Characterization of Indian Bentonite Clay Samples for Water-based Drilling Fluids

Abstract

The rheological properties and filtration loss property of water-based drilling fluids greatly depends upon the quality and quantity of the bentonite clay, as well as the additives that are used in their formulations. To ascertain the quality of the bentonite clay, three raw Indian bentonite clays have been characterized using X-ray diffraction techniques and X-ray fluorescence techniques. The physicochemical properties, like swelling index, cation exchange capacities, and yield of clay, have also been carried out using standard API recommended procedures. The laboratory investigation reveals that these three bentonite clays are quite suitable for the development of water-based oil well drilling fluids.     

Cyclohexane Dehydrogenation Using an Economical Iron Catalyst: Influence of Alumino-Silicate Structure on the Catalytic Activity

Abstract

The effect of mixing both local Egyptian hematitic ore and activated aluminosilicate material (bentonite clay) on the dehydrogenation activity of the former was studied.

Three mixtures were prepared in which bentonite percentages were 10, 20, and 40 wt%. Cyclohexane used as a model reactant for the catalytic dehydrogenation reaction carried out in catalytic flow system within reaction temperature ranged from 150 to 500°C in the presence of hydrogen stream (75 mL/min) and at constant space velocity 3.71 h^?1.

The results obtained indicated that in spite of the drop in the selectivity of the local material toward benzene formation by clay addition, a distinct increase in the benzene yield was observed. The maximum conversion attained ～28.14% at reaction temperature 500°C using a mixture containing 20 wt% activated bentonite.     

RHEOLOGICAL BEHAVIOR OF BENTONITE SUSPENSIONS

ABSTRACT

The objective of this research is to investigate the concentration effect on the rheological properties of different bentonite suspensions. Experiments were performed with different bentonite type and concentrations and the results were evaluated by different rheological models (Bingham plastic, Power law, Sisco, Casson, Herchel Bulkley and Robertson Stiff) describing the flow of non-Newtonian fluids by mathematical equations in terms of shear rate and shear stress.     

Electrical resistivity and rheological properties of sensing bentonite drilling muds modified with lightweight polymer

In this study, the electrical resistivity and rheological properties of a water-based bentonite clay drilling mud modified with the lightweight polymer (guar gum) under various temperature were investigated. Based on the experimental and analytical study, the electrical resistivity was identified as the sensing property of the bentonite drilling mud so that the changes in the properties can be monitored in real-time during the construction. The bentonite contents in the drilling muds were varied up to 8% by the weight of water and temperature was varied from 25 °C to 85 °C. The guar gum content (GG%) was varied between 0% and 1% by the weight of the drilling mud to modify the rheological properties and enhance the sensing electrical resistivity of the drilling mud. The guar gum and bentonite clay were characterized using thermal gravimetric analysis (TGA). The total weight loss at 800 °C for the bentonite decreased from 12.96% to 0.7%, about 95% reduction, when the bentonite was mixed with 1% of guar gum. The results also showed that 1% guar gum decreased the electrical resistivity of the drilling mud from 50% to 90% based on the bentonite content and the temperature of the drilling mud. The guar gum modification increased the yield point (YP) and plastic viscosity (PV) by 58% to 230% and 44% to 77% respectively based on the bentonite content and temperature of the drilling mud. The rheological properties of the drilling muds have been correlated to the electrical resistivity of the drilling mud using nonlinear power and hyperbolic relationships. The model predictions agreed well with the experimental results. Hence the performance of the bentonite drilling muds with and without guar gum can be characterized based on the electrical resistivity which can be monitored real-time in the field.     

环保水基钻井液用聚合物M-TSP的合成与性能评价

针对环保水基钻井液在应用中存在流变性能不理想、滤失量较高、稳定性较差、与常规添加剂配伍性差和滤液对储层伤害较大的问题,以马来酸酐、罗望子胶(TSP)和三乙胺为主要原料制得天然可生物降解聚合物改性罗望子胶(M-TSP),在质量分数为4.5％的膨润土悬浮液中加入不同浓度的M-TSP得到聚合物膨润土悬浮液,研究了M-TSP膨...     

新型聚酰胺-胺树枝状聚合物页岩抑制特性研究

树枝状聚合物由于其独特的分子结构和特性，近年来日益受到关注。聚酰胺-胺（PAMAM）作为研究最为成熟的树枝状聚合物，目前已在各领域得到应用，并在油田化学方向发挥潜力。采用抑制膨润土造浆实验、页岩滚动分散实验和粒度分布测试综合评价不同代数聚酰胺-胺树枝状聚合物的抑制性，借助表面张力、Zeta电位测试和X-射线衍射等表征测试了不同代数聚酰胺-胺的特性。结果表明，不同代数（G0~G5）聚酰胺-胺树枝状聚合物均具有优良的抑制性，其中G0和G5抑制性优于传统的KCl和国外聚胺Ultrahib。不同代数树枝状聚合物在黏土层间的吸附状态与其浓度有关，低浓度下为单层吸附，高浓度下为双层吸附。聚酰胺-胺树枝状聚合物表面胺基密度高，水溶液中部分质子化后，通过静电作用、氢键作用等强吸附在泥页岩表面，降低黏土水化斥力，排挤出层间水分子，抑制泥页岩水化分散。      

杂多糖苷水基钻井液稳定性研究

运动中的黏土颗粒表面与溶液电中性介质形成的电动电位决定了黏土的流变学性质和渗透性质。黏土颗粒的电动电位变化是钻井液流变性能变化的依据。为此，进行了实验室试验：将不同量杂多糖苷加入4%膨润土基浆中，分别复配聚丙烯酸钾、木质素磺酸盐，测定钻井液流变性能参数，并以电泳法测定杂多糖苷钻井液黏土颗粒的电动电位。结果表明：杂多糖苷（SJ）2%～6%添加量，3%SJ与0.1％～0.5％木质素磺酸盐，或3%SJ与0.1％聚丙烯酸钾复配，钻井液具有良好的稳定性和流变性。     

疏水纳米SiO2抑制黏土膨胀机理

纳米减阻技术是针对高压欠注问题研发的一项有效新技术,其减阻机理尚不十分明确。疏水纳米材料抑制黏土的膨胀是纳米减阻机理之一。采用一种适用于疏水纳米粉体防膨率的测试方法,测试了多种疏水纳米SiO₂对黏土的防膨率。采用吸附实验和扫描电子显微镜（SEM）研究了纳米颗粒在岩心表面的吸附特征。防膨实验结果显示,所测疏水纳米SiO₂大多具有一定的防膨作用,但防膨效果差异较大。纳米SiO₂的表面修饰剂以及纳米粉体与黏土的比值(纳土比)对防膨效果有较大的影响,合适的纳土比和表面修饰材料可达到较好的防膨效果。HNP2在纳土比为1∶25时,防膨率为46.9%,而HNP4在纳土比为1∶25时,防膨率却为-25.8%。SEM照片显示,疏水纳米SiO₂通过吸附作用在岩心表面形成了纳米颗粒层,使岩心表面具有了强疏水特性,接触角达到138.3°。研究表明,疏水纳米SiO₂通过在黏土矿物表面吸附,形成具有强疏水特性的隔离层,起到隔离水分子与黏土矿物的作用,从而产生了防膨效果,这与一般黏土稳定剂的防膨机理有所不同。     

废水基钻井液中固相颗粒电吸附选择性实验

废水基钻井液是油气勘探开发主要废物之一,提高再生回用率是钻井弃物处理技术的迫切需要。为了给废钻井液电吸附再生回用工艺技术开发和实验装置升级改造提供可靠依据,利用自制的废水基钻井液动态电吸附实验装置,开展了动态模拟电吸附对废钻井液中固相颗粒选择性去除实验研究,考察了对废钻井液中钻屑颗粒的电吸附效果,并评估了装置的运行稳定性和适用性。研究表明,电化学吸附对膨润土钻井液中的钻屑颗粒具有选择性吸附作用,尤其是对低于30 μm颗粒吸附效果显著,且对膨润土钻井液的流变性、膨润土当量等指标影响不大,有效剔除钻井液中的劣质固相的同时保持了膨润土钻井液的稳定性,提高了钻井液回用性能指标,表明电化学吸附工艺是提高水基钻井废物循环利用和资源化利用率的有效途径。     

Rheological and wall-slip behaviour of composite propellant suspension containing Al-nanopowder

ABSTRACT

Hydroxyl terminated polybutadiene composite propellant suspension mainly containing ammonium perchlorate (70%) and aluminium nanoparticles (ANP) (0–6%) was evaluated rheologically to determine the effect of wall slip occurring due to the formation of an apparent slip layer. True rheological properties have been obtained from gap-dependent steady-shear data using Tikhonov regularization method for the composite suspension. The advantage of this method is that it converts the gap-dependent steady-shear data into true rheological properties. The two-stage method can successfully establish both the true shear stress vs. shear rate behaviour and wall-slip parameters. The errors during rheological experimentation are analysed by determining the slip velocities and slip layer thickness. Slip velocity is observed to increase linearly with shear stress. Also, the slip layer thickness decreases with the increase in ANP content in the composite suspension. The maximum slip layer thickness of 2.13 µm is obtained for composition in which ANP is absent, and the same decreased to 0.24 µm for the composition containing 6% ANP. The rheological measurements show least deviation from gap-independent values as the amount of ANP in the propellant increases. Finally, a correlation of apparent slip layer thickness with normalized filler fraction is investigated to check the effect on wall-slip behaviour.     

Improving the performance of clay from Gabal Um Qumar as drilling mud

The main component of water base drilling fluids to perform common properties that facilitate safe and satisfactory drilling is bentonite operations. This paper represents composition and treatment capability of clays collected from clayston quarries in Gabal um Qumar north Cairo-Ismailia Desert Road, Egypt for its application as water base drilling mud. Chemical analysis, XRD and particle size distribution showed that these clays consist of montmorillonite. The rheological properties of the prepared suspension from these clay samples and its activation products by using chemicals and polymers were investigated. Results of untreated samples indicate that they cannot be used as a drilling mud but after activation processes by soda ash, Carboxi Methyl Cellulose (CMC) and Drispac Polymer significant changes were observed in yield and rheological properties. Accordingly this type of clay after activation by polymer can be classified as sub-bentonite and classified between bentonite grade and medium bentonite grade that can be used as drilling mud for medium depth wells.     

Analysis of influence factors of methane adsorption capacity of the Lower Silurian shale

Abstract

The Lower Silurian marine shale gas in South China has great potential. In order to study the influence factors of methane adsorption capacity of the marine shale in Sangzhi block, six samples from the Lower Silurian were investigated by a series of experiments. The total organic carbon (TOC) content ranges from 1.97 to 3.49% and organic matter are in the state of over-maturity. The dominant mineralogical compositions are quartz and clay minerals. The methane adsorption capacity of the studied shale ranges from 1.5627 to 2.2033?cm³/g, and is mainly influenced by the TOC content.     

含纳米级有机改性膨润土润滑液的极压性能

在实验室制备了低含量的有机改性膨润土油基悬浮液，考察了膨润土在油中的分散稳定性和该悬浮液的润滑性能。TEM电镜照片显示粒子已在晶层厚度上达到纳米数量级，并有较好的分散稳定性。四球试验结果表明，该悬浮液具有较好的极压性能，抗磨性能一般，MTM试验显示该悬浮液对摩擦系数影响不大。表面分析结果显示，并未在磨斑表面检测出膨润土相关元素，推测可能是膨润土片层起单纯的隔离作用，使油基液有一定的极压性能。     

Platinum-tin/Alumino-silicate Catalyst Preparation and Characterization

Abstract

Kaolinite and bentonite clay materials were used as support for preparing Pt, Sn, and platinum-tin (Pt-Sn) catalysts. The preparation of different catalysts (either mono- or bi-metals) was carried out via the conventional impregnation technique using a rota-evaporator. For preparing Pt or Sn catalysts, either chloroplatinic acid or tin chloride solutions were used. For bi-metal catalysts, a complex solution of both metal precursors (Pt and Sn) was used. All catalysts were physically characterized using different techniques: X-ray diffraction analysis, differential scanning calorimetry, and transmission electron microscope. The analyses clarify the role of the type of support and the effect of adding tin on Pt catalyst. The structure of support clay materials plays a significant role in controlling the interaction occurring between the impregnated metals and the clay support materials.     

CO2 adsorption on systems involving ethylenediamine impregnated on nanoporous materials

Abstract

MCM-41 and MCM-48 materials were synthesized by the hydrothermal method, calcined and modified with ethylenediamine (EDA) by wet impregnation method. The X-ray diffraction patterns showed characteristic peaks of highly ordered MCM-41 and MCM-48 nanoporous materials, even after impregnation with amine. The MCM-41 and MCM-48 materials showed N₂ adsorption isotherms type IV and BET surfaces areas higher than 1000?m² g^?1. The carbon dioxide adsorption tests were carried out at room temperature in a magnetic suspension microbalance. The materials presented good performance for CO₂ capture, being favorable for applications where medium and high pressures are required.     

聚合物纳米微球封堵剂CQ-NSA性能研究

针对页岩储层纳米级孔缝封堵的问题,研究了水基钻井液聚合物纳米微球封堵剂CQ-NSA的分散性、封堵性与配伍性。通过超声分散,其粒度中径为82.14;采用常规高速搅拌,17.5%的颗粒仍保持纳米级分布。将CQ-NSA加入膨润土浆中,总颗粒中仍有 6%的颗粒呈纳米级分布。CQ-NSA加量在1.0之间可以显著降 低滤饼渗透率!有效降低膨润土浆与体系配方的高温高压渗透封堵仪滤失量,表明CQ-NSA具有良好的封堵性能。流变性能分析结果表明,CQ-NSA加量不超1.5%,对膨润土浆与水基钻井液体系的流变性能影响不大,具有较好的配伍性能。该研究为页岩气水基钻井液用纳米封堵剂提供了理论与实验依据。     

Evaluation of Egyptian bentonite and nano-bentonite as drilling mud

Nano-particles of bentonite have been prepared by nano-grinding. The nano-bentonite was characterized by X-ray fluorescence analysis (XRF), X-ray powder diffraction (XRD), thermal gravimetric analysis (TGA) and Transmission electron microscopy (TEM). The bentonite particles had been ground to the size ranging from 4 to 9 nm. Both natural and nano-bentonite were evaluated as drilling mud. The evaluation involved the study of the rheological properties, filtration and gel strength before and after treatment with viscosities and filter loss agent, and compared with the American Petroleum Institute API bentonite. With decreasing the grain size of bentonite to the nano-scale, the results were not satisfied to the API -standard.     

Formation mechanism of micro-flows in aqueous poly（ethylene oxide） droplets on a substrate at different temperatures

The drying of aqueous poly(ethylene oxide)(PEO) droplet on a substrate at different temperatures was studied.It was found that the contact line receded when the substrate was at a temperature above 60 oC.Different nucleation behavior and surface profiles of PEO films were found in different droplets drying processes.The rheological properties of aqueous PEO solutions were studied to understand the mechanism of contact line recession and micro-flow in drying aqueous PEO droplets.It was found that at low temperature,the contact line was static because of great viscous stress;while at high temperature,it receded because of great Marangoni force and the decrease of viscous stress.It was indicated that Marangoni convection was inhibited by the outward capillary flow and viscous stress at low temperature,whereas it became dominant at high temperature.Two types of mechanism for surface profiles and nucleation of PEO film from drying droplets are proposed,providing a theoretical guide for polymer solution application in oil and gas foam flooding technology.     

Interaction of alkali, alkaline-earth and sulphate ions with clay minerals and sedimentary rocks

Ion-exchange isotherms of kaolinite and montmorillonite for calcium, barium and sulphate ions in a solution at constant pH near neutral have been examined. The ionic strength of the solutions ranged from seawater to formation waters from oil reservoirs in the North Sea. ⁴⁵Ca-, ¹³³Ba- or ³⁵SO₄-tagged solutions with added NaCl as supported electrolyte were used for adsorption measurements. From distribution coefficients found for CaCl₂/NaCl or BaCl₂/NaCl in the clay suspensions, the adsorbed quantities of divalent cations can be predicted for sedimentary rocks with a given mineralogical composition. These results show that the equivalent ionic fractions of alkaline-earth ions adsorbed on clay pretreated with seawater, or formation water, fit the normalized isotherms obtained for the calcium-sodium exchange on the clay within uncertainties of ± 10%. The same correlation was not found for sulphate adsorption from seawater because the clay minerals pretreated with seawater were less reactive for sulphate adsorption. These results suggest that in addition to adsorption due to electrostatic forces, some ions were chemisorbed to the clay minerals during the pretreatment with seawater. The lower sulphate adsorption may be due to ion pair formation.     

FLOCCULATION OF ASPHALTENES IN HEAVY OIL AT ELEVATED TEMPERATURES

ABSTRACT

It has been observed that there is a dispersed phase of particles in vacuum residue that is associated with the heptane insoluble asphaltenes. The particles are in the size range of 100 Aˇ. In this paper we present rheological and small angle X-ray scattering(SAXS) data for the vacuum residue of Arabian Medium/Heavy crude oil that suggests the dispersed particles flocculate at elevated temperatures. We find the asphaltenic particles are stabilized below 200 ^° C against the attractive dispersion forces between asphaltenic particles by an adsorbed layer of non-asphaltenic molecules. However the strength of the interaction holding the adsorbed layer to the particles is only about 1.8 kcal/mole(3kT), and so this layer is dissipated as the temperature is increased. We estimate the particles are unprotected at 200 ^°C. The strength of the attraction due to the dispersion force is about 7kT in this state, and so the dispersion becomes thermodynamically unstable with respect to flocculation. Additionally, the driving force for flocculation is augmented by the formation of particles in the non-asphaltenic phase at elevated temperatures. The appearance of these particles increases the osmotic pressure, and forces the asphaltenic particles together. We suggest the asphaltenic phase formed by flocculation, well below the temperatures at which chemical reactions occur, is the precursor to the coke-producing phase in the reacting residue discussed by Wiehe.