Carbon nanotube enhanced water-based drilling fluid for high temperature and high salinity deep resource development

Drilling fluids face failure during drilling deep reservoir with high temperature and high salt.The experimental results show that high temperature and salinity reduce the negative charge on the surface of bentonite in the drilling fluid and cause the coalescence of bentonite particles.As a result,the particles coalesce,the grid structure is destroyed,and the rheological properties,rock-carrying capacity and filtration properties are lost.To resolve the foregoing,in this study,0.05-wt%carbon nanotubes are introduced into a 4%bentonite drilling fluid under conditions where the temperature and concentration of added Na Cl reach 180°C and 10 wt%,respectively.The carbon nanotubes adsorb on the bentonite surface and increase the space among bentonite particles.The steric hindrance prevents the coalescence of bentonite in high temperature and high salt environment.Thus bentonite maintains the small size distribution of bentonite and supports the bentonite grid structure in the drilling fluid.As a result,the rock-carrying capacity of the drilling fluid increases by 85.1%.Moreover,the mud cake formed by the accumulation of small-sized bentonite particles is dense;consequently,the filtration of bentonite drilling fluid reduced by 30.2%.

A novel polymer gel with high-temperature and high-salinity resistance for conformance control in carbonate reservoirs

Plugging agents have been widely used to enhance oil recovery in fractured-vuggy carbonate reservoirs.However,the harsh conditions of fractured-vuggy carbonate reservoirs yield a significant challenge in maintaining a long-term stabilization of plugging agents.In this work,we developed an anti-hightemperature and high-salinity polymer gel(APG)with excellent resistance to high temperature(140℃)and ultra-high salinity(240000 mg/L).The rheology and microstructure of APG were characterized before and after gelation.Core plugging tests on fractured cubic cores were conducted to quantify the plugging performance of the gel system.Experimental results showed that the Sclerglucan and Cobalt(Ⅱ)Chloride Hexahydrate filled the three-dimensional(3-D)network with various morphologies,providing extra protection to the cross-linking points of the 3D network structure of APG and thus,leading to a prolongation of the dehydration time.The dehydration rate of APG was only 5%within 30days,and the strength of APG could be maintained at a rigid or near-rigid level over 150 days.Moreover,APG exhibited satisfactory shear and scour resistance.Core plugging tests showed that APG could achieve a plugging rate of 90%and demonstrate ignorable minor damage to the substrate.Our results indicate that APG can serve as a great candidate in channel plugging in fractured-vuggy carbonate reservoirs where fractures are fully developed.

Enhanced Biodegradation of High-Salinity and Low- Temperature Crude-Oil Wastewater by Immobilized Crude-Oil Biodegrading Microbiota

High salt and low temperature are the bottlenecks for the remove of oil contaminants by enriched crude-oil degrading microbiota in Liaohe Estuarine Wetland(LEW),China.To improve the performance of crude-oil removal,microbiota was further immobilized by two methods,i.e.,sodium alginate(SA),and polyvinyl alcohol and sodium alginate(PVA+SA).Results showed that the crude oil was effectively removed by the enrichment with an average degrading ratio of 19.42-31.45 mg(L d)^(−1).The optimal inoculum size for the n-alkanes removal was 10%and 99.89%.Some members of genera Acinetobacter,Actinophytocola,Aquabac-terium,Dysgonomonas,Frigidibacter,Sphingobium,Serpens,and Pseudomonas dominated in crude-oil degrading microflora.Though the removal efficiency was lower than free bacteria when the temperature was 15℃,SA and PVA+SA immobilization im-proved the resistance to salinity.The composite crude-oil degrading microbiota in this study demonstrated a perspective potential for crude oil removal from surface water under high salinity and low temperature conditions.

Study and Application of a New Association Polymer System for Profile Control

A new polymer system, referred to simply as the AP-P4 polymer system, aims at solving the problems of high temperature, high salinity and the poor shearing resistance, all of which are encountered by conventional polymers (such as polyacrylamide) used in profile control, profile performance improvement and EOR operations in the Zhongyuan Oilfield, Sinopec. This system has been developed on the basis of the specific molecular structure and the better properties of high temperature resistance, high salinity resistance and strong shearing resistance of the new type of AP-P4 association polymer. Acidity modifying agents and cross-linking agents (MZ-YL, MZ-BE, MZ-XS), compatible with the new polymer system, are selected. Results of performance tests have shown that the new polymer system has excellent thickening, high temperature, high salinity and shearing resistance and anti-dehydrating properties. In 2003, it underwent its first pilot test in 26 wells in China, with remarkable effects in increasing oil production and decreasing water production. The newly developed polymer system and its application technology described in this paper may play a guiding role in polymer profile control operations in the oil reservoirs of high temperature and high salinity.

针对ANDES油田的抗高温高盐二元复合驱油体系研究

ANDES油田属于高温(96℃)、高盐(71.5 g/L)油藏。在此条件下,将耐温耐盐理想的疏水缔合聚合物AP-P5与4种表面活性剂复配,发现0.3%的磺酸盐(MJ2)或大庆石油磺酸盐(DQ)与2500mg/LAP-P5形成的二元体系界面张力可以达到10^(-3)mN/m数量级。考察了温度、矿化度对这两种二元复合体系黏度的影响。结果表明,两种二元复合体系黏度随着温度、矿化度的增加而降低。在96℃、矿化度为70 g/L的条件下,3000 mg/L AP-P5+0.3%MJ2+稳定剂硫脲二元复合体系的黏度为99.4mPa·s,达到现场要求。并且该二元体系在此条件下放置两个月后,黏度趋于稳定,界面张力波动幅度不大。室内物理模拟驱油实验中,当二元复合体系注入体积为0.65 PV时,采收率增幅最大(24.5%)。前期水驱至含水85%+0.65 PV(3000 mg/L AP-P5+0.3%MJ2)+后期水驱至出口含水98%为最佳驱油方案。

Soil respiration in typical plant communities in the wetland surrounding the high-salinity Ebinur Lake

Soil respiration in wetlands surrounding lakes is a vital component of the soil carbon cycle in arid regions. However, information remains limited on the soil respiration around highly saline lakes during the plant growing season. Here, we aimed to evaluate diurnal and seasonal variation in soil respiration to elucidate the controlling factors in the wetland of Ebinur Lake, Xinjiang Uygur Autonomous Region, western China. We used a soil carbon flux automatic analyzer （LI-840A） to measure soil respiration rates during the growing season （April to November） in two fields covered by reeds and tamarisk and one field with no vegetation （bare soil） from 2015 to 2016. The results showed a single peak in the diurnal pattern of soil respiration from 11：00 to 17：00 for plots covered in reeds, tamarisk, and bare soil, with minimum values being detected from 03：00 to 07：00. During the growing season, the soil respiration of reeds and tamarisk peaked during the thriving period （4.16 and 3.75 μmol.m-2.s-1, respectively）, while that of bare soil peaked during the intermediate growth period （0.74 pmol-m-2-s-1）. The soil respiration in all three plots was lowest during the wintering period （0.08, 0.09, and -0.87 μmol.m-2.s-1, respectively）. Air temperature and relative humidity significantly influenced soil respiration. A significant linear relationship was detected between soil respiration and soil temperature for reeds, tamarisk, and bare soil. The average Q10 of reeds and tamarisk were larger than that of bare soil. However, soil moisture content was not the main factor controlling soil respiration. Soil respiration was negatively correlated with soil pH and soil salinity in all three plot types. In contrast, soil respiration was positively correlated with organic carbon. Overall,CO2 emissions and greenhouse gases had a relatively weak effect on the wetlands surrounding the highly saline Ebinur Lake.

Temperature effect on performance of nanoparticle/surfactant flooding in enhanced heavy oil recovery

Recently,nanoparticles have been used along with surfactants for enhancing oil recovery.Although the recent studies show that oil recovery is enhanced using nanoparticle/surfactant solutions,some effective parameters and mechanisms involved in the oil recovery have not yet been investigated.Therefore,the temperature effect on the stability of nanoparticle/surfactant solutions and ultimate oil recovery has been studied in this work,and the optimal concentrations of both SiO2 nanoparticle and surfactant(sodium dodecyl sulfate)have been determined by the Central Composite Design method.In addition,the simultaneous effects of parameters and their interactions have been investigated.Study of the stability of the injected solutions indicates that the nanoparticle concentration is the most important factor affecting the solution stability.The surfactant makes the solution more stable if used in appropriate concentrations below the CMC.According to the micromodel flooding results,the most effective factor for enhancing oil recovery is temperature compared to the nanoparticle and surfactant concentrations.Therefore,in floodings with higher porous medium temperature,the oil viscosity reduction is considerable,and more oil is recovered.In addition,the surfactant concentration plays a more effective role in reservoirs with higher temperatures.In other words,at a surfactant concentration of 250 ppm,the ultimate oil recovery is improved about 20%with a temperature increase of 20°C.However,when the surfactant concentration is equal to 750 ppm,the temperature increase enhances the ultimate oil recovery by only about 7%.Finally,the nanoparticle and surfactant optimum concentrations determined by Design-Expert software were equal to 46 and 159 ppm,respectively.It is worthy to note that obtained results are validated by the confirmation test.

Effect of six kinds of scale inhibitors on calcium carbonate precipitation in high salinity wastewater at high temperatures

Precipitation of calcium carbonate （CaCOs） scale on heat transfer surfaces is a serious and expensive problem widely occurring in numerous industrial processes. In this study, we compared the scale inhibition effect of six kinds of commercial scale inhibitors and screened out the best one （scale inhibitor SQ-1211） to investigate its scale inhibition performance in highly saline conditions at high temperature through static scale inhibition tests. The influences of scale inhibitor dosage, temperature, heating time and pH on the inhibition efficiency of the optimal scale inhibitor were investigated. The morphologies and crystal structures of the precipitates were characterized by Scanning Electron Microscopy and X-ray Diffraction analysis. Results showed that the scale inhibition efficiency of the optimal scale inhibitor decreased with the increase of the reaction temperature. When the concentration of Ca^2＋ was 1600 mg/L, the scale inhibition rate could reach 90.7% at 80℃ at pH 8. The optimal scale inhibitor could effectively retard scaling at high temperature. In the presence of the optimal scale inhibitor, the main crystal structure of CaCOs changed from calcite to aragonite.

Characteristics and displacement mechanisms of the dispersed particle gel soft heterogeneous compound flooding system

Considering high temperature and high salinity in the reservoirs, a dispersed particle gel soft heterogeneous compound(SHC) flooding system was prepared to improve the micro-profile control and displacement efficiency. The characteristics and displacement mechanisms of the system were investigated via core flow tests and visual simulation experiments. The SHC flooding system composed of DPG particles and surfactants was suitable for the reservoirs with the temperature of 80-110 °C and the salinity of 1×10~4-10×10~4 mg/L. The system presented good characteristics: low viscosity, weak negatively charged, temperature and salinity resistance, particles aggregation capacity, wettability alteration on oil wet surface, wettability weaken on water wet surface, and interfacial tension(IFT) still less than 1×10^(-1) mN/m after aging at high temperature. The SHC flooding system achieved the micro-profile control by entering formations deeply and the better performance was found in the formation with the higher permeability difference existing between the layers, which suggested that the flooding system was superior to the surfactants, DPG particles, and polymer/surfactant compound flooding systems. The system could effectively enhance the micro-profile control in porous media through four behaviors, including direct plugging, bridging, adsorption, and retention. Moreover, the surfactant in the system magnified the deep migration capability and oil displacement capacity of the SHC flooding system, and the impact was strengthened through the mechanisms of improved displacement capacity, synergistic emulsification, enhanced wettability alteration ability and coalescence of oil belts. The synergistic effect of the two components of SHC flooding system improved oil displacement efficiency and subsequently enhanced oil recovery.

高温高盐油藏化学驱提高采收率理论技术与矿场应用

化学驱是提高采收率的重要方法之一,在油田高效开发中发挥了重要作用。基于中外化学驱技术的发展现状,针对高温高盐的苛刻油藏条件,系统总结了胜利油田化学驱提高采收率的理论技术。通过梳理胜利油田60a来化学驱技术从室内研究到矿场应用所攻克的理论和技术难题,介绍了高温高盐油藏化学驱的发展历程。通过认识驱油剂之间以及驱油剂与原油之间的相互作用和构效关系,迭代创建了高温高盐油藏聚合物“黏弹并重扩波及”理论、表面活性剂“油剂相似富集、阴非加合增效”理论和黏弹性颗粒“变形调驱”理论,并攻关形成了具有胜利特色的高温高盐油藏聚合物驱技术、无碱二元复合驱技术和非均相复合驱技术,攻克了温度为85℃、矿化度为30000 mg/L的油藏大幅度提高采收率的难题,矿场实施的96个化学驱项目的年产油量连续20a占油田年产油量的11%以上。该系列技术为胜利油田产量稳定和可持续发展做出了重要贡献。

高温高矿化度油藏提高采收率用聚合物驱油剂研究

为满足高温高矿化度油藏继续提高采收率的需求,室内以丙烯酰胺、2-丙烯酰胺-2-甲基丙磺酸、长碳链疏水单体和刚性单体为合成原料,制备了一种耐温抗盐型聚合物驱油剂KWY300,并对其综合性能进行了评价。结果表明,聚合物驱油剂KWY300具有良好的增黏性能和耐温抗盐性能,当溶液矿化度为133000 mg/L,老化温度为110℃时,质量浓度为1200 mg/L的聚合物溶液黏度值仍能达到80 mPa·s以上,增黏效果明显优于HPAM。聚合物驱油剂KWY300具有良好的渗流性能,在储层温度和矿化度条件下,阻力系数可以达到50以上,残余阻力系数约为10。此外,聚合物驱油剂KWY300还具有良好的驱油效果,注入PV数为0.5、质量浓度为1200 mg/L的KWY300溶液后,能使岩心水驱后的采收率继续提高16.4%,驱油效果明显优于HPAM。高温高矿化度油藏现场实施聚合物KWY300驱油措施后,区块内生产井的日产油量提升至措施前的3倍以上,含水率有所下降,起到了明显增油效果。

大庆油田海外多类型油藏高效开发配套技术

针对大庆油田海外多种类型油藏开发面临的挑战和技术需求,梳理近5 a大庆油田海外油藏开发形成的技术成果,系统总结已形成的适合海外多种类型油藏的特色高效开发技术。大庆油田经过近5 a来的海外油藏开发实践,将成熟油藏开发技术与海外油藏特征相结合,依靠已有优势技术创新驱动,形成了3项海外特色开发技术:一是以油藏精细描述和“优、分、调”立体开发调整为核心的复杂断块砂岩油藏有效开发技术;二是以化学剂研制及性能评价和化学驱试验方案优化为核心的高温高盐砂岩油藏化学驱提高采收率配套技术;三是以碳酸盐岩油藏测井精细评价、高渗透层识别和注水开发为核心的孔隙型碳酸盐岩油藏开发配套技术。海外油藏开发实践证明,大庆油田针对海外多类型油藏的高效开发配套技术,有力支撑了中国石油权益区块的高效开发,提升了大庆油田的国际知名度和影响力。

抗超高温220℃聚合物水基钻井液技术

我国深层油气资源丰富,其高效开发对保障国家能源安全具有重大意义。钻井液是深部地层钻探的关键,但目前常规聚合物钻井液的抗温能力普遍低于220℃,且盐会大幅降低钻井液性能,钻探过程中往往由于钻井液失效引发安全事故,对深层油气开发造成重大损失。针对钻井液高温高盐条件下性能恶化的难题,合成了具有协同作用的抗高温两性离子聚合物和抗高温阴离子聚合物,通过高强度的网架结构调控钻井液流变性;合成抗超高温高效封堵剂来提高钻井液封堵性能和滤失性能,封堵泥饼和砂床,阻止压力传递。以抗高温两性离子聚合物、抗高温阴离子聚合物和抗超高温高效封堵剂为核心处理剂,构建了一套抗超高温220℃的聚合物水基钻井液体系,并评价了该钻井液的性能。实验结果表明,该钻井液具有良好的流变滤失性、沉降稳定性、封堵性和润滑性,其高温高压滤失量仅为9.6 mL,高温高压下仍保持黏度和切力稳定,直立老化72 h沉降因子仅为0.5113,砂床侵入深度仅为6 mm,老化后润滑系数和泥饼黏滞系数分别为0.1224和0.0875。该钻井液具有良好的抗温性能和稳定性,对深部油气的开发具有重要意义。

高温高盐碎屑岩油藏注气用复合磺酸盐起泡剂性能

碎屑岩油藏岩石表面带负电,注气用起泡剂应优先选择阴离子表面活性剂。α-烯烃磺酸钠(AOS)是常用的阴离子类起泡剂,但在高盐含量水中溶解性差。将AOS和烷基二苯醚二磺酸钠(B2)复配,形成在矿化度1.12×10^(5) mg/L模拟地层水中具有较好溶解性的起泡剂AOS51(m(AOS)∶m(B2)=5∶1)。在温度110℃、压力30 MPa条件下,AOS51发泡率与在高盐条件下性能最好的羟磺基甜菜碱类起泡剂S23相当,而泡沫稳定性略逊于S23。静态吸附实验结果表明,AOS51在质量分数0.05%~1.0%范围内吸附量低于0.30 mg/g;起泡剂质量分数小于0.20%时AOS51与S23吸附量差异不大,但当起泡剂质量分数大于0.20%时S23的吸附量明显高于AOS51。岩心流动实验结果表明,质量分数0.10%和0.20%的AOS51在气测渗透率为80 mD和180 mD岩心中形成泡沫的阻力因子分别大于65、75和125、270,同时还表现出选择性流度降低特征;相同条件下AOS51流度调控能力优于S23。

美济礁沉积砂可培养细菌多样性分析

南海岛礁特殊的环境造就了丰富多样的微生物,大量微生物资源尚待挖掘和利用,但由于地理因素限制导致目前研究较少。本研究运用寡营养结合高盐和高温条件对美济礁沉积砂中的可培养微生物进行选择性分离,探究其多样性及分布情况,并运用多种特殊培养基对所获得微生物功能进行分析。鉴定结果显示,分离获得的674株细菌属于5门、6纲、26目、38科、62属、146种,相似性低于98.65%的潜在新种有42个,占28.7%。在获得的可培养细菌中,假单胞菌门和放线菌门是最为丰富的类群,占所有分离菌株数量的61.6%。功能筛选发现2种降解磷细菌、36种产脲酶细菌和57种产铁载体细菌。以上结果显示,美济礁珊瑚砂环境微生物丰度和丰富度较高,新种资源丰富。这为后续岛礁微生物资源开发和岛礁珊瑚砂环境生态修复等工作奠定了基础。

低成本耐高温海水基胍胶压裂液

海上油气田压裂由于条件限制,采用淡水配制压裂液导致运输成本高、周期长。海水配制压裂液,碱性交联环境螯合剂加量大,材料成本高,耐温能力一般。针对以上情况采用钛酸四异丙酯、硫酸锆等物质作为反应原料,分步合成有机钛锆交联剂。经核磁碳谱、交联剂沉析后扫描电镜表征,表明交联剂为有机螯合物,动静态同步激光光散射仪表征交联剂尺寸,表明交联剂粒子直径主要为1~100 nm,具有良好的反应活性。该交联剂在中性条件下即可交联,适应海水等高矿化度水质配制压裂液,其交联微观形态为蜂窝状六元网格状结构,结构稳定,黏弹性相比单钛交联有明显的提升,耐温能力可达180℃以上。在中海油南海区域施工实验一口海水配液高温井,效果良好。

一种高温高矿化度复合冻胶的研制与应用

为了解决高温高矿化度油藏深部调驱问题,以丙烯酰胺(AM)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)和N,N-二甲基丙烯酰胺(DMAA)为原料合成共聚物PASD,并以酚醛树脂作为交联剂、硫脲作为稳定剂,添加增强剂MZQ制备得到复合冻胶体系。通过红外光谱仪、扫描电镜、岩心流变仪等对冻胶体系进行应用研究,考察了共聚物PASD、交联剂、稳定剂、增强剂加量的影响,确定复合冻胶体系的最佳配方;在150℃、矿化度为25.198×10^(4) mg·L^(-1)下条件下应用,其冻胶强度为Ⅰ级,抗老化脱水性能良好,有效耐温脱水时间超过180d;冻胶封堵能力超过93%,具有良好的封堵性能以及抗盐耐温性能。

海洋性气候环境下电梯主要零部件腐蚀案例分析及防腐蚀措施研究

电梯作为人们出行的重要垂直交通工具,其设备的安全运行受到的关注度越来越高。以福建省平潭综合实验区内的在用电梯为研究对象,该地区处于海洋性气候环境中,其高温、高湿、高盐分的环境会加速机电类设备的腐蚀,导致其机械零部件以及电气部件的功能的失效,影响电梯的安全运行。从定期检验中发现的电梯主要零部件腐蚀案例出发,从多个角度分析可能造成腐蚀的原因。并在此基础上,从电梯的采购、设备的安装、使用单位的日常管理、维保单位的日常维护保养以及定期检验的角度出发,提出电梯防腐蚀的具体相关措施,以减少因腐蚀造成电梯的机械或者电气部分的功能失效几率,保障人们乘坐电梯的安全运行,避免特种设备事故的发生。

含盐有机废液焚烧处理技术概述

随着工业化进程加快,含盐有机废液的环境治理问题日益凸显,焚烧技术作为一种有效的处理方法而备受瞩目。文章系统评述了液中焚烧技术、高温热解技术、传统高温焚烧技术、余热锅炉内高温焚烧技术以及高温等离子体焚烧技术在处理含盐有机废液中的应用,分析了其技术原理、技术要点、优缺点,以及处理效率、二次污染控制、运营成本和可持续性等关键指标。同时,对新兴的高温等离子体焚烧技术予以重点讨论,其因具有较高的固化率和有机物去除能力而表现出潜在的应用价值。虽然以上技术各有优点,但仍存在发展空间,尤其是在提升运行稳定性、降低能耗和成本以及降低环境影响等方面,提倡未来的研究应聚焦于技术创新、流程优化以及经济性评价,以期达成更加环境友好和经济合理的含盐有机废液处置方案。

面向水下导航的温盐深数据采集与标定方法

海洋存在温度、盐度突变的海水跃层,会大幅改变海水浮力导致水下潜航器急剧下沉或上浮造成巨大危害,因此温度、盐度和深度数据是潜航器在水下导航的重要环境参数,已越来越多地被应用于潜航器的水下多源融合导航。近年来随着水下导航精度的不断提升,对温盐深数据的精度要求也越来越高,而提高传感器及采集电路的稳定性与精度、优化数据标定方法是保障数据精度的关键。传统温盐深数据采集与标定方法存在稳定性差、精度低等缺点,因此提出了一种基于最小二乘法的温盐深数据采集与标定方法,旨在提高测量精度的同时降低成本与设计难度,便于产品的工程实现。相比传统方法,本方法精度提升1个数量级,达到JJG 763-2019的一级计量要求。