在顺北油田深井、超深井钻井中,重晶石加重高密度钻井液体系存在流变参数调节难、沉降稳定性差、储层固相颗粒损害严重等问题.国外微锰(Micromax)在钻井液中的性能表现良好,但其技术垄断和高使用成本限制了其在国内推广应用.为研发高性价比国产微锰产品、构建储层友好型钻井液体系,采用锰矿法制备出钻井液用微锰(DFMT01),并进行结构表征和性能评价,测试了顺北区块高密度聚磺钻井液体系的性能及泥饼酸溶效果,讨论了含锰废液的循环利用.结果表明,DFMT01理化性质良好,密度大于 4.7 g/cm3,酸溶率大于 99%,D50 为 1.17 μm,颗粒球形度为 0.967,均与国外同类产品相当;该产品加重的聚磺钻井液体系在流变性、滤失性、沉降稳定性、冲蚀性和储层保护特性均达到或超过Micromax加重体系.确定了"碳酸钙中和沉淀-硫酸回收锰离子-混凝法处理废水"处理高浓度酸性含锰废液的组合工艺,处理后水中锰的质量浓度为 0.45 mg/L、固体悬浮物为 10 mg/L,达到一级标准要求,可实现DFMT01生产、使用和处理的闭环利用.该产品性能优良,成本低,具有非常广阔的推广应用价值.

对于裂缝发育等破碎性地层,在井筒内外压差作用下钻井液极易沿裂缝等天然通道侵入地层,致使近井裂缝发育带孔隙压力增加,引发泥页岩水化膨胀及强度性能下降,导致坍塌压力增加,从而使得井壁垮塌越加严重,搞清破碎性地层垮塌机理至关重要.结合延安气田石盒子和石千峰组裂缝性泥页岩"越提密度、垮塌越严重"井塌处理误区,指出缺乏对裂缝有效封堵是症结所在.为此提出适用于裂缝发育等破碎性地层"封堵为先、抑制水化、合理密度"的防塌技术对策,在此基础上,优选出延安气田强封堵钻井液配方并在现场成功应用,相关技术思路及研究成果可为类似破碎性地层防塌提供参考.

致密性气藏具有低孔低渗、高含水饱和度、高应力敏感性和黏土矿物发育等特点,气体渗透率一般小于0.001 mD,这使得气藏损害具有不同于油藏损害的特殊性.目前国内外尚未形成统一的针对致密性气藏储层损害评价方法,而常规储层敏感性评价方法采用液相为驱替介质,在评价致密储层时出现测试时间长、实验误差大、易发生应力敏感的局限.因此,通过对致密性气藏储层损害方法研究,制定了一套"致密性气藏储层损害评价方法,评价了BZ19-25区块储层岩心敏感性损害,并采用行业标准方法对其敏感性损害进行复测,结果表明新方法测试结果与行业标准方法测试结果一致,说明新研究的方法具有可靠性,适合致密性气藏储层损害评价.

重晶石在储层段钻井液中使用时,会对储层带来损害,且后续作业很难恢复,而微锰(Micromax)作为高密度钻井液的新型可酸溶加重材料,目前已开始应用于储层段钻井液中.综述了微锰加重剂对储层保护钻井液性能的影响,并分析了微锰提高钻井液储层保护特性的机理.其均一、高硬度、高球度的颗粒特征,可以保证微锰侵入储层后具有良好的返排特性,可降低对储层的伤害.微锰还具有可酸化的特性,调研了适用于微锰酸化的酸液,并对比了酸化前后对储层渗透率的变化,通过优选合适类型、浓度的酸液,在酸化后可消除钻井液对储层的损害.

井漏是油气井钻井过程中经常遇到的难题之一.由于井漏问题的复杂性和差异性,常规治理措施很难达到预期效果.近年来,研究学者开始利用数据科学,如机器学习和大数据,来解决井漏问题.文章介绍了国内外学者利用数据科学研究防漏堵漏技术取得的研究成果.

钻井液加重剂重晶石在储层中的迁移、转化、沉淀形成了难以酸溶的重晶石泥饼,对油气藏造成严重伤害,需要安全可靠地解除重晶石堵塞.而对重晶石堵塞重视程度不够、堵塞机理与解堵机制不明、解堵决策设计不当、投入产出得不偿失、商家技术保密等种种原因,制约了我国重晶石解堵技术的进步.以氨基多羧酸盐为主要组分的螯合型解堵剂是解除重晶石堵塞最有前途的工艺选择,而螯合剂结构(氨基种类、羧基数量、环链大小、化学稳定性等)、金属离子的性质(电荷、离子半径、电离电位或碱度、共伴生金属离子等)、介质环境(pH值、温度、压力等)等对重晶石的溶解效应都有较大影响.经济高效的螯合型解堵剂及其解堵工艺的设计必须要考虑不同螯合剂的解堵特点、使用浓度、催化剂、碱性转化剂、聚合物溶蚀剂、井底温度、环境友好性、腐蚀性、地层岩石基质、解堵过程造成的二次储层伤害等因素.借助滤饼溶蚀、溶蚀产物组分及形貌、岩心流动等现代实验技术测评,精心设计解堵剂注入量、注入压力、浸泡时间、返排液处理等螯合解堵工艺细节,以便全面了解重晶石堵塞机理、螯合型解堵剂设计及其在油气田重晶石解堵决策中的应用.综述了近几年先行研究者在解除重晶石滤饼堵塞方面所做的比较系统的工作,希望能为读者提供一个新视角,以提高我国钻井液与完井液技术创新水平.

由于油气勘探开发逐步向深层、非常规等油气藏发展,要求采用抗高温超高密度油基钻井液钻进,该钻井液必须具有良好流变性、低的高温高压滤失量、良好的封堵性与动/静沉降稳定性.研讨了抗160℃超高密度柴油基钻井液配方.通过大量实验得出,采用重晶石加重,无法配制出具有良好流变性能与动沉降稳定性能的超高密度柴油基钻井液;形成了抗160℃密度为2.4～3.0 g/cm3超高密度柴油基钻井液配方为,0#柴油与25％ 氯化钙盐水的质量比为90:10,加入有机土+0.8％ 主乳化剂+1％ 辅乳化剂+1％ 润湿剂+5％ 降滤失剂+3％CaO+加重剂(重晶石:MicroMax为6:4),其中有机土加量随钻井液密度增加而下降,密度为2.4、2.6、2.8和3.0 g/cm3的柴油基钻井液,最佳有机土加量分别为1％、0.5％、0.3％、0.

在塔里木盆地库车山前钻遇库姆格列木群盐膏地层时,要求采用抗高温超高密度油基钻井液,该钻井液必须具有良好流变性、低的高温高压滤失量、良好的封堵性与动、静沉降稳定性.研讨了不同类型加重剂对抗160℃超高密度柴油基钻井液性能的影响;采用重晶石(ρ=4.2 g/cm3)、重晶石(ρ=4.3 g/cm3)、氧化铁粉、Microdense等单一加重剂配制超高密度柴油基钻井液,钻井液性能无法全面满足钻井工程的需要;采用具有超微细、高密度、球形等特点的MicroMax加重的超高密度柴油基钻井液拥有非常好的流变性能和良好的沉降稳定性,但无法控制钻井液的高温高压滤失量;当重晶石和MicroMax按60:40比例复配时,可配制出性能良好的超高密度(2.4～3.0 g/cm3)抗高温柴油基钻井液,能满足库车山前钻进高压盐水层与易漏地层的需求.

基于安全钻井液密度窗口研究,充分考虑大位移井岩屑床以及钻柱偏心等特点,形成了一套结合现有机泵条件的大位移井钻井液性能及水力参数优化设计方法,并在渤海CFD油田某区块成功应用,有效指导了该油田大位移井的顺利施工.大位移井钻井液性能强调限制塑性粘度、合理提高动塑比,保障钻井液携岩能力的同时有助于保持较好流变性,同时为兼顾大位移井施工泵压高及排量大的两方面要求,推荐多泵同时作业并选用小尺寸缸套的做法,提高额定泵压、保障施工排量.本研究成果对于类似大位移井设计与施工具有指导意义.

随着深水井、大位移井、高温高压井以及窄密度窗口井钻井作业的进行,对钻井液性能的要求越来越高,尤其是对高密度及超高密度钻井液的流变性、造壁性、沉降稳定性以及储层保护性能的要求,常规API重晶石加重的钻井液已经不能满足特殊井段的钻进需求,因此需寻求新型加重剂.近年来微细重晶石、微锰、微细钛铁粉等新型加重剂在现场使用取得较好的效果.通过对国内外文献的调研,研讨了微细钛铁粉的特性、微细钛铁粉对水基以及油基钻井液流变性、滤失造壁性和沉降稳定性的影响及该剂在高密度/超高密度水基/油基钻井液中的使用情况.得出:微细钛铁粉无论是用作水基还是油基钻井液的加重剂,或与API重晶石混合使用,钻井液流变性好,其酸溶性好,形成的泥饼更容易去除,沉降稳定性好,对储层损害程度低.该剂磁性可通过去除赤铁矿杂质得以解决;尽管其硬度高于重晶石,但由于其D90为15 μm,因而其磨蚀性低于API重晶石.此外,由于微细钛铁粉颗粒分布集中(D50≈5μm),高温高压滤失量稍高,可以通过加入一些粒径分布宽的酸溶性架桥颗粒来得到解决.整体上来说,微细钛铁粉用作钻井液加重剂是非常有前景的.该剂已在阿拉伯湾以及阿联酋等现场应用,取得了较好的结果.

Formate completion fluid is mainly used in Tarim Basin to drill high temperature deep wells with bottom hole temperature to 180℃.Successfuldrillingofthesehightemperaturedeepwellsimposesrigorousrequirementsonthepropertiesofcompletionfluid,such as thermal stability, viscosity, filtration rate, plugging capacity, settling stability and permeability recovery etc. Selection of appropriate formate completion fluid additives is essential for the completion fluid to have properties satisfying the needs aforementioned. This paper discusses the pattern of compatibility between completion fluid additives and formate water solution, providing a basis on which formate completion fluid additives can be screened and used. The composition of a high temperature high density clay-free formate completion fluid that can be used at 180 ℃ is also presented in this paper.

This paper summarizes the progresses made abroad in micro manganese weighted drill-in fluids,analyzes the advantages and disadvantages of weighting materials used in high density drilling fluids,and describes the properties of micro manganese powder weighting agent,such as its chemical composition,physic-chemical property,microscopic shape,particle size distribution,Zeta potential,dynamic stability,density,acid solubility and Mohs' scale of hardness.Compared with traditional weighting materials (barite and hematite etc.) used in high density drilling fluids,micro manganese powder has these properties such as smaller particle sizes,better sphericity and higher specific surface area.Drilling fluids weighted with micro manganese powder show good rheology,antisettling property and lubricity,satisfactorily resolving the contradiction between the rheology and anti-settling property of a high density drilling fluid.The authors have paid much attention in introducing the effects of micro manganese powder on the properties of drill-in fluids and reservoir protection,and presented the application results of the micro manganese powder weighted drilling fluids in north Kuwait and Cormorant North oilfields.

This paper analyzes the mechanisms under which the hard and brittle shale formations destabilize,introduces the characteristics and application of nano materials,and summarizes the progresses made in the studies of drilling fluid nano material plugging agents,including organic and inorganic nano plugging agents.Also discussed in this paper are several case histories of the application of nano plugging agents.The authors believe that plugging agents having core-shell structures,which take advantage of the rigidity of inorganic nano materials and the deformability and filming ability of organic polymers,do not heavily affect the viscosity and gel strength of the drilling fluids in which the plugging agents can well dispersed.This kind of nano plugging agents can plug the pore throats of shales at low concentrations,thereby produce a pseudo hydrophobic "borehole wall" with some strength.This pseudo "borehole wall" not only hinders the invasion of drilling fluids,it also increases the pressure bearing of formation.The authors thus believe that the combination of inorganic nano materials and organic polymers indicates the direction for the development of anti-collapse additives in the future.

Drilling fluid additives should have their range of use clearly defined to make the best use of them, and great attention should be paid on this issue. Take the SMP-Ⅰ and SMP-Ⅱ as examples, the application characteristics, production technology, and the mechanisms of reducing filtration rate and resisting salt contamination are analyzed in this paper. The ranges of use of SMP-Ⅰ and SMP-Ⅱ are discussed and the differences in high temperature and salt-resistant performances of the two additives manufactured by different production technologies are compared. Laboratory experiment has shown that in drilling fluids with salinity less than 2%, and borehole temperature below 180 ℃, the performance of SMP-Ⅰ was better than SMP-Ⅱ. At 120 ℃ and 150 ℃, SMP-Ⅰ worked well in different salinities up to saturation, while SMP-Ⅱ only functioned in drilling fluids containing 25% salts or in under-saturated and saturated drilling fluids. At 180 ℃, SMP-I can be used in saltwater drilling fluids with salinities less than 20%, while SMP-Ⅱ can be used in saltwater drilling fluids with salinities greater than 20% to saturation.

在徐闻区块钻井过程中,钻遇涠洲组时发生了井塌等井下复杂事故,但通过对测井数据和地层3个压力剖面数据分析,发现钻井使用的钻井液密度均高于地层坍塌压力当量密度,且涠三段地层层理裂隙比较发育.利用给出的坍塌压力当量钻井液密度简化计算式,计算了钻井液浸泡后岩心坍塌压力的变化,其结果表明,随着钻井液浸泡时间的增加,岩石强度下降,进而造成地层坍塌压力大幅度增加,岩心浸泡5d坍塌压力增加了12.15％.对涠三段地层井壁失稳情况及影响因素进行了分析,认为该层位井壁失稳机理为:钻井液封堵性不足以阻止钻井液滤液侵入地层,造成地层强度下降和近井壁孔隙压力升高,进而导致地层坍塌压力升高,诱发井壁坍塌.采用有机盐、包被剂和胺基抑制剂改善了钻井液抑制性,采用ZHFD、QS-4和NFA-25作为封堵剂,形成了强封堵强抑制的有机盐胺基钻井液,延长了井壁坍塌周期,有效解决了涠三段井壁失稳的技术难题.

Standard method for evaluating the corrosion rate of formatesis not presently available.A method of evaluating the corrosion rate of formates to casing / tubing strings has been presented with an idea borrowed from the methods of evaluating the corrosion rate of metals.In laboratory experiment,metal coupon weight loss method and a CGF-II HTHP static corrosion tester were used to study the influencing factors such as the type of the formate,production technique,pH,steel material quality,density,and retarder etc.It has been found that using TPl40 steel coupon,the corrosion rate of sodium formate was more than 2 times that of potassium formate,because the C1 content in sodium formate (0.619％) was greater than the Cl content in potassium formate (0.0243％).For potassium formate,different production processes resulted in different sulfur contents;potassium formate A contained 0.18％ sulfur,far more than that of potassium formate B (0.0477％) and potassium formate C (0.046％),and thus,the corrosion rate of potassium formate A was much higher than that of the latter two.The corrosion of formate salts to steel is much severe under acidic conditions.Water solutions of formate salts taken from a well site needed to be buffered with sodium carbonate and sodium bicarbonateor potassium carbonate and potassium bicarbonate.The corrosion rate of TP140 steel in potassium formate solution was 20 times of the steel BG 13 Cr or JFE 13Cr,indicating that potassium formate had lower corrosion rate to stainless steel than to carbon steel.Since high concentration of HCOO-is good for the protection of steel,the corrosion rate of TPl40 steel in 1.20 g/cm3 potassium formate solution was more than 2 times of the corrosion rate of TP140 in potassium formation solution of 1.40-1.57 g/cm3.Thus,corrosion inhibitors should be used when low density formate muds are used.Based on these experimental data,the use of corrosion inhibition measures can be justified when using formate drilling fluids.

调研了钻井液封堵性评价方法,并针对硬脆性泥页岩的特点,筛选出4种方法进行对比实验.研究发现:高温高压滤失量能表征钻井液泥饼渗透性;高温高压砂床、渗透性封堵(PPT)等评价方法,能评价钻井液对泥页岩微米级固定裂缝或孔喉的封堵效果,但不能够准确地评价纳米级封堵剂的封堵效果,也不能反映钻井液与泥页岩相互作用过程中,岩石裂缝或孔喉发生变化情况下封堵剂的封堵效果;而压力传递实验能够评价各种类型封堵剂对硬脆性泥页岩裂缝或孔喉的封堵效果,还能反映不同类型的封堵剂在钻井液与泥页岩相互作用过程中,发生裂缝或孔喉尺寸变化情况下的封堵效果.

为了解决全油基钻井液在钻井循环过程中发生的重晶石动态沉降问题,通过测量抗高温全油基钻井液流变性和动态沉降密度差,对钻井液动态沉降密度差与单独流变参数之间关系进行研究,确定钻井液动态沉降密度差与塑性粘度关系不密切,而与影响钻井液结构特性的流变参数R6读数,动切力,终切力关系密切.采用统计软件R建立了钻井液动态沉降密度差与钻井液R6,YP和终切力关系模型,为现场钻井液工程师调控钻井液动态沉降密度差提供途径.

为了解决抗高温高密度油基钻井液存在的静态沉降稳定性与动态沉降稳定性难以控制的技术难题,采用改进的VST沉降测试法对抗高温高密度油基钻井液的动态沉降稳定性进行了测量,分析了有机土、提切剂、润湿剂以及提切剂与有机土配比对钻井液沉降稳定性及流变性的影响.结果表明,有机土加量越大,钻井液静态与动态沉降稳定性越好,密度差越小,但钻井液黏度越高;提切剂与有机土达到合理配比时,可以提高钻井液沉降稳定性;抗200℃、密度为2.0 g/cm3全油基钻井液优化配方为:有机土加量为3.5％～4.5％,提切剂加量为0.25％～0.3％,提切剂与有机土加量最佳配比为1∶(17～18),润湿剂加量为2.5％.

针对延长气田地层特性、井壁失稳原因、储层特性等特点,开展了强抑制强封堵胺基钻井液研究.实验室采用抑制膨润土造浆实验,优选出抑制效果与聚醚胺相同、成本较低的胺基抑制剂AI-1.采用延长气田刘家沟组泥岩进行的页岩滚动分散实验和膨胀率实验表明,AI-1的抑制性好,对钻井液性能影响小.采用AI-1作抑制剂,改性淀粉、SPNH及PAC-LV作降滤失剂,ZHFD和FT-1作封堵剂,优选出强抑制强封堵胺基钻井液.该钻井液的流变性能较好,滤失量低,具有良好的泥饼质量、强的抑制性与封堵性能,对气层的损害程度低,对延长气田石盒子组、山西组、本溪组等气层岩心的渗透率恢复值在90％以上.该钻井液在延长气田3口井的使用,防止了井塌、井漏的发生,井径规则,提高了钻井速度,减少了对气层的损害.