水平井冲砂洗井技术进展评述

近年来水平井应用规模迅速扩大,但由于其井身结构的特殊性,地层出砂问题比直井更加突出,水平井冲砂洗井效果将直接影响其产能和开采成本。阐述了水平井冲砂洗井过程中水平井段、斜井段和直井段的岩屑运移机理,介绍了现阶段应用和发展的冲砂洗井技术(常规密封连续冲砂技术、连续管清砂技术、真空清砂技术和泡沫流体冲砂技术)的原理及特点。在此基础上,论述了目前国内外水平井冲砂洗井使用的主要工具(普通油管旋流连续冲砂工具、连续管旋转射流冲砂工具及同心连续管真空清砂工具)的结构及工作原理。最后指出水平井冲砂洗井技术的发展主要集中在冲砂与压裂一体化、低压/衰竭储层冲砂和大尺寸井筒冲砂等3个方面。     

水平井洗井工艺技术研究

井眼清洗是水平井钻完井技术的关键之一,也是影响该技术运用的主要难点之一。文章从水平井洗井存在的难点着手,分析总结了影响水平井洗井效果的因素——井斜角、井眼轨迹、管柱偏心对携岩的影响、岩屑颗粒直径、环空返速以及洗井液流变性能,并针对上述影响因素提出了相关的工艺措施,形成了包括水平井洗井方式优选、洗井管柱和洗井液优化在内的工艺技术体系。江沙8—H井的实践证明,采用优化施工参数和优选洗井液、多次起下或拖动管柱洗井的方式能达到良好的洗井效果。     

筛管完井水平井酸洗管柱改进与应用

筛管完井水平井酸洗是解除裸眼段钻井液污染的有效措施,酸洗效果的优劣对油井的产能有着直接的影响。胜利油田前期的酸洗管柱存在着洗井阀关闭不严、洗井封隔器密封效果差、无泄流通道等问题,直接导致了水平井的酸洗效果差。对水平井酸洗管柱进行了针对性的改进,完善了洗井阀的密封结构,设计了带泄流通道的洗井封隔器,改善了酸洗的效果,有效地提高了筛管完井水平井的产能。     

水平井螺杆泵地面工艺技术应用研究

油田在用的水平井螺杆泵举升工艺没有一套切实可行的地面管理配套技术,给水平井的开发和管理带来一定的难度,影响油藏开发效益的进一步提高.为此,通过建立热洗周期基本模型,实施定期高压(掺水或加药)洗井,确定合理洗井周期和洗井量,优化螺杆泵参数,应用变频控制抽空保护技术、螺杆泵监测诊断技术、地面驱动螺杆泵电动机功率选择方法等一系列管理技术,使水平井得以有效开发,目前取得了较好的效果.     

水平井钻井第二洗井区环空止动返速的计算

根据水平井钻井液携岩要求和岩屑床理论模型，给出了大斜度井及水平井钻井第二洗井区环空止动返速的计算方法，分析了影响环空止动返速的诸种因素。统计得出，我国目前水平井钻井第二洗井区环空止动返速为０．８０～１．０３ｍ／ｓ，可供该洗井区的水力参数及流变参数设计时参考。实例分析表明，采用环空止动返速能准确地评价第二洗井区岩屑床的运移状态。     

MBHW04井冲砂洗井技术

介绍在克拉玛依油田上修的第一口井深4000m以上水平井中冲砂洗井工艺设计与施工情况，分析井况，为今后在高油气比大井深的水平井中进行冲砂洗井作业积累了经验。     

低压地层水平井冲砂工艺创新设计

针对低压地层水平井冲砂洗井,为提高冲砂效率、效果,从液体方面主要采用低密度、低摩阻、高携砂性能冲砂洗井液;从工艺方面主要采用旋转射流连续冲砂、水射流负压冲砂方式,其中代表性的冲砂工艺技术:一是井下液流换向旋转射流反循环连续冲砂技术,在实现连续、水平段旋转射流冲砂的同时,对长水平段井筒冲砂时返排液流速低、返排效果有待提高;二是同心油管反循环负压旋转射流连续冲砂技术,能够实现连续、负压、旋转射流冲砂,但同心油管柱设计局限于浅水平井冲砂应用。在总结分析两种冲砂工艺技术原理、特点基础上,通过集成创新、取长补短,创新设计出适应长水平井段、低压地层、深水平井井况条件的井下液流换向、井底负压旋转射流冲砂工艺技术,对低压地层水平井冲砂洗井具有一定指导借鉴意义。     

水平井泡沫流体冲砂洗井技术研究

针对漏失井使用水基冲砂洗井液不返液或漏失量大的问题，不用添加任何化学堵漏剂，使用低密度泡沫流体冲砂洗井，可有效地减轻低压井中冲砂液的漏失。为此，以流体力学为基础，建立了水平井泡沫流体冲砂洗井的数学模型，给出了边界条件和限制条件，并编制了相应的参数设计程序。通过对水平井泡沫流体冲砂洗井过程的模拟，得到了泡沫流体密度、泡沫质量、压力、泡沫流速在井筒内的分布，以及环空回压与注入压力、井底压力、泡沫流量等参数的关系。现场应用表明，泡沫流体冲砂洗井有效地防止了冲砂液漏失，并且作业后能够迅速恢复生产，延长了平均检泵周期，是清除低压油气井井底出砂的一项有效的技术措施。     

水平井裸眼防砂失效因素分析及解决措施

针对水平井裸眼防砂完井一体化工艺技术失效的情况,对工艺进行了反复研究与分析,认为水平井裸眼防砂失效的主要因素为基管强度低、筛网强度差及洗井阀密封机构可靠性差。解决措施为:(1)选用专为稠油热采井设计的钢级为TP110的套管作为滤砂管的中心管;(2)对筛管的网眼布局和孔眼参数进行优化,优化后的网眼布局为177.9 mm×9.19 mm筛管、相位角30°、孔密240孔/m、孔半径12.6 mm;(3)研制了密封洗井阀球座的水平井洗井阀堵塞装置。     

应用蒙特卡络优化方法评价水平井岩屑床厚度

本文根据理论研究所得到的计算大斜度段及水平井段岩屑床厚度的经验模式，引用蒙特卡络非线性优化方法，对我国已完钻的７口水平井的资料进行了分析，并且提出了以２ｃｍ为大斜度段和水平井段钻进的岩屑床安全厚度，再考虑适当的附加值来设计第三洗井区的环空返速的方法。     

水平井钻井液完井液技术新进展

简要回顾了近年来国内外钻水平井的情况,着重从适用于钻水平井的钻井液完井液体系、水平井井眼净化和水平井保护油气层等三个方面综述了水平井钻井液完井液技术所取得的重要研究成果与进展;并对今后该项技术的进一步发展进行了讨论。     

国内水平段最长的水平井钻井液技术

为了更好地推进水平井钻井液的现场应用技术,论述了水平2井中出现的复杂事故、对煤层防塌及长段水平井钻井液的处理情况。试用了无机阳离子胶技术,较好地解决了井下漏失、井塌、携砂及润滑防卡等一系列问题,满足了钻井工程和保护油层的需要。     

水平井岩屑床清除的室内模拟试验

水平井水平段环空易形成岩屑床。模拟水平井水平段岩屑床形成、发展及清除过程进行了室内试验研究。结果发现,调整钻井液特性及水力条件可以使岩屑运移并清除岩屑床,当环空返速高于临界返速时,转动钻具,延长洗井时间,也可以改善环空净化。     

泥浆性能影响环空岩屑运移的实验研究

在文献调研的基础上,对泥浆性能影响环空岩屑运移进行了实验研究。讨论了动塑比、表观粘度、塑性粘度、有效粘度、泥浆密度等因素对无因次岩屑床面积的影响。结果表明:层流下泥浆携岩能力随动塑比升高而增加,紊流时泥浆动塑比值与携岩能力关系不大;提出了一种极限粘度的概念,低于极限粘度时,泥浆携岩能力随粘度升高而降低,高于极限粘度时,两者关系相反;泥浆密度增加可使环空岩屑床面积大大降低。低粘紊流是清洗大斜度井与水平井的最佳措施。     

Annular flow analysis by tracers in drilling operations

A study of drilling fluid flow in the annular space and drill pipe by residence time distribution analysis using a tracer is presented. This is a new method which can be used to assess the rate of removal of cuttings during the drilling process.Two field trials were conducted to evaluate the technical feasibility and potential application. The results are analyzed using the flow behavior, carrying capacity of the drilling fluid, and hole cleaning conditions. Analysis of tracer response indicates the presence of anomalous flow in both trials, characterized by two fluid volume fractions traveling with different velocities. The magnitude of these volume fractions is related directly to the carrying capacity of the drilling fluid (hence, the hole cleaning conditions) which is explained. The dispersion coefficient, as well as other distribution functions, is suggested to measure the overall behavior of fluid in a drill-hole.This method is compared with empirical correlations employed in the industrial practice and potential advantages are demonstrated using tracers.     

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粘稠泡沫在对付大量水侵和有效改进岩屑携带能力方面的稳定性,进一步促进了欠平衡泡沫钻井的应用。泡沫品质是控制泡沫携带岩屑能力的一个重要参数,井底泡沫品质不应低于５３ ％ 。聚合物的加入增强了泡沫流体的稳定性、流变性和失水性。采用泡沫钻井,具有井眼清洗良好、减少流体分离、机械钻速高、井下不发生着火和爆炸等优点,降低了钻井成本。由于安全、井控和环境方面的原因,越来越多的地区将采用封闭循环欠平衡泡沫钻井系统。旋转控制头、四相分离器等装置是进行欠平衡泡沫钻井的关键设备。我国的欠平衡泡沫钻井较少。中原油田采用清水混气钻了一口毛８ 井,吐哈地区在恰１０２ 井进行了泡沫钻井试验。在成本意识日益增强的工业中,正不断寻找节约成本的方法以提高现有油气田的生产寿命,泡沫钻井技术将是可靠的选择。     

A New Hole Cleaning Criteria for Drilling Operations of Oil Wells

Abstract

A study of drilling fluid flow in the annular space and drill pipe through residence time distribution (RTD) analysis of a tracer injected in impulse form while drilling an oil well is presented in this article. Two field trials were carried out in order to evaluate the technical feasibility and potential practical application of the RTD theory and the dispersion model. From the results it is possible to explain physically the flow behavior and its relation with parameters such as carrying capacity of the drilling fluid and hole cleaning conditions. The RTD analysis of tracer response indicates the presence of anomalous flow in both trials, characterized by two fluid volume fractions traveling with different velocities. The magnitude of these volume fractions concerns directly with the carrying capacity of the drilling fluid, hence, the hole cleaning conditions as is explained along the work. The dispersion number (RDN) as well as other distribution functions are suggested as a measure of the overall behavior of the fluid in a hole. This criterion is compared with empirical correlations employed in the industrial practice.     

A New Hole Cleaning Criteria for Drilling Operations of Oil Wells

A study of drilling fluid flow in the annular space and drill pipe through residence time distribution (RTD) analysis of a tracer injected in impulse form while drilling an oil well is presented in this article. Two field trials were carried out in order to evaluate the technical feasibility and potential practical application of the RTD theory and the dispersion model. From the results it is possible to explain physically the flow behavior and its relation with parameters such as carrying capacity of the drilling fluid and hole cleaning conditions. The RTD analysis of tracer response indicates the presence of anomalous flow in both trials, characterized by two fluid volume fractions traveling with different velocities. The magnitude of these volume fractions concerns directly with the carrying capacity of the drilling fluid, hence, the hole cleaning conditions as is explained along the work. The dispersion number (RDN) as well as other distribution functions are suggested as a measure of the overall behavior of the fluid in a hole. This criterion is compared with empirical correlations employed in the industrial practice.     

Effect of drilled solids on drilling rate and performance

This paper describes the results of laboratory investigations into the effect of drilled solids on the drilling rate and drilling performance. Drilling fluid performance and a successful result during drilling operations are characterised by the fluid's properties providing hole cleaning and cutting transport. Various concentrations of bentonite which has the same specific gravity with drilled solids were used to simulate drilling performance. The results were discussed in terms of electric stability (emulsion stability), high-pressure high-temperature (HPHT) including the resultant filter cake, rheological properties of the active fluid Experiments show that the ES drops in half as the drilled solid (bentonite) concentration increases from 0 to 75 lb/bbl. The HPHT FL test produced thicker filter cake and the HPHT FL doubles while the YP quadruples as the bentonite concentration increases. Accumulation of filter cake on the bit or BHA during pull out of hole of a drill string and hole problems are attendant problems associated with inefficient solid control. The use of bentonite to simulate the drilled solid is good agreement with previous works.     

高性能硬胶泡沫钻井液体系的研究及现场应用

硬胶泡沫钻井液在具备普通泡沫钻井液提高机械钻速、及时发现油气层特点的同时,还具有较强的携岩能力和抗污染能力。本文针对欠平衡钻井可能遇到的高温、高浓度盐水地层和原油污染问题,通过对原材料的优选,运用自主研发的高效发泡剂TSB研制出高性能硬胶泡沫体系,在室内评价了其抗温、抗盐、抗油污染性能,并分别在BJ7168井、白22井应用实施。现场应用表明,硬胶泡沫钻井液的发泡量大、稳定时间长、抗污染能力强,能很好地满足携岩的要求。