Research on Horizontal Vibration of Heavy-Weight Drill Pipes in Directional Drilling

The mode of load and deformation of directional drilling string and the expression of trigonometric series of deflection equation are established by means of elastic deformation energy and of the vertical and horizontal bending. A calculation formula for natural frequency of horizontal resonance and rotational speed is derived based on the calculation method by Ritz, with which analysis is made for the cause and affecting factors of the excessive abrasion of heavy-weight drill pipe in high-angle holes so as to provide reference and basis for rational selection of drilling parameters and drilling tools in the future high-angle directional drilling.

Numerical calculation of temperature and phase change during the process of atomizing spray quenching on drilling pipe

A finite element method (FEM) procedure was developed in order to simulatethe quenching process for drilling pipe (DP). The calculating model was based ontime-temperature-transformation (TTT) diagrams, and incorporated with material properties dependenton temperature. The procedure was used to calculate the temperature-time histories, describe thephase transformations of atomizing spray quenching for DP in the welding zone, and predict thehardness distribution in radius direction after quenching in the zone. The calculated results metwell with that of experiments. It was easy to determine the parameters such as volume and pressureof the cooling water and compressed gas by use of the numerical calculation and experiments, becausethe value of convection coefficient was decided greatly by the mixture of the cooling water andcompressed gas. Moreover, the simulating results were helpful not only to design the quenchingequipment, but also to optimize the quenching process for DP's welding zone.

Processing practice of Baosteel drill pipes

Drill pipe products are the most critical service requirement,the highest performance requirement and the highest quality reliability OCTG products.Through the continuous research on steelmaking,upset, heart treatment,straightening and friction welding,Baosteel improves the key technical parameters which affect the quality of drill pipe,such as material purity,Miu of internal upset transition area,toughness and straightness.Baosteel drill pipe products have met the demanding requirement of drilling operations.By BRP dephosphorization and LF desulfurization,the P,S content of Baosteel drill pipe is very low.The S content of S-135 drill pipe can be controlled in less than 10ppm.Baosteel designs a new closed-loop control system of upset end induction heating system.The system use temperature measurement inside the oven and closed-loop control.The temperature accuracy of the system can be guaranteed within the±15℃to get a stable upset quality.The upsetting process of the drill pipe is optimized by using patented technology and made the Miu from 100 mm to 140 mm.This make a substantial increase in fatigue life of the drill pipe.To improve the impact toughness of the drill pipe body,the drill pipe body material is changed from Cr-Ni-Mo system to Cr-Mo-V system and the heat treatment is changed from oil quenching to water quenching.To improve the impact toughness of the tool joint,the tool joint furnace is upgraded to improve heating capacity.To improve the impact toughness of the weld zone,a new fuzzy control system of weld zone heat treatment is developed.The temperature accuracy of the system can be guaranteed within the±5℃to get a stable heat treatment quality.A new drill pipe straightness automatic detection devices and self-learning method of straightening are developed to achieve automated straightening.A welding process with high speed,single-stage pressure and high forging force is applied to inertia friction welding.A welding process with low speed,three-stage pressure and low forging force is applied to continous friction welding.

Corrosion characteristics and mechanism of the S135 drill pipes in slurry

The corrosion mechanism of the S135 drill pipes was investigated through observation of the corrosion morphology and analysis of the corrosion products by scanning electronic microscope （ SEM）, energy dispersive spectrum （EDS） and X-ray diffraction （XRD）. The results show that the localized corrosion on the outer surface of the drill pipes was caused by oxygen corrosion due to the action of retained slurry. Cl - contained in slurry accelerated the corrosion and promoted the development of corrosion pits. Suggestions for mitigating or preventing such corrosion of the drill pipes are proposed based on the research results.

Calculation of the Gas Injection Rate and Pipe String Erosion in Nitrogen Drilling Systems

Detailed information is provided for the design and construction of nitrogen drilling in a coal seam.Two prototype wells are considered.The Guo model is used to calculate the required minimum gas injection rate,while the Finnie,Sommerfeld,and Tulsa models are exploited to estimate the ensuing erosion occurring in pipe strings.The calculated minimum gas injection rates are 67.4 m^(3)/min(with water)and 49.4 m^(3)/min(without water),and the actual field of use is 90–120 m^(3)/min.The difference between the calculated injection pressure and the field value is 6.5%–15.2%(formation with water)and 0.65%–7.32%(formation without water).The results show that the Guo model can more precisely represent the situation of the no water formation in the nitrogen drilling of a coal seam.The Finnie,Sommerfeld,and Tulsa models have different sensitivities to cutting densities,particle size,impact velocity and angle,and pipe string hardness.

A numerical method for determining the stuck point in extended reach drilling

A stuck drill string results in a major non-productive cost in extended reach drilling engineering. The first step is to determine the depth at which the sticking has occurred. Methods of measurement have been proved useful for determining the stuck points, but these operations take considerable time. As a result of the limitation with the current operational practices, calculation methods are still preferred to estimate the stuck point depth. Current analytical methods do not consider friction and are only valid for vertical rather than extended reach wells. The numerical method is established to take full account of down hole friction, tool joint, upset end of drill pipe, combination drill strings and tubular materials so that it is valid to determine the stuck point in extended reach wells. The pull test, torsion test and combined test of rotation and pulling can be used to determine the stuck point. The results show that down hole friction, tool joint, upset end of drill pipe, tubular sizes and materials have significant effects on the pull length and/or the twist angle of the stuck drill string.

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.

UBD Technology Plays an Effective Role in Overcoming Drilling Challenges

For decades,some geological formations have been drilled with a drilling fluid that exerted a bottom-hole pressure less than the formation pressure,allowing formation fluids-oil,gas and water-to flow from the reservoir into the well bore while drilling proceeds.A growing number of Iranian case histories have shown that when UBD is applied in the right reservoir with the proper planning,well productivity can be orders of magnitude greater than with a conventional well drilled into the same formation.Wells drilled underbalanced have been proven to add

Stress Corrosion Cracking of High-strength Drill Pipe in Sour Gas Well

In high sour gas reservoir drilling process, it happens occasionally that high-strength drill pipe suffers brittle fracture failure due to stress corrosion cracking, and poses serious hazard to drilling safety. To solve this problem, this paper studied the stress corrosion cracking mechanism and infl uencing factors of highstrength drill pipe in sour environment with hydrogen permeation experiments and tensile tests. We simulated practical conditions in laboratory and evaluated the stress corrosion cracking performance of the high-strength drill pipe under conditions of high stress level. For the problems occurring in use of high-strength drill pipe on site, the paper proposed a technical measure for slower stress corrosion cracking.

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.

S135钻杆接头螺纹三维参数化建模及力学特性分析

S135钢级钻杆在矿井勘探、探放水、瓦斯抽采等钻孔施工中得到了广泛使用。然而,由于钻杆接头螺纹承受轴向拉压、扭转、弯曲及其复合载荷的循环作用,导致接头螺纹的使用寿命远远低于其设计寿命,是整个钻杆结构中最薄弱的环节。因此,通过万能拉伸试验获得钻杆接头材料的力学性能参数,经计算转化得到其本构参数,对钻杆接头进行有限元分析。为了提高有限元分析效率,推导垂直于钻杆接头轴线的螺纹截面轮廓几何表达式,基于旋转、抬升、缩径和连接节点的设计思路,提出了一种考虑钻杆接头锥度和台肩的三维螺纹参数化建模方法,并根据单元和节点之间的关系开发了钻杆接头连接的参数化三维六面体网格建模程序,通过与交互式建模方法计算结果的对比验证了其有效性和可行性。此外,对上扣扭矩、压扭及压弯扭复合载荷作用下接头外螺纹的力学特性进行了分析。结果表明:3种工况下钻杆接头外螺纹上的应力近似呈现“浴盆”形态,第1螺纹牙上的应力最大;随着圈次的增加,螺纹牙上的应力迅速下降,最后一圈螺纹牙上的应力呈现上升趋势;在弯矩的作用下,螺纹牙上的应力具有非对称特征。在接头螺纹设计时,必须考虑井眼曲率的影响并且需要重点关注接头压缩边第1螺纹牙上的应力。

钛合金/钢钻杆复合钻柱动力学特性分析与优化设计

钻井深度的持续增加使钻柱面临的载荷工况越来越严苛。钛合金具有密度小、屈服强度高和弹性模量低等特点,基于井口钻杆抗拉余量设计要求,设计3种钛合金/钢钻杆复合钻柱,即复合钻柱1(Φ101.6 mm钻杆段全段使用钛合金钻杆)、复合钻柱2(Φ101.6 mm钻杆上半段使用钛合金钻杆)和复合钻柱3(Φ101.6 mm钻杆下半段使用钛合金钻杆)。为了探究钛合金/钢钻杆复合钻柱(简称为复合钻柱)的动力学特性,基于Hamiton原理建立复合钻柱的动力学模型,并采用节点迭代法和Newmark-β法对模型进行求解,分析3种复合钻柱的涡动特征、动态应力和振动特性,并与常规钢钻柱进行比较。结果表明:钛合金钻杆的使用可有效减缓钻柱涡动速度、动态应力,其中复合钻柱3的涡动速度、动态应力最小;基于振动特征强度对钻井作业参数进行优化,形成复合钻柱3的钻井作业参数推荐图版并给出合理的施工参数范围。

基于改进YOLOv8n的煤矿井下钻杆计数方法

为提高煤矿井下钻杆计数的效率和精度,提出了一种基于改进YOLOv8n模型的煤矿井下钻杆计数方法。建立了YOLOv8n−TBiD模型,该模型可准确检测矿井钻机工作视频中的钻杆并进行有效分割:为有效捕获钻杆的边界信息,提高模型对钻杆形状识别的精度,使用加权双向特征金字塔网络(BiFPN)替换路径聚合网络(PANet);针对钻杆易与昏暗的矿井环境混淆的问题,在Backbone网络的SPPF模块后添加三分支注意力(Triplet Attention),以增强模型抑制背景干扰的能力;针对钻杆在图像中占比小、背景信息繁杂的问题,采用Dice损失函数替换CIoU损失函数来优化模型对目标钻杆的分割处理。利用YOLOv8n−TBiD模型分割出的钻杆及其掩码信息,根据打钻过程中钻杆掩码面积变小而装新钻杆时钻杆掩码面积突然增大的规律,设计了一种钻杆计数算法。选取综采工作面实际采集的钻机工作视频对基于YOLOv8n−TBiD模型的钻杆计数方法进行了实验验证,结果表明:①YOLOv8n−TBiD模型检测钻杆的平均精度均值达94.9%,与对比模型GCI−YOLOv4,ECO−HC,P−MobileNetV2,YOLOv5,YOLOX相比,检测准确率分别提升了4.3%,7.5%,2.1%,6.3%,5.8%,检测速度较原始YOLOv8n模型提升了17.8%。②所提钻杆计数算法在不同煤矿井下环境的视频数据集上实现了99.3%的钻杆计数精度。

小井眼水平井洗井岩屑清除效率研究

为研究小井眼水平井洗井钻柱旋转时的岩屑清除规律,针对玛湖深层三叠系长水平井小井眼洗井工况,进行了相似试验设计,开展了岩屑启动流速和岩屑清除效率的试验研究。试验发现,采用不同排量冲洗岩屑床时,岩屑床呈现稳定运移、沙丘式波浪运移和整体运移等3种运移形态。试验研究了岩屑床稳定运移形态下岩屑粒径、排量和钻柱转速对岩屑启动流速及钻柱转速对岩屑床高度和形成稳定岩屑床所需时间的影响规律,分析了岩屑床整体运移形态下岩屑粒径、排量和岩屑床初始质量对岩屑床清除效率的影响。研究结果表明,岩屑粒径越小所需启动流速越低,钻柱旋转后等效岩屑启动流速降低45.5%,钻柱转速升高会使形成稳定岩屑床所需时间缩短,岩屑清除效率提高;当岩屑床发生整体运移后,较低排量下岩屑床清除速度受岩屑粒径影响较小,高排量下大粒径岩屑床的运移速度快。排量和钻柱转速是提高洗井过程岩屑床清除效率的关键,而现在洗井时钻柱转速较低,可适当提高钻柱转速,以提高洗井效率。

含表面双裂纹的钻杆管体断裂性能研究

钻杆刺漏是钻杆在服役过程中最常见的失效形式,而钻杆表面裂纹的扩展是钻杆发生刺漏的直接原因。为更有效地评估钻杆表面含有多条裂纹时的安全性能,以某超深直井G105钻杆井口段为研究对象,建立管体外表面双裂纹有限元模型,分析了拉扭载荷下裂纹间距、次裂纹尺寸以及走向对环向主裂纹前缘J积分的影响。结果表明:轴向排列的环向次裂纹是相对最安全的,可大幅消减钻杆主裂纹前缘的J积分;环向排列的环向次裂纹相对最危险,可大幅增大钻杆主裂纹前缘的J积分;轴向次裂纹可增大钻杆主裂纹前缘或部分前缘的J积分,但增幅相对环向排列的环向次裂纹来说要微弱得多。次裂纹对主裂纹前缘J积分的影响强度随两裂纹间距的增大或次裂纹尺寸的减小而减小。因此在对含表面双裂纹的钻杆进行分析时,在次裂纹尺寸较大且距离较近的情况下应考虑次裂纹的影响;在次裂纹尺寸较小或距离较远时则可忽略次裂纹,将模型简化为单裂纹钻杆模型进行分析。

超深井控温钻井隔热涂层参数影响机制研究

为揭示隔热涂层对超深井井筒温度场的影响规律,针对隔热涂层与钻杆的导热特点,采用传热热阻形式计算钻杆的综合传热系数,构建了考虑钻杆内隔热涂层影响的超深井井筒–地层瞬态传热模型,并采用有限差分法对模型进行离散,利用高斯–赛德尔算法进行迭代求解。通过理论分析和现场数据验证了模型的准确性。研究发现,钻杆内隔热涂层的导热系数对井底循环温度影响显著,随着导热系数减小,井筒环空温度迅速降低,出口温度升高;隔热涂层的厚度和长度对井筒温度也有重要影响,隔热涂层厚度越大,井底循环温度越低。这些发现为超深井钻井过程中井筒温度的调控和隔热钻杆参数的优选提供了重要理论依据。

钻杆在扭转作用下的变形及抗扭性能分析

钻杆在煤矿勘探开发过程中占据着重要地位,因工作条件恶劣,易失效并造成钻井事故。基于材料力学、工程力学等对钻杆扭转时的切应力及变形量进行分析,建立钻杆在施加纯扭矩作用下的剪应力、单位长度扭转角及抗扭强度计算的力学模型。同时,通过ANSYS仿真得出切应力分布规律及扭转变形量。通过对比,ANSYS仿真结果与理论模型计算结果基本一致,为钻杆失效等进一步研究提供了理论依据。

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。

基于DeepSORT和改进YOLOv5的煤矿井下钻杆计数方法

针对煤矿井下钻杆计数存在精度较差、效率较低等问题,提出一种基于DeepSORT和改进YOLOv5的煤矿井下钻杆计数方法。首先,设计DR-C3模块,提高YOLOv5网络提取特征的能力;其次,引入GAM注意力机制,减少复杂背景的干扰;然后,通过CARAFE上采样算子扩大感受野;最后,结合DeepSORT算法对钻杆进行实时追踪计数。实验结果表明,改进后的YOLOv5 mAP@0.5提升了2.8%;钻杆计数平均精度达99.4%,检测速度达到93帧/s,计数精度高,满足实际需求。

某油井G105钻杆断裂失效分析

在某油井深400~500 m处,钻杆1在解卡时断裂,随后钻杆2在打捞落鱼时断裂。采用断口形貌分析、化学成分分析、显微组织分析、力学性能测试等手段分析了两根钻杆断裂的原因。结果表明,钻杆1与井壁摩擦过程中发生相变,强度下降塑性增加,发生韧性断裂;钻杆2与井壁摩擦时,形成大量马氏体,韧性恶化,当再次承受拉力时发生脆性断裂。建议监测井内结构变化,保证钻井液的循环畅通,优化钻具结构设计,防止钻杆因相变而断裂,同时禁止工人违规操作,避免钻杆因超载发生断裂。