Methods in Oil Recovery Processes and Reservoir Simulation

The exploitation of an oil field is a complex and multidisciplinary task, which demands a lot of prior knowledge, time, and money. A good reservoir characterization is deemed essential in the accomplishment of Enhanced Oil Recovery (EOR) processes in order to estimate accurately the properties of the porous medium affecting the flow properties. Several techniques at a field scale are currently being used to determine these properties, which are time and money consuming. But these alone do not guarantee the success of the project. Reservoir simulation and numerical techniques were then included in the pre-development and follow-up studies as an effective tool to determine the productivity and future behavior of the oil field. As the computational power increased, more advanced and detailed models were developed, including different chemical and physical phenomena. But alongside this process, there was an active research in the area of reservoir simulation, improving the accuracy and efficiency of the numerical schemes used for the flow, transport, and energy equations. The aim of this review is to address the topics described. Firstly, the origin of an oil recovery process, the economic factors and field tests involved are introduced. Secondly, the oil and porous medium origin and characterization as well as an introduction to the fundamental concepts and equations are associated to reservoir simulation. Finally, a brief description and analysis of the techniques are used in reservoir simulation employing finite difference methods, their downsides and possible ways to overcome these problems.

A Mathematical Modeling of 3D Cubical Geometry Hypothetical Reservoir under the Effect of Nanoparticles Flow Rate,Porosity,and Relative Permeability

This study aims to formulate a steady-state mathematical model for a three-dimensional permeable enclosure(cavity)to determine the oil extraction rate using three distinct nanoparticles,SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3),in unconventional oil reservoirs.The simulation is conducted for different parameters of volume fractions,porosities,and mass flow rates to determine the optimal oil recovery.The impact of nanoparticles on relative permeability(kr)and water is also investigated.The simulation process utilizes the finite volume ANSYS Fluent.The study results showed that when the mass flow rate at the inlet is low,oil recovery goes up.In addition,they indicated that silicon nanoparticles are better at getting oil out of the ground(i.e.,oil reservoir)than Al_(2)O_(3)and Fe_(2)O_(3).Most oil can be extracted from SiO_(2),Al_(2)O_(3),and Fe_(2)O_(3)at a rate of 97.8%,96.5%,and 88%,respectively.

Technologies and practice of CO2 flooding and sequestration in China

The latest advancement of CO2 flooding and sequestration theory and technology in China is systematically described, and the future development direction is put forward. Based on the geological characteristics of continental reservoirs, five theories and key technologies have been developed:(1) Enriched the understandings about the mass transfer characteristics of components between CO2 and crude oil in continental reservoirs, micro-flooding mechanism and sequestration mechanism of different geological bodies.(2) Established the design method of reservoir engineering parameters, injection-production control technology and development effect evaluation technology of CO2 flooding, etc.(3) Developed a series of production engineering technologies such as separated layer CO2 injection technology, high efficiency lifting technology, on-line wellbore corrosion monitoring and protection technology.(4) Innovated a series of surface engineering technology including CO2 capture technology, pipeline CO2 transportation, CO2 surface injection, and production gas circulation injection, etc.(5) Formed a series of supporting technologies including monitoring, and safety and environmental protection evaluation of CO2 flooding reservoir. On this basis, the technological development directions in the future have been put forward:(1) Breakthrough in low-cost CO2 capture technology to provide cheap CO2 gas source;(2) Improve the miscibility technology between CO2 and crude oil to enhance oil displacement efficiency;(3) Improve CO2 sweeping volume;(4) Develop more effective lifting tools and technologies;(5) Strengthen the research of basic theory and key technology of CO2 storage monitoring. CO2 flooding and sequestration in the Jilin Oilfield shows that this technology has broad application prospects in China.

The Value Constrained Production Decline Model and Its Application in Reserve Valuation

In the asset valuation of oil and gas reserves, it is discovered that the production decline trend of wells is not very obvious and that it is hard to make a production forecast matching the production history, thus resulting in a significant deviation of oil and gas asset value. For production with a significant fluctuation, the value deviation is also considerable if the matching production, which is predicted with classical decline methods, cannot appropriately reflect the time value distribution of actual production. To mitigate such a deviation, a concept is proposed concerning the value constrained production forecast and the value constrained production decline model is developed. A field case is demonstrated as an application of such a model. The model can significantly decrease the risk in the value deviation of a production decline analysis and be applied to the production forecasts for a single well, well clusters, blocks or field scale, and even for other mining industries.

Application of thermotolerant petroleum microbes at reservoir conditions for enhanced oil recovery

Primary oil recovery is the first stage of hydrocarbon production in which a reservoir uses its natural energy to force hydrocarbon to its wellbore.Secondary oil recovery comes to play when hydrocarbons can no longer be further produced by natural means.The purpose of secondary recovery is to maintain reservoir pressure so as to displace hydrocarbons toward the wellbore.Both primary and secondary recovery processes cannot displace more than 50%of the available hydrocarbons in a reservoir.The remaining hydrocarbons are further recovered through Tertiary/Enhanced Oil Recovery techniques.According to literature,microbial enhanced oil recovery has been identified as a tertiary method used to improve the efficiency of hydrocarbon production from reservoirs.Microbial enhanced oil recovery is a feasible reservoir technology,which has not been widely used in the oil and gas industry owing to the attainment of the requisite reservoir conditions such as temperature within which microbes can thrive.Literature has shown that thermotolerant microbes can withstand optimum temperatures of 50e90℃,while deep and ultra-deep hydrocarbon reservoir temperatures are often above 100℃.This study identifies some isolated thermotolerant microbes from a sandstone reservoir that can withstand temperatures as high as 110℃via conventional methods and molecular analysis.The identified thermotolerant petroleum microbes:Bacillus amyloliquefaciens(A)and Bacillus nealsonii(B)were used to enhance oil recovery from a reservoir.The results showed that the microbial species A and B at a confined pressure of 3.0 MPa and temperature of 27℃,gave 46.4%and 48.6%oil recoveries,respectively,which is comparably higher than the value(26.9%)obtained for the water flooded samples.At temperatures of 80,90,100,110 and 120℃,the oil recovery results show that the recovery factor(55.2%e64.1%)of species B were higher compared to the range(46.7e57.5%)recorded for species A.At the onset of the core flooding experiments,there was an initial increment in oil recovery factor as the temperature increased from 80 to 110℃,whereas,it remained constant within 110e120℃.This trend coincides with the drop in the thermal resistance exhibited by the microbes when exposed to such conditions.The cumulative oil production from the commercial Eclipse simulation closely matched those of the experiment results,whereas,the slight difference can be attributed to the adjustment of the simulation input parameters.The experimental results show that species B can be used to enhance oil recovery at reservoir temperature conditions above 100℃.

Potential application of functional micro-nano structures in petroleum

This paper takes micro-nano motors and metamaterials as examples to introduce the basic concept and development of functional micro nano structures, and analyzes the application potential of the micro-nano structure design and manufacturing technology in the petroleum industry. The functional micro-nano structure is the structure and device with special functions prepared to achieve a specific goal. New functional micro-nano structures are classified into mobile type(e.g. micro-nano motors) and fixed type(e.g. metamaterials), and 3 D printing technology is a developed method of manufacturing. Combining the demand for exploration and development in oil and gas fields and the research status of intelligent micro-nano structures, we believe that there are 3 potential application directions:(1) The intelligent micro-nano structures represented by metamaterials and smart coatings can be applied to the oil recovery engineering technology and equipment to improve the stability and reliability of petroleum equipment.(2) The smart micro-nano robots represented by micro-motors and smart microspheres can be applied to the development of new materials for enhanced oil recovery, effectively improving the development efficiency of heavy oil, shale oil and other resources.(3) The intelligent structure manufacturing technology represented by 3 D printing technology can be applied to the field of microfluidics in reservoir fluids to guide the selection of mine flooding agents and improve the efficiency of mining.

微生物提高油藏原油采收率进展

文章从油藏中普遍存在的采油微生物类群及其驱油机制、微生物采油技术的矿场应用、采油微生物的响应等方面对油藏微生物及其提高原油采收率进展进行综述.同时从营养剂在油藏储层中的分布、油藏环境下微生物生长代谢活性、油藏微生物定向调控等方面阐述了微生物采油技术发展的基础问题.

鄂尔多斯盆地西部古峰庄地区三叠系延长组裂缝特征及其对低渗透油藏的控制作用

[研究目的]鄂尔多斯盆地西部古峰庄地区三叠系延长组属于低渗透储层,天然裂缝较为发育,以往对裂缝特征研究较少,开展天然裂缝特征和形成时期研究对低渗透油藏勘探开发具有重要作用。[研究方法]文章通过野外露头、钻井岩心、成像测井、扫描电镜裂缝识别和流体包裹体、断裂活动、构造应力分析等方法展开了古峰庄地区延长组天然裂缝特征和控藏作用研究。[研究结果]延长组各段天然裂缝均发育,以长7段最为发育,其次为长8、长6段;裂缝以高角度裂缝和垂直裂缝为主,走向以NEE向为主,NE向次之,少量NW和NWW向;裂缝面可见方解石充填和明显过油痕迹。天然裂缝发育程度与岩层厚度、断裂活动密切相关。裂缝形成时期具有多期性,主要为燕山期和喜马拉雅期。[结论]延长组天然裂缝的发育改善了研究区低渗透储层的孔渗能力和储集空间,为低渗透油藏运移、储集和富集提供了良好条件,其发育程度与形成时期影响着低渗透油藏的成藏和产能。

中国页岩油勘探开发研究进展与科学技术问题

近年来,全球页岩油探明资源量和产量持续上升,成为重要接续资源。针对中国页岩油勘探开发现状与资源潜力,提出加快推进实现页岩油规模开发的建议,这对于保障中国能源安全意义重大,并将对全球能源经济和石油工业产业产生深远影响。中国勘探开发领域实现了非常规油气对经典石油天然气地质学理论的突破,发展了全油气系统理论,长水平井、多级压裂、夹层型页岩油开发关键技术等;提出当前页岩油勘探开发在基础理论、关键技术、效率成本、持续发展等方面仍面临一定挑战。分析指出:①中国页岩油勘探取得积极进展,具有巨大潜力,要进一步加大页岩油勘探开发支持力度;②基础理论突破是页岩油开发的关键,重点夯实理论基础有助于深化对页岩油成藏机理、储层特性、流动规律等方面的认识,为开发技术创新提供科学依据和指导;③成本控制与效率提升面临双重挑战,应充分借鉴美国的经验,结合自身特点,探索适合中国国情的发展模式,以实现效率和成本的最优平衡;④通过勘探开发一体化、地质工程开发经济一体化、全生命周期管理、提高原油采收率、储层管理、产量分配以及储量评估等措施,提升页岩油产业的持续发展能力。中国页岩油已进入规模化开发阶段,随着勘探开发的不断推进,页岩油将成为保障国家能源安全的重要支撑。

中国海油海上油田采油工程技术进展与展望

针对海上油田面临的油气开采技术难度大、重大技术迭代慢、大型作业技术应用成本高等多方面的挑战,中国海油经过数十年的发展,从稳产上产、技术迭代和降本增效等3方面推动技术变革,逐步形成了以“两提一降”为主线的数智化精细注水和稳油控水、大井距高强度稠油热采、低渗储层改造等三大工程技术,以及机采井延寿降耗、低产低效井增产、大修井作业、提高采收率等四类技术。提出了采油工程技术发展的10条技术路线,加快构建海上低成本采油工程技术体系,为推进中国海上油田采油工程技术高质量发展提供支撑。

油藏微生物在油气开发中的应用及展望

油藏是典型的高温、高压、高矿化度且厌氧的多重极端环境,油藏微生物是其中重要的组成部分。研究油藏微生物对阐明油气资源的形成、生物地球化学循环及生命起源与进化等过程有重要意义。通过文献调研,对油藏中微生物的相互作用方式、机理和主要功能进行了阐述,对油藏微生物在提高石油采收率、石油污染生物修复以及碳捕集、利用与封存(carbon capture,utilization and storage,CCUS)等领域中的作用机理和应用进展进行了总结,并提出了未来在利用油藏微生物过程中还需要解决的关键问题。油藏微生物在油气勘探及环境修复应用中具有经济成本较低和环境友好的优势,未来具有良好的应用前景。研究成果可为油藏微生物的研究和应用提供参考。

中国CO2驱油与埋存技术及实践

系统阐述近年来中国CO2驱油和埋存理论及技术的最新进展,并提出了下一步发展方向。基于陆相油藏地质特征,发展和形成了5个方面的理论和关键技术:①丰富了对陆相油藏CO2与原油间的组分传质特征、微观驱油和不同地质体埋存机理的认识;②形成了CO2驱油藏工程参数设计、注采调控、开发效果评价等油藏工程技术系列;③发展了CO2分层注气工艺、高效举升工艺、井筒腐蚀在线监测与防护等采油工程技术系列;④创新了CO2捕集、管道输送、地面注入、产出气循环注入等地面工程技术系列;⑤形成了CO2驱油藏监测、安全环保评价等配套技术系列。在此基础上提出了下一步技术发展方向:①突破低成本CO2捕集技术,提供廉价的CO2气源;②改善CO2与原油之间混相的技术,提高驱油效率;③研发提高CO2波及体积技术;④研制更高效举升工具和技术;⑤加强CO2埋存监测基础理论研究和关键技术的攻关。吉林油田的实践表明CO2驱油与埋存技术在中国具有广阔的应用前景。

非常规油藏地应力和应力甜点地球物理预测——渤南地区沙三下亚段页岩油藏勘探实例

渤南地区沙三下地层发育非常规油气藏,预测地应力及应力甜点是该类油藏勘探及评价的关键。本文提出的地应力及应力甜点地球物理预测方法结合了前人研究成果,以测井岩石物理参数分析为基础,建立地应力、破裂压力与岩石弹性参数的关系,通过多元线性回归拟合力学计算公式,并以弹性参数反演和多体融合技术为依托,实现了应力场及应力甜点的地震预测。理论研究及钻探结果均表明,渤南洼陷中部及南部的低应力区是油气成藏的优势条带,Ⅰ型和Ⅱ型应力甜点是泥岩裂缝型油藏的主要发育区,且具有页岩油产能。实际应力数据和钻探效果验证了方法的有效性,该方法可为非常规油藏勘探提供参考依据。

油藏厌氧微生物研究进展

地下深层油藏是独特的缺氧环境,目前还没有直接的微生物学证据表明油藏中存在真正意义上的“本源微生物”,但经注水开发后的油藏中确实蕴藏着复杂的微生物区系.油藏性质决定了油藏厌氧微生物特殊的群落结构,而油藏微生物的作用也可以改变油藏的理化及地质学特性.油藏中厌氧微生物按生理类群主要可分为发酵细菌、硝酸盐还原菌、铁还原菌、硫酸盐还原菌和产甲烷古菌.本文综述了国内外近年来油藏微生物学的研究进展,简述了微生物分子生态学在油藏微生物学研究中的应用,并对当前的研究提出了一些思考.

雁翎油田注氮气提高采收率现场试验

翎油田注氮井组试验是一项与ＴＯＴＡＬ法国石油公司合作开展的针对碳酸盐岩底水油藏注水开发后期提高采收率的现场试验。在进行了大量油藏地质再研究及开采历史再认识的基础上编制了试验方案，１９９４年１０月开始正式注氮气试验。注气试验过程中，重点监测了油气、油水界面和注气井、观察井的井口压力变化，根据油气、油水界面的变化特点及试验进展要求，开展了界面运动规律、气驱效果和试生产方案等油藏工程方面的研究。通过注气及开井生产动态变化的研究，认识了注气和开井生产时各项动态指标的变化规律，积累了一定的经验，为继续开展注气、采油工作奠定了基础。

特低渗透油藏非达西渗流模型及其应用

根据矿场试验和室内试验的研究成果,开发低渗透和特低渗透油藏时会产生非达西渗流现象,尤其是原油渗流会存在较为明显的启动压力梯度。结合低渗透油藏注水开发的特点,考虑油、水两相渗流均存在启动压力梯度,以及岩石存在应力敏感,建立三维油、水两相非达西渗流数学模型。利用差分方法得到该模型的数值差分格式,在此基础上编制模拟软件。以大庆肇源油田源121-3区块为研究对象,首先将建立的非达西渗流的数值模拟结果与现场实测的生产动态数据进行对比验证。然后,在五点注采井网的基础上,设计一个“正方形注采单元”,在保持采油井和注水井井底流压的前提条件下,改变注采井距,通过模拟计算得到油井见水时地层流体压力、流体压力梯度、地层绝对渗透率和启动压力梯度的空间分布,最后得到有效驱动注采井距,从而为该特低渗透油藏的注采井网部署提供依据。

地质体中的有机氮化合物及其在油藏地球化学中的应用

本文阐述了石油地质体中有机氮化合物的基本地球化学性质、分布与检测方法，以及可能的成因机制，浅析了此类化合物的研究意义，旨在介绍有机氮化合物的研究现状及其在油藏地球化学中的应用。

大位移井井壁稳定三维弹塑性有限元分析

现有井壁围岩应力求解模型大都基于平面应变假设,相对岩石真实应力状态会有一定的误差。在空间坐标变换基础上建立了大位移井井壁稳定分析三维弹塑性有限元模型,将井斜角与方位角的变化转化为井轴坐标系下地应力场应力分量的变化,保证了模型的稳定性。利用所建模型对弹性和弹塑性条件下的大位移井井壁围岩稳定性进行了研究。计算结果表明岩石在弹塑性条件下能够通过塑性变形吸收更多能量;在相同外载条件下,弹塑性岩石比脆性岩石更稳定。经过现场实例验证,在深部弹塑性地层钻进时,可以采取比常规设计稍低的泥浆密度,即能保持井壁稳定,又可以减少地层伤害。

储层中菌体微观调剖驱油效果分析

为说明菌体在储层孔道中的滞留对微生物驱油效果的贡献,借助微观仿真孔隙透明模型观察了菌体在多孔介质孔道中滞留聚集现象,测定了岩心中菌体滞留引起的油水两相相对渗透率的变化,分析菌体在储层孔道中的滞留聚集规律,及其对储层中油水两相流体流动能力的影响.研究发现,微观仿真孔隙透明模型中的驱动压力随菌体在储层孔道中的滞留量增加呈阶梯状渐升,驱出液中的菌体含量下降到一定值后趋于相对稳定;岩心中菌体的滞留造成油水两相的共渗区域扩大,油相相对渗透率曲线后移,水相相对渗透率曲线下降.表明储层孔道中滞留的菌体降低了水流沿大孔道渗流的能力,扩大了注水波及体积,起到了微观调剖作用,有助提高原油采收率.

边底水非均质性稠油油藏蒸汽驱关键技术

锦91块为非均质性较强、边底水活跃的特稠油油藏,目前蒸汽吞吐采出程度已达35.8%,局部已有边底水侵入,产量以10%-20%的速度递减,蒸汽驱是该块下一步需要转换的开发方式。采用热采工程、数值模拟方法,优选出蒸汽驱设计的关键技术:井网形式为83 m井距反九点井网;转驱时油层压力及蒸汽驱过程中的压力必须控制在5 MPa以下;单位油藏体积注入速度为1.65 t/(d.hm2.m),注入井底蒸汽干度达到55%,采注比为1.1∶1.0。