compositional model include (a) dry gas injection, (b) CO₂ injection, and (c) N₂ injection. Simulation results show that CO₂ injection has the maximum oil recovery between the EOR scenarios.     

海上稠油油田水驱开发时效采出比计算方法及评价

由于海洋钻井平台寿命有限,且海上油田相比陆上油田投资成本巨大,一般海上油田开发追求较短的开发周期和较高的采油速度,因此,在海上油田水驱开发效果评价中提出了体现时效性的新指标——时效采出比。基于不同油水黏度比下的含水率与采出程度关系,并利用收支平衡原理确定不同产量级别下的单井经济极限含水界限,进而建立了时效采出比理论值计算方法。以海上稠油油田某2个典型油藏进行了实例计算,得到典型油藏时效采出比理论值及其评价分级标准。通过评价时效采出比指标,可体现海上油田水驱开发时效性的强弱与水驱效果的好坏。时效采出比计算及评价方法的建立,可作为海上油田水驱开发效果评价指标体系的重要补充。     

Synthesis and interfacial activity of petroleum sulfonate

Four petroleum sulfonates including first vacuum distillate sulfonate, second vacuum distillate sulfonate, third vacuum distillate sulfonate, and vacuum residue sulfonate were synthesized. The tensions of the petroleum sulfonates were measured. It shows that the third vacuum distillate sulfonate can produce ultralow interfacial tension when the concentrations are higher than 0.010%. Synergism between Na₂SO₄ and CaCl₂ (or MgCl₂) in the formation water was proved, which is crucial to reduce the tension. Moreover, synergism between the second and third vacuum distillate sulfonates occurs. This work is useful for enhanced oil recovery.     

20×104 t/a硫磺回收装置液硫池废气回收技术应用分析

为降低硫磺回收装置排放烟气中SO₂质量浓度,对装置进行工艺技术改造,分别将液硫池废气引入克劳斯炉和加氢反应器,从工艺原理、技术改造投入、运行效果、能耗等方面对两套工艺进行了对比分析。分析结果表明:①液硫池废气入克劳斯炉工艺虽然运行能耗较高,但减排效果明显、工艺运行稳定、能够保证液硫产品质量合格;②液硫池废气入加氢反应器工艺同样具备减排效果,运行能耗低,但因受急冷塔出口氢气含量的限制,无法充分发挥抗氧型低温加氢催化剂的节能效果,抗上游波动、防SO₂穿透能力下降。      

新增探明储量技术采收率主控因素

在申报探明可采储量时，关键是采收率的取值，由于油藏处在勘探评价或开发初期，受资料所限，采收率只能是应用经验公式法、经验取值法、类比法和数值模拟法求取，然后综合确定一个值，在求取过程中关键是明确此阶段采收率的主控因素，从而相对准确地求取采收率值。通过分析，明确了探明储量技术采收率的主控因素为油藏驱动类型、储层渗透率、储层非均质性、原油地下粘度及井网密度，为此阶段科学评价采收率奠定了基础。     

应用正态概率模型预测油田含水率变化规律

应用正态概率模型可以方便地确定水驱动态变化、描述水驱特征参数,这就使得预测油田含水率、采收率、评价开发措施变得比较简便而实用。油田开发实践表明,当油田进入中含水期后,不论是S型、凸型,还是凹型水驱特征曲线都可以应用正态概率模型进行预测。     

稠油热采纳米乳化降粘技术研究与应用

对常规稠油降粘剂和加入纳米助剂后的乳化降粘剂进行了对比评价。试验结果表明,加入纳米助剂后在表面张力、降粘效果、耐温、耐盐和脱水等方面略有改善,在驱替效果方面明显改善。现场应用纳米降粘剂后,油井平均日产油量、产油量、和油汽比等吞吐指标均有所提高,蒸汽吞吐效果明显改善,单井措施增油120t,为稠油热采进一步改善开发效果和提高原油采收率提供了技术支持。     

偏远小断块油田地面工程设计新技术的应用

在红南、连木沁油田产能建设工程设计中．通过广泛调研及方案优化,采用了多相混输泵实现油气混输、井口用天然气发动机直接带动抽油机、站内用气体经处理后的干气发电、油罐气回收及两相分离三相计量变压控制等几项新技术,充分利用了能源,保护环境,节约了投资,管理方便,投产运行情况较好。     

特高含水期油藏平面分区调控方法

针对特高含水期平面剩余油分布复杂,不同区域开发对策不同的特点,提出了基于油藏数值模拟计算结果的油藏分区调控方法。首先通过极限含水率对应的含水饱和度值作为水淹区与潜力区的划分依据;其次以建立的考虑经济因素的剩余可采储量丰度界限和渗流速度界限,将潜力区进一步划分为低速新井调控区、低速注采调控区、高速新井调控区、高速注采调控区4类。综合考虑各分区分布特征,采用连通区域标记算法统计各分区连片区域网格数,计算连片区域的面积和剩余可采储量,确定不同连片区域开发政策。实际油藏的应用结果表明,调控后低速新井调控区和低速注采调控区面积大幅度减小,调控5年油藏采出程度增加3.1%。     

CO2泡沫提高原油采收率研究

CO2地下埋存起到减排作用,还能提高原油采收率。综述了CO2驱技术和泡沫驱技术在国内外的应用和研究进展,分析了CO2驱油机理和CO2泡沫驱油机理CO2泡沫驱集中了CO2驱和泡沫驱的双重优点,在提高原油采收率和CO2地下埋存方面有着巨大的应用前景：