Gas-hydrate formation,agglomeration and inhibition in oil-based drilling fluids for deep-water drilling

One of the main challenges in deep-water drilling is gas-hydrate plugs,which make the drilling unsafe.Some oil-based drilling fluids（OBDF） that would be used for deep-water drilling in the South China Sea were tested to investigate the characteristics of gas-hydrate formation,agglomeration and inhibition by an experimental system under the temperature of 4 ？C and pressure of 20 MPa,which would be similar to the case of 2000 m water depth.The results validate the hydrate shell formation model and show that the water cut can greatly influence hydrate formation and agglomeration behaviors in the OBDF.The oleophobic effect enhanced by hydrate shell formation which weakens or destroys the interfacial films effect and the hydrophilic effect are the dominant agglomeration mechanism of hydrate particles.The formation of gas hydrates in OBDF is easier and quicker than in water-based drilling fluids in deep-water conditions of low temperature and high pressure because the former is a W/O dispersive emulsion which means much more gas-water interfaces and nucleation sites than the later.Higher ethylene glycol concentrations can inhibit the formation of gas hydrates and to some extent also act as an anti-agglomerant to inhibit hydrates agglomeration in the OBDF.

Rheological properties of oil-based drilling fluids at high temperature and high pressure

The rheological properties of two kinds of oil-based drilling fluids with typically composition were studied at pressures up to 138 MPa and temperatures up to 204 ℃ using the RheoChan 7400 Rheometer.The experimental results show that the apparent viscosity,plastic viscosity and yield point decrease with the increase of temperature,and increase with the increase of pressure.The effect of pressure on the apparent viscosity,plastic viscosity and yield point is considerable at ambient temperature.However,this effect gradually reduces with the increase of temperature.The major factor influencing the rheological properties of oil-based drilling fluids is temperature instead of pressure in the deep sections of oil wells.On the basis of numerous experiments,the model for predict the apparent viscosity,plastic viscosity and yield point of oil-based drilling fluids at high temperature and pressure was established using the method of regressive analysis.It is confirmed that the calculated data are in good agreement with the measured data,and the correlation coefficients are more than 0.98.The model is convenient for use and suitable for the application in drilling operations.

Squeeze-Strengthening Effect of Silicone Oil-based Magnetorheological Fluid

In order to study the squeeze-strengthening effect of silicone oil-based magnetorheological fluid （MRF）, theoretical basis of disc squeezing brake was presented and a squeezing braking characteristics test-bed for MRF was designed. Moreover, relevant experiments were carded out and the relationship between squeezing pressure and braking torque was proposed. Experiments results showed that the yield stress of MRF improved linearly with the increasing of external squeezing pressure and the braking torque increased three times when external squeezing pressure achieved 2 MPa.

Comparison and application of different empirical correlations for estimating the hydrate safety margin of oil-based drilling fluids containing ethylene glycol

As the oil and gas industries continue to increase their activity in deep water, gas hydrate hazards will become more serious and challenging, both at present and in the future. Accurate predictions of the hydrate-free zone and the suitable addition of salts and/or alcohols in preparing drilling fluids are particularly important both in preventing hydrate problems and decreasing the cost of drilling operations. In this paper, we compared several empirical correlations commonly used to estimate the hydrate inhibition effect of aqueous organic and electrolyte solutions using experiments with ethylene glycol （EG） as a hydrate inhibitor. The results show that the Najibi et al. correlation （for single and mixed thermodynamic inhibitors） and the Ostergaard et al. empirical correlation （for single thermodynamic inhibitors） are suitable for estimating the hydrate safety margin of oil-based drilling fluids （OBDFs） in the presence of thermodynamic hydrate inhibitors. According to the two correlations, the OBDF, composed of 1.6 L vaporizing oil, 2% emulsifying agent, 1% organobentonite, 0.5% SP-1, 1% LP-1, 10% water and 40% EG, can be safely used at a water depth of up to 1900 m. However, for more accurate predictions for drilling fluids, the effects of the solid phase, especially bentonite, on hydrate inhibition need to be considered and included in the application of these two empirical correlations.

Development of a High Temperature and High Pressure Oil-Based Drilling Fluid Emulsion Stability Tester

When drilling deep wells and ultra-deep wells, the downhole high temperature and high pressure environment will affect the emulsion stability of oil-based drilling fluids. Moreover, neither the demulsification voltage method nor the centrifugal method currently used to evaluate the stability of oil-based drilling fluids can reflect the emulsification stability of drilling fluids under high temperature and high pressure on site. Therefore, a high-temperature and high-pressure oil-based drilling fluid emulsion stability evaluation instrument is studied, which is mainly composed of a high-temperature autoclave body, a test electrode, a temperature control system, a pressure control system, and a test system. The stability test results of the instrument show that the instrument can achieve stable testing and the test data has high reliability. This instrument is used to analyze the factors affecting the emulsion stability of oil-based drilling fluids. The experimental results show that under the same conditions, the higher the stirring speed, the better the emulsion stability of the drilling fluid;the longer the stirring time, the better the emulsion stability of the drilling fluid;the greater the oil-water ratio, the better the emulsion stability of the drilling fluid. And the test results of the emulsification stability of oil-based drilling fluids at high temperature and high pressure show that under the same pressure, as the temperature rises, the emulsion stability of oil-based drilling fluids is significantly reduced;at the same temperature, the With the increase in pressure, the emulsion stability of oil-based drilling fluids is in a downward trend, but the decline is not large. Relatively speaking, the influence of temperature on the emulsion stability of oil-based drilling fluids is greater than that of pressure.

Complement components of nerve regeneration conditioned fluid influence the microenvironment of nerve regeneration

Nerve regeneration conditioned fluid is secreted by nerve stumps inside a nerve regeneration chamber.A better understanding of the proteinogram of nerve regeneration conditioned fluid can provide evidence for studying the role of the microenvironment in peripheral nerve regeneration.In this study,we used cylindrical silicone tubes as the nerve regeneration chamber model for the repair of injured rat sciatic nerve.Isobaric tags for relative and absolute quantitation proteomics technology and western blot analysis confirmed that there were more than 10 complement components（complement factor I,C1q-A,C1q-B,C2,C3,C4,C5,C7,C8β and complement factor D） in the nerve regeneration conditioned fluid and each varied at different time points.These findings suggest that all these complement components have a functional role in nerve regeneration.

Development of key additives for organoclay-free oil-based drilling mud and system performance evaluation

Traditional oil-based drilling muds(OBMs) have a relatively high solid content, which is detrimental to penetration rate increase and reservoir protection. Aimed at solving this problem, an organoclay-free OBM system was studied, the synthesis methods and functioning mechanism of key additives were introduced, and performance evaluation of the system was performed. The rheology modifier was prepared by reacting a dimer fatty acid with diethanolamine, the primary emulsifier was made by oxidation and addition reaction of fatty acids, the secondary emulsifier was made by amidation of a fatty acid, and finally the fluid loss additive of water-soluble acrylic resin was synthesized by introducing acrylic acid into styrene/butyl acrylate polymerization. The rheology modifier could enhance the attraction between droplets, particles in the emulsion via intermolecular hydrogen bonding and improve the shear stress by forming a three-dimensional network structure in the emulsion. Lab experimental results show that the organoclay-free OBM could tolerate temperatures up to 220 ?C and HTHP filtration is less than 5 m L. Compared with the traditional OBMs, the organoclay-free OBM has low plastic viscosity, high shear stress, high ratio of dynamic shear force to plastic viscosity and high permeability recovery, which are beneficial to penetration rate increase, hole cleaning and reservoir protection.

Calculation and application of partition coefficients of light hydrocarbons in oil-based mud system

To find out the relationship between the oil-based mud,the formation fluid and the extracted gas,we use a thermodynamic approach based on static headspace gas chromatography technique to calculate the partition coefficients of 47 kinds of light hydrocarbons compounds between nC5 and nC8 in two kinds of oil-based mud-air systems,and reconstruct the original formation fluid composition under thermodynamic equilibrium.The oil-based drilling mud has little effect on the formation fluid compositions in the range of nC5-nC8(less than 1%for low-toxicity oil-based mud and less than 10%for oil-based mud).For most light hydrocarbon compositions,the partition coefficients obtained by vapor phase calibration and the direct quantitative methods have errors of less than 10%,and the partition coefficients obtained by direct quantitative method are more accurate.The reconstructed compositions of the two kinds of crude oil have match degrees of 91%and 89%with their real compositions,proving the feasibility and accuracy of reconstructing the composition of original formation fluid by using partition coefficients of light hydrocarbon compositions between nC5 and nC8.

Research on High Temperature and High Density White Oil Based Drilling Fluid and Its Application in Well 201H7-6

As the depth and horizontal length of shale gas development wells increase,the requirement for the temperature resistance and the ability of the drilling fluids to stabilize the shale formation becomes higher.A new type of high temperature and high density white oil based drilling fluid system has been developed in laboratory.Research shows that the drilling fluid system has good rheological property,low filtration loss,strong anti-debris pollution capability and good plugging performance at high temperature and high density.The system has been successfully applied in the 201H7-6 well.Application results show that the drilling fluid rheology,high temperature and high pressure fluid loss and demulsification voltage meet the field requirements.The drilling fluid performance is stable in drilling an 1800 m horizontal section,and no stuck or shale swelling and wellbore collapsing are induced.It is the first well drilled successfully with domestic white oil-based drilling fluid in Zigong Region.It also sets several new records including the deepest well,the shortest drilling cycle,and the fastest drilling speed in that region,which provides valuable experience for the future drilling activities.

The utilization of spent palm cooking oil for formulating oil-based drilling muds with excellent H_(2)S scavenging capability

In this study,a spent palm cooking oil-based mud with an excellent H_(2)S scavenging capability induced by the inclusion of a small quantity of potassium permanganate is formulated and tested for the first time.The mud formulation,containing the spent palm oil as the continuous phase and water as the dispersed phase,respectively,was stabilized by Span 80 and rhamnolipid biosurfactant as primary and secondary emulsifiers,respectively,while hydrophobic zinc nanoparticles(NPs)were used as weighting agent.The results showed that H_(2)S scavenging capacity at the breakthrough time reached 182.4 g H_(2)S/barrel mud,which increased to 417.9 g H_(2)S/barrel mud at the saturation time,demonstrating the effective H_(2)S scavenging performance of the formulated mud.The spent palm oil-based mud(SPOBM)also showed a good flow behavior that could be well fitted using the Herschel-Bulkley and Casson models.The effect of temperature on the apparent viscosity of the SPOBM has been investigated,and the fitting of the viscosity-temperature data provided an estimate of the activation energy as 23.53 kJ/mol.The findings reported in this article reveal the feasibility of transforming the spent/waste cooking oils into a valuable commodity for formulating greener drilling fluids with acceptable rheology and excellent H_(2)S scavenging performance.

温肺化饮汤治疗慢性阻塞性肺疾病急性加重期疗效及对患者气道重塑和CTRP-4、CTRP-5水平的影响

目的:探究温肺化饮汤治疗寒饮停肺型慢性阻塞性肺疾病急性加重期(AECOPD)的疗效,并分析其对患者气道重塑指标及血清补体C1q肿瘤坏死因子相关蛋白-4(CTRP-4)、CTRP-5水平的影响。方法:将102例AECOPD患者随机分为两组。对照组51例予以常规西药治疗,观察组51例在此基础上加服温肺化饮汤。评价两组患者临床疗效及中医症候积分,比较两组治疗前后的气道重塑指标[基质金属蛋白酶-2(MMP-2)、基质金属蛋白酶-9(MMP-9)、神经生长因子(NGF)]及CTRP-4、CTRP-5水平,观察两组的不良反应情况。结果:观察组的临床疗效高于对照组(P<0.05);相较于对照组,观察组治疗后的各中医症候积分降低(P<0.05);与对照组比较,观察组治疗后的血清MMP-2、MMP-9、NGF、CTRP-4、CTRP-5水平均降低(P<0.05);两组不良反应情况组间比较差异无统计学意义(P>0.05)。结论:温肺化饮汤治疗寒饮停肺型AECOPD患者的疗效显著,可有效缓解临床症状,并可通过调节气道重塑指标及CTRP-4、CTRP-5水平发挥作用。

仿刺参补体类似物活性的测定

用3种方法对仿刺参Apostichopus japonicus体腔液、体腔液上清液及体腔细胞中的总补体溶血活性和补体类似物AjC3、AjC4活性进行测定。结果表明:在仿刺参体腔液、体腔液上清液和体腔细胞中能够检测到总补体溶血活性和补体类似物AjC3、AjC4,表明仿刺参体内存在有脊椎动物的补体类似物,且活性与正常人补体活性相似。仿刺参体内总补体溶血活性和补体类似物AjC3、AjC4的活性依次顺序均为体腔液>体腔细胞>体腔液上清液。

仿刺参体腔液补体类似物化学发光免疫检测

首次应用酶联化学发光免疫检测(Chemiluminesent Immunoassay,CLIA)技术测定仿刺参体腔液补体类似物AjC3和AjC4。羊抗人C3、C4抗体吸附到经过紫外线处理的聚苯乙烯管内,采用辣根过氧化物酶(HRP)标记抗体。过氧化氢和鲁米诺为辣根过氧化物酶的底物。捕获抗体包被最适浓度为1μg/ml,免疫反应20℃孵育2h达到平衡。HRP-IgC3、IgC4抗体复合物适宜稀释度为1:2000,HRP-IgC3I、gC4抗体复合物4℃下保存8d性能稳定,室温下5d内性能稳定。标准品浓度在0.1～10ng/ml范围内时与化学发光值之间具有良好的线性相关性,检测灵敏度为0.1ng/ml。结果表明应用酶联化学发光免疫检测技术能够检测到仿刺参体腔液中含有补体类似物,AjC3含量为6.58±1.4μg/ml,AjC4含量为0.67±0.3μg/ml。

中枢神经系统感染患儿脑脊液补体C_3,C_4和β-2微球蛋白联合检测的诊断意义

目的:研究小儿脑脊液(CSF)中补体C_3、C_4和β-2微球蛋白(β-2-MG)的含量与中枢神经系统(CNS)感染的关系,探讨联合检测该3项指标鉴别诊断脑膜炎类型的意义。方法:应用速率散射比浊法和化学免疫发光法分别检测37例病毒性脑炎(VE)、12例化脓性脑膜炎(PM)、11例结核性脑膜炎(TM)患儿和20例对照组健康儿童CSF的上述3项指标。结果:①VE组补体C_3、C_4含量大部分低于仪器最低检出值,其阳性率显著低于PM、TM组。对照组全部低于最低检出值。TM组C_3、C_4的监测值明显高于PM组,差异具有显著性(P<0.01)。②β-2-MG方差分析F=77.7,两两比较差异均有显著性(P<0.05),TM组>PM组>VE组>对照组。结论:CSF补体C_3、C_4和β-2-MG能够鉴别不同类型的脑膜炎,而联合检测可以提高诊断的准确性。

病毒性脑炎患儿血清和脑脊液中ficolin-3、C3和C4的变化分析

目的探讨病毒性脑炎(VE)患儿血清和脑脊液中纤维胶凝蛋白3(ficolin-3)及补体C3、C4水平的变化。方法选取2018年5月至2019年7月儿科住院治疗的70例VE患儿作为VE组,同期进行外科手术且需腰麻的非感染性疾病患儿30例作为对照组。根据入院时临床体征将VE患儿分为轻症组39例和重症组31例,按照入院时病情缓急程度将VE患儿分为非急性期34例和急性期36例。使用酶联免疫吸附试验(ELISA)双抗体夹心法检测血清和脑脊液中ficolin-3水平,使用散射比浊法检测血清和脑脊液中C3、C4水平。采用ROC曲线分析血清和脑脊液中ficolin-3、C3、C4水平对VE患儿急性发作的预测价值。结果VE组患儿血清和脑脊液中ficolin-3、C3、C4水平均显著高于对照组患儿,差异有统计学意义(P<0.05)。VE重症组患儿血清和脑脊液中ficolin-3、C3、C4水平均明显高于轻症组患儿,差异有统计学意义(P<0.05)。VE急性期患儿血清和脑脊液中ficolin-3、C3、C4水平均显著高于非急性期患儿,差异有统计学意义(P<0.05)。VE患儿血清和脑脊液中ficolin-3水平呈正相关(P<0.05),血清和脑脊液中C3水平呈正相关(P<0.05),血清和脑脊液中C4水平呈正相关(P<0.05)。血清ficolin-3、C3、C4水平联合预测VE患儿急性发作的曲线下面积(AUC)为0.938,敏感度高达93.50%,特异度为87.50%;脑脊液ficolin-3、C3、C4水平联合预测VE患儿急性发作的AUC为0.916,敏感度为85.00%,特异度高达91.00%,预测价值均优于三者单独使用。结论血清和脑脊液中ficolin-3、C3、C4水平升高与VE发生及其病情严重程度有关。

视网膜脱离患者网膜下积液的免疫学检测及其临床意义

检测了21例视网膜脱离患者网膜下积液免疫球蛋白和补体的含量,发现视网膜脱离患者可能在眼局部存有免疫反应,随病程增长,免疫反应加重,高度近视患者易发生免疫反应和发生免疫反应患者手术愈后不理想,并讨论了与网脱范围和裂孔大小、数目的关系。

几种理化因子对仿刺参体腔液补体溶血活性的影响

测定了仿刺参Apostichopus japonicus体腔液补体溶血活性,并研究了几种理化因子对仿刺参体腔液补体溶血活性的影响。结果表明:仿刺参体腔液补体溶血活性为(68.8±13.5)U/mL;仿刺参体腔液在pH为7.5、Mg2+浓度为8 mmol/L的EGTA-Mg-GVB缓冲液和20℃条件下恒温水浴90 m in时,其溶血活性最高;Mg2+对仿刺参体腔液补体的溶血活性有影响,苯甲基磺酰氟(PMSF)、酵母聚糖、甲胺和肼对仿刺参补体旁路溶血活性均有明显的抑制作用。

引入补偿刚度的流体力学标准伽辽金有限元研究

对一维定常对流扩散方程有限元解的波动问题进行了研究,指出提高单元间形函数一阶导数的连续性是改善有限元解数值波动的有效方法.在标准伽辽金有限元基础上引入考虑补偿刚度的补偿项,即在单元与单元之间的节点上增加一个"不平衡力",形成补偿标准伽辽金有限元格式.针对线性拉格朗日插值和指数型插值分别探讨补偿项中补偿刚度表达式,并对比了补偿有限元解与解析解结果.研究表明,引入补偿项后能提高单元间形函数的连续性,从而明显改善一维对流扩散方程的数值波动.与标准线性拉格朗日插值相比,补偿指数型插值不仅在单元内可精确给出变量的分布,而且单元之间的连续性更好,因而能更好地控制数值波动现象,取得问题较好的数值解.

儿童喘息性疾病患儿血微量元素 体液免疫及补体水平的变化

目的分析儿童喘息性疾病患儿血微量元素及体液免疫的变化。方法选择64例喘息性疾病患儿为观察组,同时随机抽取来院体检的同年龄段的正常健康儿童56例作为对照组,对两组儿童进行血清中锌、铁、钙、镁的含量检测。结果观察组患儿Zn、Ca含量明显低于对照组儿童,差异有统计学意义(P<0.05);两组间Fe、Mg含量比较,差异无统计学意义(P>0.05)。患儿血清补体C4水平高于健康组,而IgG水平降低,差异有统计学意义(P<0.05)。结论儿童喘息性疾病与微量元素的缺乏及体液免疫、补体水平的改变密切相关,定期测量微量元素,及时纠正体液免疫及补体水平的紊乱,这对减少儿童喘息性疾病的发生有着重要意义。

孕兔羊水栓塞补体C3a、凝血功能的研究

目的通过孕兔羊水栓塞动物模型测定凝血功能、补体C3a的含量以及补体C3a在肺组织中的表达,初步探索羊水栓塞(AFE)的发病机制。方法健康妊娠晚期孕兔随机分3组(对照组、羊水组、羊水胎粪组),暴露子宫抽取羊水、胎粪。按2.5 m L/Kg注入自体羊水、羊水胎粪混合液(羊水原液与胎粪按质量比配成1%混合液)入血,对照组注入等剂量生理盐水。注射30 min后取血分别用血凝仪测凝血功能(凝血酶原时间(PT)、活化部分凝血活酶时间(APTT)、凝血酶时间(TT)、纤维蛋白原(FIB))及ELISA法测血浆补体C3a含量。取血后10%KCl处死孕兔,取孕兔双肺做病理学检查。结果1补体C3a浓度:羊水组、羊水胎粪组补体C3a含量降低(P<0.05);2凝血功能检查结果:PT、APTT、TT羊水组、羊水胎粪组延长(P<0.05),FIB羊水组、羊水胎粪组降低(P<0.05)。结论 1发生AFE时补体C3a含量降低,说明补体系统被激活,消耗补体成分发生类过敏反应;2AFE时PT、TT、APTT均延长,FIB降低,说明AFE时有发展为DIC的趋势。