Rapid accuracy determining DNA purity and concentration in heavy oils by spectrophotometry methods

DNA analysis is the core of biotechnology applied in petroleum resources and engineering. Traditionally accurate determination of DNA purity and concentration by spectrometer is the first and critical step for downstream molecular biology research. In this study, three different spectrophotometry methods, BPM, NDTT and NPMTTZ were compared for their performance in determining DNA concentration and purity in 32 oil samples, and molecule methods like quantitative real-time PCR (qPCR) and high-throughput sequence were also performed to help assess the accuracy of the three methods in determining DNA concentration and purity. For ordinary heavy oil (OHO), extra heavy oil (EHO) and super heavy oil (SHO), the characteristics of high viscosity (η), density (ρ) and resin plus asphaltene content will affect the DNA extraction and UV determination. The DNA concentration was decreased as density increased: OHO (11.46 ± 18.34 ng/μL), EHO (6.68 ± 9.67 ng/μL) and SHO (6.20 ± 7.83 ng/μL), and the DNA purity was on the reverse: OHO (1.31 ± 0.27), EHO (1.54 ± 0.20), and SHO (1.83 ± 0.32). The results suggest that spectrophotometry such as BPM and NPMTTZ are qualitatively favorite methods as the quick non-consumable methods in determining DNA concentration and purity of medium oil and heavy oil.

Effects of nitrate concentration in interstitial water on the bioremediation of simulated oil-polluted shorelines

Nutrient addition has been proved to be an effective strategy to enhance oil biodegradation in marine shorelines. To determine the optimal range of nutrient concentrations in the bioremediation of oil-polluted beaches, nitrate was added to the simulated shoreline models in the initial concentration of 1, 5 and 10 mg/L. Whenever the NO3-N concentration declined to 70% of its original value, additional nutrients were supplemented to maintain a certain range. Results showed adding nutrients increased the oil biodegradation level, the counts of petroleum degrading bacteria （PDB） and heterotrophic bacteria （HB）, and the promoted efficiency varied depending on the concentration of nitrate. Oil degradation level in 5 mg/L （NO3-N） group reached as much as 84.3% accompanied with the consistently highest counts of PDB; while in l mg/L group oil removal efficiency was only 35.2%, and the numbers of PDB and HB were relatively low compared to the other groups supplemented with nutrients. Although counts of HB in the 10 mg/L group were remarkable, lower counts of PDB resulted in poorer oil removal efficiency （70.5%） compared to 5 mg/L group. Furthermore, it would need more NO3-N （0.371 mg） to degrade 1 mg diesel oil in the 10 mg/L group than in the 5 mg/L group （0.197 mg）. In conclusion, Nitrate concentration in 5 mg/L is superior to l and 10 mg/L in the enhancement of diesel oil biodegradation in simulated shorelines.

Effect of HCO_3^- concentration on CO_2 corrosion in oil and gas fields

The effect of HCO3^- concentration on CO2 corrosion was investigated by polarization measurement of potentiodynamic scans and weight-loss method, Under the conditions of high pressure and high temperature, the corrosion rate of steel X65 decreased with the increase of HCO3^- concentration, while pH of solution increased. SEM, EDS, and XRD results of the corrosion scales indir cated that the typical FeCO3 crystallite was found at low HCO3^- concentration but Ca（Fe,Mg）（CO3）2 was found at high HCO3^- con- centration. Ca^2＋ and Mg^2＋ are precipitated preferential to Fe^2＋ at high pH value. Potentiodynamic polarization curves showed that the cathodic current density decreases with the increase of HCO3^- concentration at low HCO3^- concentration. When the HCO3^- concentration reaches 0.126 mol/L, increasing HCO3^- concentration promotes cathodic reactions. Anodic behavior is an active process at low HCO3^- concentration and the anodic current density decreases with the increase of HCO3^- concentration. An evident active-passive behavior is exhibited in anodic process at 0.126 mol/L HCO3^-.

The Relationship between Nigerian Bonnylight Crude Oil-Induced Hypoglycaemia and Endogenous Serum Insulin Concentration in Male Wistar Rats: The Role of Antioxidant Vitamins C and E

The relationship between Nigerian Bonny Light crude oil (NBLCO) induced hypoglycaemia and endogenous serum insulin concentration;the role of antioxidant vitamin C or E supplementation was the focus of this study. Forty adult male Wistar rats were randomly divided into group I, which served as the control, group II, which was oral gavaged 6 ml/kg of NBLCO, groups III and IV, which were in addition to 6 ml/kg of NBLCO supplemented with 9 ml/kg and 1 mg/kg of vitamin E or C, respectively for 28 days. Results showed that NBLCO significantly (p < 0.05) lower body weight and food intake compared with control. These effects exerted by NBLCO were however significantly (p < 0.05) reversed by vitamin E or C supplementation. The NBLCO significantly (p < 0.05) reduced fasting blood glucose (FBG) when compared with control, the antioxidant vitamins supplementation significantly (p < 0.05) reversed the crude oil effect. The mean serum insulin level in NBLCO, vitamin E or C supplemented groups is not significantly different from the control. There was no significant correlation between FBG and fasting serum insulin concentrations in all the groups on day 28. It has been demonstrated in this study that direct oral ingestion of crude oil (NBLCO) could reduce food intake, body weight and cause hypoglycemia;the hypoglycemia may not be a function of serum insulin concentration. Interestingly, the hazardous effects of NBLCO could be ameliorated with antioxidant vitamin C or E supplementation.

Spectral Transmittance of Di-methyl Silicon Oil as a Heat Transfer Material for Concentrator Solar Cells

The accelerated life test was carried out to investigate the change of spectral transmittance of di-methyl silicon oil and the effects on the electrical performance of silicon solar cell. The di-methyl silicon oil samples before and after accelerated life test were analyzed by FT-IR, GC-MS and LC-MS. The ring compounds and linear compounds with larger molecular weight were detected. The spectral transmittance of di-methyl silicon oil decreased because the chromophore and auxochrome of the products made a sunlight receive decrease on the surface of the solar cell, and resulted in the reduction of cell performance. According to the decrease of spectral transmittance of di-methyl silicon oil, two recovery methods were proposed. The results showed that extraction was superior to vacuum distillation in recovering the aged di-methyl silicon oil.

Adsorption of Natural Surfactant on Sandstone in Enhanced Oil Recovery: Isotherms and Kinetics Studies

In chemical enhanced oil recovery, surfactants are injected into the reservoir with the intention to lower interfacial tension (IFT) between the water and oil phases, and thereby bring about efficient displacement of oil. However, the adsorption of the surfactants to reservoir rock surfaces leads to the loss and reduction in concentration of the surfactants, which in turn reduces the overall efficiency of the oil recovery process, with attendant financial losses. In this work, the adsorption of Quillaja Saponaria (QS), a novel, natural, non-ionic surfactant, on crushed sandstone reservoir rock is investigated. X-ray diffraction (XRD) study of clean sandstone particles has been undertaken to determine the main components present in the sand particles. The conductivity method was used to measure CMC and the surfactant concentrations in aqueous solutions. Batch adsorption experiments were used to determine the amount of QS adsorbed on rock surface. Equilibrium conditions were reached after almost 5 days. From the results of the study, the Langmuir isotherm model is more suited for predicting the adsorption behaviour of QS on sandstone. The kinetic adsorption of QS obeys the pseudo-second order model. This study is particularly relevant in surfactant selection for chemical EOR processes.

The Feasibility of ASP Flooding with Low Alkali Concentration in Heterogeneous Reservoirs

In this paper, as far as the ASP flooding in the pilot area of Daqing oilfield is concerned, the effect of apparent viscosity of ASP solution on enhanced oil recovery have been studied by comparison of experiments on artificial heterogeneous cores with on natural cores. The results showed that the decrease in the concentration of alkali could increase the apparent viscosity of ASP solutions, namely, the apparent viscosity increased and the IFT couldn’t get ultra low, and the oil recovery efficiency by ASP solution with a reasonably lower concentration of alkali was not less than that with a higher concentration of alkali and ultra low IFT. The experiments with models having impermeable interlayers between adjacent layers, and by means of “co-injection and separate production” showed that the ASP solution with a higher viscosity and a lower alkali concentration was more beneficial to starting-up medium and low permeability layers and enhancing total oil recovery. Therefore, to heterogeneous reservoir, as factors of affecting oil recovery, the apparent viscosity may be more important than the ultralow IFT. Furthermore, on the premise that the concentration of surfactant and the concentration of polymer keep constant, ASP flooding with low alkali concentration not only enlarges the selectable range of surfactants and decreases the cost of ASP flooding, but also solves the problem of alkali scales. Finally, a dynamic absorption experiment was performed with a 05 meter long linked-up natural core to determine alkali wastage in formation. The result being accord with the application case in the pilot confirmed that it was not necessary to add the alkali too much in ASP flooding from a new direction.

复合磨损套管爆裂失效机理及剩余强度预测

超深井、水平井、大位移井等复杂油气井服役工况异常恶劣,套管复合磨损严重,将对井筒完整性构成巨大威胁,且磨损套管剩余强度难以精准预测。为此,基于塔里木盆地塔中北坡顺南区块501井套管磨损数据及P110管材应力—应变本构关系,建立了充分考虑钻杆本体和接头联合造成的磨损模式、夹角、磨损重叠深度及磨损深度的复合磨损套管有限元力学模型,并开展了多种复合磨损模式下套管弹塑性变形、屈服、裂纹萌生、扩展及爆裂行为模拟,得到了不同复合磨损套管应力分布、剩余抗内压屈服强度及爆裂强度。研究结果表明:(1)月牙夹角在0°~90°时,应力干涉削弱应力集中,月牙夹角在90°~180°时,应力干涉增强应力集中,这种交互作用机制导致磨损套管剩余强度随着月牙夹角增加而先增加后降低;(2)裂纹萌生并起始于等效应力最大的位置即磨损月牙中心,并垂直于最大环向应力沿径向从套管内壁向外壁扩展,且裂纹一旦萌生,裂纹将迅速扩展并发生爆裂失效;(3)灰色关联度分析确定了复合磨损套管剩余强度对磨损深度、月牙夹角、复合磨损形式、月牙重叠深度的敏感性,分析结果表明磨损深度是决定套管剩余强度的主控因素。结论认为,该认识为套管强度设计与优化提供了技术参考,并对准确预测复合磨损套管剩余强度和确保井筒安全及完整性具有重要意义。

复配絮凝处理高浓度含盐原油罐切水的研究

采用不同类型絮凝剂聚合[聚合氯化铝(PAC)、聚合硫酸铁(PFS)和聚丙烯酰胺(PAM)]处理高浓度含盐原油罐切水,探索絮凝剂投量浓度、搅拌速度、p H值和投加时间间隔对絮凝效果的影响。结果表明:复配使用絮凝剂聚合氯化铝与阳离子型聚丙烯酰胺(CPAM)处理高浓度含盐原油罐切水的絮凝效果更佳。絮凝剂的投量浓度、絮凝搅拌速度、p H值和投加间隔时间均影响絮凝的效果,其中絮凝剂的用量影响最大。较为适宜的絮凝条件:p H值为6~11,PAC投量浓度为400 mg/L且混合搅拌速度为200 r/min,CPAM投量浓度为1.0 mg/L且混合搅拌速度为100 r/min,2种絮凝剂的投加间隔为60 min。絮凝对浊度的去除率高达98.7%,固体悬浮物(SS)的去除率高达96.5%,废水中的石油类含量从0.339 mg/L降到0.115 mg/L,废水的氨氮、化学需氧量(COD)以及254 nm波长紫外光下的吸光度(UV_(254))的去除率分别达到55.0%,36.6%和20.4%,最终絮凝出水的总铁含量从41.85 mg/L降到5.42 mg/L。

煤与油气协调开采物理相似模拟研究

针对煤与油气协调开采中,煤层开发扰动油气圈闭层稳定性及油气井筒的问题,利用二维模拟试验开展了煤与油气开采地层响应规律研究;采用“先油气后煤炭”的开采工序,得到了煤与油气各覆岩层的应力演化、破断变形特征及油气井筒变形破坏规律。研究结果表明:若油气层高强度抽采至采收完毕,模型整体结构未出现明显扰动,仅层间岩层局部存在应力集中现象,而此时对煤层进行开采会对下方200 m处油气层产生一定扰动;采动初期,油气层采收边界上方应力不断上升,煤层底板存在应力传递现象,煤层顶板无明显应力变化,初次扰动范围为100 m,二次扰动范围为75 m;当进入充分采动阶段,油气层采收边界上方应力集中沿水平向右侧偏移,煤层底板相继经历应力集中-卸压的过程,层间岩层结构趋于稳定,岩层运移程度逐渐向煤层顶部附近岩层转移,说明煤层采动作用在叠置资源协调开采过程中对整体岩层稳定性影响程度较大,应着重关注煤层开采对煤与油气协调开采中的影响;覆岩内井筒主要破坏模式为剪切变形破坏,位于工作面中心处的井筒下侧则发生拉伸-剪切变形破坏,应着重关注工作面中心处的井筒防护。

胍胶压裂液有机硼交联剂JSA-1的合成与性能评价

以硼酸、正丁醇、乙二醇、二乙烯三胺为反应原料,采用一锅法合成了有机硼交联剂(JSA-1)。考察了胍胶质量分数(即含量,以胍胶占胍胶基液总质量计)、JSA-1用量(即添加量,以胍胶基液质量为基准,下同)、pH对JSA-1交联性能的影响。结果表明,胍胶质量分数越大(0.09%~0.4%),胍胶压裂液的交联状态越好、交联时间越短、表观黏度越高、耐温能力越强;JSA-1用量越大(0.04%~0.4%),胍胶压裂液的交联状态越好、交联时间越短、耐温能力越强;pH(pH=4~14)越高,胍胶压裂液的交联时间越长、耐温能力越强。JSA-1对pH和胍胶质量分数的适用范围较广,在低温配方中,可以使低质量分数的胍胶实现有效交联,胍胶质量分数为0.13%的胍胶基液与JSA-1交联后,在常温、100 s^(–1)剪切下表观黏度可达到50 mPa·s;在高温配方中,胍胶质量分数为0.4%的胍胶基液与JSA-1交联后制备的压裂液具备较好的耐温耐剪切能力,在120℃、100 s^(–1)剪切条件下表观黏度可以稳定保持在300 mPa·s左右。

拉曼光谱结合改进稀疏编码器特征优选的成品油混合浓度预测方法

成品油混合浓度的预测对成品油顺序输送过程中的安全监控、混油段分割具有重要的意义。本研究配制92#汽油-3#航煤以及3#航煤-0#车柴两组包含不同浓度的混合样品,并对其进行拉曼光谱采集;依次采用归一化、多元散射校正、BaselineWavelet基线校正3种光谱预处理方法进行优化;之后采用改进的栈式稀疏自编码器(Stacked Sparse Autoencoder,SSAE)模型对预处理之后的拉曼光谱进行稀疏特征提取,并结合全连接层进行回归预测;最后根据均方根误差(Root Mean Square Error,RMSE)和决定系数(R^(2))两项评价指标,与偏最小二乘回归(Partial Least Square Regression,PLSR)、最小二乘支持向量回归(Least Square Support Vector Machine,LSSVR)以及SSAE 3种模型进行对比。结果表明:改进的SSAE-FC模型表现出更优的预测精度和稳定性,92#汽油-3#航煤混油测试集的R^(2)和RMSEC指标分别为0.9952和0.8932,3#航煤-0#车柴混油测试集的R^(2)和RMSEC指标分别为0.9837和1.1967,且学习得到的稀疏特征的可解释性强。

基于光闪烁法的油雾浓度在线检测方法研究

针对压缩机出口除油器效率性能评价,提出一种基于光闪烁法的润滑油油雾液滴浓度在线检测方法。基于颗粒系层模型和Lambert-Beer定律,以层测量体透过率作为泊松分布随机变量,推导了光闪烁法在长光程平行光束下的颗粒浓度检测模型。闪烁频率根据测量体大小、颗粒直径和颗粒速度确定,并通过影响闪烁信号的拟合方差影响检测精度。对于某型压缩机润滑油,通过光谱扫描和主成分分析法确定了在可见光波段,400 nm波长光束具有最佳的检测灵敏度和正相关性。实验结果表明,相较于光透射法,在0~50 mg·m^(−3)油雾浓度范围内基于光闪烁法检测标定结果误差小于10%,线性相关系数R2=0.989。

页岩油伴生气二氧化碳浓度连续监测技术研究

页岩油井压裂过程中注入的大量CO_(2)随着原油和天然气生产而分离出来,为了准确了解CO_(2)产出情况,基于红外线气体分析法,研制了CO_(2)浓度连续监测装置,介绍了该监测装置核心模块,及各部件的技术参数和性能,通过在页岩油井现场应用,实现了页岩油伴生气中φ(CO_(2))的实时、连续监测。该监测装置检测快速、结果准确、高效,大幅降低人工劳动强度,数据准确性能达到资料录取及生产管理的要求。

波浪式拖管法铺设海底管道力学性能研究

海底管道铺设是海洋油气资源开发的重要环节,传统的拖管法不能很好地适应海洋深度和复杂环境的变化。针对Acergy公司在Girassol项目中提出的一种波浪式拖管方法,对其应用于2.0 km长海底管道铺设进行分析。首先,结合深水海洋环境特征,采用集中质量法建立管道拖航数值模型,并介绍管道、拖缆和浮筒力学计算及水动力荷载计算方法;其次,基于非线性有限元OrcaFlex软件对拖管过程建模,以模拟实际项目拖管过程;然后,通过对比相同条件下的单波式和双波式两种拖管方式,探讨管道和拖缆的动态力学性能变化;最后,针对不同浮重比、拖航速度、拖缆长度和悬垂角、海流流速和流向角等因素展开敏感性分析。结果表明:波浪式拖管法可以有效地降低施工时对拖缆的张力需求,但也会因此增加管道局部弯矩和应力响应;相对于单波式拖管,双波式拖管在缓解由于拖航速度等变化而产生的管道局部损伤效应上更有优势,并能较好地适应不同水深环境;复杂的海流工况对拖航时管道的力学性能影响十分显著,施工前应选择合适的铺设窗口期以防止管道产生损伤。

油气田压裂返排液中污染气体浓度及扩散模型研究

油气田在实施压裂作业时,返排液中的污染气体会排放至大气中,造成大气污染。为此,研究油气田压裂返排液中污染气体浓度及扩散模型。以延安油气田为研究区域,采集和分析区域内污染气体样本,设计污染气体测定流程。利用多元矢量值函数获取污染气体扩散程度,建立点、线、面源扩散模型。结合上述模型,构建污染气体不同成分的浓度扩散模型。根据扩散分布形式可知,污染成分浓度峰值多维持在活动较为频繁的日间,地点上多位于返排池中心上方,随风向以点源、线源、面源等形式向下风口呈不同程度递减。

埋地油气管道磁记忆检测机理及影响因素综述

金属磁记忆检测技术作为一种新型的埋地油气管道非开挖无损检测手段,具有无须磁化、可预判缺陷等优势。但目前该技术主要围绕小型构件展开探究,且试验以实验室条件居多,服役环境下埋地管道的研究成果不多。鉴于此,本文纵观近年国内外研究进展及现状,概述了效应原理,梳理了基础理论的学说流派,分析了埋地管道工作环境下磁记忆信号的影响因素及作用效果。在此基础上,归纳出目前有待解决的问题,展望了未来的研究方向。

Methane in soil gas and its transfer to the atmosphere in the Yakela condensed gas field in the Tarim Basin,Northwest China

In this study, by analyzing CH4 concentration and 613CCH4 in soil-gas profiles, the potentials of CH4 gas transfer from ground to atmosphere were studied at four representative sectors in the Yakela condensed gas field in the Tarim Basin, Xinjiang, China. These are： 1） the oil-gas interface sector, 2） fault sector, 3） oil-water interface sector, 4） an external area. Variation in CH4 in soil-gas profiles showed that CH4 microseepage resulted from the migration of subsurface hydrocarbon from deep-buried reservoirs to the earth＇s surface. It was found that CH4 from deep-buried reservoirs could migrate upwards to the surface through faults, fissures and permeable rocks, during which some CH4 was oxidized and the unoxidized methane remained in the soil or was emitted into the atmosphere. The lowest level of CH4 at the soil-gas profile was found at the CH4 gas-phase equilibrium point at which the CH4 migration upwards from deep-buried reservoirs and the CH4 diffusion downwards from the atmosphere met. The 613CcH4 and ethane, propane in soil gas exhibited thermogenic characteristics, suggesting the occurrence of CH4 microseepage from deep-buried reservoirs. A linear correlation analysis between CH4 concentrations in soil gas and temperature, moisture, pH, Eh, Ec and particle size of soil indicated that both soil Eh and soil temperature could affect CH4 concentration in soil gas while soil pH could indirectly influence soil methanotrophic oxidation via impacting soil Eh.

Status, trends and enlightenment of global oil and gas development in 2021

By analyzing the distribution of global oil and gas fields and the reasons why some oil and gas fields are not in production, the distribution characteristics of oil and gas remaining recoverable reserves and their year-on-year changes, the distribution characteristics of oil and gas production and their year-on-year changes, and the development potential of oil and gas to be tapped in 2021, this paper sorts out systematically the current status and characteristics of global oil and gas development, summaries the major trends of global oil and gas development, puts forward enlightenment for international oil and gas cooperation. In 2021, oil and gas fields were widely distributed, the number of non-producing oil and gas fields was large;the whole oil and gas remaining recoverable reserves declined slightly, unconventional oil and gas remaining recoverable reserves dropped significantly;the overall oil and gas production continuously increased, the outputs of key resource-host countries kept year-on-year growth;undeveloped oilfields had abundant reserves and great development potential. Combined with global oil and gas geopolitics, oil and gas industry development trends, oil and gas investment intensity, and the tracking and judgment of hotspot fields, the major trends of global oil and gas development in 2021 are summarized. On this basis, the four aspects of enlightenment and suggestions for international oil and gas cooperation and development strategies are put forward: attach great importance to the obligation of marine abandonment to ensure high-quality and long-term benefit development of offshore oil and gas;adhere to the principle of not going to dangerous and chaotic places, strengthen the concentration of oil and gas assets, and establish multi stable supply bases;based on the multi-scenario demand of natural gas, realize the transformation from integrated collaboration to full oil and gas industry chain development;increase the acquisition of high-quality large-scale assets, and pay attention to the continuous optimization of the shareholding ratio of projects at different stages.

Efficiency of Ionic Liquid 1-Ethyl-3-Methyl-Imidazolium Acetate ([EMIM][Ac]) in Enhanced Medium Oil Recovery

Chemical flooding is one of the most efficient methods for Enhanced Oil Recovery (EOR). This study demonstrates the efficiency of mixing different concentrations of Ionic Liquid (IL), 1-Ethyl-3-Methyl-Imidazolium Acetate ([EMIM][Ac]), with Weyburn brine to improve a medium oil recovery, Weyburn oil, from an unconsolidated sand pack sample at room conditions. Effects of Slug Size (SS), IL + brine slug initiation time, and combining IL with alkali on the Recovery Factor (RF) were investigated. This study showed that the optimum concentration of ([EMIM][AC]) was 1000 ppm and the most efficient injection time of the chemical slug was at the beginning of the flooding procedure (as secondary flooding mode). In addition, it was proved that the potential of injecting a slug of IL + brine is much better than that of introducing a slug of alkali + brine. Besides, the combination of IL and alkali (AIL) resulted in better RF than injecting either of them alone. Finally, the Surface Tension (SFT), pH, wettability alteration, and viscosity of the displacing phases were measured.