孔隙型碳酸盐岩储层注气注水提高采收率试验

中东地区部分碳酸盐岩储层类型以孔隙型为主,裂缝不发育,气测渗透率低,流体物性较差。以中东某油田S油藏为例,开展注气和注水可行性试验研究,并探讨其提高采收率的微观渗流机制。结果表明:受物性特征影响,储层注伴生气驱最小混相压力高,地层条件下不易达到混相驱替,但整体上岩心注烃类气驱效率要高于水驱效率,尤其当达到混相条件时,气驱效率明显提高;注烃类非混相驱油效率也相对较高,主要是由于储层原油黏度较高,气驱使原油体积膨胀,黏度降低,进而改善流动性;试验采用的水驱和气驱方式在微观上主要动用大孔隙中的可动流体,可考虑优化驱替方式进一步提高驱油效率。     

注入二氧化碳驱替煤层甲烷模拟实验研究

采用大型物理模拟试验装置模拟研究了往煤中注入CO2气体过程中对CH4气体的驱替过程,而进一步获得这一过程中相关物理作用特征。试验结果表明,在含瓦斯煤体内注入CO2之后CH4气体的解吸量显著增加。试验初始阶段获得的主要是游离态的 CH4成分。随着时间推移,驱替置换效应显著,先期注入的CH4解吸量大大增高;在CO2和CH4两种气体的各自注气阶段的煤体内压力变化速度方面也存在明显的差别,注入CO2时的煤体压力变化速度慢比煤吸附CH4气体时的变化速度快;实验同时表明,注气驱替过程中煤体温度有了显著提高,温度的提高。     

ZJD油田阜宁组大倾角油藏注CO_2方式探讨

倾角对于CO2驱利用重力来改善驱油效率和提高原油采收率具有重要意义。针对ZJD油田阜宁组大倾角油藏,应用数值模拟方法研究了地层倾角和注气部位对CO2驱油效果的影响。结果表明:随着地层倾角的增加,注CO2驱油采出程度也增加,而油藏高部位剩余油饱和度降低。低部位注气采出程度均低于高部位注气,且地层倾角越小,高部位注气的优势越不明显,地层倾角越大,高部位注气效果越好,CO2可在高部位形成小的气顶,更有利于气驱油。应用大倾角油藏实际地质模型研究注气方式对CO2驱油效果的影响,高部位注气比低部位注气可提高采收率8.69%,并可动用更多的储量。油藏现场实际应用后取得初步效果,高部位注气半年后油藏腰部的中心井从无产量恢复到9.3 t的原油产量。     

地层条件下凝析气藏的多相渗流特性

 在进行凝析气藏的数值模拟、试井分析以及开发动态预测的过程中,需要获取具有代表性的凝析油气、油水和气水相对渗透率曲线。深层高温高压凝析气藏在开采过程中地层流体渗流伴随着复杂的相变,因此,不能用传统的油气相渗曲线来代替实际地层条件下凝析油气相对渗透率的变化规律。在地层常规物性和流体特性分析的基础上,以实际凝析气藏的凝析油、气和地层水为实验流体,用实际凝析气藏的岩石作为多孔介质,在地层温度和压力条件下研究了多相渗流特征,得到了油气、油水和气水多相渗流的相渗曲线,表明地层条件下低孔低渗岩石的油水、油气和气水两相共渗能力较弱,而对于含裂缝或孔洞的高孔高渗岩石,油水、油气和气水两相共渗区较宽,驱替效率较高。这些成果为高温高压凝析气藏的动态模拟与预测提供重要的数据和相渗曲线。     

延长油田致密砂岩油藏CO_2驱油机理研究

CO_2驱是提高低渗透油田产量、缓解温室效应的有效途径。针对鄂尔多斯盆地油藏压力系数低、原油轻质组分含量高的特点,通过PVT和最小混相压力等测试分析方法,揭示了低压、低孔、低渗油藏CO_2驱提高采收率主要机理。开展了CO_2注入储层与无机、有机物作用后的沉淀研究,表明CO_2在无机盐溶液中不会形成沉淀堵塞孔隙,CO_2与有机质作用后沉积点高于油藏压力,且注入压力越高,CO_2在地层原油中的溶解能力越强,目标区块CO_2注入后不易形成沥青质沉淀。物模驱替实验结果表明,均质岩心的采出程度明显高于非均质岩心,且随着岩心非均质性的增加,水驱采出程度、气驱采出程度及最终采出程度均明显下降。     

海上轻质油藏水驱渗流阻力特征研究

轻质油藏注水井常存在井口压力不断升高的现象,酸化、微压裂等常规措施并不能有效降低井口压力。为进一步探究注入压力过高的原因,以流管模型为基础,依据水电相似原理,开展井间渗流阻力变化规律研究。结合达西定律推导了渗流阻力表达式:渗流阻力与储层形状和总流度有关。而非活塞驱替过程的总流度变化通常分为两种:单调增加(中、高黏),先减小后增加(低黏)。原油黏度较小时,总流度会呈现减小的趋势,渗流阻力随之增加,导致注入压力升高,此时表现在注水井井口压力不断升高,即发生了"伪堵塞",严重制约油田注水。通过对渤海南部区域不同油田注采井间渗流阻力的计算,得到了能够反应渗流阻力变化规律的无因次阻力系数图版,图版展示了"伪堵塞"可能发生的含水阶段,能够有效指导注水井的治理。结合KL油田群的治理实践,当注水井发生"伪堵塞"时,可采取以下措施:(1)对高破裂压力、低裂缝发育的油藏,实施提压增注;(2)对低破裂压力、高断裂程度的油藏,采取层内生气调驱;(3)对超低原油黏度、埋藏深的油藏,可考虑气驱开发;(3)对多层合采开发油藏,应优先解决纵向水驱矛盾。     

界面消失技术确定注CO_2驱油混相条件

重新回收温室气体CO2注入地层原油进行混相驱油是实现CO2封存和利用的主要途径之一,但其最小混相压力(MMP)被认为是该技术的一个关键参数。采用悬滴法测定了CO2和4种不同地层原油之间的界面张力,并直观地确定了4种不同地层原油注CO2驱油的MMP分别为:24.12MPa、24.81MPa、26.87 MPa和31.69 MPa。同时,采用多项式外延法确定各自的MMP,对比发现外延法确定的MMP误差均在3.0%以内,且MMP越高,误差越小。该实验表明,采用界面消失技术确定MMP具有操作简单、耗时少、成本低、准确度高等特点。     

油藏CO_2驱及封存过程中地化反应特征及埋存效率

油藏CO_2驱过程中,CO_2与地层水和岩石矿物发生化学反应,影响地层物性和CO_2的埋存形式。基于吉林油田某高温油藏的地层及流体性质,建立考虑地层水蒸发、水中CO_2溶解扩散、CO_2-地层水-岩石地化反应和孔渗关系的CO_2驱及埋存综合模拟模型,分析不同阶段的地化反应特征和CO_2埋存形式,研究CO_2注入方式对提高采收率和埋存效率的影响。结果表明:在CO_2驱油阶段,地化反应对储层孔隙度和渗透率产生一定影响,但对采收率的影响较小,CO_2主要以构造形式埋存于油藏内;在后续埋存阶段,气态CO_2通过地化反应不断转化为矿物形式,造成地层压力下降;水气交替注入方式可提高原油最终采收率和CO_2一次埋存效率,应为首选注入方式;对于其CO_2埋存量的不足,可在CO_2驱后注入一定的CO_2进行补充,同时起到维持地层压力的作用。     

粗糙裂隙气驱液特性研究

裂隙岩体气液渗流会导致岩体失稳形成灾害,也会促进地下水、油、气运移。文章采用激光扫描获取天然粗糙裂隙面三维数据,使用3D打印技术生成可视化裂隙模型,基于高速相机获得气驱液过程瞬态影响数据,研究粗糙裂隙气驱液受流量、液体物性与裂隙面展布方向的影响特征。结果表明,气体流量显著影响气液驱替时间,流量越大驱替完成越快。液体物性不同,驱替效果差别不显著。裂隙倾角对驱替行为影响显著,低角度下驱替效果较好。此结果可为裂隙气液两相流研究提供实验基础。     

致密油储层气驱油核磁共振实验研究

针对鄂尔多斯盆地致密油储层岩心,将核磁共振(nuclear magnetic resonance, NMR)技术与气驱油物模实验相结合,对储层原油赋存特征和气驱油后微观剩余油分布特征进行研究。研究表明:气驱油前目标储层总含油率较高,但微米孔隙(>1μm)赋存油量较少(7.27%),原油主要赋存于亚微米(0.1～1μm,包括0.1μm及1μm)和纳米孔隙(<0.1μm)中(分别为27.67%和24.00%);气驱油1 PV(pore volume)后,微米孔隙原油相对采出程度R较高(64.34%),亚微米孔隙次之(37.27%),纳米孔隙较低,气驱早期首先将赋存于较大孔隙内的原油驱出,较小孔隙内原油动用程度较低;气驱油50 PV后,储层微米孔隙几乎无剩余油,R达到90%以上,亚微米孔隙有一定量剩余油,R约为60%,纳米孔隙R较低,是剩余油主要赋存空间;随渗透率的降低,储层较大孔喉比例减少,微观非均质性降低,气驱油微观波及程度增加,亚微米孔隙采出油量有增加的趋势;致密油储层注气能力明显优于注水能力,且渗透率越低,注气能力优势越明显。研究成果可为致密油有效开发及制定合理开发方式提供依据。     

Becoming Vulnerable to Flooding: An Urban Assemblage View of Flooding in an African City

ABSTRACT

Assemblage thinking has emerged over the last two decades as an important theoretical framework to interrogate emerging complex socio-material phenomenon in cities. This paper deploys the assemblage lens to unpack the vulnerability of informal communities to flood hazards in an African city. Focusing on Agbogbloshie and Old Fadama, the largest informal settlements in Accra, Ghana, this paper employs multiple methods including archival analysis, institutional surveys, focus group discussions, and mini-workshops to study the processes of exposure and vulnerability to flood hazards in these two communities. We find that being vulnerable to flood hazards in these informal settlements emerges from historically contingent, co-constitutive processes and actants: the city officials’ modernist imaginaries and socio-cultural identities of residents in informal settlements; the social material conditions experienced by residents in these settlements; and the translocal learning networks of government and non-government actors that simultaneously (re)produce oppressive urban planning policies and grassroots resistance to these policies. The paper concludes with a call to urban planners and allied built environment practitioners to understand flood vulnerability as both a process and product of these complex interactions.     

Flooding and the Quantification of 'Intangibles'

S ources of both systemic and parameter uncertinties in flood alleviation cost-benefit analysis are discussed. Cost-benefit analyses are assessments of the future effects of different scheme options; consequently, there are inherent uncertainties. The omission of consideration of some impacts as 'intangibles', because it has not been possible to measure them, is a form of systemic uncertainty.
A significant omission in the past from flood alleviation cost-benefit analyses has been the non-monetary impacts of flooding upon households. It is shown that these impacts are both large and more important to the households affected than are the direct monetary losses.     

Flooding,Pollution And Agriculture

There has been a noticeable silence amongst environmental studies concerning the relationship between agriculture, flooding and pollution. This paper, which emerges from research funded by the Economic and Social Research Council and United Utilities, attempts to redress this neglect and stimulate both debate and research in to this important area. Utilising research undertaken in the UK, the contention underlying this paper is that much of current agricultural policy and practice is fostering an environment susceptible to flooding and pollution. The paper highlights a number of issues concerning the ways in which certain agricultural practices exacerbate the risk from both flooding and pollution, drawing linkages with current legislation and policy. Finally, an attempt is made to identify agricultural policies and practices that could help to reduce the incidence of flooding and pollution.     

英国地表径流水灾管理的战略应对

每当雨季来临,中国部分城市频繁遭受暴雨引起的地表径流水灾困扰。地表径流水灾已引起政府高度重视,各地都在争先恐后地申请海绵城市试点,以期解决地表径流水灾。相关海绵城市的设计如雨后春笋般出现,国家政策层面大力扶持海绵城市试点的开展。本文介绍英国地表径流水灾的战略管理,并配以实例说明相关具体措施,以期为中国海绵城市的良性运行提供借鉴。     

Influence of Transient Flooding on Multi-Anchor Walls

The paper presents the results of three full-scale tests that were carried out to investigate the influence of transient flooding on the performance of multi-anchor reinforced soil walls (MAW). The walls were constructed to a height of 6 m and flooded from the front of the structures to about mid-height and then drained in two to four stages. The walls were constructed with three different sand soils varying with respect to permeability, fines content and shear strength. Earth pressures and anchor loads were monitored during the flooding and draining stages and in-situ anchor pullout tests were performed. The analysis of results showed that the wall facings were very permeable and thus prevented unbalanced hydrostatic or seepage forces from developing during drawdown that could increase anchor loads beyond drained condition values. The accuracy of the current PWRC (2002) analytical model to estimate anchor capacity of MAW systems was demonstrated to vary widely depending on soil type and whether the soil was flooded or drained. However, on the load side, the method proposed by Miyata et al. (2009) to predict anchor loads was judged to be more accurate than the current BS8006 (2005) and PWRC (2002) methods based on the mean and spread of bias statistics where bias is defined as the ratio of measured to predicted anchor load.     

防洪观念的变迁

洪水的防治,从来不是一个单纯的技术问题,而是与人们对待洪水的态度、观念以及时代精神紧密联系在一起的。从观念的角度.梳理了其类型与转变过程,以及欧洲在当下的实践与经验。西方发达国家的河流治理实践表明:以多目标协同发展为导向,基于全流域的生态化、自然化的主动管理模式,是从根本上解决洪水问题,实现人与自然和谐发展的必由之路。     

回收与降解聚驱采出水的工艺探讨

含聚污水的处理是困扰石油行业的难题之一。基于聚驱采出水的特点,围绕聚合物的回收利用和降解理论及技术,探讨国内外含聚污水处理技术的研究与应用现状,对比分析现有处理技术存在的问题及适应性,提出采用化学混凝、气浮和水质改性等技术来回收利用PAM(聚丙烯酰胺)的新思路,打破了降解PAM的传统思维,同时分析含聚污水处理与利用技术的可行性与应用前景,有望实现含聚污水的循环利用。     

湛江市淹水原因分析及对策

介绍作者在作湛江市排水专项规划时 ,对该城市的水淹情况进行原因分析 ,并提出解决对策。     

提升城市道路防汛能力之方法研究

近年来,全国各大城市内涝多发,如何提升城市道路防汛能力成为重要问题。本文分析了目前城市道路防汛中主要存在的几个问题,并针对这些问题提出了自己的解决方法,同时对目前提升城市道路防汛能力的新技术、新方法进行了研究。     

殖民语境下的《非洲夜谈》叙事分析——从口头叙事到再书面化

西非豪萨语虚构叙事作品诞生于殖民文化机制和压迫性政治语境,既受殖民建制的规约,又具有事物发生于逆境时所独有的特征。豪萨文学在殖民语境中实现了从口头传统向再书面化的转变。北尼日利亚作家阿布巴卡尔·伊芒所著的民间故事集《非洲夜谈》是证实这一转化过程的散文体叙事作品。本文拟将其置于特定的社会历史语境进行叙事分析,旨在揭示早期豪萨虚构文学的文本特征与结构特性,从一个侧面勾陈非洲语言现代文学在殖民语境中的生发轨迹,并解释早期的豪萨文学创作与殖民权力的互动关系,同时旁及非洲语言文学在当代非洲文学批评中的边缘境况。