Prediction of casing wear in extended-reach drilling

Intermediate casings in the build sections are subject to severe wear in extended-reach drilling. This paper presents a new method for predicting the depth of a wear groove on the intermediate casing. According to energy principle and dynamic accumulation of casing wear by tool joints, a model is established to calculate the wear area on the inner wall of the casing. The relationship functions between the wear groove depth and area are obtained based on the geometry relationship between the drillstring and the wear section and the assumption that the casing wear groove is crescent-shaped. The change of casing wear groove depth versus drilling footage under different-sized drillstrings is also discussed. A mechanical model is proposed for predicting casing wear location, which is based on the well trajectory and drillstring movement. The casing wear groove depth of a planned well is predicted with inversion of the casing wear factor from the drilled well and necessarily revised to improve the prediction accuracy for differences between the drilled well and the planned well. The method for predicting casing wear in extended-reach drilling is verified through actual case study. The effect of drillstring size on casing wear should be taken into account in casing wear prediction.

Effective administration of cranial drilling therapy in the treatment of fourth degree temporal,facial and upper limb burns at high altitude:A case report

BACKGROUND Fourth degree burns damage the full thickness of the skin and affect underlying tissues.Skin grafting after debridement is often used to cover the wounds of salvageable severe burns.A granulation wound can be formed by drilling the skull to the barrier layer to solve the problem of skull exposure.Low oxygen levels present at high altitudes aggravate ischemia and hypoxia which can negatively impact wound healing.The impaired healing in such cases can be ameliorated by hyperbaric oxygen therapy.CASE SUMMARY We describe a patient who presented with fourth degree burns to the left temporal and facial regions upon admission in December 2018.The periosteum of the skull and the deep fascia of the face were exposed.After the first stage of debridement and skin grafting,the temporal skin did not survive well.Granulation was induced by cranial drilling,and then a local flap was transferred to cover the wound.The left temporal and facial wounds were completely covered and the patient recovered well.CONCLUSION Skin grafting and flap transfer after early debridement to cover the wound and control infection were of great significance.In the later stages of the patient's treatment,survival of the skin graft and skin flap was observed.The second stage repair was performed to achieve successful skin grafting by cranial granulation.Granulation was formed by drilling the skull,and then the wound was closed,which is suitable for cases with skull exposure and wounds with poor blood supply.We consider that hyperbaric oxygen treatment and improving tissue oxygen supply were beneficial in this patient.

Tooth arrangement design of retractable DTH hammer bit used for drilling while casing

Down-the-hole(DTH)hammer with casing while drilling(CWD)is a technology that has been proven to be able to alleviate many of the problems faced by complex formations.However,the drill bit is suffered from rapid wear,low drilling efficiency,and high energy consumption due to the unreasonable tooth arrangement and impact energy selection in drilling process,which affect the application effect of this technology.ABAQUS software was used for numerical simulation of rock breaking behavior under impact load with the single,three,and five teeth arrangement drill bit respectively,to improve the application effect and solve the aforementioned technical problems.Based on the calculated parameters of tooth arrangement,we designed a novel drill bit for hard rocks and provided a theoretical basis for the tooth arrangement of largediameter drill bits.

Microwave propagation in air drilling

This paper examines the feasibility in air drilling of transmitting down-hole signals by using microwaves. Firstly the basic theory of microwave propagation in the drill-pipe or casing was studied, including power loss, cutoff wavelength, and dust scattering. Theoretical analysis indicates that the microwave propagation distance in a cb214mm casing can easily reach 5,000 m. When the effect of dust particles is taken into account, the propagation distance decreases to 2,000 m. We conducted both laboratory experiments and field tests in casings commonly used in oil fields. The field tests show that the effective propagation distance of microwave in the casing is about 1,300 m. The experimental results do not match well with theoretical prediction, but are acceptable. In future commercial applications, by applying multiple relay amplifiers, the microwave propagation distance could be long enough for most drilling wells.

Deep Drilling Technology of China

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Analysis of Drill Pipe＇s Effect on Casing

Frictional wear of inner walls of drill pipe and casing is produced by rotational advance of drill pipe in the casing due to the joint effect of drilling fluid, temperature and contact load during drilling, among which the main wear is on the drill string. With development of drilling technology, deep well, ultradeep well, high angle well, directional well, extended reach well and horizontal well are taking more and more proportion. Meanwhile, the problem of serious frictional wear between drill pipe and casing are becoming more significant due to long time of drilling, high probability of dogleg severity, high contact normal stress between drill pipe and casing etc. Tool sticking may also occur due to large frictional resistance. Therefore, higher requirements are made on the study of how to predict and prevent the wear of drill pipe and casing during drilling. The residual strength of the worn casing is also studied by analysis of the law of drill pipe＇s effect on the casing wear in this paper.

Technical Challenges and Countermeasures for Deep Shale Gas Drilling by SINOPEC

Deep shale gas reservoirs being developed by SINOPEC are characterized by significant buried depths, high rock strengths, high temperatures and pressures, multiple layers, low ROPs, prolonged drilling time and prohibitoryhigh costs. All of these factors may negatively affect the economic and effective development of shale gas. Under such circumstances, existing drilling techniques for deep shale gas around the world have been reviewed to highlight technical challenges in deep shale gas drilling in China. With consideration to the previous drilling operations of SINOPEC for deep shale gas, technical solutions for deep shale gas drilling have been proposed with regard to the optimization of casing programs, enhanced drilling, trajectory control, high-density oil-based drilling fluid, cementation for deep shale gas development and other aspects. Some of these research findings have been deployed with great successes in Pingqiao, Jiangdong Block in the 2nd Phase of Fuling Project, Dingshan Block and other blocks with deep shale gas development. Among them, Well JY-74-2HF has had a drilling time of only 54.25d, whereas Well JY-187-2HF has a TVD up to 4024.14m. Relevant research results may provide valuable guidance and references for the optimization of drilling programs andthe enhancement ofdrilling ef^ciency for deep shale gas development.

Multistring analysis of wellhead movement and uncemented casing strength in offshore oil and gas wells

This paper presents a theoretical method and a finite element method to describe wellhead movement and uncemented casing strength in offshore oil and gas wells.Parameters considered in the theoretical method include operating load during drilling and completion and the temperature field,pressure field and the end effect of pressure during gas production.The finite element method for multistring analysis is developed to simulate random contact between casings.The relevant finite element analysis scheme is also presented according to the actual procedures of drilling,completion and gas production.Finally,field cases are presented and analyzed using the proposed methods.These are four offshore wells in the South China Sea.The calculated wellhead growths during gas production are compared with measured values.The results show that the wellhead subsides during drilling and completion and grows up during gas production.The theoretical and finite element solutions for wellhead growth are in good agreement with measured values and the deviations of calculation are within 10％.The maximum von Mises stress on the uncemented intermediate casing occurs during the running of the oil tube.The maximum von Mises stress on the uncemented production casing,calculated with the theoretical method occurs at removing the blow-out-preventer （BOP） while that calculated with the finite element method occurs at gas production.Finite element solutions for von Mises stress are recommended and the uncemented casings of four wells satisfy strength requirements.

Evaluation of Limestone Interval in the Drilled Surface Section of Bn-1 Oil Well

The first exploration oil well in any oil block consumes in general more time and cost than the other wells in the same block. Evaluating the drilled wells serves to improve the future operations. This paper evaluates the drilled surface section through real field data for the first exploration oil well drilled in one of the oil blocks, in Kurdistan north of Iraq. The surface section of the well was drilled with the conventional method to penetrate many different geological formations with tight intervals. Drilling efficiency and the difficulties encountered are discussed and explained using various data sources. All daily drilling reports concerning a specific interval were studied. This includes weight on bit, string rotation, mud pump flow and penetration rate. Evaluation was carried out by analyzing the used controllable drilling parameters with the formations features. Penetration of the Pila Spi formation (Middle Eocene) was the most difficult formation in the drilled section. Microsoft Office 365 Pro Plus used in making graphs and Excel tables. Evaluations showed that the conventional technology used left many negative effects, like increase in None Productive Time NPT, cost and ground water pollution. Simultaneous Casing Drilling method proposed as an alternative method for the future campaign.

急救模拟演练结合典型病例在产科临床教学中的应用

目的本研究旨在探讨急救模拟演练与典型病例教学法结合应用于产科临床教学中的价值。方法选取南华大学附属第一医院2022年5月至2023年2月在产科实习的医学生80名,随机分为研究组(n=40)和对照组(n=40);研究组采用急救模拟演练与典型病例教学相结合的方法,而对照组则接受常规临床教学。通过对比2组学生的专业理论知识与临床实践能力考试成绩,评估教学方法的效果。教学活动结束后,通过教学满意度调查表收集并分析2组学生对教学方法的满意度。结果研究组学生的总分为(88.62±1.69)分,高于对照组的(81.24±2.17)分,差异有统计学意义(P<0.05)。研究组学生的专业理论知识和临床实践能力考试成绩均高于对照组,差异有统计学意义(P<0.05)。研究组学生对教学的满意度较高,其对教学的学习兴趣、学习效果、自主学习能力、快速反应能力、病例分析能力、实践操作能力、沟通能力、团队协作能力评分高于对照组,差异有统计学意义(P<0.05)。结论在产科临床教学中,采用急救模拟演练与典型病例教学法的结合,能够有效提高学生的专业理论知识和临床实践能力,增强学生的教学满意度,证明了其作为产科临床教学方法的可行性。

近千米大直径穿强厚含水层降温管井钻孔设计

制冷降温是深部矿井热害防治的有效技术手段。以核桃峪矿井制冷降温系统建设工程为背景,针对降温管井钻孔深度大,穿过洛河组巨厚强含水层,长距离输送冷媒保冷等技术难题,在分析工程及水文地质条件基础上,确定管井钻孔两次开孔分段设计参数;通过调研管路保冷材料性能,提出复合钢管、静态空气、玻璃微珠增强水泥、钢基复合保温套管四种保冷方法条件下基岩段护壁管设计方案;综合考虑保冷效果、固井可靠性、施工难度等因素,优选工作管采用钢基复合保温套管;并根据套管受力计算,校验护壁管规格参数。工程实施效果表明,井上下降温管始末端温度损失约1℃,可以满足冷媒长距离输送冷量损失要求,对于类似工程具有借鉴价值。

石油钻井套管磨损及防护措施

为延长钻井套管的使用寿命,提高耐用性,文章首先通过分析石油钻井套管的重要性和价值,说明了研究套管磨损防护的必要性;其次,通过对套管磨损原因的深入剖析,揭示了磨削、腐蚀和疲劳等因素是导致套管磨损的主要原因。探讨了石油钻井套管磨损防护面临的挑战,如参数要求高、成本较大、异常条件下防护难等。最后,提出了有效的石油钻井套管磨损防护措施,包括使用新型材料和涂层技术、控制循环载荷、减少振动冲击、针对性结构加固、加强巡检维护等。通过上述措施实现了降低套管磨损率、延长使用寿命和提高钻井安全性的目标,为相关人员提供实践参考。

高架桥梁和盾构隧道的相互影响研究

根据江阴滨江路快速化改造及江阴靖江长江隧道工程现场实际施工工序,在桥墩桩基部分完成情况下,隧道左线穿越高架节点,在隧道左线建成工况下完成桥梁剩余桩基及满堂支架上部结构施工,在桥梁完成施工后,隧道右线穿越高架桥梁节点。论文通过Plaxis3D模型分析了盾构隧道施工对已建桥梁的影响,提出施工方案优化及监测等保障措施以确保桥梁施工过程中的隧道绝对安全。

单级套管扩孔一次跟进钻孔技术在滑坡治理中的应用

河南某山地滑坡前后两次治理,效果欠佳,滑坡体未得到有效抑制。工程预应力锚索需穿越残积层与各风化层中成串孤石群及中风化岩层中发育的破碎带,成孔深度长、孔径大。解决成孔中塌孔、卡钻、埋钻等问题,确保成孔质量,成为本滑坡治理工程施工难点与重点。基于此,采用了单级套管扩孔一次跟进钻孔技术。本文详细介绍其基本原理和施工技术要点,并对其治理效果评价分析,结果表明,利用单级套管扩孔一次跟进钻孔技术不仅可较好地对滑坡体进行治理,且可缩短工期、减少施工成本。

贵州省岩风阡铝土矿钻探施工工艺研究

贵州岩风阡铝土矿项目实施中钻遇硅质岩层,在钻进过程中产生的钻屑在钻井液漏失孔段不容易排出,易发生埋钻、卡钻、无芯等现象。通过优化钻孔结构、合理选择钻进参数,采用跟管钻进配合绳索取心工艺,有效解决了穿越溶洞的护壁难题,大大提高了钻遇溶洞成孔率。采用聚合物凝胶护壁堵漏减少了破碎地层掉块卡钻事故的发生。提高了钻进效率,节约了钻探成本。采用长套管穿越溶洞,降低了报废工作量,提高了工作进度。通过一系列技术措施的实施,如期完成了项目施工任务。本文对该矿区的施工经验进行了总结,希望为类似矿区钻探施工起到借鉴作用。

黔西地区石炭系页岩气钻井工程难点与对策

黔西地区石炭系地质条件复杂,工程风险和难点多,导致钻探工作面临很大挑战。根据该地区获得的地质资料,结合区内多口页岩气井的钻井工程实践,分析该地区存在以下钻井工程难点:浅表层溶洞、裂缝发育导致钻井漏失严重,打屋坝组目的层泥页岩段井壁易垮塌失稳,气层和裂缝发育层共存,部分地区含硫化氢,安全钻进风险高等。针对以上难点,提出了钻前浅表溶洞工程地球物理探测、“三开”井身结构优化设计、钻井设备优选和优快钻井等技术或方法。最后建议开展石炭系打屋坝组“漏、溢、塌”耦合作用机理研究,形成黔西地区页岩气钻井适应性工程技术体系,为实现该地区页岩气高效勘探开发提供技术支撑。

套管定向钻井锁定器设计与仿真分析

套管定向钻井技术是一种新型定向钻井工艺方法,兼备套管钻井和定向钻井的优势,能够实现高效的定向钻井目标。锁定器作为套管定向钻井系统中的关键部件,其性能好坏将对钻井可靠性产生直接影响。本文设计了一种将锁定器活动机构部件全部密封的结构形式,对锁定器中的传扭和轴向限位进行承载力计算分析,采用两参数Mooney-Rivlin超弹性本构模型,对两端关键密封O形圈的装配间隙以及橡胶硬度的承受密封压力情况进行分析,研究表明,锁定器芯承受最大65011 N·m的制动扭矩时,单个传扭键承受10835 N·m的扭矩,应力为74.86 MPa,单个定位卡可承受184520 N的竖向承载力,应力为659 MPa,两者的应力均小于所使用材料的屈服强度930 MPa,锁定器的轴向承载能力和传扭性能均满足设计要求;配合间隙以及橡胶硬度均对O形圈密封性能产生影响,仿真结果表明,在所选公差配合范围内,O形圈表面接触压力均大于外界压力,能够实现有效密封,考虑到间隙越小,Mises应力和剪切应力也随之增大,过大的应力会使密封圈损坏,且不易装配,因此配合间隙选择大值;橡胶硬度越大O形圈的密封性能越好且在相同介质压力下O形圈的形变越小,通过数值模拟选择90 HA硬度的O形圈,可以满足锁定器的密封需求。

舰艇指控原理课程改革与建设研究——突出实战运用能力

舰艇指控原理作为军事学作战类火力指挥与控制工程专业必须掌握的专业背景课程,必须面向装备实际,突出实战运用能力培养,一是要加大作战案例教学的力度,缩短教学情景与岗位任职的差距;二是在课程中引入部队实装或模拟训练器的使用,为学员的第一任职提供训练平台;三是将演练任务和复盘分析用来完善教学内容,缩短课堂到作战的距离;四是要加大院校与部队、军工集团等之间的联教联训,增强人才培养的保障力度;五是要提升主讲教员的专业教学能力,提高院校育人质量。

深地塔科1井钻井设计关键技术

深地塔科1井设计井深11100 m,预测井底温度213℃,预测地层压力133 MPa,钻井作业面临超深、超高温、超高压、高含硫“三超一高”的极端恶劣井况。通过开展地质工程一体化研究,确定了火成岩、膏盐岩及碳酸盐岩内裂缝的分布规律及其所带来的工程风险,在实现地质目标的前提下进行了井位优化,以降低工程施工难度。在地质工程一体化研究和五压力剖面预测的基础上,充分考虑深部地层地质、工程风险,设计了五开井身结构;开展了超深井套管设计及校核,除考虑套管抗拉强度、钻机承载力外,模拟计算了井口工具对超长超重套管的作用力,避免了套管下入过程中发生塑性变形;钻具组合设计时,充分考虑了水力学参数及振动的影响,在最优钻井参数范围内实现安全钻进和提速。现场施工进展表明,深地塔科1井钻井设计关键技术能够解决面临的系列钻井技术难点,实现万米钻探工程目标。

柯柯亚深层煤岩气水平井钻井实践

吐哈盆地侏罗系煤岩天然气区块位于山前高陡构造,地层倾角大,地质条件复杂,为国内陆地埋藏最深的煤岩气气藏,煤层水平井钻探技术在该领域尚属空白,钻井过程中“斜、慢、阻、卡”矛盾突出,亟须开展煤岩气水平井钻完井技术研究。为此,针对井身结构优化、井眼轨道优化、防斜打快技术、煤层坍塌机理、水平段安全钻完井开展了深入分析研究,柯新1H先导试验结果表明:①大三层井身结构可以满足水平井安全钻进,但具有较大的优化潜力;②垂直钻井技术在2500 m以浅的煤上地层应用效果佳,为中上部地层防斜打快提供了技术手段;③技术套管下深的确定是关键,是保障水平段能否成功实施的基本条件;④水平段通过多靶点轨道设计、随钻岩性追踪、无扶单弯螺杆+缩小底部钻具外径、双向通井工具、强抑制强封堵钻井液等手段降低卡钻风险,在煤层起伏变化大的情况下,确保了千米长水平段钻进与下套管作业顺利实施。