提高注水泥质量的综合因素.pdf

提高注水泥质量的综合因素 郭小阳 刘崇建 张明深 张勇 张朝晖(西南石油学院国家重点实验室,四川南充637001)(南海西部石油公司钻采工艺研究所)摘要 分析现场固井实例说明,提高固井质量是一项系统工程,围绕水泥浆特性、浆体压力平衡、流态、井身质量、套管居中及水泥浆与泥浆流变性能等方面,拟定固井工艺措施,是提高水泥浆顶替效率,防止水泥浆窜槽,保证水泥石密封质量的较好方法。文中还对水泥石的的声幅测井及变密度测井进行了对比和分析,初步得出了声幅值的变化幅度与两个交界面的质量并不完全吻合。主题词 注水泥;综合因素;压力平衡;密封中图分类号 TE 256.5前 言油气井注水泥质量是保证油、气井寿命,提高采收率以及合理开发油气资源的关键技术之一。现场及室内研究表明1,提高油气井固井质量所涉及的问题很多,如水泥浆特性、水泥浆流动规律、压力平衡、井身质量、套管居中及水泥浆与泥浆流变性能的合理配合等方面。如何把这些因素作为一项系统工程有机地结合起来,是当前提高固井质量(见表5)的主要方向。现场将这些问题作了进一步归纳,形成提高固井质量的八字方针,即压稳、居中、替净和密封。具体要求解决的问题有以下几方面:(1)水泥浆注替和凝结过程,必须保证浆柱压力与地层压力的平衡关系,作到水泥浆不漏,油、气、水不因水泥浆失重而造成窜流问题;(2)清除和替净环空泥浆,提高水泥浆的顶替效率和水泥环的胶结质量;(3)提高水泥石的密封质量,无局部水槽、横向水带和窜槽现象,保证后继工程的要求。围绕上述问题,应用LD14-1井固井实例,说明影响固井质量的几项关键因素。1LD14-1井眼基本情况111 井身结构958 套管及7 尾管注水泥结构为:1214 井眼(5011191 245.0 m)+958 套管(01 242115 m)+水泥浆返高840196 m(实际为592115 m,井段为6501 242.15 m)。812 井眼(1 242.151 778 m)+7 尾管(1 1021 631 m)+水泥浆返高527 m(1 1001 631 m)。112 钻井及井眼情况当用958 套管固井后,使用密度为1116的泥浆钻至1 54118 m时,因欠平衡,所以在812 井眼内,井深1 541 m处卡死,从1 1991 280 m开窗侧钻,钻出的812 井眼极不规则,井径呈尖峰锯齿形变化,出现多段糖葫芦井眼,特别在井段1 4701 495 m,其井径变化为:30.5 cm35.6 cm45.70 cm;在井段1 5631 580 m,其井径变化为:25.4 cm38.1cm48.3 cm。113 侧钻时气侵情况侧钻时,使用的泥浆密度为1125,并逐步将密度提高到1173,但气测值仍较大(见表1)。表1 不同井深的气侵情况井径井深(m)m气测值含量(%)8121 388113042(1 260单位)1 580115028(850单位)1 77011732314(702单位)第20卷 第3期 西 南 石 油 学 院 学 报 Vol.20No.31998年 8月 Journal of Southwest Petroleum InstituteAug199819980304收稿郭小阳,男,1951年生,副教授,现主要从事固井、完井方面的教学和科研工作 1994-2008 China Academic Journal Electronic Publishing House.All rights reserved.http:/114 泥浆及水泥浆性能表2表3为LD14-1井958 套管及7 尾管固井时,泥浆与水泥浆的流变性能和水泥浆防气窜的有关因子。表2 泥浆与水泥浆的流变性能液体类型1214 958m0(Pa)s(PaS)nk(PaSn)812 7c0(Pa)s(PaS)nk(PaSn)海水聚合物 泥 浆1.181.255100.010.020.4640.4510.5591.2151.73100.3990.6240.622水 泥 浆1.9023.510.1080.6561.3141.909.200.1320.8560.369表3 水泥浆性能及防气窜因子井身结构GFP水泥浆性能指标c失 水 量(ml/30min)自由水量(ml)t100BC(min)t50BC(min)Ap(MPa)1214 9581.041.901480.43232700.2807.95812 712.581.905302782500.0470.65注A=0.182(t100BC)12-(t30BC)12眼极,用t50BC代替t30BC,计算A值。GFP为气窜潜力系数,用水泥浆柱压力最大降低值pmax与井内浆柱过平衡压力p的比值表示。pmax为水泥浆胶凝强度c=240Pa时,水泥柱的压力降低值。很显然当 p愈大,pmax愈小,GFP愈小,气窜危险性愈小;当 GFP=14,气窜可能性较小;当 GFP=58,气窜可能性中等;当 GFP 8,气窜危险大。从表23可知:(1)水泥浆的流性指数nc或动塑比(0s)c分别大于和小于泥浆的流性指数nm或动塑比(0s)m,易于造成两种液体沿顶替界面窜槽的情况;(2)7 尾管的水泥浆,其稳定性良好,阻力A值极小,对防止气窜非常有利。958 套管水泥浆的质量不如7 尾管的水泥浆。115 套管偏心时水泥浆的流动特性在有斜度的裸眼井径扩大井中,套管扶正器易于靠井壁下侧形成套管偏心。套管偏心对不同间隙处的水泥浆顶替流动的影响有(1)当宽间隙处流速大时,易发生紊流;(2)当窄间隙流速小时,泥浆容易滞留在环空内,形成顶不干净的死区。针对LD14-1井的情况,958 套管处于直井中,完全偏心的可能性不大;而7 尾管在有井斜为5.5的井中,形成套管完全偏心的可能性较大。958 套管和7 尾管扶正器靠在井壁,处于完全偏心状态时,水泥浆在宽、窄间隙内的流场分布情况(见表4)。从表4可知:(1)7 尾管在不规则井眼内,偏心度e=55%80%,大于保证顶替效率的极限偏心度30%;(2)尾管偏心形成了井眼上侧的宽间隙和下侧的窄间隙,宽间隙的平均返速Vw不仅大于套管居中的平均返速Vc,而且又远远地大于窄间隙的平均返速Vn,即Vw Vc Vn,VwVc=50120窄间隙的水泥浆,基本上处于不流动状态,泥浆滞留在窄间隙处,造成水泥浆在环空的顶替不均匀;(3)在该机泵条件下,水泥浆在环空处于层流05西南石油学院学报 1998年 1994-2008 China Academic Journal Electronic Publishing House.All rights reserved.http:/状态,雷诺数较低,即使在宽间隙,水泥浆仍处于层流状态,不利于水泥浆对泥浆的完全顶替。表4 套管偏心时水泥浆在宽、窄间隙内的流场分布井身结构井 段(m)实际平均井径(cm)扶正器直 径(cm)eVc(m/s)Vw(Vn)(m/s)VwVnRew(Ren)1214 958812 7050131.12501124534.231 1991 37021.591 3701 46527.61 4651 48035.51 4801 49840.61 4981 52230.51 5221 58236.81 5821 60233.031.122.200.870.87(0.87)1429(429)0.320.5620.174(0.919)5.3713(49)01.6131.613(1.613)1742(742)0.550.5430.917(0.063)14.61270(21)0.750.2560.427(0.006)68.4975(1.5)0.810.1820.299(0.002)126.6827(0.5)0.650.3940.667(0.023)29.41163(6)0.770.2330.387(0.005)81.4934(1)0.710.3130.526(0.011)46.71065(3)2LD14-1井的固井质量表5列出了958 套管及7 尾管注水泥后不同井段的声幅值及变密度测井评价的第一界面和第二界面胶结情况。从表5可知:表5958 套管及7 尾管注水泥浆质量评价井身结构井段(m)实际平均井径(cm)井眼描述声幅(%)1界面胶结情况2界面胶结情况1214 958812 71 0131 0211 0211 0331 0331 0411 0411 0551 0551 0831 0831 1001 241.51 4111 4111 4271 4271 4301 4301 4651 4651 4801 4801 4981 4981 5221 5221 5821 5821 60227.6027.6027.6027.6035.5040.6030.5036.8033.00井径规则井径规则井径极不规 则,呈突变的锯齿形变化 5 51020 5 5525 5 15 51080好好好好差好好好好 中等 好 中等 好 差 差 中等 好 中等 好 差(1)测井声幅值较低,一般在5%25%以内,第一界面胶结情况良好;而第二界面胶结情况并不理想,出现了不合格的情况。(2)测井声幅值与第一界面(下转67页)15第3期 郭小阳等:提高注水泥质量的综合因素 1994-2008 China Academic Journal Electronic Publishing House.All rights reserved.http:/度,降低汽油机的HC、NOX排放和柴油机HC、CO排放;后者促进燃油完全燃烧,抑制CO、HC和碳烟生成4。排气温度上升和碳烟下降还证实FA-1具有减少燃烧室积炭和机械磨损作用。4FA-1节能剂的经济效益分析FA-1节能剂的售价定为60元/L,节油率为15%20%,添加量为0.1%(v),按目前燃油价格计算(汽油和柴油平均为2元/L),1 L FA-1可节油150200 L,价值300400元,扣出FA-1成本后,可净节约购油费240340元。FA-1节能剂是一种新型高效的减污节能产品,它的推广和应用,可节省大量的汽油和柴油,大大降低汽车尾气对大气的污染,这对于缓解我国车用燃料的紧张状况,以及环境保护都具有重大意义。5 结 论(1)FA-1无灰通用型燃油节能剂不含金属元素,属于无灰型,完全克服了MeL型的缺点。(2)本剂适用范围广,汽油和柴油通用。(3)FA-1的台架试验节油率4.7%,在汽油车和柴油车上的行车试验平均节油率为15%20%,新车 10%。(4)FA-1的作用机理是改善燃油雾化质量,与氧发生三分子生链反应;它具有助燃、消烟、除积炭和节油等多项功能。参考文献1 唐晓东.我国汽车减污节能的有效途径 燃料结构多元化.中国能源,1995,(5):38412 许世海等.消烟助燃剂的研究现状与发展趋势.小型内燃机,1996,25(1):34383 朱育元等.燃料型节能油节能剂在发动机台架上的测试.石油炼制,1992,(3):59644 朱崇基等.内燃机环境保护学,浙江大学出版社,19885 唐晓东,徐荣.燃油消烟节能剂的作用机理.西南石油学院学报,1994,16(2):1231296苏A.A.布拉特柯夫(李奉孝译).发动机化学理论基础.烃加工出版社,19907 陈绍州等.石油化学,华东理工大学出版社,19938 刘天新等.水蒸汽助燃机理的研究与应用.中国能源,1995,(10):2023(编辑 袁国君)(上接51页)的胶结情况吻合程度好;而与第二界面的胶结情况吻合程度不甚理想,出现了声幅值小,第二界面胶结差和中等的情况;声幅值较大,第二界面胶结中等的情况。(3)井径规则,套管偏心度小的井段(1 241.51 430 m),一般注水泥质量都较好。3 固井质量不理想的原因(1)7 尾管固 井 时,过 平 衡 压 力 偏 小,为0.64 MPa,GFP=12.54,属于强气窜可能性范围。实测气测值也说明泥浆密度m=1.73,未压稳地层;(2)井径极不规则,尾管在有斜度的井内处于完全偏心状态,井壁下侧水泥浆流速极慢,顶替效率较低,造成了锯齿尖峰形糖葫芦井段(1 4301 602m)的声幅值偏高,第一界面胶结情况中等,第二界面胶结差的情况;(3)水泥浆在宽间隙的雷诺数Rew在1 000左右,处于层流状态,特别是水泥浆的流性指数nc大于泥浆的流性指数nm,使水泥浆顶替泥浆时,出现尖峰形的速度剖面驱替平缓形的速度剖面,水泥浆容易造成窜槽情况,影响注水泥质量。通过LD14-1井固井质量分析说明,压力平衡、井身质量、套管居中及水泥浆与泥浆的流态及流变性能的合理配合,是提高固井质量的几项关键因素。参 考 文 献1 刘崇建,张玉隆等译.国外油井注水泥技术.四川科技出版社,1992.172178,2123052 刘崇建,刘孝良.注水泥流变性设计.北京:石油工业出版社,19933SPE75884SPE85535ERIKB.Nelson,Well Cemsting,Elsevier AmsterdamOx2fordNew YorkTokyo 1990,Chap 5(编辑 朱和平)76第3期 唐晓东等:FA-1无灰通用型燃油节能剂的研制 1994-2008 China Academic Journal Electronic Publishing House.All rights reserved.http:/belts formed at the end of Indosinian are geologicallyfavorable for the formation of oil and gas fields.TheJurassic in this area developed thick and highly-po2tential source beds and good reservoir and sealingconditions,thus constituting an important target ofexploration.On the basis of this work,the explo2ration potential of the area is predicted.Key words:Hexi area;Subsidence belt;Jurassic;Ex2ploration potentialThe Calibration and Sonde Error Correction ofHorizontal Array Induction Logging Tool inHalf Space,JSWPI,1998,20(3):3437Wei Baojun(Dept.ofResources,University ofPetroleum,Shandong,257062),ZhangZhongqing,Zhang GengyiThe theory and method for measuring the sondeerrors of horizontal array induction logging tool inhalf space are discussed,and the correction chartsand correction formulae are presented.The influenceof conductivity of homogeneous formation on the cal2ibrating value of the tool factor in half space is dis2cussed.According to the predetermined relationshipbetween background signals and the difference oflower and upper signals,the sonde errors of individ2ual output curves of each array can be determinedwith the tool horizontally hanging at two differentheights,even if the conductivity of the formation isunknown.The results suggest that influence of theformation on the calibrating value of the tool factorcan be neglected if the coils are far away form thesurface and the formation conductivity is small.Key words:Array induction logging;Instrument;Cal2ibration;Error;CorrectionLow Pressure Under-balanced DrillingANew Approach in Exploratory Drilling,JSW2PI,1998,20(3):3844Luo Pingya(Centre for Well Completion Technique,SWPI,Sichuan,637001),Meng YingfengThe development and application of under-bal2anced drilling in abroad are reviewed,and the exist2ing problems of this technology are discussed.Basedon these,the technology of low pressure drilling,anintegration of special drilling fluid(air,aerated flu2id,special foam,light fluid),special pressure con2trol(balanced,underbalanced,overbalanced),lowhead pressure and special temporary plugging,issuggested.Key words:Underbalanced drilling;Problems;Lowpressure;Drilling fluid;Pressure control;Temporary pluggingDefining Mud Density Under Conditions ofUnequal Horizontal Stresses,JSWPI,1998,20(3):4548Ma Dexing(Bohai Oil Company of China Offshore OilCompany,Tianjin,300452)Lowering pressure difference on production zoneand keeping well wall stability are problems muchneeded to be solved in petroleum engineering,espe2cially in areas with abnormal rock stress.Based onthe theory of elasto-plasticity and rock mechanics,applying Mohr-Coulomb yield criteria,this paperpresents a mechanism of elasto-plastic state occur2ring in rocks around the wellbore,describes the cor2responding distribution of stress and displacement,and formulates the equation relating mud hydraulicpressure,horizontal rock stress to rock strength.Compared with other approaches,range of mud den2sity values required for a stable well wall is wider inthis approach,which is beneficial to lowering pres2sure difference on production zone and to performingnear balance drilling.Key words:Hole stability;Rock stress;Displacement;Mud viscosityAn Analysis of the Factors Influencing theQuality ofWell Cementing:A Field CaseStudy,JSWPI,1998,20(3):4951Guo Xiaoyang(State Central Lab.,SWPI,Sichuan,637001),Liu Chongjian,Zhang Mingshen,ZhangYong,Zhang ZhaohuiThe analysis of an actual field case study indi2cates that the improvement of cementing quality is asystematic engineering.Factors such as proper slurrydesign,adjusting rheological parameters of mud andslurry,selecting flow regime of displacement mud,central casing,maintaining balance between forma2tion pressure and slurry column pressure,and regu2larity of hole shape are all needed to be carefully tak2en into consideration when planning a cementing jobin order to enhance the displacement efficiency ofmud by slurry,prevent channeling and obtain excel2lent zone sealing.3Journal of Southwest Petroleum Institute 1994-2008 China Academic Journal Electronic Publishing House.All rights reserved.http:/Key words:Cementing;Quality;Factor;Pressure bal2ance;Sealing;Case studyA Study of the Method of Controlling Bore2hole Trajectory with Controllable Eccentric,JSWPI,1998,20(3):5254Yu Ziqing(Xian Petroleum Institute,Shaanxi,710065)Automatic control of borehole trajectory is oneof the most frontier research areas in drilling engi2neering.This paper presents the resultsof a study onthe realization of automatic trajectory control withcontrollable eccentric to improve the precision of con2trol and reduce drilling cost.The controllable eccen2tric is a kind of downhole guided drilling tool consist2ing of a central axle,measuring and controlling sys2tem units,eccentricblades and eccentricshell,which can be controlled within the wellbore and canbe used with rotary drilling.Automatic trajectorycontrol is realized during drilling by way of adjustingthe force of eccentric blades against wellwall and thelength of the blades at all time.When controllableeccentric is used in drilling practice,trajectory con2trol can be performed without tripping frequently.This feature of the method has great significance andprospects in accomplishing the goal of highly-densecluster drilling,all kinds of directional drilling,hori2zontal drilling and emergency drilling.Key words:Borehple trajectory;Controlsystem;Method;Controllable eccentricMechanistic Research on Self-excited Oscil2lating Impulse Jet Flow,JSWPI,1998,20(3):5558Jiang H aijun(Dept.of Petroleum Engineering,SW2PI,Sichuan,637001),Liao RongqingFirstly a brief review of previous researches onself-excited oscillating impulse jet flow(SEOIJ F)is presented in the paper.Based on this and accord2ing to the theory of fluid network,we simplify thephysical model of self-excited oscillating impulse jetflow by applying the principle of electric circuit withload resistance.Based on analog,we build the math2ematical model.In discussing the solution of nonlin2ear equations,we analyze the formative mechanismof impulse jet flow by using the theory of modern self-organization.Because of the systems complexityand the simulations approximation,if one wants toknowunderwhichconditionsstabledissipationstructure and stable frequency can be formed,onemay need to employ more complex analogy circuitwith nonlinear analog and have more dependence ondetailed experimental studies.Key words:Jet drilling theory;Nozzle;Oscillator;Pulse;Flow model;MechanismThe Processing of Roller Cone Bit with Grind2ing Instead of Cutting,JSWPI,1998,20(3):5961Xiao Xiaohua(Dept.of Mechanical Engineering,SWPI,Sichuan,637001),Liu Qingyou,Luo MingdongThe structural properties and performance be2havior of Roller Cone Bit used in oil drilling are dis2cussed.The methods and technological character ofRoller Cone Bit processing are analyzed,and prob2lems associated with conventional grinding processingof the internal hole and secondary radial placing arediscussed in detail.A further analyses is made on thetechnological aspects of replacing cutting by grind2ing,including feature of the machine tools,selectionand performance of the cutting tools,selection of thecutting regimes,property of the cutting fluid,andmounting and locating,etc.The validity and valueof the method of processing roller cone bit withgrinding instead of cutting is demonstrated not onlyby the reduction in production cost,but also by pro2longed working time of the bit as shown by the wellsite statistic data.Key words:Roller bit;Machining;Technological pro2cess;Method;ResearchGenetic Algorithms as Applied to RegressionAnalysis of Cutting Experiments Data,JSW2PI,1998,20(3):6263Zhou Jianxin(Dept.of Mechanical Engineering,Beijing University of Science and Technology,Beijing,100081),Liu Yutong,Yu QixunIn this paper,Genetic Algorithms(GA)as usedin regression analysis is introduced.The GA is pro2grammed with Database(FoxPro 2.6 for Win2dows),in which the gene is transferred into field,chromosome into record,population into table,andgenetic operator into databases operator.With theproposed Genetic Algorithms,regression analysis is4Abstract 1994-2008 China Academic Journal Electronic Publishing House.All rights reserved.http:/