Synthetic polymers:A review of applications in drilling fluids

With the growth of deep drilling and the complexity of the well profile,the requirements for a more complete and efficient exploitation of productive formations increase,which increases the risk of various complications.Currently,reagents based on modified natural polymers(which are naturally occurring compounds)and synthetic polymers(SPs)which are polymeric compounds created industrially,are widely used to prevent emerging complications in the drilling process.However,compared to modified natural polymers,SPs form a family of high-molecular-weight compounds that are fully synthesized by undergoing chemical polymerization reactions.SPs provide substantial flexibility in their design.Moreover,their size and chemical composition can be adjusted to provide properties for nearly all the functional objectives of drilling fluids.They can be classified based on chemical ingredients,type of reaction,and their responses to heating.However,some of SPs,due to their structural characteristics,have a high cost,a poor temperature and salt resistance in drilling fluids,and degradation begins when the temperature reaches 130℃.These drawbacks prevent SP use in some medium and deep wells.Thus,this review addresses the historical development,the characteristics,manufacturing methods,classification,and the applications of SPs in drilling fluids.The contributions of SPs as additives to drilling fluids to enhance rheology,filtrate generation,carrying of cuttings,fluid lubricity,and clay/shale stability are explained in detail.The mechanisms,impacts,and advances achieved when SPs are added to drilling fluids are also described.The typical challenges encountered by SPs when deployed in drilling fluids and their advantages and drawbacks are also discussed.Economic issues also impact the applications of SPs in drilling fluids.Consequently,the cost of the most relevant SPs,and the monomers used in their synthesis,are assessed.Environmental impacts of SPs when deployed in drilling fluids,and their manufacturing processes are identified,together with advances in SP-treatment methods aimed at reducing those impacts.Recommendations for required future research addressing SP property and performance gaps are provided.

THE LUBRICATING MECHANISMS OF LUBRICATINGDRILLING FLUIDS ON SYNTHETIC DIAMOND BIT

The functions of lubricants in diamond drilling were discussedin this paper. The influences of lubricant on drilling efficiency and bit′s life were compared and analyzed with simulated drilling test and lubrication test apparatus. Lubricating mechanisms were also discussed.

A high-temperature resistant and high-density polymeric saturated brine-based drilling fluid

Three high-temperature resistant polymeric additives for water-based drilling fluids are designed and developed:weakly cross-linked zwitterionic polymer fluid loss reducer(WCZ),flexible polymer microsphere nano-plugging agent(FPM)and comb-structure polymeric lubricant(CSP).A high-temperature resistant and high-density polymeric saturated brine-based drilling fluid was developed for deep drilling.The WCZ has a good anti-polyelectrolyte effect and exhibits the API fluid loss less than 8 mL after aging in saturated salt environment at 200°C.The FPM can reduce the fluid loss by improving the quality of the mud cake and has a good plugging effect on nano-scale pores/fractures.The CSP,with a weight average molecular weight of 4804,has multiple polar adsorption sites and exhibits excellent lubricating performance under high temperature and high salt conditions.The developed drilling fluid system with a density of 2.0 g/cm^(3)has good rheological properties.It shows a fluid loss less than 15 mL at 200°C and high pressure,a sedimentation factor(SF)smaller than 0.52 after standing at high temperature for 5 d,and a rolling recovery of hydratable drill cuttings similar to oil-based drilling fluid.Besides,it has good plugging and lubricating performance.

Research and Application of Fuling Shale Gas Anti-Collapse and Anti-Leakage Drilling Fluid System

Aiming at the problems of microfracture development in hard brittle shale gas layer in Fuling block, Chongqing, such as collapse of borehole wall and the existence of permeability loss of microfracture during drilling, and serious pollution of drilling environment with oil-based drilling fluid, a water-based drilling fluid system for anti-collapse and anti-leakage was studied. A water-based drilling fluid system with anti-collapse and anti-leakage was formed by introducing functional treatment agents, such as polypolysaccharide MEG, polymer emulsion film forming wall cementing agent LFGB, polyamine inhibitor LCFA and deformable particle plugging agent BXLZ, into the conventional water-based drilling fluid. After rolling at 130°C for 16 h, the system has good rheological properties, low filtration loss, good inhibition, lubrication and plugging properties. It has good plugging properties for 0.12 mm, 0.24 mm, 0.38 mm micro-cracks and 400 mD and 800 mD sand plates. The system was successfully tested on site in August 2019 in Fuling Reef Block, showing good rheological properties, solid wall plugging, and strong ability to seal and inhibit fracture expansion. There was no block falling in the drilling process, and the tripping, casing running and well cementing operations were all smooth, which provided a new technical idea and scheme for environmental protection and green drilling in Fuling shale gas exploitation.

Synthesis and mechanism of environmentally friendly high temperature and high salt resistant lubricants

With the exploration and development of deep and ultra-deep oil and gas,high torque and high friction during the drilling of deep and ultra-deep wells become one of the key issues affecting drilling safety and drilling speed.Meanwhile,the high temperature and high salt problem in deep formations is prominent,which poses a major challenge to the lubricity of drilling fluids under high temperature and high salt.This paper reports an organic borate ester SOP as an environmentally friendly drilling fluid lubricant.The performance evaluation results show that when 1%lubricant SOP is added to the fresh water-based mud,the lubrication coefficient decreases from 0.631 to 0.046,and the reduction rate of lubrication coefficient is 92.7%.Under the conditions of 210℃ and 30%NaCl,the reduction rate of lubricating coefficient of the base slurry with 1%SOP was still remain 81.5%.After adding 1%SOP,the wear volume decreased by 94.11%compared with the base slurry.The contact resistance experiment during the friction process shows that SOP can form a thick adsorption film on the friction surface under high temperature and high salt conditions,thus effectively reducing the friction resistance.Molecular dynamics simulation shows that lubricant SOP can be physically adsorbed on the surface of drilling tool and borehole wall through hydrogen bond and van der Waals force.XPS analysis further shows that SOP adsorbs on the friction surface and reacts with metal atoms on the friction surface to form a chemically reactive film.Therefore,under high temperature and high salt conditions,the synergistic effect of physical adsorption film and chemical reaction film effectively reduces the frictional resistance and wear of the friction surface.In addition,SOP is non-toxic and easy to degrade.Therefore,SOP is a highly effective and environmentally friendly lubricant in high temperature and high salt drilling fluid.

安全环保的新型水基钻井液ULTRADRILL

针对渤海地区钻进过程中遇阻遇卡 ,起下钻困难 ,密度难以控制 ,机械钻速低等问题 ,采用了安全环保的新型水基钻井液ULTRADRILL ,ULTRADRILL新型钻井液的合成聚合物不含铬及其它对环境有害的物质。该钻井液主要由两种基本的页岩抑制剂和钻速增效剂组成。该钻井液能提供优异的页岩抑制性、润滑性和井眼稳定性 ;滤失量小、滤饼薄 ,可防止钻头泥包 ;携砂能力强 ,流变性易于控制 ;具有较广的密度和盐的选择性。现场应用表明 ,ULTRADRILL钻井液性能稳定 ,具有独特的流变性能 ,滤失量小、泥饼坚韧、致密而光滑 ;钻井过程中悬浮携砂能力强 ,钻速快 ,井壁稳定。该钻井液容易降解 ,且无生物毒性 ,满足了海洋环保的要求。

页岩油储层环保型高性能水基钻井液体系研究及应用

为了满足页岩油储层钻井对钻井液环保性能的要求,以环保型页岩抑制剂HBY-S和环保型复合润滑剂HBR-L为主要处理剂,并结合其他环保型处理剂,研制出了一种适合页岩油储层钻井的环保型高性能水基钻井液体系。室内对钻井液体系的耐温性能、抗污染性能和环保性能进行了评价,结果表明:体系具有良好的耐温性能,经过160℃老化后钻井液体系的高温高压滤失量为9.6mL,岩屑滚动回收率可以达到90.6%,润滑系数为0.089;体系具有较强的抗污染能力,钻井液中加入10%NaCl、1.0%CaCl_(2)或者15%岩屑粉时流变性能和滤失性能均比较稳定;体系的环保性能优良,钻井液的EC_(50)值为85000(无毒),BOD_(5)/COD值为26.5%(易降解),重金属含量均低于行业标准值。环保型高性能水基钻井液在某页岩油区块水平井钻井过程中进行了成功应用,其中DG-1井钻井期间未出现井下复杂事故,现场钻井液性能稳定,环保性能达标,实现了安全高效钻井的目标,在页岩油水平井钻井中具有良好的推广应用前景。

一种钻井液润滑剂的制备及其性能评价

基于现有钻井液润滑剂吸附、润滑抗磨性能差的问题,本文以多元醇、多元羧酸为原料制备一种强吸附、抗剪切的润滑剂(HR-1),采用极压润滑仪和四球摩擦试验机评价其润滑抗磨性能,并通过扫描电镜&能谱仪对其润滑机理进行探讨。实验发现,润滑剂HR-1显著提高了膨润土基浆的润滑抗磨性能,优于现场应用效果较好的润滑剂BLOE;另外,润滑剂HR-1使钢球表面的C元素含量升高以及Na、O元素含量降低,这表明,润滑剂HR-1的加入使润滑剂分子取代了原本吸附在钢球表面的钠基膨润土,且降低了摩擦腐蚀产物(Fe_(3)O_(4))的形成,起到润滑抗磨作用,达到保护金属的目的。

颗粒流钻削润滑中颗粒介质导入的离散相仿真

颗粒流润滑是一种高效、绿色固体润滑技术,在切削加工领域已得到初步应用。然而,对于钻削等半封闭加工工艺,有效促进颗粒润滑介质通过钻头与孔壁之间的狭小空隙进入切削区是实现可靠润滑的前提与保障。为探究颗粒介质在钻头和孔壁间隙中的流动特性,促进其有效导入,利用Fluent软件中的离散相模型进行颗粒润滑介质导入的数值仿真。通过不同颗粒介质和钻削参数下的模拟计算,对钻杆与孔壁间隙及内孔壁面的颗粒浓度进行了比较。结果表明,固体颗粒的材质是影响导入量的重要因素,在同一孔深截面处,钻杆与孔壁间隙中的MoS2浓度比石墨浓度更高,且其孔壁黏附量也更大;刀具转速和进给速度的提高有利于润滑颗粒的导入,且转速的作用效果更明显。该研究对于改善颗粒流钻削润滑效果、促进该技术在难加工材料钻削中的应用具有一定的实践价值。

两亲性碳点在硅酸盐钻井液中的润滑性能

硅酸盐钻井液具有抑制封堵能力强、环保等优点,但其润滑性能差,这制约了硅酸盐钻井液的广泛应用。利用极压润滑仪测定含有两亲性碳点和聚氧乙烯型表面活性剂的硅酸钠溶液的润滑系数,筛选出性能优异的润滑剂,并采用总有机碳分析仪、动态光散射和接触角仪等分析其润滑机理。实验结果发现,两亲性碳点具有优良的润滑性能和耐温性,在5%硅酸钠水溶液中添加0.3%两亲性碳点C_(12)-CDs,经过110℃高温热滚16 h前后体系的极压润滑系数可从0.500左右分别降低至0.065和0.063,润滑系数降低率高达87.52%,而聚氧乙烯型表面活性剂并无润滑效果。进一步探究其润滑机理,C_(12)-CDs在石英砂表面具有优异的吸附性能,100 mg/L的C_(12)-CDs溶液吸附前后的表面张力从44.81 mN/m上升为64.03 mN/m,其吸附量可达到89.23 mg/L;且粒径分析数据表明,C_(12)-CDs可将Na_(2)SiO_(3)溶液的平均粒径从514.0 nm分散为63.2 nm。碳核表面的多羟基结构和长疏水链可促进两亲性碳点在金属钻杆、井壁和硅酸聚集体表面的吸附,两亲性碳点作为润滑剂与硅酸钠钻井液体系配伍性能好,添加C_(12)-CDs的现场硅酸盐钻井液润滑系数降低率可达到86.34%,可为硅酸盐水基钻井液润滑剂的现场应用提供理论指导。

超支化高分子水基钻井液仿生润滑机理

随着定向钻井技术的发展,水基钻井液润滑性逐渐成为确保定向井钻进的关键指标,设计新型钻井液润滑材料已成为油田化学领域的研究热点和重点。为探究超支化高分子水基钻井液仿生润滑机理,首先采用发散法合成了第1.5代超支化聚丙烯酸乙二胺基丙烯酸十八酯G1.5 P(EDA—MA—OA),然后进行了合成产物结构、微观形貌与热稳定性检测及其强化水基钻井液润滑性能评价,最后系统分析了超支化高分子与膨润土粒子的吸附行为。研究结果表明:①G1.5 P是粒径分布在几十纳米的分散性粒子,具有良好的热稳定性,热解温度集中在214℃;②以G1.5 P为润滑添加剂,构建的水基钻井液润滑系数为0.068,具有良好降摩减磨性;③G1.5 P呈“分子刷”状吸附于亲水材料表面,不仅改变了表面润湿性,而且还可促进膨润土粒子聚结形成致密、韧性的泥饼;④基于超支化高分子强化水基钻井液润滑的构效关系,提出了一种水基钻井液边界—固体润滑新模型,即超支化高分子促进在钻具与井壁摩擦副间形成低剪切强度泥饼,以泥饼结构内摩擦代替钻具刚性外摩擦,实现钻井液降摩减磨功能。结论认为,该认识完善了水基钻井液润滑添加剂的设计思路,为新型高性能润滑处理剂设计及超滑水基钻井液的开发提供了理论与技术支撑。

南海东部浅层大位移井聚合物钻井液优化研究与应用

南海东部恩平油田浅层大位移井钻遇层位浅,地层胶结疏松,泥岩含量高,钻井过程中存在钻井液增稠、井壁失稳、循环当量密度升高诱发井漏、摩阻扭矩大等问题。优选了低分子量酰胺基聚合物PF-BIOCAP、胺基聚合物PF-UHIB和硼酸酯复合植物油PF-EXLUBE以改善聚合物钻井液包被抑制性、造浆抑制性和润滑性。评价结果表明,优化后钻井液泥岩滚动回收率达到96%,经(w)15%泥岩钻屑污染后表观黏度上升率明显下降,摩擦系数和泥饼黏滞系数均低于0.1,表现出优异的抑制性和润滑性,且流变性能满足井眼清洁要求。该聚合物钻井液体系在恩平油田浅层大位移井中取得了良好的应用效果,解决了泥岩井壁失稳、泥岩岩屑造浆和高摩阻扭矩等技术难题,对海上浅层大位移井的推广应用具有指导意义。

冷却润滑对金属玻璃钻削特征及可加工性的影响研究

金属玻璃钻削高温极易导致光发射、大毛刺和孔烧蚀等严重问题。研究锆基金属玻璃在干切削、冰冻切削和切削油条件下的钻削过程、钻削特征及孔质量,通过对比三种冷却润滑条件下的轴向力动态变化过程、钻削能、刀具磨损以及孔口毛刺,提出适用于金属玻璃钻削加工的工艺方法。研究结果表明:刀具磨损积累与热软化是影响金属玻璃钻孔过程及轴向力动态变化的主要因素;干切削会使孔材料处于过冷液态,导致孔无法成形。金属玻璃入口孔毛刺主要为冠状和无规则扭曲形毛刺;出口孔毛刺主要为冠状毛刺。冰冻切削仅适用于低速钻削金属玻璃;切削油条件下高速钻削金属玻璃可获得最佳孔口质量和最长刀具寿命。

涡流冷却静电润滑复合干式钻削技术研究

为降低机械加工过程中切削液对环境造成的污染以及处理切削液时高昂的成本,提出一种兼有涡流冷却效应和静电润滑效应的干式钻削技术与装置。将气体离子化、臭氧化后吹到切削加工区域,代替切削液实现润滑、冷却的作用,获得良好的断屑效果,同时延长刀具的寿命。基于结构参数对系统放电性能、臭氧浓度以及冷却效果的影响规律,优化装置结构,形成干式辅助钻削装置。实验结果表明:当电极锥度为15°、电极直径为1 mm、铜帽内径为3 mm、气体流量为20 L/min、驱动电压为6 kV时,臭氧浓度达到峰值34.2×10^(-6)。通过与纯干式切削对比发现:所提技术的切削温度降低40.9%,刀具刃口基本没有损伤,切屑微观表面切痕分布清晰、条理均匀。所设计的涡流冷却静电润滑干式钻削技术在切削效应、冷却效果、刀具磨损以及切屑形态等方面均优于传统的干式钻削技术,可以用于六系铝材的钻削加工。

青海省锡铁山矿区坑道钻探技术研究

近几年,锡铁山主矿带逐步进入深部找矿,在矿井下主要借助坑道钻探查明深部矿床分布与储量,在实施坑道钻探过程中面临机场硐室支护、破碎地层钻进、水敏地层护壁取心、涌水地层处理等挑战,如果处理不当会造成机场硐室掉块、坍塌,钻孔出现卡钻、埋钻、坍塌等事故,严重时造成钻孔报废,制约了找矿进程。针对上述复杂地层钻进技术难点,开展加强硐室支护、选择合理钻进参数、优化钻孔结构、制定复杂地层冲洗液配方以及使用速凝水泥封堵等技术措施研究,保障了坑道机场的施工安全,有效解决了该区多种复杂地层的钻进难题,降低了孔内事故发生率和钻孔报废率,提高了钻探效率和钻探质量,为后续相似地层钻探施工提供了参考。

青海油田风西区块长水平段水平井钻井液技术

青海油田为实现稀井高产开发技术方案,在柴达木盆地大风山地区风西构造部署五口长裸眼水平井,并同时应用水基、油基钻井液进行施工对比,总结完善风西长裸眼长水平段水平井钻完井工艺技术模板。以优质复合盐水基钻井液在风西ⅠH1-5井的现场应用实例进行总结,并对相关钻井工艺技术应用、工程参数控制、流变性与携带等进行分析。风西ⅠH1-5井完钻井深为5478 m,水平段长2541 m,创青海油田水平段最长、油层钻遇率最高(100%)、水平井单趟进尺最多(1566 m)、水平段短程起下钻井段最长(达1000 m)、首次采用漂浮下套管技术等多项施工新纪录,该井的成功钻探对于超长水平段水平井的钻完井工艺在青海油田应用具有里程碑意义。与应用油基钻井液施工的邻井就钻井周期进行了对标分析,该优质复合盐水基钻井液施工井均优于油基钻井液施工井,对今后钻探长裸眼、长水平段水平井钻井液体系优选有较好的指导借鉴。

LS-2600五缸钻井泵设计与应用

针对现有应用于超深井、复杂井石油开采的三缸钻井泵存在的效率低等问题,研制了一种大马力、单电机、五缸钻井泵。通过变频电机的选型,设计了与之匹配的减速箱、动力端总成及液力端总成,并配置有控制系统、喷淋系统、动力端润滑系统和在线监测系统,从而实现钻井作业。通过样机试制、厂内型式试验及胜利油田工业性试验,对五缸钻井泵性能、稳定性和可靠性进行充分验证,试验期间设备运行良好、性能可靠、各系统稳定可靠、各项参数均满足设计要求。试验表明,该五缸钻井泵对钻井提速提效、节能减排、井下压力安全控制等效果显著,具有较好的市场前景及推广价值。

新型硫化聚酯在深孔钻切削油中的润滑极压性能研究

采用四球极压抗磨试验及攻丝扭矩试验对比新型硫化聚酯和氯化石蜡等添加剂在深孔钻切削油中的润滑性和极压抗磨性,探讨新型硫化聚酯在深孔钻切削油中取代氯化石蜡的可行性。结果表明:新型硫化聚酯相比氯化石蜡具有更优异的性能,能有效提高切削油的润滑和极压抗磨性能,能显著提高切削油的烧结负荷。新型硫化聚酯能有效取代氯化石蜡,作为深孔钻切削油的无氯极压添加剂。

环保型钻井液用润滑剂的研发与性能评价

随着人们环境保护意识的提高,石油钻井行业也在不断寻求更加环保、可持续的解决方案。钻井液作为石油钻井过程中的重要原料,其使用的润滑剂往往含有对环境有害的成分。作者研究了一种新型环保型钻井液润滑剂,并对其各方面性能进行了评价。

油基钻井液用氮杂石墨烯的研制与应用

对川西海相雷口坡组地层破碎、水平井后期托压严重、井壁失稳突出等问题进行分析发现,现用油基钻井液体系的封堵润滑性不能有效满足施工需求。为提高油基钻井液的封堵润滑性,通过分子结构设计,采用氮掺杂改性与熔盐法相结合的方式,制备出氮杂石墨烯,并通过热稳定性、分散稳定性、XRD、红外光谱、粒径分析等手段表征其热稳定性、分散性、结构、基团和粒径大小。实验结果表明,当氮杂石墨烯在现场油基钻井液中的加量为0.5%时,高温高压滤失量降低率达到76.2%,润滑系数降低50%左右,抗温180℃,石墨烯与油基钻井液的配伍性好,能够很好地提高油基钻井液的润滑性和封堵性。现场应用表明,石墨烯可以显著改善油基钻井液在施工过程中存在的水平井托压、高摩阻、井壁失稳等问题。通过采用氮杂石墨烯封堵润滑油基钻井液技术,为川西海相易坍塌地层井壁失稳及水平井托压等当前实际问题提出了新思路和技术支撑。