Reliability Analysis Method of a Control System for Subsea All-Electric Christmas Tree

The subsea all-electric Christmas tree(XT) is a key equipment in subsea production systems.Once it fails,the marine environment will be seriously polluted.Therefore,strict reliability analysis and measures to improve reliability must be performed before a subsea all-electric XT is launched;such measures are crucial to subsea safe production.A fault-tolerant control system was developed in this paper to improve the reliability of XT.A dual-factor degradation model for electrical control system components was proposed to improve the evaluation accuracy,and the reliability of the control system was analyzed based on the Markov model.The influences of the common cause failure and the failure rate in key components on the reliability and availability of the control system were studied.The impacts of mean time to repair and incomplete repair strategy on the availability of the control system were also investigated.Research results show the key factors that affect system reliability,and a specific method to improve the reliability and availability of the control system was given.This reliability analysis method for the control system could be applied to general all-electric subsea control systems to guide their safe production.

Development and Control Strategy of Subsea All-Electric Actuators

The development of subsea all-electric Christmas trees is an area of focus in the offshore oil industry worldwide.The main difficulties are associated with the development and control strategies for subsea all-electric actuators,which are the most criti-cal components of subsea Christmas trees.A single-motor-level fuzzy PID control with an integrated working condition detection mod-ule and a three-motor redundant-level deviation strategy with coupled joint synchronous control were proposed in this paper to real-ize the real time determination of algorithm parameters according to the working conditions,solve the rapid redistribution problems,and maintain the fast speed of the servo motor of the subsea all-electric tree valve actuator.A synchronous control electrical system was built,tested,and verified through simulation analysis.Test results show that the two redundant servo motors can still control the all-electric valve actuator and provide good synchronization control capabilities despite the failure of one servo motor,and the verti-cal and horizontal vibration values of the system are within reasonable ranges.The synchronous control strategy can be applied to the synchronous control problem of subsea all-electric production systems,which is of considerable importance for the development of subsea all-electric production systems.

Combinatorial reasoning-based abnormal sensor recognition method for subsea production control system

The subsea production system is a vital equipment for offshore oil and gas production.The control system is one of the most important parts of it.Collecting and processing the signals of subsea sensors is the only way to judge whether the subsea production control system is normal.However,subsea sensors degrade rapidly due to harsh working environments and long service time.This leads to frequent false alarm incidents.A combinatorial reasoning-based abnormal sensor recognition method for subsea production control system is proposed.A combinatorial algorithm is proposed to group sensors.The long short-term memory network(LSTM)is used to establish a single inference model.A counting-based judging method is proposed to identify abnormal sensors.Field data from an offshore platform in the South China Sea is used to demonstrate the effect of the proposed method.The results show that the proposed method can identify the abnormal sensors effectively.

Adjusting the Parameters of PI Regulator in All-electrical Tank Gun Control System by Computer Program

Both the traverse subsystem and the elevation subsystem of the all-electrical tank gun control system are composed of electrical drive control system respectively. The parameters of PI regulator in these electrical drive control systems affect the performance of the control system seriously. Up to now, there is not a simple and practical method for choosing regulator parameters, which are usually determined by repeated and continual readjustment. This method is low efficient, and the parameters got are not always optimal. A method for on-line adjusting the parameters of PI regulator in the electrical drive control system by computer program is introduced in this paper. The function of adjusting PI parameters of the electrical drive control system is realized by PC program written by VC++ and controlling program written by assemble language and by the communication between PC and DSP completed by the control MSCOMM in VC++6.0. The method as mentioned above which is applied for an all-electrical tank gun control system under development is proved very available, a better performance might be obtained for the all-electrical tank gun control system easily.

Design and Experimental Investigation for Subsea Control Module Test System

As a core part of subsea production systems,subsea control modules(SCMs)are costly,difficult,and expensive to install and inconvenient to use in underwater maintenance.Therefore,performance and function tests must be carried out before launching SCMs.This study developed a testing device and an SCM test by investigating SCMs and their underwater.The testing device includes four parts:a hydraulic station,an SCM test stand,a signal generating device,and an electronic test unit.First,the basic indices of the testing device were determined from the performance and working parameters of the SCM.Second,the design scheme of the testing device for the SCM was tentatively proposed,and each testing device was designed.Finally,a practical measurement of the SCM,in combination with the hydraulic station,SCM test stand,signal generator,electronic unit,and highpressure water tank,was carried out according to the test requirements.The measurement mainly involved equipment inspection before testing and an experimental test for the SCM.The validity and feasibility of the testing device and method were simultaneously verified through an association test.

Development of a Robot for In-service Radiography Inspection of Subsea Flexible Risers

The extreme operational environmental conditions and aging conditions of subsea structures pose a risk to their structural integrity and is critical to their safety.Nondestructive testing is essential to identify defects developing within the structure,allowing repair in a timely manner to mitigate against failures that cause damage to the environment and pose a hazard to human operators.However,to be cost effective,inspections must be carried out without taking the risers out of service.This poses significant safety risks if undertaken manually.This paper presents the development of an automated inspection system for flexible risers that are used to connect wellheads on the seafloor to the offshore production and storage facility.Due to the complex structure of risers,radiography is considered as the best technique to inspect multiple layers of the risers.However,radiography inspection,in turn,requires a robotic system for in-situ inspection with higher payload capacity,precise movement of source and detector which is able to withstand an extreme operational environment.The deployment of a radiography inspection system hasbeen achieved bydeveloping acustomized subsearobotic system called RiserSure that can provide precise scanning motion of a gamma ray source and digital detector moving in alignment.The prototype has been tested on a flexible riser during shallow water sea trials with the system placed around a riser by a remotely operated vehicle.The results from the trials show that the internal inner and outer tensile armor layer and defects in the riser can be successfully imaged in real operational conditions.

水下控制模块安装工具结构设计与对接精度分析

水下控制模块是水下生产系统的关键部件,针对水下控制模块在水下如何精准、高效、安全地实现回收和再安装工作的问题,本文设计了一种水下控制模块安装工具。对此安装工具进行了机械结构的设计,将安装工具各部分结构在工作过程中的作用进行了介绍。针对安装工具能够顺利完成水下控制模块的安装,基于安装工具各部分结构对接精度关系分析,通过数学建模与仿真分析,得到影响水下控制模块安装精度的原因,设计合理的安装精度参数。将仿真分析得到的数据与设计参数相比较,可证明水下控制模块的结构设计能满足水下控制模块的对接定位精度要求。结果表明:各精度参数满足水下控制模块安装工具设计要求,在此设计参数下安装工具能够完成水下控制模块的精确安装。

浅水受限区水下油气田开发方案

针对国内浅水油气资源开发环境影响及空间受限等问题,本文提出了国产浅水水下生产系统的总体设计方案。通过对浅水水下生产系统关键设备结构进行分析,提出了一种满足受限区海域开发要求的环境友好型设计思路。结果表明:通过系统和总体布置的设计,国产浅水水下生产系统与深水相比在单体重量、作业方式、维护检修方面更加经济。

水下控制系统测试台设计及试验研究

针对水下控制模块测试需求,文中设计了一种多功能水下控制模块测试台。水下控制模块(SCM)作为水下生产系统的核心部分,其安装成本高、难度大,且不便于在水下维护,因此,在其入水前必须对其进行严格的功能测试,确保在水下工作的可靠性。首先,对关于水下控制模块测试的相关技术和标准进行研究,得出水下控制模块在测试台上进行的测试主要包括内部静水压力测试、液压内部泄漏测试和液压系统功能测试;然后,基于被测水下控制模块的性能指标对测试台的机械结构和液压系统进行了设计,并对上述测试内容的测试方法进行了研究;最后,通过试验对测试台的测试功能进行验证。文中研究为我国设计和研制国产水下生产系统测试设备提供了宝贵经验。

国产水下生产系统在渤海油田的首次应用

为了突破外国的技术限制,实现国产化水下油气生产技术的顺利实现,因此有必要开展对国产化水下油气生产技术的研究。文章概括了中国水下油气生产装置的研究开发历程,并阐述了全水式、电液复合式和全电式等水下生产系统的主要运行模式和特征,并归纳出各生产装置的主要优势与缺陷。以流花11-1油气田、流花16-2/20-2/21-2油田群、陵水17-2气田等为主要技术平台,进行了渤海首次国产水下油气生产系统的试验应用,基本概括了渤海首次的水下油气工程技术特征,并对通讯不稳定问题解决方案进行验证,最后并对其应用前景进行了展望。

水下控制系统网络可靠性测试方法及在乐东22-1气田的应用

针对水下控制系统网络开展可靠性测试方法研究。首先,分析水下控制系统网络结构,提出一种水下控制系统网络可靠性测试方法,测试网络的连通性及通信质量。其次,从层次结构、通信协议、冗余配置、设备接入网络方式等方面分析水下控制系统网络可靠性。最后,该测试方法成功应用于乐东22-1气田水下控制系统网络通信可靠性测试。

135/8-10M卡爪式水下液压连接器国产化研制

在分析国内外技术现状的基础上,详细说明宝鸡石油机械有限责任公司研制的135/8-10M卡爪式水下液压连接器的总体结构、技术参数和有限元分析结果,介绍样机制造和试验情况,并对卡爪式水下液压连接器的结构特点进行总结。该卡爪式水下液压连接器具有液压锁紧和多重解锁、位置指示、型面自锁、垫环固位和更换等功能,产品通过挪威船级社(DNV)和中国船级社(CCS)双认证,并取得API 17D证书,开展与用户设备的现场联调测试,有力推动水下油气装备关键部件的国产化。

基于K-means的水下控制系统集成测试风险分析

采用危险源辨识分析(HAZID)工具对南海某水下控制系统集成测试进行风险识别,研究水下电力和通信设备的联合测试等过程存在的风险,针对HAZID技术识别的测试风险,定义风险的3个指标,包括风险发生可能性、风险后果严重程度和风险预防控制能力,将风险进行K-means聚类分析,采用SPSS软件将风险分为重大风险、高风险、中风险、低风险等4个聚类等级,识别4类共21个测试风险。在实际运用中,该方法可为水下控制系统集成测试风险制定有针对性的措施,可高效、科学和系统地指导水下控制系统集成测试工作开展。

水下控制模块的清洗技术

介绍了一种用于水下控制模块(SCM)的清洗设备,该设备由电机、液压泵、过滤器、阀门及管路等构成。通过改变清洗设备的输出流量使得流体在不同尺寸的元件内部形成紊流,从而达到清洗元件的目的。使用该设备可以保证SCM中的清洁度达到相应的要求,从而提高SCM在使用过程中的可靠性。

海管铺设过程中节点防腐质量问题及原因分析

通过分析某项目海底管道铺设过程中节点防腐出现的质量问题,查找出现质量问题的原因,并针对性地改良现场施工工艺和做法,最终降低了海底管道铺设过程中节点防腐的不合格率,提高了节点防腐质量及施工效率。

海底钻机机架的同步升降控制方案设计

为了满足新型海底连续管钻机对可变高度机架的功能需求,开展了机架升降控制方案设计。首先根据海底钻井工艺和深海服役环境,设计了一套基于超长行程柱塞缸和电液比例节流调速的双层机架升降方案及作业流程,具有结构紧凑、稳定性好、油缸及高压管线安装方便、开发成本低的优点。为了减轻大跨距偏载和水下洋流扰动等因素对同步运动控制过程的影响,采用四缸主从同步闭环控制结构,并根据系统理论模型设计了一种内模鲁棒性控制算法,通过调节滤波器时间常数来改善控制器动态特性,仿真结果表明该系统具有良好的抗干扰能力,为深海环境下的准确和稳定控制提供了依据。

深水带控制系统水下管汇国产化进程与展望

深水带控制系统水下管汇是制约中国独立开发南海深海油气资源的关键设备之一。为加快深水带控制系统水下管汇的国产化进程,对深水带控制系统水下管汇的国产化意义、系统组成和要求、现阶段国产化取得的成绩等进行分析,阐述了其设计、制造、测试、安装技术和工程化产品自主化研制情况。中国已在关键技术上取得突破,研制了国内首台500 m水深级带控制系统水下管汇,已示范应用到气田开发项目中,同时在紧凑型水下管汇和基盘式水下管汇的研发中取得了较大进展。最后对新型深水带控制系统水下管汇国产化研发和应用进行了展望。

全电式水下阀执行器多电机协同控制策略研究

水下采油树全电执行器多电机协同工作时,由于误差等导致减速器发生振动。为了减少同步误差导致传动系统发生振动的情况,通过对多电机协调策略进行研究,从控制算法层面提出了一种基于改进粒子群算法优化模糊PI补偿器的多电机协同控制策略。使用Logistic混沌映射并结合中心耦合游移的策略改进粒子群算法,采用改进后的算法离线优化模糊控制器的隶属度函数。为了得到最小的同步误差,在适应度评价函数中引入同步误差项。为了验证该方案,建立了Simulink/Adams联合仿真模型,在Adams中以轴套力柔性连接替换理想约束,建立了联合仿真模型和传动机构动力学模型,对传动机构的振动情况进行了仿真。研究结果表明,该方法通过减小同步误差,能有效减轻传动系统的振动情况。所得结论可为多电机协同控制提供参考。

CANopen通讯的水下阀门电机控制设计与实现

文章针对水下阀门电机控制提出了基于CANopen通讯协议的控制方案,介绍了CANopen通讯协议的技术及特点,深入研究了电机驱动器状态机执行过程,详细设计了水下阀门电机控制硬件结构、通讯结构和主站软件控制流程图,编程实现了水下阀门电机控制的上、下位机,并通过搭建的试验台对其进行测试验证。试验结果表明,利用CANopen通信可以对水下阀门电机实现精确控制,控制网络运行快捷简便、稳定可靠、实时效果好、数据交换流畅,能够满足水下阀门电机控制的需求,提高了控制性能。

海洋石油708船深水离线电池分配系统的研制与应用

针对海洋石油708船在深远海勘察作业时,海底钳因电能不足被频繁提至甲板更换电池的问题,研制了一套深水离线电池分配管理系统。该系统主要由控制舱、深水电池组、水密电缆等组成,能够在海底独立实现4个深水电池的自动切换功能。控制舱采用高强度铝合金制成,系统耐压≮30 MPa;采用三菱PLC作为核心控制器,完成了控制程序的编写。通过室内实验,验证了控制功能,能够稳定实现电池的切换与电能输出。在我国南海某海域1800 m水深处进行了现场应用,成功将海底钳的水下作业时间由3天提升至不低于10天,极大地延长了其在海底的工作时间,为海洋石油708船节约了宝贵作业时间,圆满辅助该船完成了勘察作业任务。