Influence of pore structure heterogeneity on channeling channels during hot water flooding in heavy oil reservoir based on CT scanning

Hot water flooding is an effective way to develop heavy oil reservoirs.However,local channeling channels may form,possibly leading to a low thermal utilization efficiency and high water cut in the reservoir.The pore structure heterogeneity is an important factor in forming these channels.This study proposes a method that mixes quartz sand with different particle sizes to prepare weakly heterogeneous and strongly heterogeneous models through which hot water flooding experiments are conducted.During the experiments,computer tomography(CT)scanning identifies the pore structure and micro remaining oil saturation distribution to analyze the influence of the pore structure heterogeneity on the channeling channels.The oil saturation reduction and average pore size are divided into three levels to quantitatively describe the relationship between the channeling channel distribution and pore structure heterogeneity.The zone where oil saturation reduction exceeds 20%is defined as a channeling channel.The scanning area is divided into 180 equally sized zones based on the CT scanning images,and threedimensional(3D)distributions of the channeling channels are developed.Four micro remaining oil distribution patterns are proposed,and the morphology characteristics of micro remaining oil inside and outside the channeling channels are analyzed.The results show that hot water flooding is more balanced in the weakly heterogeneous model,and the oil saturation decreases by more than 20%in most zones without narrow channeling channels forming.In the strongly heterogeneous model,hot water flooding is unbalanced,and three narrow channeling channels of different lengths form.In the weakly heterogeneous model,the oil saturation reduction is greater in zones with larger pores.The distribution range of the average pore size is larger in the strongly heterogeneous model.The network remaining oil inside the channeling channels is less than outside the channeling channels,and the hot water converts the network remaining oil into cluster,film,and droplet remaining oil.

Effect of pore size in mesoporous MnO_2 prepared by KIT-6 aged at different temperatures on ethanol catalytic oxidation

KIT‐6 mesoporous silica aged at 40,100,and 150°C were used as hard templates to prepare different mesoporous MnO2 catalysts,marked as Mn‐40,Mn‐100,and Mn‐150,respectively.The catalytic activities of these catalysts and the effect of pore sizes on ethanol catalytic oxidation were investigated.Mn‐40,Mn‐100,and Mn‐150 have triple,double,and single pore systems,respectively.On decreasing the aging temperature of KIT‐6,the pore sizes of KIT‐6 decrease and that of mesoporous MnO2 catalysts increase.The pore sizes and catalytic activities increase in the order:Mn‐40>Mn‐100>Mn‐150.Mn‐40 catalyst has a higher TOF(0.11 s–1 at 120°C)and the best catalytic activity for ethanol oxidation because of a bigger pore size with three pore systems with maximum distribution at 1.9,3.4,and 6.6 nm,decrease in symmetry and degree of order,more surface lattice oxygen species,oxygen vacancies resulting from more Mn3+ions,and better low‐temperature reducibility.

Cystic fibrosis transmembrane conductance regulator chloride channel blockers:Pharmacological,biophysical and physiological relevance

Dysfunction of the cystic fibrosis transmembrane con-ductance regulator(CFTR) chloride channel causes cys-tic fibrosis, while inappropriate activity of this channeloccurs in secretory diarrhea and polycystic kidney dis-ease. Drugs that interact directly with CFTR are there-fore of interest in the treatment of a number of diseasestates. This review focuses on one class of small mol-ecules that interacts directly with CFTR, namely inhibi-tors that act by directly blocking chloride movementthrough the open channel pore. In theory such com-pounds could be of use in the treatment of diarrheaand polycystic kidney disease, however in practice allknown substances acting by this mechanism to inhibitCFTR function lack either the potency or specificity forin vivo use. Nevertheless, this theoretical pharmaco-logical usefulness set the scene for the developmentof more potent, specific CFTR inhibitors. Biophysically,open channel blockers have proven most useful as ex-perimental probes of the structure and function of theCFTR chloride channel pore. Most importantly, the useof these blockers has been fundamental in developing afunctional model of the pore that includes a wide innervestibule that uses positively charged amino acid sidechains to attract both permeant and blocking anionsfrom the cell cytoplasm. CFTR channels are also subjectto this kind of blocking action by endogenous anionspresent in the cell cytoplasm, and recently this blocking effect has been suggested to play a role in the physio-logical control of CFTR channel function, in particular as a novel mechanism linking CFTR function dynamically to the composition of epithelial cell secretions. It has also been suggested that future drugs could target this same pathway as a way of pharmacologically increasing CFTR activity in cystic fibrosis. Studying open channel blockers and their mechanisms of action has resulted in significant advances in our understanding of CFTR as a pharmacological target in disease states, of CFTR chan-nel structure and function, and of how CFTR activity is controlled by its local environment.

Quantitative criteria for identifying main flow channels in complex porous media

To identify the type of main flow channels of complex porous media in oil and gas reservoirs,the"main flow channel index"is defined as the ratio of comprehensive permeability obtained from well test to matrix permeability obtained from core analysis or well logging.Meanwhile,a mathematical model is established based on equivalent flow assumption,the classification method for main flow channels is put forward,and quantitative characterization of main flow channels is realized.The method has been verified by analysis of typical gas reservoirs.The study results show that the"main flow channel index"can quantitatively classify types of flow channels.If the index is less than 3,the matrix pore is the main flow channel;if the index is between 3 and 20,the fracture is the main flow channel and the matrix pore acts as the supplement one;if the index is more than 20,the fracture is the only seepage channel.The dynamic analysis of typical gas reservoirs shows that the"main flow channel index"can be used to identify the type of flow channel in complex porous media,guiding the classified development of gas reservoirs,and avoiding development risk.

The influence of pore characteristics on rock fragmentation mechanism by high-voltage electric pulse

High-voltage electric pulse(HVEP)is an innovative low-energy and high-efficiency technique.However,the underlying physics of the electrical breakdown within the rock,and the coupling mechanism between the various physical fields involved in HVEP still need to be further understood.In this study,we establish a 2D numerical model of multi-physical field coupling of the electrical breakdown of porous rock with randomly distributed pores to investigate the effect of pore characteristics(porosity,pore media composition)on the partial electrical breakdown of rock(i.e.the generation of a plasma channel inside the rock).Our findings indicate that the generation of a plasma channel is directionally selective and extends in the direction of a weak electrical breakdown intensity.As the porosity of the rock increases,so does the intensity of the electric field in the‘electrical damage’region—the greater the porosity,the greater the effectiveness of rock-breaking.As the fraction of pore fluid(S_(water)/S_(air))gradually declines,the generation time of the plasma channel decreases,and the efficacy of rock-breaking by HVEP increases.In addition,in this study,we conducted an indoor experiment utilizing an electric pulse drill to break down the rock in order to recreate the growth mode of the plasma channel in the rock.Moreover,the experimental results are consistent with the simulation results.In addition,the development of this type of partial electrical breakdown is confirmed to be related to electrode polarity and pore characteristics via the experiment of the symmetrical needle-needle electrode arrangement,which further demonstrates the mechanism of partial electrical breakdown.This research is significant for comprehending the process of electric impulse rock-breaking and gives theoretical guidance and technological support for advancing electric impulse drilling technology.

Pore structure characteristics of the relative water-resisting layer on the top of the Ordovician in Longgu Coal Mine

In order to study the permeability and water-resisting ability of the strata on the top of the Ordovician in Longgu Coal Mine, this paper tested the permeability and porosity of the strata, investigated the fracture and pore structure features of the strata, and identified the main channels which govern the permeability and water-resisting ability of the strata. The permeability of the upper, central and lower strata shows as 2.0504 × 10^-3-2.782762× 10^-3, 4.1092 × 10^-3 -7.3387 × 10^-3 and 2.0891 ×10^-3-3.2705 × 10-3 μm^2, respectively, and porosity of that is 0.6786-0.9197%, 0.3109-0.3951% and 0.9829-1.8655%, respectively. The results indicate that： （I） the main channels of the relative water-resisting layer are the pore throats with a diameter more than 6 μm; （2） the major proportion of pore throats in the vertical flow channel and the permeability first increases and then sharply decreases; （3） the fractures occurring from the top to 20 m in depth of the strata were filled and there occurred almost no fracture under the depth of 40 m; and （4） the ratio of turning point of the main flow channel in the strata on top of Ordovician can be used to confirm the thickness of filled water-resisting lavers.

Preparation of Chiral Silica Nanostructures with Radial Pores through Single-templating Approach

A chiral low-molecular-weight gelator(LMWG) L-16Ala5PyPF6 was synthesized from L-alanine, which can cause physical gel in n-propanol, ethyl acetate, butylene oxide, water, benzene, 1,4-dioxane and chloroform. The sol-gel reactions were carried out in a mixture of stronger ammonia water and n-propanol at the volume ratio of 2:8. Single-handed twisted silica nanostructures with pore channels vertical to the wall surfaces were first prepared through a single-templating approach comparing with the reported double template method. The formation mechanism of radial pore structure was studied by transmission electron microscopy at different reaction time intervals, which indicated that the radial pore structure was formed via a structural transition in the sol-gel transcription process.

Pore Characteristic Design Method of High-strength Pervious Concrete Based on the Mechanical Properties and Rainstorm Waterlogging Resistance

High-strength pervious concrete(HSPC) with porosity ranging from 0.08% to 2.011% was prepared. The mechanical properties and rainstorm waterlogging resistance of HSPC were evaluated,and a design method of HSPC pore characteristics(porosity and pore diameter) based on the mechanical properties and rainstorm waterlogging resistance was proposed. The results showed that the reduction of effective cross-sectional area caused by artificial channels was the main factor affecting flexural strength but had limited influence on compressive strength. Compared with the concrete matrix without artificial channels,the compressive strength of HSPC with porosity of 2.011% decreased by 7.4%, while the flexural strength decreased by 48.3%. The permeability coefficient of HSPC can reach 16.35 mm/s even at low porosity(2.011%).HSPC can meet the requirements of no rainstorm waterlogging, even if exposed to 100-year rainstorms. When the mechanical properties and rainstorm waterlogging resistance are compromised, the recommended porosity ranges from 1.1% to 3.5%, and the recommended pore diameter ranges from 0.8 to 2.7 mm.

Engineering two-dimensional pores in freestanding TiO_2/graphene gel film for high performance lithium ion battery

As the key component of electrochemical energy storage devices, an electrode with superior ions transport pores is the important premise for high electrochemical performance. In this paper, we developed a unique solution process to prepare freestanding TiO_2/graphene hydrogel electrode with tunable density and porous structures. By incorporating room temperature ionic liquids（RTILs）, even upon drying, the non-volatile RTILs that remained in the gel film would preserve the efficient ion transport channels and prevent the electrode from closely stacking, to develop dense yet porous structures. As a result, the dense TiO_2/graphene gel film as an electrode for lithium ion battery displayed a good gravimetric electrochemical performance and more importantly a high volumetric performance.

基于NMR的非饱和土相对渗透系数快速预测新方法

非饱和土的渗透系数作为研究非饱和土中水分运移的重要参数,直接测量方法原理简明但试样尺寸较大,耗时较长;土-水特征曲线(SWCC)间接预测方法由于需要获取土-水特征曲线,同样较为耗时,工作量较大。为此,结合核磁共振(NMR)理论与渗流理论提出了不同孔径孔隙通道渗透系数与弛豫时间的关系,通过对不同大小孔隙通道渗透系数进行累加,提出了基于核磁共振的饱和/非饱和土渗透系数预测模型和快速预测方法。为验证模型的合理性,以湖南黏土为研究对象,进行了不同初始孔隙比试样脱湿、吸湿过程以及饱和状态下的95次核磁共振试验,获取相应的NMR曲线,采用瞬时剖面法获取不同初始孔隙比试样非饱和相对渗透系数,并与该模型预测值对比。研究发现:利用脱湿、吸湿过程不同含水率下NMR曲线以及饱和状态的NMR曲线均具有较好的预测效果,但基于饱和状态下试样的NMR曲线预测效果相对最好,测量成本和耗时也最小,因此建议采用饱和状态试样NMR曲线直接预测非饱和相对渗透系数。

柳赞油田多层砂岩优势渗流通道特征及喉道体积

陆相油藏储集层非均质性强,长期注水开发容易形成优势渗流通道,导致油井快速水淹,驱油效率降低,开发效果变差。以柳赞油田古近系渐新统沙河街组为例,综合分析测井岩电响应、储集层非均质性、注采特征、储集层孔隙特征等,描述柳赞油田多层砂岩优势渗流通道特征,确定了该区优势渗流通道形成条件,通过建立优势渗流通道喉道体积的计算方法,明确了油藏下一步调驱剂用量,达到了有效封堵优势渗流通道的目的,研究成果可为油田下一步稳油控水提供技术支撑。

疏松砂岩油藏长期水驱高渗透通道形成机理研究

A油田疏松砂岩油藏由于长期水驱而呈现出高渗透通道发育的特征,而孔喉的大小和结构影响着堵剂的选择,因此,了解这些通道发育的特征对油田控水稳油具有重要意义。本文利用A油田提供的天然砂岩岩心设计了长期水驱实验,研究了在流体剪切应力长期作用下储层物性和孔喉微观结构的变化。结果表明,在长期水驱过程中,黏土矿物很容易发生运移,使得较小的孔喉逐渐消失,较大的孔喉进一步扩大,孔喉体积比变小,储层润湿性更多转变为水湿,进而导致油藏微观非均质性增强,储层物性改变,最终,注入水低效循环日趋严重,形成了高渗透通道。

汉防己甲素抗病毒及抗炎作用研究进展

研究国内相关文献,概述汉防己甲素在抑制严重急性呼吸系统综合征冠状病毒Ⅱ型、猪流行性腹泻病毒、登革热病毒等方面的作用,以及其在风湿免疫系统、呼吸系统、神经系统、消化系统等疾病中的抗炎作用等。总结发现,汉防己甲素可以作为双孔通道拮抗剂抑制病毒进入和抑制病毒复制发挥抗病毒作用,还可以通过调控核转录因子蛋白家族(NF-κB)、Janus激酶信号转导和转录激活因子(JAK-STAT)、环氧化酶-2/前列腺素E2(COX-2/PGE2)、Nod样受体蛋白3(NLRP3)等相关信号通路调控炎症因子产生,调节机体抗病毒免疫,从而发挥抗炎和抗病毒的作用。重点分析了汉防己甲素对冠状病毒、埃博拉病毒等多种病毒的干预作用及机制,以及其发挥抗炎作用所涉及到的机制,旨在为今后对汉防己甲素进行深入的药用研究与应用提供参考。参考文献70篇。

基于“玄府-通道-孔隙”理论探讨原发性干燥综合征的诊治

玄府是一种遍布人体周身的至微结构,有行气机、通津液、渗气津、运神机的作用,具有“通道”和“孔隙”的属性,功能上以“通利”“开阖”为用。原发性干燥综合征为自身免疫性炎症性疾病,属于中医学“燥痹”范畴,该病因腺体受损常出现口眼干燥症状,亦会出现脏腑的病变,中医药对于该病具有独到的治疗优势。本文从玄府的角度探讨该病的诊治,认为阴津亏、燥毒侵、瘀血阻、气机滞导致玄府病变,丧失“通利性”与“开阖性”,导致津液无法循形敷布,无法濡养脏腑诸窍进而发病。故治疗当以恢复玄府的生理功能为要,以期为燥痹的治疗提供新的思路。

钾离子通道在抑郁症治疗中的研究进展

抑郁症是一种由多种因素引起的情感障碍性疾病,其发病率呈现逐年上升趋势,严重危害人类的身心健康。当前抗抑郁药的治疗机制主要是以增加脑内5-羟色胺、去甲肾上腺素和多巴胺等单胺递质的浓度为主,但其存在抗抑郁响应率低、不良反应严重等缺点。因此,抑郁症治疗仍未满足临床需求。近年来越来越多的临床前研究和临床实验表明,钾离子通道开放剂或拮抗剂在抑郁症治疗中具有巨大潜力。该文重点综述了近年来钾离子通道中电压门控钾离子通道、双孔钾离子通道与抑郁症的相关研究进展,为新型抗抑郁药物的研发提供新的思路。

柴达木大门口深层卤水矿产勘查双流道取心钻具研究

为有效获取深层孔隙卤水储卤层岩心,精准表征储卤层地质信息,提高钻探施工效率,解决传统单管、双管钻具应用过程中存在的取心率低、憋压跳钻、憋钻等问题。本文紧密结合卤水矿产勘查要求及柴达木盆地大门口地区地层情况,提出了该区域卤水矿产勘查钻探取心技术要点,基于已有钻进技术参数、护壁钻井液等提出了影响钻进效率及岩心采取率的钻具压力不平衡问题,分别设计了双流道压力平衡侧喷取心钻进、双流道压力平衡超前取心钻进工艺,研发了双管单动钻具、双管双动钻具、单向流道阀及配套器具等,在柴达木盆地大门口ZK03钻孔200~600 m孔段进行了试验应用,未发生憋钻情况、取心率>80%,满足了设计要求,为卤水矿产勘查提供了钻探技术支撑。

双孔道管状有序介孔炭对维生素B12的吸附缓释性能

通过纳米铸型法，以硅基介孔分子筛SBA-15为模板，糠醇为碳源，草酸作为聚合催化剂合成了具有双孔道管状有序介孔炭CMK-5．利用粉末X射线衍射（XRD）、扫描电子显微镜（SEM）和氮气物理吸附法等对其结构进行了表征．结果表明合成的CMK-5具有有序结构，比表面积和孔容积分别高达1856m^2·g^-1和2．10cm^2·g^-1，在3．1和5．5nm具有集中的双孔分布．由于独特的双孔道结构特点，CMK-5在120min内快速吸附维生素B12至平衡，吸附量高达943mg·g^-1，远高于商用活性炭．CMK-5吸附维生素B12后可以直接用于缓释，动态缓释浓度维持在-9mg·L^-1，适用于维生素B12分子在人体内的缓释．

沸石改性方法研究进展

沸石作为一种廉价的非金属矿物在工业催化及环境保护中应用已久,沸石的改性研究与它们的合成和应用开发一样极大地推动了沸石化学的发展。详细综述了近年来天然沸石非骨架元素改性、骨架元素改性及沸石晶体表面改性3种方法,改性后沸石性能及其应用。同时指出了各改性方法存在的缺点,对今后沸石改性研究及开发提出了建议。

复杂多孔介质主流通道定量判识标准

为判识油气储集层中复杂多孔介质的主流通道类型,利用试井解释获取的综合渗透率与岩心测试(或测井解释)得到的基质渗透率的比值定义了“主流通道指数”,同时基于流量等效原理建立了相应的数学模型,提出了主流通道分类方法,实现了储集层流动通道类型的定量表征,并通过典型气藏实例分析验证了该方法的有效性。研究表明,“主流通道指数”能够定量划分流动通道类型:该指数小于3,基质孔隙为主要流动通道;该指数为3~20,流动通道以裂缝为主、基质孔隙为辅;该指数大于20可视裂缝为唯一渗流通道。典型气藏的动态分析显示,“主流通道指数”可用于评价多孔介质流动通道类型,进而指导气藏分类开发、规避气藏开发风险。

缝洞双重介质数值模型及渗流特征研究

按储层特征和渗流特征,将缝洞双重介质模型分为三类,从数学角度简化成两类模型,即裂缝-基岩型和裂缝-孔洞型。前者采用Woren-Root等常规双重介质模型,后者需要建立缝洞系统的窜流公式才能进行数值模拟计算。根据缝洞的组合特征以及裂缝中的压力分布特征,推导了缝洞介质的窜流计算公式,并以商业软件ECLIPSE为基础,通过修改特定的关键字,实现缝洞双重介质模型的等效模拟。在此基础上,研究分析了缝洞双重介质的渗流特征:当窜流系数较低,单相流的双对数试井曲线出现凹形特征;当窜流系数足够大,单相流的曲线形态与单一介质相似,不出现凹形特征,但油水两相流动可导致油井的含水率出现阶梯状。