新型射流提高机械钻速机理及研究进展

在油气井钻井中，喷射钻井技术能够较大幅度地提高钻井速度，其实质是喷嘴射流辅助钻井破岩，提高了井底破岩效率。为此，文章在如何向井底输送能量和充分利用井下水力能量研究的基础上，进行了多种新型射流的研究与应用。文章对断续射流、自激振荡脉冲射流、自振空化射流和它激振荡脉冲射流4种形成新型射流的理论和方法，提高机械钻速机理进行了分析。现场应用结果表明，新型射流能够较大幅度地提高机械钻速，具有广泛的研究和开发应用前景。     

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盐水钻井完井液对防止地层中的盐膏层溶解、粘土矿物发生水化膨胀分散，从而导致井壁不稳定和储层产生水敏损害具有很好的作用。然而，研究表明，高矿化度的钻井完井液对干气层会产生严重的伤害，渗透率损害率高达90％。分析研究其损害机理。主要原因是在干气返排驱替过程中，高矿化度盐水钻井完井液漶液中的盐组分会形成盐结晶堵塞储层孔道。中还介绍了防治这种损害的技术对策。     

聚乙烯醇凝胶堵漏剂的室内研究

为解决地质钻孔钻井液漏失的问题,研制了一种新型堵漏剂——聚乙烯醇凝胶堵漏剂,该堵漏剂由聚乙烯醇、硼砂、二丁酯、羧甲基纤维素钠等化学交联反应而成。根据地质钻探钻孔堵漏材料性能的要求,对该堵漏剂进行了成胶时间、成胶黏度、溶胀性、抗稀释性、抗矿化物污染、堵漏等实验。结果表明:(1)当聚乙烯醇为3%、硼砂为0.8%、二丁酯为0.3%、羧甲基纤维素钠为0.3%、交联温度为35℃、p H值为10时,制备的聚乙烯醇凝胶堵漏剂性能为最好,成胶黏度达358 600 m Pa·s,成胶时间为18min;(2)成胶时间在0.1~1.0 h范围内可调,对不同大小通道适宜性好;(3)单独的凝胶堵漏剂最大承压能力达到6.0 MPa,加入1%木屑后最大承压能力提高到7.0 MPa,具有很好的堵漏效果。结论认为,所研制的聚乙烯醇凝胶堵漏剂具有较强的溶胀度、抗稀释、抗矿化物污染和堵漏能力,并且制备方便、价格低廉,可应用于裂缝、溶洞、孔隙及含有动水的复杂漏失地层。     

对MMH泥浆使用中一些问题的探讨

针对目前MMH泥浆使用中的一些问题,如失水控制、膨润土含量、粘度控制等进行了讨论,介绍了华北油田井深3000m左右井的MMH泥浆性能控制标准。认为MMH泥浆粘度升高的原因可能是由于MMH浓度过低或过高造成的,前者可采用提高MMH浓度的方法来解决,而后者则采用SMP胶液释释的办法来处理。     

微生物—土壤联合处理废弃钻井液渣泥技术

针对废弃钻井液渣泥的性质和目前固化处理工艺的弊端,研发了利用微生物—土壤联合处理工艺技术,即根据废弃物干湿程度,按0.3%~0.5%降解菌菌剂与废弃钻井液渣泥充分混合、再加经研磨较细的1.5~2.0倍重量的土壤充分混合均匀,在混合处理物表面覆盖5~15 cm厚的土壤,最后播撒草种、栽种植物。该工艺在丹浅001-8井和莲花000-X8等井现场试验应用结果表明,经3个月的处理,钻井固体废弃物中的主要指标COD、石油类的降解率超过90%,浸出液指标达到国家《污水综合排放标准》一级指标要求;土壤重金属离子浓度没有显著变化,各指标均达到了国家《土壤环境质量标准》(旱地)三级标准;处理混合物所栽种物无有害重金属转移现象。该处理技术不需要添加其他化学处理添加剂,联合处理体系的土壤性质可基本恢复到土壤本底值水平,有效地实现了井场废弃物占用土地的生态修复和再利用,土地资源得到循环利用,符合国家节能环保政策,可实现较好经济、社会和环境效益,是一种符合节能和环境友好的处理方式。     

逆乳化凝胶润滑封堵剂XZ-RF

研制出了一种逆乳化凝胶润滑封堵剂XZ-RF,分析了其作用机理,对其润滑性和封堵性进行了评价。实验结果表明,XZ-RF具有很好的润滑能力,1%的加量即可将膨润土浆摩阻系数降低60%,当XZ-RF加量为3%时,可将膨润土浆摩阻系数降低80%以上,且XZ-RF在聚合物钻井液能表现出良好的润滑性;XZ-RF具有好的抗温、抗盐封堵能力,可将膨润土加重浆160℃高温高压滤失量降低65.8%,将欠饱和盐水加重浆120℃高温高压滤失量降低86.8%。XZ-RF在新疆油田2口预探井进行了现场应用,均取得了较好的效果,而且该产品无荧光,具有更大的应用范围。      

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如何提高小井眼固井质量是困扰钻井行业多年的老问题。中原油田针对小井眼井段易漏失、井深、井下温度高、钻井液密度高、地层存在多套压力层系等特点，从小井眼钻进阶段，通过使用双心ＢＤＣ钻头、调整钻井液性能、水泥浆设计、先期堵漏等各种工艺措施，为小井眼固井提供了良好的先期条件。同时，在注水泥施工中，采取优选注替排量、选择合适的隔离液、加旋流扶正器使套管串居中等手段，以提高水泥浆顶替效率，并进一步推广应用压稳高压油气层的四大技术及Ｇ１０１高强度低密度水泥浆体系，小井眼固井技术满足了固井质量要求，并取得良好的效果。     

钻井液固体微粒在油/水/表面活性剂体系中的乳化作用

研究了钻井液、完井液中常见的固体微粒在不同条件下对表面活性剂存在的油水体系的乳化稳定作用,并对两种测定乳化稳定性的实验方法进行了对比。结果表明,油湿颗粒能稳定油包水乳状液,中性润湿的固体微粒既可以稳定油包水型又可以穗定水包油型乳状液,而水湿颗粒的乳化情况比较复杂。在一定条件下,某些固体微粒能够代替或部分代替表面活性剂而用于油包水或水包油乳化钻井液中。     

Laser Ablation and Laser-Hybrid Ablation Processes: A Review

Laser beam machining (LBM) has proven its applications and advantages over almost all the range of engineering materials. It offers its competences from macro-machining to micro- and nano-machining of simple-to-complex shapes. The hybrid approaches in laser ablation have demonstrated much improved results in terms of material removal rate, surface integrity, geometrical tolerances, thermal damage, metallurgical alterations, and many more. The flipside of LBM is the existence of universal problems associated with its thermal ablation mechanism. In order to alleviate or reduce the inherent problems of LBM, a massive research has been done during the past decade in order to build a relatively new route of laser-hybrid processes. This paper reviews the research work carried out so far in the area of LBM and its hybrid processes for different materials and shapes. The article also highlights the research gaps and future research directions in the context of laser and laser-hybrid ablation.     

Experimental investigation,prediction and optimization of cylindricity and perpendicularity during drilling of WCB material using grey relational analysis

Manufacturing is always the heart of majority of industries. Drilling is an extremely important and an essential machining process which requires a lot of attention as in most of the cases it is required for assembly purposes. Majority of the holes produced during drilling are made with the help of Vertical Machining Centre (VMC) meant for pin- hole assembly. Though the tolerance is within limit, assembly problems arise due to the improper geometry of these holes. Various geometrical tolerances like cylindricity, circularity, perpendicularity and position errors are responsible for such assembly problems. This investigation is focussed on cylindricity and perpendicularity in the drilling of Wrought Cast Steel Grade B (WCB) material using SOMX 050204 DT insert. In this work, effect of machining variables like cutting speed, feed rate and depth of cut (canned cycle) are investigated and optimized using grey relational analysis (GRA). Reliable experiments are conducted based on a 3³ full factorial, replicated twice. Second order regression models are developed for predicting cylindricity and perpendicularity. The models’ adequacy has been checked by calculating correlation coefficient. It shows that the developed models are well fitted for the prediction of responses within the specific range of input variables.