Processing and analysis of transient pressure measurements from permanent down-hole gauges

With permanent down-hole gauges （PDGs） widely installed in oilfields around the world in recent years, a continuous stream of transient pressure data in real time is now available, which motivates a new round of research interests in further developing pressure transient processing and analysis techniques. Transient pressure measurements from PDG are characterized by long term and high volume data. These data are recorded under unconstrained circumstances, so effects due to noise, rate fluctuation and interference from other wells cannot be avoided. These effects make the measured pressure trends decline or rise and then obscure or distort the actual flow behavior, which makes subsequent analysis difficult. In this paper, the problems encountered in analysis of PDG transient pressure are investigated. A newly developed workflow for processing and analyzing PDG transient pressure data is proposed. Numerical well testing synthetic studies are performed to demonstrate these procedures. The results prove that this new technique works well and the potential for practical application looks very promising.

Feasibility Analysis of Performance Validation for Satellite Altimeters Using Tide Gauge and Deep-ocean Bottom Pressure Recorder

Independent of traditional approach of satellite altimeter calibration, the feasibility of altimeter validation using tide gauge located on solitary island at open sea (TGSI) and deep-ocean bottom pressure recorder (DBPR) separately is initially studied. Bias of Jason-3 sea surface height (SSH) and relative SSH bias (Δbias) between Jason-2 and Jason-3 is calculated using the data of tide gauge on Harvest oil platform, tide gauge No. 1890000 and DBPR No. 21419. The standard deviations of calculated SSH bias sequence are 3.98 cm, 2.87 cm and 8.61 cm respectively, and Δbias (Jason-3—Jason-2) is -3.62± 2.17 cm , -2.58±1.97 cm and -2.60±1.30 cm respectively. Comparing to the results reported by international calibration sites, the results show that Jason-3 SSH is 3.0 cm lower than that of Jason-2, the selected DBPR is appropriate to the calculation of relative SSH bias between Jason-2 and Jason-3, but it is not suitable for calibration or validation of single satellite, TGSI is appropriate to both.

Measurement of transient neutral gas puff pressure in the NUDT＿IPPTx by a fast ionization gauge

A gas injector was designed for the 400 J/pulse prototype of the planar inductive pulsed plasma thruster（IPPT） developed by the National University of Defense Technology（NUDT_IPPTx）.As the gas puff distribution over the coil surface is critical to the NUDT_IPPTx functioning efficiently, a fast ionization gauge was developed to investigate the neutral gas pressure profiles to seek the critical time when the thruster is ignited. The gauge was calibrated for argon by using a capacitance manometer. Time-resolved pressure profiles have been acquired in the condition of the gas puff mass matching with the discharge energy and the drive coil parameters of the NUDT_IPPTx. It is demonstrated that the gas injector can supply a gas puff with a sufficiently steep（dp/dt？≈？770 kPa s-1） leading and trailing edge, and the gas puff can be compressed against the drive coil as expected. The critical ignition moment is considered to appear at some instant between 525 μs and 650 μs after the valve trigger.

Design of digital pressure gauge based on ATmega16 microcontroller

The combination of sensor and computer technology makes the measurement of various physical quantities easy, convenient and smart. In this article, a digital pressure gauge that is suitable for measuring liquid pressure is designed. The design of high precision digital pressure gauge uses pressure sensor as its foundation and uses ATmegal6 as its controller.

Investigation on the Determination of Initial Shock Pressure at Near Interface Field of TNT Charge and Water for Underwater Explosion

There are few report on the directly measurement of the initial shock pressure of explosive charge at its interface of water for underwater explosion. The special technologies have been taken to the measurement system with manganin piezoresistive gauge （PRG） in order to measure the initial shock pressure at the interface and its near field of TNT chare and water. The free-holding PRG film gauge can directly determine the shock peak pressure at the interface and near field of TNT charge up to 12.85 GPa, which is satisfying for the good agreement to the 12.97 GPa with one dimensional theoretical analysis and 12.86 GPa with numerical simulation. The maximum discrepancy is 0.93 %. The results show that it is precise and reliable to determine the initial shock pressure of underwater explosion charge with the PRG technology.

Higher resolution helium measuring system for deuterium plasma on EAST tokamak via normal Penning gauge

Although the deuterium and helium have almost the same mass,a Penning Optical Gas Analyzer（POGA） system on the basis of the spectroscopic method and Penning discharging has been designed on EAST,since 2014.The POGA system was developed successfully in 2015,it was the first time that EAST could detect helium partial pressure in deuterium plasma（wall conditioning and plasma operation scenario）.With dedicated calibration and proper adjustment of the parameters,the minimum concentration of helium in deuterium gas can be measured as about 0.5% instead of 1% on the other tokamak devices.Moreover,the He and D2 partial pressures are measured simultaneously.At present,the measurable range of deuterium partial pressure is 1×10^-7 mbar to 1×10^-5mbar,meanwhile the range of helium is 1×10^-8 mbar to 1×10^-5 mbar.The measurable range can be modified by means of the adjustment of POGA system＇s parameters.It is possible to detect the interesting part of the gas with a time resolution of less than 5 ms（the 200 ms because of conductance of transfer pipe at present）.The POGA system was routinely employed to wall conditioning and helium enrichment investigation in2015.Last but not the least,the low temperature plasma of POGA is generated by normal penning gauge Pfeiffer IKR gauge instead of Alcatel CF2 P,which has been suspended for a few years and was used for almost all the POGA systems in the world.

The Evaluation of Measurement Uncertainty and Its Application in the Vacuum Pressure Measurement

In order to accurately measure the pressure and the pressure difference between two points in the vacuum chamber, a large number of experimental data were used to research the performance of the three capacitance diaphragm gauge and analysis the main influences of the uncertainly degree of pressure in the process. In this paper, three kind of uncertainty, such as the single uncertainty, the synthesis uncertainty and the expanded uncertainty of the three capacitance diaphragm gauges are introduced in detail in pressure measurement. The results show that the performance difference of capacitance diaphragm gauge can be very influential to the accuracy of the pressure difference measurement and the uncertainty of different pressure can be very influential to pressure measurement. That for accurately measuring pressure and pressure difference has certain reference significance.

A wireless-communication-based measurement of gas pressure with capsule-slime sealing device

To solve the existing problems of imperfect sealing and the inaccurate measurement of gas pressure in traditional sealing,the present study builds a new model of capsule-slime sealing device based on wireless pressure gauge.The new sealing device is mainly composed of two sets of capsules,a capsule connecting piece and a slime part,measures the pressure through the wireless communication technology,and seals through chemical reaction in the capsule,which generates gas to expand the capsule and extrude the pre-stored slime.Two methods of extruding pre-stored slime are proposed:in the first method,transverse force is generated by the expansion of the capsules at both ends,pushing the capsules toward the middle through the chute and squeezing the pre-stored slime out;in the second,high-pressure gas generated in the capsules is led into the expansion tube,which is inserted into the storage tube,squeezing it and letting the slime out to complete the sealing process.Then the research studies the effect of sealing under the condition of drilling with the structure of slime storage tube.The results indicate that the maximum standing time of slime wrapped in metal net is 2 h,instead of the expected 10 d,failing to meet the sealing requirements.When the slime viscosity is 1200–3000 m Paás in the structure of slime storage tube,the best viscosity of slime is achieved and can simulate sealing the drilling hole(5–4,4–2.36,2.36–1.18,1.18–0.15 mm in diameter),as well as the gap caused by mixed sand accumulation.

区段煤柱变形光纤光栅监测应用研究

针对近距离煤层下伏工作面过上覆遗留煤柱时,发生动静载叠加诱发强矿压显现,导致区段煤柱发生变形失稳造成人员伤亡和设备破坏。为探索基于光纤光栅实时监测区段煤柱变形发育特征,分析进、出遗留煤柱阶段矿压显现机理,将FBG、光栅应力计的光测方法相结合,结合现场实测的区段煤柱变形应力应变水平参量变化规律,研究煤柱应变空间分布规律及回采过程中工作面前方煤柱内部应变时域响应特征,验证光测方法在煤体应变水平观测的可行性。结果表明:工作面回采经过上覆遗留煤柱期间,区段煤柱顶板受集中应力影响,上部岩层块体破断并发生回转导致煤柱载荷增加,随着工作面推进覆岩断裂进一步向上传递,关键层断裂回转发生导致工作面来压,最终导致区段煤柱变形失稳。根据现场光栅应变增量幅度判断煤柱内局部变形的剧烈程度,在集中应力作用下,区段煤柱变形时发生最大应变为650×10^(-6),上覆岩层集中应力造成煤柱应变水平峰值位置为煤柱宽度11.5 m,沿煤柱宽度方向应变表现出先增加后减小然后趋于稳定的趋势,内部应变随采动过程中影响范围在5 m左右。综合研究工作面回采经过上覆遗留煤柱时应变对区段煤柱发生变形失稳的特点和规律,以及应变水平变化和煤柱物理力学性质,得到煤柱破坏的前兆特征,在外力作用下达到变形峰值前对煤柱提前进行卸压和防护的安全处理。

指针式压力表测量精度评价及误差来源分析

为了确定指针式压力表在日常使用过程中可能存在的误差及其来源,提高测量结果的准确性,本研究将测量系统分析(MSA)与正交试验设计相结合,应用于压力表的精度评价与误差分析。通过测量数据的重复性和再现性分析,确定系统存在一定误差。采用正交试验设计的方法进一步探究误差来源,通过改变测量人员、水平读数角度、垂向读数角度进行试验,结果表明,测量人员对测量结果影响较大,其次是水平读数角度,垂向读数角度影响最小。针对压力表的误差来源,提出应规范操作流程和正确安装压力表位置以减小测量误差。

振弦式土压力计自动校准系统设计及应用研究

随着智慧港口和智慧航道建设的发展,监测传感器的自动化计量已成为未来发展趋势。通过分析监测传感器——振弦式土压力计的组成和工作原理、校准需求及难点,设计并研制了一套自动化校准系统。以工控机为控制核心,以自动加压系统、频率采集仪为标准器,通过控制系统自动加压和测量被检设备输出频率模数值,可实现压力标准值的设置输出、频率测量值的自动记录存储及运算处理、历史数据管理及生成校准报告等目标。试验表明其各项程序和指标均能满足振弦式土压力计的校准要求,可直接用于相关计量校准工作。

气体减压器用压力表示值误差测量不确定度评定及自动计算

针对气体减压器校准规范给出压力表示值误差测量不确定度评定实例,结合气体减压器校准的实际情况,重点分析了评定实例的评定方法,指出评定方法的不足,并提出优化方法。根据优化后的评定实例计算过程,通过Excel设计了自动计算公式,校准人员只需输入测量值和被检表相关信息即可实现测量不确定度的自动计算,极大地提高了校准效率。

液体活塞式压力计检定及使用过程中的垂直度影响研究

液体活塞压力计稳定性较高,常被作为量值传递和溯源的标准器。但在实际使用中,其大多未配置相应的水平仪或水平仪精度不足,不能满足使用需求。因此,本文设计了两组试验,分别对其检定和使用过程中产生的倾角和垂直度变化对活塞有效面积和输出压力引起的变化进行讨论和分析,并提出生产和使用建议。

基于改进的YOLOv7油田井场压力表小目标识别

针对油田井场压力表小目标在不同光照条件下特征提取困难且目标检测率低等问题,提出一种基于改进的YOLOv7小目标井场压力表实时检测算法。首先,利用全局最大池化和全局最小池化的简单线性组合生成一种自适应池化层,并使用轻量级模块生成SPEM注意力模块,后将其加入YOLOv7主干网络中,提高网络对不同光照条件下压力表小目标的特征提取;其次,使用模量激活函数替代SiLU函数,减少死亡节点,解决梯度消失问题,提高模型的泛化能力;最后,将原来的YOLOv7中的CIoU损失函数替换为Wise-IoU,实现对损失函数的优化,并利用梯度增益分配策略来减少低质量示例产生的有害梯度,以聚焦普通质量锚盒的预测和回归。实验结果表明,改进后的算法相较于原YOLOv7算法精准率上升1.07%,召回率提升2.08%,同时也优于Faster RCNN、SSD、YOLOv3算法的检测结果,能有效满足油田井场压力表小目标的检测要求,具有较强的工程实践意义。

基于有限元分析的活塞压力计形变系数理论计算

基于有限元分析方法,计算了600 kPa气体活塞压力计和500 MPa油介质活塞压力计的形变系数。根据活塞间隙压力分布与间隙形变的耦合关系,采用迭代计算,确定了在某一测量压力下活塞系统的最终压力分布和间隙。在此基础上,计算了在各压力点下的活塞有效面积,并通过最小二乘拟合获得了压力形变系数。基于Python和ANSYS APDL编写了计算程序,研究了参数微调对计算结果的影响,并评估了形变系数计算结果的不确定度。对于600 kPa气体活塞压力计,形变系数的有限元计算结果与简单理论计算结果相差仅0.8%;对于500 MPa油介质活塞压力计,形变系数的有限元计算结果与实验测量值在不确定度范围内一致。

压力表计量的不确定度评价与校准率的研究

由于指针式压力表性能稳定、可靠性高,在工业生产中得到了广泛的使用。本文通过对指针式压力计人工检定的不确定度进行分析与评估,对其在检表过程中可能产生的各种影响因素的分析与评价,对其产生的各种不确定度进行分析,并对各不确定度进行计算,最终获得综合不确定度评价结果。同时,通过人工操纵校准设备对压力表的打压速率进行试验,探索校准过程中各校准点间的压力变化规律,获得合适的升降速度。本文研究成果能够真实地反映出被测数据的误差变化幅度,有助于正确判定测试结果的准确性,并为实现自动压降速度的自动控制提供一定的依据。

光学压力计的标定及应用

搭建了基于光学谐振腔的气体压力测量装置,即光学压力计。使用测量不确定度为0.001 1%(k=1)的活塞压力计,对两套独立的光学压力计进行标定,并对光学压力计的测量不确定度进行了系统的分析与评定,最终得到其压力测量的合成标准不确定度。利用该光学压力计对一台标称测量不确定度为0.025%的商用电容薄膜真空计进行多次校准。结果表明,在校准后的1年时间内,该薄膜压力计电容薄膜真空计的测量不确定度可达0.003%,大幅度提高了该商用电容薄膜真空计的测量不确定度。该光学压力计具有较好的长期稳定性,可应用于校准各种商用压力计,提高实际测量不确定度。

应用FMEA法加强油田压力表计量检定流程的节点控制

压力表作为油田生产中的重要仪器仪表,其计量检定也是确保压力表正常工作的主要手段。通过全面梳理压力表的计量检定流程,运用FMEA法来分析压力表失效模式及失效后产生的效应,并通过调查问卷的形式得到失效产生的风险系数,最终形成对检定流程节点的控制措施,期以对流程的初始节点至结束点的每一个节点,都能得到切实有效的控制,有效地减少压力表可能产生的失效,将失效影响降到最低。

基于深度学习的指针式压力表读数方法研究

为了降低指针式压力表的误读率,减轻人工读数压力,提高仪表读数的精度,设计了一种基于深度学习的指针式压力表读数方法。通过在DBNet网络结构基础上增加主干网络ResNet-18各个卷积层的通道数来提高模型的鲁棒性,重新设计了更适应指针式压力表刻度值检测的损失函数,在刻度值精准检测识别的基础上设计了极坐标展开的方法,将弧形的刻度值展开成一条直线,提高了读数的准确率。实验结果表明,最大误差仅1.05%,平均误差仅0.725%。相较于常用的Hough直线检测与ORB结合或DBNet+CRNN检测的方法,读数识别的平均误差大幅降低,为指针式压力表的自动读数提供了新的思路。

南宁盆地特殊地层静压随钻跟管桩适应性及单桩承载力特性研究

为了研究静压随钻跟管桩在南宁盆地特殊地层的适应性及单桩承载特性,对现场4根直径800mm的静压随钻跟管桩进行静载及低应变反射波法试验。研究结果表明:各地层中的试验桩承载力均能满足设计要求且均属于Ⅰ类桩,桩身回弹率较高,说明各试验桩仍具有较大的承载潜力;未进行破坏性试验时各地层中单桩承载力综合增强系数均大于1.00,以经验公式确定静压随钻跟管桩的单桩竖向承载力时应乘以相应的增强系数。基于以上研究,将静压随钻跟管桩工艺应用于实际工程,经验收检测表明,各项目受检基桩的桩身质量完好,承载力均满足设计要求,且仍具有一定的承载力富余量,良好的实际工程应用效果表明该工艺具有良好的适用性以及较高的推广使用价值。