Effects of Walnut Shells on the Rheological Properties of Water-Based Drilling Fluids

Abstract

In this research, three different water-based drilling fluids were prepared according to American Petroleum Institute (API) standards, and effects of walnut shells on the rheological properties of the samples were studied. The walnut shells of 2-, 4-, and 6-mm samples and their equal weight mixtures of 2–4 mm and 4–6 mm were added to the drilling fluid samples in different concentrations. The aim of this study is to determine the optimum walnut shell size, concentration and polymer concentration to minimize the fluid loss during drilling operations. It was observed that polymer (XT) has the optimum effects on the water-based drilling fluid. The optimum concentration of polymer (XT) with the 6-mm walnut shell is determined as 0.4 g/350 ml.     

提高井壁稳定性的途径及水基防塌钻井液研究与应用进展

针对泥页岩地层黏土含量高,容易水化,导致钻井过程中出现严重坍塌和膨胀缩径,以及严重造浆等问题,从4个方面(合适的钻井液密度,提高钻井液的抑制性,减少钻井液滤液进入地层,强化封堵)阐述提高井壁稳定性的途径,介绍国内在钻井用化学剂方面开展的研究工作,同时介绍近年来出现的通过添加不同新型化学抑制剂形成的强抑制水基钻井液,如聚合醇钻井液、强抑制胺基钻井液、有机硅聚合物钻井液、有机盐钻井液、甲基葡萄糖苷钻井液等.提出围绕提高井壁稳定性的研究方向:提高对钻井液中低密度固相控制的认识,重点考虑固相化学控制剂的研究,通过低密度固相的控制,提高钻井液抑制性;考虑在现场钻井液检测性能中增加抑制性检测指标和方法;以低相对分子质量聚胺为代表的钻井液抑制剂是阳离子钻井液的新发展,应加强其机理研究;重视铝基化合物或络合物的研发,强化钻井液的抑制性及封堵作用.     

UV-cured polymer electrolytes encompassing hydrophobic room temperature ionic liquid for lithium batteries

We demonstrate herewith the application of in situ one-shot free radical photo-polymerisation (UV-curing) process to incorporate room temperature ionic liquids (RTILs) into polymer membranes which can be used as electrolytes for lithium-based batteries. The reactive formulation for the preparation of the polymer membranes was based on a dimethacrylic oligomer (BEMA). The polymer electrolyte membranes were synthesized by UV radiating a mixture of BEMA and a proper radical photo-initiator with different compositions of 1-ethyl-3-methylimidazolium bis(perfluoroethylsulfonyl)imide [EMIPFSI] and, additionally, LiTFSI as lithium source.Stable and flexible polymer films with good mechanical integrity can easily be produced with varying the EMIPFSI content by using this method. Remarkable values of ionic conductivity were obtained even at ambient temperature. Galvanostatic charge/discharge cyclability tests were performed on the polymer electrolyte membranes by constructing a cell using LiFePO₄ as cathode and Li metal as anode. The preliminary results are interesting, exhibiting good reversibility and cyclability.     

Effect of nanoscopic confinement on improvement in ion conduction and stability properties of an intercalated polymer nanocomposite electrolyte for energy storage applications

Nanoscopic confinement of a cation coordinated polymer in the channels of organo-modified montmorillonite clay results in substantial improvement in conductivity, cation transport and stability properties required for energy storage/conversion devices. X-ray diffraction analysis confirms composite formation as evidenced by: (i) intercalation of PEO₈-LiClO₄ into the clay channels for clay loading ≥7.5 wt.% and (ii) partial intercalation/exfoliation for a lower clay loading (≤5 wt.%). Transmission electron microscopy analysis corroborates these findings as indicated by an enhancement in clay gallery width from 6 to 9 Å for 20 wt.% clay providing evidence for intercalation at higher clay loadings. Energy dispersive X-ray dot-mapping images confirm the homogeneous distribution of clay in nanocomposites. Thermal analysis indicates a strong dependence of thermodynamic parameters, e.g., glass transition (T_g), crystalline melting (T_m), melting enthalpy, glass transition width (ΔT_g), and thermal relaxation strength (ΔC_p), on clay concentration. These observations agree well with changes in electrical properties on nanocomposite formation. Substantial enhancement in ambient conductivity (∼208 times) occurs in a nanocomposite film (2 wt.% clay) relative to a clay-free film. The temperature dependence of conductivity obeys Arrhenius behaviour below T_m and the VTF (Vogel-Tamman-Fulcher) relationship above T_m. The ionic transport number (∼99.9%) confirms ionic charge transport with a cation contribution (tLi⁺)∼0.5 for 2 wt.% clay. It represents an increase by ∼65% in comparison with PEO₈-LiClO_4. Improvement in voltage and thermal stability is also observed with the nanocomposites.     

Electrochemical synthesis of a hydrogen storage material based on lanthanum and nickel intermetallics in the equimolar KCl–NaCl melt

Co-reduction of lanthanum and nickel ions on inert tungsten and active nickel electrodes were studied using the methods of cyclic chronovoltammetry, chronopotentiometry and open circuit chronopotentiometry in equimolar KCl–NaCl at 973 K. When both lanthanum and nickel ions are present in equimolar KCl–NaCl, the voltammetry dependences demonstrate the nickel ions reduction wave in the region of potentials –(0.00–0.1) V and lanthanum ions reduction wave in the region of potentials –(1.85–1.9) V relative to a silver chloride reference electrode. There are two more reduction waves on the opposite sides of voltammograms in the regions of potentials –(1.5–1.6) V and –(1.75–1.8) V. These waves are associated with the reduction of lanthanum ions and their depolarization on metallic nickel preliminarily deposited on the tungsten electrode, which results in the formation of intermetallic La_xNi_y phases. The (E–t) dependences of open circuit chronopotentiometry demonstrate a delay plateau, which corresponds to the time required for dissolution of separate phases of intermetallic compounds. LaNi₂ and LaNi₅ intermetallic phases were electrochemically synthesized at a definite concentration of lanthanum and nickel chlorides in equimolar KCl–NaCl. The synthesized lanthanum and nickel intermetallic compounds were characterized by the X-ray diffraction analysis, scanning electron microscopy and photon correlation spectroscopy.     

页岩气水平井钻井液技术的难点及选用原则

我国页岩气资源勘探开发已全面铺开。针对页岩气的成藏特征,页岩气开发以浅层大位移井、丛式水平井布井为主。由于页岩地层裂缝发育、水敏性强,长水平段钻井中不仅易发生井漏、垮塌、缩径等问题,且由于水平段较长,还会带来摩阻、携岩及地层污染问题,从而增大了产生井下复杂情况的几率。解决井壁稳定、降阻减摩和岩屑床清除等问题是目前页岩气水平井钻井液选择和设计的关键。选择页岩气水平井钻井液的原则是确保井壁稳定、润滑、防卡和井眼清洗。油基钻井液可提高水润湿性页岩的毛细管压力,防止钻井液对页岩的侵入,从而有效保持井壁稳定,同时还具有良好的润滑、防卡和降阻作用,是国内外目前采用最多的钻井液体系。当采用水基钻井液的时,利用低活性高矿化度聚合物钻井液或CaCl2钻井液以降低页岩和钻井液相互作用的总压力;采用浓甲酸钾、Al3+盐,可以通过脱水、孔隙压力降低和影响近井壁区域化学变化的协同作用产生良好的井眼稳定作用;对于有裂隙、裂缝或层理发育的高渗透性页岩应使用有效的封堵剂进行封堵;但对于强水敏性页岩地层,水基钻井液在抑制性方面仍然存在局限性。从环境保护的角度出发,甲基葡糖苷钻井液在井壁稳定机理方面与油基钻井液相似,未来可望作为有效的钻井液体系之一。随着以页岩气为代表的非常规油气资源的不断开发,为了满足安全钻井和环境保护的需要,未来页岩气水平井钻井液技术的研究应围绕高效、低成本水基钻井液和低毒油基钻井液来展开。     

正电性钻井液在塔河油田的应用

介绍了正电性钻井液体系的性能特点。对其性能的评价结果表明,正电性钻井液具有很强的抗钻屑固相污染、抗NaCl及CaCl2污染能力;体系性能稳定,加重后钻井液不分层;具有优良的页岩抑制性;渗透率高、保护油层效果好;对储层岩心的伤害率在15％～18％,明显小于聚合物钻井液。在油田的试验及现场应用表明．正电性钻井液完全满足钻井施工要求,能有效提高钻井速度。     

城市垃圾焚烧飞灰物理化学性质及重金属风险分析

对7种城市垃圾焚烧飞灰的物理化学性质进行了详细表征。针对飞灰中重金属成分复杂的特点对重金属含量、形态分布和浸出毒性进行了分析,并进行了风险评估指数和风险指数计算。飞灰的化学组分和晶相结构分析显示,城市垃圾焚烧飞灰中含有大量的CaO、CaSO₄、SiO₂、Al₂O₃、NaCl和KCl等化合物,具有资源化利用的潜力。但同时飞灰中含有大量的重金属,其中Pb和Cd的生态风险高,浸出毒性高于飞灰直接处理和处置要求。研究结果表明,垃圾焚烧飞灰需进行处理至达到一定要求后才能进行资源化利用。     

Effects of Polymers and CMC Concentration on Rheological and Fluid Loss Parameters of Water-Based Drilling Fluids

Abstract

Fluid loss during drilling operations has a very significant effect on both reservoir formation damage and monetary terms. There are many additives to control this unwanted phenomenon. Nevertheless, most of these substances are artificial chemicals. Thus, they are not only expensive, but also hazardous to the environment. In this article, a more natural method was applied to overcome the higher filtration problems by employing carboxyl methyl cellulose (CMC) and polymers (XT), DSHV, and MAC PR. Drilling fluids were prepared due to American Petroleum Institute (API) standards. The fluid weights were adjusted as 9 ppg. API filtration tests were applied to fluid samples including the chemicals. Tests were also conducted with non-treated bentonites + barite fluids without chemicals for comparative purposes. All of the rheological parameters including plastic and apparent viscosity and yield points were determined. Comparative graphs of shear stress vs. shear rates were plotted. The optimum CMC and polymer amounts were selected by graphical analysis of the results of rheological tests made by using shear meter and filtration tests. An optimization of the fluid loss control due to addition of the chemicals was made. The behavior of water-based fluids with CMC and polymers was examined. The accurate and sensitive industrial application of this study would reduce drilling fluid loss expenditures effectively.     

无机-有机单体聚合物钻井液体系研究与应用

确定了无机-有机单体聚合物钻井液体系配方，即由6％膨润土浆＋0．5％-0．8％Siop—A＋0．3％-0．5CPS-2000B％＋0．1％～0．2％Siop—D＋0．1％～0．2％ZSC-201．评价了钻井液体系的性能，介绍了该钻井液体系在中原油田的应用情况。现场应用结果表明：该钻井液流变性、抗温性良好，具有较强的抑制防塌能力，携砂能力好，完井电测和RFr电测均一次成功，避免了替换钻井液。     

国内钻井液及处理剂发展评述

国内开展钻井液研究与应用经历了起步、发展、完善和提高四个阶段。正是由于处理剂的发展,钻井液技术有了长足进步,钻井液由分散到不分散,到低固相、低或/和无黏土相钻井液发展过程中不断完善配套。不分散低固相聚合物钻井液、"三磺"钻井液、饱和盐水钻井液、聚磺钻井液、聚磺钾盐钻井液、两性离子聚合物钻井液、阳离子聚合物钻井液、正电胶钻井液、硅酸盐钻井液、氯化钙钻井液、有机盐钻井液、甲基葡萄糖苷钻井液、聚合醇钻井液、胺基抑制钻井液、超高温钻井液、超高密度钻井液等一系列钻井液体系,解决了不同时期、不同阶段、不同地区和不同复杂地质条件下的安全快速钻井难题。围绕井壁稳定、防漏堵漏机理和方法的研究成果的应用,有效减少了井下复杂的发生,保证了钻井质量。今后需要针对复杂地质条件下深井、超深井、大位移井钻井,以及页岩气水平井钻井的需要,从抗温、井壁稳定、润滑、防卡等方面,研究关键处理剂,实现处理剂系列化;减少关键处理剂在生产、流通及其他环节的浪费,提高产品质量;减少钻井液处理剂品种;在保证钻井液性能满足需要的前提下,尽可能降低钻井液处理剂用量;科学的选择和使用钻井液,重视油基钻井液的应用及技术水平的提高;并围绕绿色环保、抗高温抗盐的目标,开发高性能钻井液处理剂,建立钻井液及其处理剂的毒性检测评价手段,促进钻井液技术进步。     

Biocide Dosing Strategies for Biofilm Control

Abstract

In order to reduce the environmental impact of biocide for the control of biofilm formation in cooling water circuits, “environmentally friendly” biocides have been developed; however, they are generally more expensive than traditional chemicals. It is imperative, therefore, that the minimum quantity of biocide is employed so that costs are kept to a minimum. To achieve this objective, optimum dosing strategies are required. Using a pilot plant in conjunction with a monoculture of Pseudomonas fluorecsens as the biofouling bacterium, tests were carried out using a proprietary biocide to investigate the effects of dose concentration, duration, and frequency of dosing and fluid mechanics on biofilm control. With four fifteen-minute applications per day at a peak concentration of 16.8 mg/l, it was not possible to inhibit biofilm development. Control was effected, however, by doubling the peak concentration using a short dosing period. As would be expected, concentration was shown to be a critical factor for control. A boicide concentration below that for growth inhibition seemed to enhance biofilm formation. Increasing the frequency of dosing is only effective if the concentration employed is biofilm growth-inhibiting.     

聚乙烯吡咯烷酮对钻井液水合物抑制性能的影响研究

随着全球油气钻探由海洋浅水区向深水区发展,深水油气钻探中水合物的防治研究也得到了日益重视。聚乙烯吡咯烷酮作为一种非常成熟的水合物动力学抑制剂,被广泛应用于油气生产运输中。向应用于某浅水油气田的钻井液中添加0.5wt%、1.0wt%和2.0wt%的聚乙烯吡咯烷酮,首先对其低温常规性能进行实验评价。结果表明,0.5wt%和1.0wt%的聚乙烯吡咯烷酮的加入对钻井液的流变性能不会产生明显影响,2.0wt%的聚乙烯吡咯烷酮加入会影响钻井液的流变性能而导致钻井液无法满足钻井需求;随后在4℃、6 MPa ~ 10 MPa条件下,利用1.2 L定容反应釜,通过观察温度和压力的变化,研究了0.5wt%和1.0wt%聚乙烯吡咯烷酮加入后对钻井液中水合物形成的影响,研究结果表明：当温度为4℃、进气压力在6 MPa ~ 10 MPa时,进气后500 min内聚乙烯吡咯烷酮对钻井液中的水合物形成具有一定的抑制作用,浓度越高抑制效果越明显,但聚乙烯吡咯烷酮的加入不能完全抑制水合物的生成。     

含CaCl2的深水油基钻井液中甲烷水合物的生成规律研究

深水钻井常采用含有CaCl₂的油基钻井液,施工时气体侵入钻井液可能会导致水合物的生成,增加钻井风险。因此,明确钻井液中水合物的生成规律对水合物的防治工作具有指导意义。采用高压水合物搅拌釜,实验研究了含水率为10%、20%、40%的油基钻井液分别在273.15 K、275.15 K、278.15 K和CaCl₂质量浓度为3.5%、10%条件下的水合物生成规律,分析了水合物生成过程中钻井液的相对电流变化。实验结果表明,油基钻井液中水合物的生成可分为诱导、快速生成和缓慢生成三个阶段,在快速生成阶段,温度和盐度对水合物生成速率影响较小,随含水率增大,水合物生成速率增大;低含水率（10%、20%）时,水合物生成时钻井液的相对电流几乎不增大;高含水率（40%）且水合物体积分数小于15%时,钻井液的相对电流增大不明显,水合物体积分数为15% ~ 28%时,钻井液的相对电流随水合物体积分数的增大而增大,增幅为10% ~ 50%。     

Permeability Reduction Due to Formation Damage by Drilling Fluids

Abstract

In this study, investigation of permeability reduction due to formation damage by invaded drilling fluids of sandstone-based, lime-containing core plugs from the southeastern region of Turkey were studied. The tests were performed by using dynamic filtration set-up that was constructed at the laboratory. In the experiments, nine core plugs of 7 cm length and 3.81 cm (1.5 in) diameter were used. Three different drilling fluid types using two different polymers were prepared and tests were made at three different filtration pressures. The direct effect of filtration pressure on fines migration was studied. The filtration properties and the thicknesses of the filter cakes were measured. It was observed that permeability of the sandstone samples reduced due to circulation of the drilling fluid and the filter cake thickness increased with increasing differential well bore pressure.     

胜利油田博24区块水平井筛管外泥饼酸洗工艺应用

胜利油区博24区块水平井采用常规酸洗工艺时,存在成功率低、酸洗效果差的问题,主要表现为:①未考虑酸液与混油聚合物钻井液、污水以及地层的配伍性,酸洗效果差;②酸洗工艺中,未能对酸液使用量、注入与替出排量、反应时间等进行优化设计,致使酸液对近井地带的清洗效果欠佳;③酸洗泥饼时,一处的污染解除,酸液由此渗入地层,导致其余井段无法有效清除污染物。为此,开展酸液与聚合物钻井液、与过滤污水、与地层的配伍性室内实验,最终确定了酸液配方,完善了酸洗工艺,实施了多级控压泥饼清洗工艺,对酸洗程序与解堵液用量进行优化。对该区块6口水平井的现场应用表明,改进后的二次酸洗工艺可减小泥浆污染,恢复或提升油层渗流能力;多级控压、段塞顶替,增加下铣锥及通井刮管作业程序,可以提高水平井筛管外泥饼酸洗工艺成功率与应用效果。6口水平井平均日产油7.82t/d,平均日产液15.9t/d,改进后的酸洗施工成功率高达100%。     

Optimization of catholyte concentration and anolyte pHs in two chamber microbial electrolysis cells

The hydrogen production rate in a microbial electrolysis cell (MEC) using a non-buffered saline catholyte (NaCl) can be optimized through proper control of the initial anolyte pH and catholyte NaCl concentration. The highest hydrogen yield of 3.3 ± 0.4 mol H₂/mole acetate and gas production rate of 2.2 ± 0.2 m³ H₂/m³/d were achieved here with an initial anolyte pH = 9 and catholyte NaCl concentration of 98 mM. Further increases in the salt concentration substantially reduced the anolyte pH to as low as 4.6, resulting in reduced MEC performance due to pH inhibition of exoelectrogens. Cathodic hydrogen recovery was high (r_cat > 90%) as hydrogen consumption by hydrogenotrophic methanogens was prevented by separating the anode and cathode chambers using a membrane. These results show that the MEC can be optimized for hydrogen production through proper choices in the concentration of a non-buffered saline catholyte and initial anolyte pH in two chamber MECs.     

聚胺水基钻井液中天然气水合物生成过程实验研究

实验采用定容压力搜索法测量了聚胺钻井液在3℃ ~ 13℃范围内甲烷水合物的三相平衡条件。定容条件下考察了在初始压力分别为8 MPa、10 MPa、12 MPa条件下聚胺钻井液中甲烷水合物的生成过程。结果表明,聚胺钻井液对甲烷水合物生成的热力学抑制作用并不明显。同时,提高反应的初始压力会显著缩短水合物的生成时间、增加水合物的生成总量、增大反应初期生长速率以及水合物生长的不均匀性。强化聚胺钻井液的传热传质速率并降低钻探时的井下压力有利于抑制钻井液中水合物的生成。     

培养基成分含量对巴夫杜氏藻生长的影响

通过固定培养基中其它成分的含量,考察变化的成分含量对巴夫杜氏藻生长的影响,以期获得适宜生长的最佳单一养分浓度。结果表明,硝酸钠和氯化钠在实验浓度范围内（0.042 g/L ~ 1.68 g/L和14.615 g/L ~ 175.38 g/L）对巴夫杜氏藻的生长有显著影响,碳酸氢钠、氯化钾、硫酸镁、氯化钙、柠檬酸铁、A₅溶液和pH值对藻生长影响较小。可以通过调控硝酸钠和氯化钠的浓度来促进巴夫杜氏藻的生长。