Variation in Pore Space and Structure of Organic-rich Oilprone Shales from a Non-marine Basin:Constraints from Organic Matter and Minerals

Organic matter(OM)and minerals are major particle components of lacustrine shales.The influence of OM and minerals on pore space and structure in organic-rich oil-prone shales containing a large range of total organic carbon(TOC)contents is poorly understood.In this study,we investigated the variation in pore space and structure of low mature lacustrine shales in the Songliao Basin(NE China),based on a study of the mineralogy,petrography,geochemistry,and geophysical properties of shales.Different pore types make markedly different contributions to the mineral surface area(MSA)and pore volume(PV)of the shales.There exists a negative correlation between MSA/PV and TOC in mesopores(r^(2)=0.75/0.65)and macropores(r^(2)=0.74/0.68),and a positive correlation in micropores(r^(2)=0.59/0.64),which are associated with the variation of mineral and TOC contents.A positive relationship between the throat/pore ratio and TOC(r^(2)=0.82)shows an increase in throat radius and decrease in pore radius with increasing TOC content.This relationship is supported by the reduction in mean pore diameter(MPD)for large pores and increase in MPD for small pores.These variations are related to the decreased pores by quartz plus feldspar(Q+F)content,increased throats by clay minerals,an d enhanced pore-fill by OM.We propose that the variation of OM and minerals is a key control on the pore space and structure of low mature organic-rich oil-prone shales.

Use of high-resolution X-ray computed tomography and 3D image analysis to quantify mineral dissemination and pore space in oxide copper ore particles

Mineral dissemination and pore space distribution in ore particles are important features that influence heap leaching performance. To quantify the mineral dissemination and pore space distribution of an ore particle, a cylindrical copper oxide ore sample(Φ4.6 mm × 5.6 mm) was scanned using high-resolution X-ray computed tomography(HRXCT), a nondestructive imaging technology, at a spatial resolution of 4.85 μm. Combined with three-dimensional(3D) image analysis techniques, the main mineral phases and pore space were segmented and the volume fraction of each phase was calculated. In addition, the mass fraction of each mineral phase was estimated and the result was validated with that obtained using traditional techniques. Furthermore, the pore phase features, including the pore size distribution, pore surface area, pore fractal dimension, pore centerline, and the pore connectivity, were investigated quantitatively. The pore space analysis results indicate that the pore size distribution closely fits a log-normal distribution and that the pore space morphology is complicated, with a large surface area and low connectivity. This study demonstrates that the combination of HRXCT and 3D image analysis is an effective tool for acquiring 3D mineralogical and pore structural data.

含瓦斯煤体受载微破坏模型及失稳判识准则

煤体内孔隙和骨架分布对煤储层内气体运移及瓦斯动力灾害的发生具有重要的影响。为进一步探索含瓦斯煤体微观破坏机理,针对含瓦斯煤的微观破坏过程,对其微破坏形式展开详细的研究。采用原子力显微镜对加载前后突出煤样和非突出煤样表面进行了原位测试,结果表明:不同煤样受载后,煤样表面结构均会发生变化,闭孔孔径有所减小,部分孔隙遭到破坏,相邻闭孔之间有连通趋势。加载前煤样孔隙呈无规律分布,加载后孔隙连通性增强,开孔孔喉数量有所增加。煤样加载后由于孔隙的连通导致突出煤样煤骨架模量降低,而非突出煤样由于本身强度较高,施加载荷导致煤体内部结构被压实,弹性模量略有增加。定义了煤体微观破坏类型及概念,分析了煤体孔隙及煤骨架周边应力分布特征,揭示了不同情况下含瓦斯煤体微观破坏机制。同时,对闭孔微气爆的影响因素展开讨论,狭长型椭圆孔端部孔壁处所受应力更大,更容易发生闭孔微气爆。描述了开孔微损伤的2种发生形式,揭示了孔隙“瓶颈效应”的制约对微破坏发生的机理。明确了原生缺陷结构为煤骨架的薄弱环节,并对其发生破裂的演化规律进行分析。基于线弹性断裂力学、弹塑性力学以及渗流力学等理论知识,提出了应力扰动作用下孔隙破坏和煤体失稳判识准则,总结了含瓦斯煤体微观破坏特征及其诱导煤与瓦斯突出的机制,并对煤与瓦斯突出的研究方向提出展望。

松辽盆地古龙凹陷白垩系青山口组页岩油储层中微米孔缝特征及油气意义

通过岩心观察、薄片鉴定、电子背散射、二次成像及能谱分析等多种实验手段,对松辽盆地古龙凹陷白垩系青山口组页岩油储层中的微米孔和微米缝进行了研究。研究结果表明:(1)古龙凹陷页岩油储层岩性为以页岩为主的细粒碎屑岩,矿物成分以黏土和长英质为主,在结构上显示出泥岩或页岩的特点,整体为长英质页岩;储层中微米孔、缝发育,类型多样。(2)研究区微米孔直径一般为1~2μm,最大可达70μm,多呈近圆形、扁圆形、多角形和不规则形,按成因可分为压实应力屏蔽孔、成岩自生孔、溶蚀孔、生排烃扩张孔、有机质孔和硅藻残留孔6类;压实应力屏蔽孔多发育在刚性矿物的两侧;成岩自生孔常发育在白云石、绿泥石、伊利石等成岩自生矿物中,以晶间孔为主;溶蚀孔多发育在碳酸盐矿物中,内部可见次生菌丝状絮凝体;生排烃扩张孔多呈垂直或近垂直成列产出,与轻质油形成的二次生烃和排烃有关;有机质孔发育在有机质内部,与植物的残留细胞及轻质油和天然气的充填有关;硅藻残留孔主要发育在硅藻内部和边缘,孔径较大,一般为数微米至数十微米。(3)研究区微米缝以顺层为主,宽一般为1~10μm,最大可达100μm,长主要为数微米至数十微米,可见毫米级;可分为成岩收缩缝、溶蚀缝、生排烃扩张缝和构造/剪切缝4类,成岩收缩缝以张性缝为主,缝弯曲,缝壁参差不齐;溶蚀缝宽度可达60~70μm,裂缝内可见自生黏土,缝两侧有黄铁矿、磷灰石和白云石等自生矿物;生排烃扩张缝两侧多锯齿状参差不齐,绕过刚性矿物;构造/剪切微米缝一般平直,有与剪切相关的其他裂缝伴生。(4)研究区不同尺度的孔、缝之间连通性较好,形成了“纳米孔+纳米缝、微米孔+微米缝、毫米孔+毫米缝”三级储集和输导体系。

鄂尔多斯盆地W102井区长6储层成岩作用研究

通过铸体薄片观察和电镜扫描等检验方法,对鄂尔多斯盆地劳山地区W102井区长6储层的储层特征及成岩作用作了研究。研究结果表明:W102井区长6储层的岩石类型主要为灰色细粒长石砂岩,储层为典型的低孔—超低孔、特低渗—超低渗储层。此外,主要成岩作用包括压实作用、胶结作用和溶蚀作用:成岩期间的压实作用为破坏性成岩作用,对储层物性的影响不具主导性;胶结作用复杂,对孔隙度的影响较大;溶蚀作用表现为建设性成岩作用,溶蚀率增大对储层孔隙度和渗透率的改善具有积极作用。

Microscopy Observations of Habitable Space in Biochar for Colonization by Fungal Hyphae From Soil

Biochar is a potential micro-environment for soil microorganisms but evidence to support this suggestion is limited. We explored imaging techniques to visualize and quantify fungal colonization of habitable spaces in a biochar made from a woody feedstock. In addition to characterization of the biochar, it was necessary to optimize preparation and observation methodologies for examining fungal colonization of the biochar. Biochar surfaces and pores were investigated using several microscopy techniques. Biochar particles were compared in soilless media and after deposition in soil. Scanning electron microscopy(SEM) observations and characterization of the biochar demonstrated structural heterogeneity within and among biochar particles. Fungal colonization in and on biochar particles was observed using light, fluorescence and electron microscopy. Fluorescent brightener RR 2200 was more effective than Calcofluor White as a hyphal stain. Biochar retrieved from soil and observed using fluorescence microscopy exhibited distinct hyphal networks on external biochar surfaces. The extent of hyphal colonization of biochar incubated in soil was much less than for biochar artificially inoculated with fungi in a soilless medium. The location of fungal hyphae was more clearly visible using SEM than with fluorescence microscopy. Observations of biochar particles colonized by hyphae from soil posed a range of difficulties including obstruction by the presence of soil particles on biochar surfaces and inside pores. Extensive hyphal colonization of the surface of the biochar in the soilless medium contrasted with limited hyphal colonization of pores within the biochar. Both visualization and quantification of hyphal colonization of surfaces and pores of biochar were restricted by two-dimensional imaging associated with uneven biochar surfaces and variable biochar pore structure. There was very little colonization of biochar from hyphae in the agricultural soil used in this study.

Preparation and characterization of porous titanium using space-holder technique

基于钛的多孔的材料能在结构的应用被使用并且医药因为他们的优秀机械性质，在提高的温度，好腐蚀抵抗和奇妙的简历相容性植入。然而，大多数过去常生产多孔的金属罐头的方法仅仅给有限的孔和控制不了的毛孔形态学。在现在的学习，用空间持有者技术的粉末冶金学的一个最新发达的方法被用来与可控制的孔制作多孔的钛。词法特征和产品的机械性质充分被调查。结果证明孔在范围 55%75% ，并且与 ∼0.72 的平均球状，吝啬的毛孔尺寸是 600 μm。高原压力在 10 MPa 和 35 MPa 之间变化。是由 Gibson-Ashby 模型，预言了高原压力与增加减少孔。

固结压力对泥岩填料孔隙分布及土水特征曲线的影响

为研究固结压力对泥岩填料孔隙分布以及土水特征曲线(SWCC)的影响,以非饱和泥岩填料为研究对象,采用压汞试验分析不同固结压力作用下的土体微观孔隙分布,探究孔隙随荷载的演变规律,并结合毛细原理提出基于压汞实验计算SWCC的方法。结果表明:土体中收缩孔隙的存在使得进-退汞曲线表现出显著的滞回性,且瓶颈效应使得压汞试验中土体小孔隙分布密度偏大,大孔隙分布密度偏小;选择分形曲线的转折点作为泥岩填料孔隙划分界限,可将其孔隙划分为5个部分,孔隙含量的变化以大中孔隙体积被压缩为主,小微和超微孔隙几乎不受固结压力的影响;干密度为1.5 g·cm^(-3)时不同固结压力作用下的土水特征曲线可采用对数曲线表示。

Diffraction of plane P waves by a canyon of arbitrary shape in poroelastic half-space (Ⅱ): Numerical results and discussion

This paper investigates in detail the nature of diffraction of plane P waves around a canyon in poroelastic half-space, and studies the effects of incident frequency, drainage condition, porosity, etc, on the diffraction of waves. It is shown that the surface displacement amplitudes of the drained case are close to those of the undrained case, however, the surface displacement amplitudes of the dry case are very different from those of the saturated (either drained or undrained) cases. There are large phase shift between the dry case and the saturated cases, as well as slightly longer resultant wave-lengths for the undrained case than those for the drained case and longer resultant wavelengths for the drained case than those for the dry case. For small porosity the surface displacement amplitudes for the saturated cases are almost identical to those for the dry case; while for large porosity, the effect of drainage condition becomes significant, and the surface dis-placement amplitudes for the undrained case are larger than those for the drained case. As the incident frequency increases, the effect of porosity becomes significant, and more significant for the undrained case than that for the drained case. As the porosity increases, the pore pressures increase significantly but their oscillations become smoother. As the incident frequency increases, the pore pressures become more complicated.

Microscopic oil occurrence in high-maturity lacustrine shales:Qingshankou Formation,Gulong Sag,Songliao Basin

Occurrence and mobility of shale oil are prerequisites for evaluating shale oil reserves and prioritizing exploration targets,particularly for heterogeneous lacustrine shales.The Qingshankou Formation in the Gulong Sag,Songliao Basin is a classic lacustrine pure shale reservoir that contains abundant shale oil resources.The predicted geological reserves of the shale are 1.268×10^(9) t.In this study,field emission scanning electron microscope(FE-SEM),the modular automated processing system(MAPS),pyrolysisgas chromatography(Py-GC),low-pressure nitrogen gas adsorption(LPNA),Soxhlet extraction,pyrolysis,and 2-D nuclear magnetic resonance(NMR)were integrated to describe the shale oil components,microscopic occurrence,mobility,and the effective pore size distribution.Meanwhile,the related controlling factors are discussed.The shale oil in the Qingshankou Fm exists dominantly in the matrix pores of the clay minerals,with small amounts distributed in the intergranular pores of terrigenous clastic grains,intercrystalline pores of pyrite,intragranular pores of ostracod shells,and micro-fractures.Shale oil is distributed in the pore spaces of variable sizes in different lithofacies.The clay mineral-laminated shales are characterized by the broadest range of pore size and largest volume of pore spaces with shale oil distribution,while the ostracod-laminated shales have limited pore spaces retaining oil.Furthermore,the proposed integrated analysis evaluates the shale oil molecules existing in two states:movable,and adsorbed oil,respectively.The result illustrates that movable oil takes up 30.6%e79.4%of the total residual oil.TOC,mineral composition,and pore structures of the shale joint together to control the states and mobility of the shale oil.TOC values are positively correlated with the quantities of shale oil regardless of the state of oil.The mineral components significantly impact the state of shale oil.Noticeable differences in the states of oil were observed following the changing types of minerals,possibly due to their difference in adsorption capacity and wettability.Clay minerals attract more adsorbed oil than movable oil.Felsic minerals generally decrease the occurrence of total and adsorbed oil.Carbonate plays a positive role in hydrocarbon retention of all the shale oil states.As for the pore structure,the average pore size exerts a critical impact on the total,movable,and adsorbed oil content.The total pore volume and specific surface area of shales play a principal role in controlling the total yields and amounts of adsorbed oil.This research improves the understanding of the occurrence characteristics and enrichment mechanisms of shale oil in terrestrial pure shales and provides a reference for locating favorable shale oil exploration areas.

Experimental and Numerical Research on Water Transport during Adsorption and Desorption in Cement-Based Materials

The durability of cement-based materials is related to water transport and storage in their pore network under different humidity conditions.To understand the mechanism and characteristics of water adsorption and desorption processes from the microscopic scale,this study introduces different points of view for the pore space model generation and numerical simulation of water transport by considering the“ink-bottle”effect.On the basis of the pore structure parameters(i.e.,pore size distribution and porosity)of cement paste and mortar with water-binder ratios of 0.3,0.4 and 0.5 obtained via mercury intrusion porosimetry,randomly formed 3D pore space models are generated using two-phase transformation on Gaussian random fields and verified via image analysis method of mathematical morphology.Considering the Kelvin-Laplace equation and the influence of“ink-bottle”pores,two numerical calculation scenarios based on mathematical morphology are proposed and applied to the generated model to simulate the adsorption-desorption process.The simulated adsorption and desorption curves are close to those of the experiment,verifying the effectiveness of the developed model and methods.The obtained results characterize water transport in cement-based materials during the variation of relative humidity and further explain the hysteresis effect due to“ink-bottle”pores from the microscopic scale.

Fine-tuning of pore-space-partitioned metal-organic frameworks for efficient C_(2)H_(2)/C_(2)H_(4) and C_(2)H_(2)/CO_(2) separation

Acetylene (C_(2)H_(2)) and ethylene (C_(2)H_(4)) both are important chemical raw materials and energy fuel gasses.But the effective removement of trace C_(2)H_(2)from C_(2)H_(4)and the purification of C_(2)H_(2)from carbon dioxide(CO_(2)) are particularly challenging in the petrochemical industry.As a class of porous physical adsorbent,metal-organic frameworks (MOFs) have exhibited great success in separation and purification of light hydrocarbon gas.Herein,we rationally designed four novel MOFs by the strategy of pore space partition(PSP) via introducing triangular tri(pyridin-4-yl)-amine (TPA) into the 1D hexagonal channels of acs-type parent skeleton.By modulating the functional groups of linear dicarboxylate linkers for the parent skeleton,a series of isoreticular PSP-MOFs (SNNU-278-281) were successfully obtained.The synergistic effects of suitable pore size and Lewis basic functional groups make these MOFs ideal C_(2)H_(2)adsorbents.The gas adsorption experimental results show that all MOFs have excellent C_(2)H_(2)uptakes.Specially,SNNU-278demonstrates a high C_(2)H_(2)uptake of 149.7 cm3/g at 273 K and 1 atm.Meanwhile,SNNU-278-281 MOFs also show extremely great C_(2)H_(2)separation from CO_(2)and C_(2)H_(4).The optimized SNNU-281 with highdensity hydroxy groups exhibits extraordinary C_(2)H_(2)/CO_(2)and C_(2)H_(2)/C_(2)H_(4)dynamic breakthrough interval times up to 31 min/g and 17 min/g under 298 K and 1 bar.

Fractal analysis of polyferric chloride-humic acid(PFC-HA) flocs in different topological spaces

The fractal dimensions in different topological spaces of polyferric chloride-humic acid(PFC-HA) flocs,formed in flocculating different kinds of humic acids(HA) water at different initial pH(9.0,7.0,5.0) and PFC dosages,were calculated by effective densitymaximum diameter,image analysis,and N2 absorption-desorption methods,respectively. The mass fractal dimensions(Df) of PFC-HA flocs were calculated by bi-logarithm relation of effective density with maximum diameter and Logan empirical equation. The Df value was more than 2.0 at initial pH of 7.0,which was 11% and 13% higher than those at pH 9.0 and 5.0,respecively,indicating the most compact flocs formed in flocculated HA water at initial pH of 7.0. The image analysis for those flocs indicates that after flocculating the HA water at initial pH greater than 7.0 with PFC flocculant,the fractal dimensions of D2(logA vs. logdL) and D3(logVsphere vs. logdL) of PFC-HA flocs decreased with the increase of PFC dosages,and PFC-HA flocs showed a gradually looser structure. At the optimum dosage of PFC,the D2(logA vs. logdL) values of the flocs show 14%-43% difference with their corresponding Df,and they even had different tendency with the change of initial pH values. However,the D2 values of the flocs formed at three different initial pH in HA solution had a same tendency with the corresponding Df. Based on fractal Frenkel-Halsey-Hill(FHH) adsorption and desorption equations,the pore surface fractal dimensions(Ds) for dried powders of PFC-HA flocs formed in HA water with initial pH 9.0 and 7.0 were all close to 2.9421,and the Ds values of flocs formed at initial pH 5.0 were less than 2.3746. It indicated that the pore surface fractal dimensions of PFC-HA flocs dried powder mainly show the irregularity from the mesopore-size distribution and marcopore-size distribution.

松辽盆地古龙凹陷青山口组页岩油储层中有机质微孔特征

页岩油储层中的有机质一直是页岩油研究的重点。用电子背散射(HDBSD)详细地研究了松辽盆地古龙凹陷古龙页岩油储层中的有机质中的微孔,发现了古龙页岩油储层有机质中的微孔非常发育。有机质微孔可以分为4种类型:①结构镜质体微孔;②均质镜质体微孔;③沥青质体微孔;④有机黏土微孔。有机质微米孔的直径多在1μm到数微米,圆形、近圆形或不规则;研究还发现,古龙页岩油储层中的孔隙度与有机碳呈一定的正相关关系。对有机质中的微孔孔隙度进行了初步的定量分析,获得了平均值为22.39%;初步计算表明有机微孔对储层孔隙度总的贡献在0.44%左右(有机碳取2.0%)。有机质中的微米孔(包括其他微米孔)可以与更高一级的微缝和页理缝互相联结,构成了一个很好的空间连通网络系统,为松辽盆地古龙页岩油的有效开发奠定了物质基础。

纤维对超高性能混凝土力学性能及微观结构影响研究

将玄武岩纤维、玻璃纤维和聚丙烯纤维按照不同掺量(0、0.2%、0.4%、0.6%、0.8%)分别掺入水胶比为0.18的超高性能混凝土(ultra high performance concrete,UHPC)中,研究不同纤维和掺量对UHPC抗压强度和抗折强度的影响。优选出单掺玄武岩纤维、玻璃纤维以及聚丙烯纤维力学性能最佳的掺量;测定玄武岩纤维、玻璃纤维以及聚丙烯纤维最佳掺量下UHPC孔隙结构,并通过SEM表征其微观结构,探究不同种类纤维对UHPC力学性能影响的机理。试验结果表明,玄武岩纤维和玻璃纤维掺量为0.4%,聚丙烯纤维掺量为0.2%时,UHPC基本力学性能达到最优。压汞试验结果表明,纤维的掺入能够有效降低孔隙及裂缝的数量,提高无害孔和少害孔的数量,并细化大孔径促使有害孔和多害孔往少害孔和无害孔转变。SEM试验结果显示:纤维的加入能够减少裂缝和细化孔径,使试件内部更加致密;同时均匀分布的纤维在试件内部构成网状结构,当承受荷载时,纤维对荷载进行分散,使得裂缝发展需要消耗更多的能量。

渤海湾盆地沧东凹陷孔二段页岩储层特征及页岩油可动性评价

渤海湾盆地沧东凹陷孔二段页岩油资源丰富,但对于页岩油的储层特征、油气赋存、可动性及其关联性研究较少。为此,采用氩离子抛光-场发射扫描电镜、中子散射、高压压汞、低温氮气吸附等实验,对孔二段页岩油储层开展微观孔隙结构描述,对比抽提前后的孔体积之差与饱和-离心核磁共振结果,揭示了页岩油赋存及可动性特征。研究结果表明:孔二段页岩主要发育纳米级的粒间孔、溶蚀孔、有机质孔及微米级的微裂缝等储集空间;页岩油主要赋存于直径为20~40 nm和80~200 nm的孔隙中;长英质页岩具有较高的可动油饱和度,表明其具有更好的孔隙连通性和渗流能力,有利于页岩油的运移。页岩储层中矿物含量和孔隙结构共同控制了页岩油的可流动性。孔径小于50 nm的孔隙具有较大的比表面积,对页岩油的吸附能力较强,不利于页岩油的流动。该研究成果对页岩油的勘探开发具有重要指导意义。

离子界面反应对土壤孔隙状况的影响机制

[目的]分析不同价态离子对土壤颗粒表面电荷性质、颗粒间净作用力的变化规律,阐明离子界面颗粒的相互作用对孔隙状况的影响机制。[方法]利用工业CT扫描技术,对不同价态离子条件下的土壤孔隙状况进行测定,并分析了其形成的土壤孔隙特征差异。[结果]①Mg^(2+)体系下土体中孔隙数量远大于Na^(+)体系孔隙数量,为其1.43倍,其中,>1 mm孔隙数量分别占1.43%,1.06%。②Mg^(2+),Na^(+)体系土体中>1 mm土壤孔隙体积占所有孔隙体积比例分别为50.4%,40.2%;而且,Mg^(2+)体系下土体中>1 mm土壤孔隙体积是Na^(+)体系的1.42倍,Na^(+),Mg^(2+)体系土体中土壤孔隙度分别为2.06%,2.35%。③随着Na^(+),Mg^(2+)浓度升高,紫色土的表面电位分别从-391.7 mV降至-96.7 mV,从-167.3 mV降至-67.0 mV。在相同浓度下,紫色土表面电位(绝对值)表现为Na^(+)大于Mg^(2+)。④随着Na^(+),Mg^(2+)浓度的升高,土壤颗粒间净作用力呈减小规律,在同一浓度下,Mg^(2+)体系下紫色土颗粒间静电斥力小于Na^(+)体系,同时,在Na^(+),Mg^(2+)体系下,紫色土胶体颗粒间表现为净引力的临界浓度值分别为0.1 mol/L,0.005 mol/L。[结论]Na^(+),Mg^(2+)通过改变紫色土颗粒表面电荷性质,进而引起土壤颗粒间相互作用力发生变化,最终影响土壤的孔隙状况。

多元复合超细掺合料制备混凝土内部结构研究

研究多元复合超细掺合料制备混凝土内部结构的变化规律。结果表明:高活性超细矿物掺合料替代率为30%时,新拌混凝土性能优良,混凝土出机坍落度245 mm、扩展度700 mm,7 d抗压强度49.0 MPa、28 d抗压强度65.6 MPa,可明显改善混凝土工作性能且能保证较高的力学性能。超细掺合料的加入可改善胶凝材料颗粒分布,提高密实度。混凝土总孔隙率降低42.1%,200 mm以上孔隙率降低39.6%,混凝土气泡间距系数降低21.9%,同时可减少混凝土内部气泡的生成。

离子特异性效应对紫色土孔隙状况的影响机制研究

土壤孔隙对土壤水分和养分迁移及水土保持有着关键作用,不同离子条件下土壤颗粒相互作用控制着土壤团聚体稳定性,而土壤团聚体形成和结构对土壤孔隙状况起重要影响。紫色土是三峡库区代表性土壤之一,探究离子特异性效应下颗粒的相互作用对紫色土孔隙状况的影响,对三峡库区水土生态环境安全具有重要意义。采用工业CT扫描技术和联合测定法分别对不同类型离子条件下的土壤孔隙状况和颗粒表面电荷性质进行测定,并分析其形成土壤孔隙特征差异原因。结果表明,(1)当浓度为0.01 mol·L^(−1)时,Cs^(+)体系下土壤孔隙的数量分别是Li^(+)、Na^(+)和K^(+)体系下的2.90、2.23和1.44倍,其中,Li^(+)、Na^(+)、K^(+)和Cs^(+)体系下>1 mm孔隙数量分别占0.33%、1.06%、1.57%和1.88%;同时,Cs^(+)体系下土壤最大孔隙的直径分别是Li^(+)、Na^(+)、K^(+)体系下的1.97、1.81、1.30倍。(2)当浓度为0.01 mol·L^(−1)时,Li^(+)、Na^(+)、K^(+)、Cs^(+)体系土体中>1 mm土壤孔隙体积占所有孔隙比例分别为22.7%、40.1%、56.5%、59.9%,并且,Cs^(+)体系下土体中>1 mm土壤孔隙体积分别为Li^(+)、Na^(+)、K^(+)体系的13.70、5.22、2.70倍;同时,土壤孔隙度在Li^(+)、Na^(+)、K^(+)、Cs^(+)体系下分别为1.36%、2.06%、2.84%、7.22%。(3)在测定孔隙相同离子浓度条件下,Li^(+)、Na^(+)、K^(+)、Cs^(+)体系中紫色土颗粒表面电位分别为−210.34、−198.63、−186.29、−175.57 mV,绝对值表现为Li^(+)>Na^(+)>K^(+)>Cs^(+),进一步计算发现,在相同颗粒间距离3 nm时,Li^(+)、Na^(+)、K^(+)、Cs^(+)体系下颗粒间净作用力分别为4.68、3.90、2.32、−0.15 atm,同样表现为Li^(+)>Na^(+)>K^(+)>Cs^(+)。该研究表明Li^(+)、Na^(+)、K^(+)、Cs^(+)通过改变紫色土表面电荷性质,进而引起土壤颗粒间相互作用力发生变化,最终影响土壤的孔隙状况。

基于微电阻率成像测井的致密碳酸盐岩孔隙空间参数定量表征技术及其应用

孔隙空间参数测井定量表征是致密碳酸盐岩储层有效性评价的核心难点。基于致密碳酸盐岩地层特征,通过岩心分析孔隙度、分析渗透率,结合铸体薄片数据、压汞孔喉分布资料刻度电成像测井资料,探索建立一套致密碳酸盐岩孔径分布谱的转换方法,并基于此建立了微孔、细孔、中孔、粗孔、洞5种孔隙组分孔隙度及地层渗透率计算方法,实现了致密碳酸盐岩孔隙空间参数定量表征评价。该技术在鄂尔多斯盆地50多口气探井的致密碳酸盐岩储层中得到良好应用,有助于认识储层、判断储层的有效性,能够快速、精准优选试气射孔井段,可助力新领域、新层系勘探获得重大发现和突破。