Influence of the Repeated Flooding on Growth and Development of Acorus calamus Vegetation in Water-level-fluctuation Zone of the Three Gorges Reservoir

[ Objective] The research aimed to study influence of the repeated flooding on growth and development of A. calamus in water-level-fluc- tuation zone of the Three Gorges Reservoir. [ Method] A. calamus plants were exposed to water under the dark conditions respectively in Septem- ber 2009 and September 2010. Then, they were taken away from the water, and grew in natural conditions in the following March and April respec- tively （ marked as S1, S2, S1 and S2）. The plant number was conducted statistics respectively. On May 7, the leaf number was made statistics. Length, width and rapid light responding curve of the leaf were determined. [ Result] Repeated flooding restrained significantly plant germination un- der the dark condition. Plant number in S1 and S2 groups decreased by 38.9% and 33.3% respectively compared with the control. It also reduced survival rate of the plant. Plant number in S2 group decreased by 16.7% （P 〈 0.05） compared with that of S2 group when they were taken away from the water. Both of flooding promoted elongation of the leaves, restrained leaves to grow wider, and also restrained leaf formation of the plants except for S1 and S1 groups. Total leaf length of a plant decreased markedly after the second flooding which in S1 and S2 groups were 50.6% and 36.9% respectively less than that after the first flooding. Total leaf number of the plant in S1and S2 groups reduced significantly, and they were only 63.1% and 38.5% respectively of the control. Compared with the first flooding, total leaf length of a plant in the control increased signifi- cantly and decreased remarkably in S2 group after the second flooding. Furthermore, light response ability of the relative electronic transfer rate （rETR） in S1 group wasn＇t significantly different from the control, and rETRmax, in S2 group was significantly less than the control. Moreover, non- photochemical quenching （NPQ） decreased remarkably in S1 and S2 groups. It indicated that A. calamus had good restore ability of the light re- sponse, but restoring of its heat dissipation capacity was slower. [ Conclusion] Repeated flooding inhibited plant growth and population recovery of A. calamus under the dark condition.

Reclamation of the Polymer-Flooding Produced Water

In order to resolve the discharge problem of the polymer-flooding produced water (PFPW) in crude oil ex-traction, the PFPW was treated by a four-grade and four-segment (four GS) electrodialysis reversal(EDR) set-up. The testing results show that the treated PFPW has two kinds, one is the diluted treated PFPW, the total dissolved solids (TDS) of the diluted treated PFPW is less than the original PFPW, the diluted treated PFPW is feasible for confecting polymer solution;another one is the concentrated treated PFPW, the TDS of the concentrated treated PFPW exceeds the original PFPW, the concentrated treated PFPW is feasible for replacing the PFPW as the injecting water in the water-flooding process for high permeability layer. This treatment technology can not only decrease environment pollution resulted by the PFPW discharge, but also achieve closed-circuit of the water resource during crude oil extraction by using polymer flooding technology.

Geochemical characteristics of reservoir after water and polymer flooding in Xingshugang oilfield of Daqing

Collecting 44 oil-sand specimens of Pu-I Member in two inspection wells before and after polymer flooding in the thirteenth district of Xingshugang oilfield,with experimental analysis,the author obtained the data about oil viscosity,flow,oil saturation and oil displacement efficiency.The result shows that viscous oil predominates in the main remaining oil in Xingshugang oilfield after water flooding with a certain amount of low viscosity oil,high viscosity oil and heavy oil;after polymer flooding,the viscous oil is main ingredient.Compared with water flooding,the low mobility and poor oil can be spread by polymer flooding,expanding the affected area and improving sweep efficiency and oil recovery.The geochemical affecting factors of water flooding and oil displacement efficiency refer to reservoir flow,permeability and the viscosity of residual oil.In the reservoir with permeability from low to high,the polymer flooding efficiency is better than water flooding.It provides the basis for improving the water and polymer flooding efficiency of the Xingshugang oilfield.

Comparison of oil displacement mechanisms and performances between continuous and dispersed phase flooding agents

To compare the oil displacement mechanisms and performances of continuous phase flooding agent(traditional polymer solution) and dispersed phase flooding agent(particle-type polymer SMG dispersion), the particle phase separation of SMG dispersion migrating in pores was simulated by using the microfluidic technology. Theoretically guided by the tree fork concentration distribution of red cells in biological fluid mechanics, the concentration distribution mathematical model of SMG in different pores is established. Furthermore, the micro and macro physical simulation experiments of continuous and dispersed phase flooding agents were carried out. The results show that the continuous flooding agent enters all the swept zones and increases the flow resistance in both larger and small pores. On the contrary, the particle phase separation phenomenon occurs during the injection process of dispersed flooding agent. The SMG particles gather in the larger pore to form bridge blinding, and the carrier fluid displace oil in the small pore. Working in cooperation, the SMG particle and carrier fluid drive the residual oil in the low permeability layers step by step and achieve the goal of enhanced oil recovery. The laboratory experimental results indicate that, the oil increment and water reduction effect of dispersed flooding agent is much better than that of continuous flooding agent, which is consistent with the field test results.

Migration and speciation transformation mechanisms of mercury in undercurrent zones of the Tongguan gold mining area, Shaanxi Loess Plateau and impact on the environment

In order to study the migration and transformation mechanism of Hg content and occurrence form in subsurface flow zone of gold mining area in Loess Plateau and its influence on water environment,the field in-situ infiltration test and laboratory test were carried out in three typical sections of river-side loess,alluvial and proluvial strata in Tongguan gold mining area of Shaanxi Province,and the following results were obtained:(1)The source of Hg in subsurface flow zone is mainly caused by mineral processing activities;(2)the subsurface flow zone in the study area is in alkaline environment,and the residual state,iron and manganese oxidation state,strong organic state and humic acid state of mercury in loess are equally divided in dry and oxidizing environment;mercury in river alluvial or diluvial strata is mainly concentrated in silt,tailings and clayey silt soil layer,and mercury has certain stability,and the form of mercury in loess is easier to transform than the other two media;(3)under the flooding condition,most of mercury is trapped in the silt layer in the undercurrent zone where the sand and silt layers alternate with each other and the river water and groundwater are disjointed,and the migration capacity of mercury is far less than that of loess layer and alluvial layer with close hydraulic connection;(4)infiltration at the flood level accelerates the migration of pollutants to the ground;(5)the soil in the undercurrent zone is overloaded and has seriously exceeded the standard.Although the groundwater monitoring results are safe this time,relevant enterprises or departments should continue to pay attention to improving the gold extraction process,especially vigorously rectify the small workshops for illegal gold extraction and the substandard discharge of the three wastes,and intensify efforts to solve the geological environmental problems of mines left over from history.At present,the occurrence form of mercury in the undercurrent zone is relatively stable,but the water and soil layers have been polluted.The risk of disjointed groundwater pollution can not be ignored while giving priority to the treatment of loess and river alluvial landform areas with close hydraulic links.The research results will provide a scientific basis for water conservancy departments to groundwater prevention and control in water-deficient areas of the Loess Plateau.

Automatic measurement of three-phase contact angles in pore throats based on digital images

With the help of digital image processing technology, an automatic measurement method for the three-phase contact angles in the pore throats of the microfluidic model was established using the microfluidic water flooding experiment videos as the data source. The results of the new method were verified through comparing with the manual measurement data.On this basis, the dynamic changes of the three-phase contact angles under flow conditions were clarified by the contact angles probability density curve and mean value change curve. The results show that, for water-wetting rocks, the mean value of the contact angles is acute angle during the early stage of the water flooding process, and it increases with the displacement time and becomes obtuse angle in the middle-late stage of displacement as the dominant force of oil phase gradually changes from viscous force to capillary force. The droplet flow in the remaining oil occurs in the central part of the pore throats, without three-phase contact angle. The contact angles for the porous flow and the columnar flow change slightly during the displacement and present as obtuse angles in view of mean values, which makes the remaining oil poorly movable and thus hard to be recovered. The mean value of the contact angle for the cluster flow tends to increase in the flooding process, which makes the remaining oil more difficult to be recovered. The contact angles for the membrane flow are mainly obtuse angles and reach the highest mean value in the late stage of displacement, which makes the remaining oil most difficult to be recovered. After displacement, the remaining oils under different flow regimes are just subjected to capillary force, with obtuse contact angles, and the wettability of the pore throat walls in the microfluidic model tends to be oil-wet under the action of crude oil.

大庆油田二类B油层聚驱剖面动用规律及其改善

大庆油田聚合物驱应用规模不断扩大,开发对象转向性质较差的二类B油层,现有聚合物与油层适应性不强,剖面动用规律不明确,不同地区聚驱开发效果差异较大。针对上述问题,应用矿场剖面数据统计和室内实验分析,研究了二类B油层剖面动用规律和剖面改善方法。结果表明:从吸水层动用情况来看,喇嘛甸地区由于发育厚层河道砂,油层物性好,油层有效厚度动用比例最高,油层以多次动用为主,突进层多,相对吸液量高;萨中和萨南地区河道砂发育规模小,薄砂层较多,物性差,有效厚度动用比例较低,但聚驱后,有效厚度动用比例相比水驱分别增大了12.5%和15.4%,渗透率为100~300 mD的储集层吸入剖面改善明显;从未吸水层动用来看,二类B油层纵向非均质性强,导致层间有效厚度未动用比例较高,剖面改善应以均衡层间动用为主;抗盐聚合物高、低质量浓度交替注入可延缓含水率上升时间,增加低渗透层吸液量,聚驱采出程度提高显著。在喇嘛甸北北块A区开展了DS1200抗盐聚合物和高、低质量浓度交替注入试验,降水增油效果好,可为大庆油田二类B油层聚驱剖面改善提供技术指导。

含聚污水重力沉降分离过程淤泥增长特性预测

重力沉降作为污水处理的基本工艺,其常用设施重力沉降罐在运行过程中,来水中的悬浮物会不断向罐底沉积形成淤泥,为了防止水质二次污染,保障设施的高效运行,需根据淤泥量来制定清淤方案。文章基于大庆某油田污水处理站运行实际,从日处理量、含聚浓度、悬浮物含量、含油量、悬浮物脱除率等特征量出发,通过构建重力沉降罐清淤数据集,分析各特征量间的关系,并确定影响淤泥增长的主导因素,进而基于BP神经网络架构建立淤泥增长速率预测模型。研究结果表明,污水中含聚浓度在一定程度上影响含油量和悬浮物含量,随着沉降罐日处理量的增加,油珠脱除率和悬浮物脱除率降低,淤泥增长速率正相关于污水悬浮物含量、悬浮物脱除率和含聚浓度,基于生产数据训练的预测模型拟合度分布在0.9以上,满足精度要求,为污水沉降罐清淤操作的时间选择提供了依据和方法。

Characteristics of remaining oil viscosity in water-and polymer-flooding reservoirs in Daqing Oilfield

The experimental analysis of 21 crude oil samples shows a good correlation between high molecular-weight hydrocarbon components (C 40+) and viscosity.Forty-four remaining oil samples extracted from oil sands of oilfield development coring wells were analyzed by high-temperature gas chromatography (HTGC),for the relative abundance of C 21-,C 21-C 40 and C 40+ hydrocarbons.The relationship between viscosity of crude oil and C 40+ (%) hydrocarbons abundance is used to expect the viscosity of remaining oil.The mobility characteristics of remaining oil,the properties of remaining oil,and the next displacement methods in reservoirs either water-flooded or polymer-flooded are studied with rock permeability,oil saturation of coring wells,etc.The experimental results show that the hydrocarbons composition,viscosity,and mobility of remaining oil from both polymer-flooding and water-flooding reservoirs are heterogeneous,especially the former.Relative abundance of C 21- and C 21-C 40 hydrocarbons in polymer-flooding reservoirs is lower than that of water-flooding,but with more abundance of C 40+ hydrocarbons.It is then suggested that polymer flooding must have driven more C 40- hydrocarbons out of reservoir,which resulted in relatively enriched C 40+,more viscous oils,and poorer mobility.Remaining oil in water-flooding reservoirs is dominated by moderate viscosity oil with some low viscosity oil,while polymer-flooding mainly contained moderate viscosity oil with some high viscosity oil.In each oilfield and reservoir,displacement methods of remaining oil,viscosity,and concentration by polymer-solution can be adjusted by current viscosity of remaining oil and mobility ratio in a favorable range.A new basis and methods are suggested for the further development and enhanced oil recovery of remaining oil.

三峡水库消落带生境特征与植被恢复模式

[目的]三峡水库蓄水运行后消落带生境破碎斑块化加剧,极端生境胁迫严重损害植被的结构和功能。厘清三峡水库消落带生境状况,提出适宜性植被恢复对策,重建河流受损廊道综合生态功能,对构建区域生态安全格局和保障长江流域水资源安全具有重要意义。[方法]针对三峡水库消落带植被退化与生态功能受损的突出问题,系统解析了消落带生境特征及其对植被生长的影响,围绕水库河岸受损廊道生态修复重大需求,探讨面向消落带微生境构建与植被格局功能优化的三峡水库消落带植被恢复模式。[结果]三峡水库消落带生境状况受水库运行形成的独特水位节律、出露期植被生长季气候条件、土壤侵蚀与泥沙沉积过程、土壤环境等多生境因子协同影响,呈现高度空间异质性特征。水位变动形成的淹没时长、出露时令、淹水强度是影响植株繁衍、生长的首要因素;土壤侵蚀、泥沙掩埋、土壤水养条件等影响植被生长状况。[结论]三峡水库消落带植被恢复需综合考虑水位节律、立地条件与物种形态-功能性状,选育优质抗逆物种,注重土壤基质保育,突出植被格局的分区优化配置。重建消落带综合生态功能,为水库消落带生态治理提供理论支撑和科学依据。

一种净水型破乳剂在孤岛油田的应用

文章探讨了孤岛油田聚合物驱原油的乳化状态,发现胶质和沥青质是影响原油破乳的主要因素,导致孤岛油田原油难以破乳并且污水含有较高的油分。为解决这一问题,实验室中通过对聚头与环氧乙烷(EO)、环氧丙烷(PO)进行聚合反应成功地制备出净水型破乳剂,并经过多次试验选定破乳剂5050作为效果最佳的配方。同时,确定了5050最佳的反应物料质量(聚头、EO、PO)比为1∶149∶149,并找到了EO和PO各自最优的聚合反应温度分别为125℃和140℃。

三峡库区消落带植物群落及其功能性状对水淹强度的响应

植物功能性状能表征其对资源的利用能力和对外界环境的响应,而水淹强度的不同使得三峡库区消落带不同高程的生境存在较大差异,因此开展不同水淹梯度下消落带植物群落生态策略及功能性状差异的研究,对全面理解植物对消落带不同生境的适应机理具有重要意义。研究选取受三峡水库水位变化影响的澎溪河流域,沿高程梯度对不同水淹强度下的植物群落及其功能性状指标进行分析。结果表明:(1)消落带植物群落处于演替的初级阶段,不同水淹梯度下的植物群落存在显著分化;(2)环境胁迫是决定消落带植物生态策略的主要因素,总体呈现较为集中的耐压策略,随着高程升高有逐渐向杂草策略转移的趋势;(3)随着高程升高,植物的高度、主茎干物质量、比根长及叶组织密度都有增大的趋势,比叶面积则相反。(4)各功能性状之间存在显著相关性,并通过形成不同的性状组合以适应不同强度水淹干扰的生境。消落带下部更倾向于投资于叶片使植物在出露期能快速获取资源和完成生活史,而消落带上部则更倾向于投资防御组织及根系以抵御干旱,研究结果可为消落带生物多样性保护及其生态系统修复提供理论依据。

基于油藏化学驱能耗分配原理的理想流度控制型驱油剂研究Ⅰ:聚/表二元复合驱油体系的渗流阻力调控机理及应用

针对驱油剂的深部流度控制能力与近井地带注入性之间的矛盾,提出了理想流度控制型驱油剂应满足低黏度配制/输送、近井地带低吸附量长期稳定注入和低浓度产出液的技术要求,同时,在渗流过程中能够在储层深部不同位置建立多级渗流阻力峰值,并且前缘后驱替相渗流阻力应始终保持在较低水平。基于固/液界面吸附作用与分子间相互作用的协同效应,设计了在渗流过程中具备动态改变体系组成和微观溶液结构,从而改变其渗流阻力特征的疏水缔合聚合物/阴离子型表面活性剂二元体系。相较于HP-1(1500 mg/L),表观黏度相近、组成不同的二元体系HP-1(1500 mg/L)/SDSB(150 mg/L)和HP-1(1500 mg/L)/SDSB(200 mg/L),在段塞注入及其后续水驱过程中可以在多孔介质的中、后部构建数值更高、空间分布更优的动态渗流阻力,说明二元体系具备运移增黏特征和延迟突破特征,其前缘的流度控制能力更强,并且渗流阻力在储层的空间分布更合理,从而延长了段塞整体突破时间,有利于提高波及体积和驱油效率。在相对稠油、强非均质性和水驱含水率为80%的渤海某油田油藏条件下,采用基本相同剂量、相近成本的化学剂工业产品进行的驱油实验表明:二元体系后续水驱突破之前驱油剂段塞渗流阻力的空间动态分布特征是影响驱油效率的关键因素,二元体系(AP-P4(1400 mg/L)/ZX-27(300 mg/L),黏度为6.4 mPa·s)比疏水缔合聚合物AP-P4(1750 mg/L,黏度为62.9 mPa·s)多提高10%的原油采收率。

D油田二类油层聚驱上返时机计算方法

为合理确定不同经济条件下的经济极限含水率,充分考虑油田效益最大化,评估油田生产是否具有经济效益,针对二类油层聚驱潜力层系接替投产时机问题,基于盈亏平衡原理与产量递减规律提出一种明确上返开发时机的新方法.打破选取98%(水的体积分数)作极限含水率行业标准的限制,基于油价、油田实际产出、成本和税金等经济参数,运用投入产出平衡理论,推导出聚合物驱油田单井经济极限含水率计算模型.利用产量递减规律预测处于后续水驱阶段的油层未来含水变化趋势,结合经济极限含水率,明确达到盈亏平衡点的时机,即层系接替投产时机.以D油田二类油层为例,计算不同油价和产液规模下的经济极限含水率,评价油井生产是否具有经济效益,并预测油田含水率变化,明确了开发投产时机.结果表明,经济极限含水率与油价和日产液量均呈正相关,对于具有较高采油速度的化学驱油层而言,高油价下的极限含水率可达99.02%,远超行业标准.根据建立的经济极限含水率模型预测的开发投产时机,延长了油井高含水期效益生产的寿命,大幅度提高了经济效益,对油田化学驱开发具有重要的指导意义.

大庆油田二类油层注聚时机研究

大庆油田聚驱开发对象已由一类油层向二类油层转变,以往基于一类油层区块建立的标准已不适用,需要开展适合于二类油层的注聚时机研究。基于二类油层地质特征和开发状况,利用数值模拟方法建立二类油层地质模型,研究开始注聚时含水率和结束注聚时含水率对聚驱开发效果的影响,并结合现场进行验证,确定合理的开始和结束注聚时机。研究结果表明,在结束注聚时含水率相同情况下,开始注聚时含水率越高,聚驱阶段采出程度越低,聚合物用量越大,吨聚增油量越低,含水下降幅度越小,含水最低值越高。即开始注聚时含水率越低,聚驱效果越好。在开始注聚时含水率相同情况下,结束注聚时含水率越高,聚合物用量、聚驱阶段采出程度越高,吨聚增油量越低。当水驱至含水率96%时开始注聚,选择含水回升到96%~97%时结束注聚比较合理,含水最好不要超过97%。

海上S油田用自破乳聚合物制备及其性能研究

以线形嵌段聚醚破乳剂合成具有破乳功能的可聚单体PD,以丙烯酰胺、丙烯酸、2-丙烯酰胺-2-甲基丙磺酸及PD为原料,通过水溶液聚合制备了具有破乳功能的四元共聚物PPDM。通过红外、核磁等方式对共聚物的结构进行了表征,评价了聚合物溶液的溶解性能、增黏性能以及在S油田条件下的驱油和破乳性能。结果表明:加入破乳剂功能单体后,共聚物PPDM与聚丙烯酰胺(PAM)溶解时间均在20 min黏度即可达到最终黏度的96%以上,随着破乳功能单体用量的增加,黏度有一定程度增加。驱油性能结果表明,共聚物PPDM的采收率比PAM提高5.7%,破乳性能比PAM提高2.5倍。

杏北开发区葡Ⅰ1~3聚驱注入界限实验研究

特高含水期油田注聚合物能够有效封堵大孔道,改变液流方向,提高波及体积,从而提高采收率。针对杏北开发区葡Ⅰ1~3主力非均性储层聚驱注入界限识别不清、注入参数选取缺乏依据的问题,基于不同储层渗透率、聚合物相对分子质量和聚合物质量浓度开展注入性实验,评价了注聚效果,确定了注聚界限。结果表明:聚合物相对分子质量越大、质量浓度越大,注入速度越低;注入速度高于0.35 m·d^(-1)为注入能力强,0.35~0.25 m·d^(-1)为注入能力中等,0.25~0.15 m·d^(-1)为注入能力较差,小于0.15 m·d^(-1)为注入能力差。

低阻水淹层地化录井识别技术在南海北部A油田的应用

在油田开发过程中,常采用注水方式为地层提供能量。由于储层的非均质性,通常物性好、连通性好的层位被快速水淹,剩余油较少,而物性差、连通性差的层位因注入水未波及,则留存较多剩余油。部署调整井开发剩余油需避开水淹层射孔,因此需要对水淹层进行准确识别。通过优选S_(1)、nC_(24)/nC_(29)、∑(C_(1)-C_(5))/∑(C_(1)-C_(9))等地化录井优势参数进行有机组合,建立了基于地化谱图对比识别方法、热蒸发烃气相色谱参数nC24/nC29比值法,以及轻烃组分∑(C_(1)-C_(5))/∑(C_(1)-C_(9))比值与岩石热解S1交会图板法用于低阻水淹层地化录井识别。该技术在南海北部海域A油田的应用表明,水淹层识别符合率达到87.5%,取得了较好的应用效果,为油田开发避开水淹层提供了科学依据。

色连二矿多煤层开采对导水裂隙带高度影响的数值模拟探讨

导水裂隙带高度确定对煤矿水害防治及煤炭高效开采具有深远意义。为研究多煤层开采导水裂隙带发育规律,以色连二矿5号煤层为研究对象,采用理论分析和UDEC软件数值模拟的方法,研究色连二矿的3,4,5号煤层依次开挖对覆岩层导水裂隙带发育高度的影响情况。结果表明,运用数值模拟的手段预测的3、4和5煤层导水裂缝带高度分别为38 m、50 m和70 m,其中开采4-1上煤对3-1煤导高有一定影响,开采5-1上煤促进4-1上煤导高进一步增大,且影响程度较大,对3-1煤导高具有较小的促进作用。该成果为色连二矿5煤层安全高效开采提供了理论技术支持。

GIS-based Risk Zone of Flood Hazard in Anhui Province

[Objective] The aim was to study the flood disaster risks in Anhui Province based on GIS. [Method] Taking country as basic unit, the 1∶ 250 000 basic geographic data in Anhui Province as basis, from the angle of flood disaster hazard and economic vulnerability, and by dint of the calculation of the weight of each impact factor with entropy-based fuzzy AHP method, flood risk assessment model was established to study the flood disaster risks zoning in Anhui Province. Using nearly 10 years of disaster information in Anhui Province, the flood risk zoning of Anhui Province was studied. And the risks evaluation results of flood disaster risks in Anhui Province in recent 10 years were checked. [Result] The regional difference of flood disaster in Anhui Province was large. The most serious area of flood disaster was in Lingquan in Fuyang and Lingbi in Huaibei. The risks degree degraded from south mountainous area in north Anhui Plain to the mountainous area of west Anhui Province, from Huaibei Plain to the hilly area of Jianghuai and mountainous area of south Anhui Province. The disaster situation in Anhui Province in recent 10 years suggested that the areas suffering from serious economic losses were in Lingbi, Guzheng and Huainan in the south part of Huaibei Plain. The places having serious agricultural crops damages were in Tangshan and Xiao County in Huaibei Plain. Besides, the Jingzhai area in the Dabieshan in west Anhui Province also had serious agricultural crops in Jinzhai. Other places had limited disaster-stricken impacts; the distribution of disaster-stricken population and impacted area of agricultural crops were basically consistent. Therefore, the risk evaluation of flood disaster of Anhui Province based on GIS was basically consistent with reality. [Conclusion] This GIS-based flood risk zoning method had good practicability.