深海钻井甲烷气侵超声波检测理论与方法研究

发布时间：2018-04-25 04:02

本文选题：气侵检测 + 超声波　；参考：《电子科技大学》2017年博士论文

【摘要】：气侵检测是石油钻井安全中的一个重要组成部分,也是当前石油天然气开采井控安全研究领域的一个研究热点。传统气侵检测方法基于井口钻井液流速变化,检测结果延迟性较高;而基于井下参数的最新气侵检测方法则需要对旧的钻井工艺设备进行更新,成本较高,难以快速应用。针对深海钻井,在泥线处通过非介入式流量计进行气侵检测的方法是目前成本较低,实时性较强的一种可行方案。本文在此基础上,对泥线处使用超声波进行非侵入式气侵检测的理论及方法进行了全面研究。根据研究层次的不同,本文主要包括气侵检测理论方法,检测应用方案以及验证实验三个方面。在检测理论方法上,本文提出基于连续型超声波流速,空隙率以及气侵检测的一套完整的理论及方法。首先根据气侵模型,垂直管道内气液多相流以及超声波相关理论,对连续超声波在环空管内泥浆与甲烷多相流中的传播特性,反射特性,多普勒效应等进行了分析。然后根据波形转换理论以及板波相关理论,从理论上推导了环空管管内泥浆中反射体反射的超声波信号能够在入射管壁时生成板波,并且板波的幅度与反射超声波入射角度相关。基于这些理论分析的结果,结合不同流型状态下气泡分布,流体中质点速度分量分布,接收超声波信号与超声波入射,反射角度,距离,衰减特性等多方面因素构建了一种基于均匀分布的连续超声波反射模型。通过该模型将接收到的反射信号幅度,频谱与环空管内流体流速,空隙率,流型建立确定性关系,并推导出了相应的数学表达式。最后根据这些理论基础,提出了一套基于板波检测对深海钻井过程中泥线处环空管内泥浆及气液两相液的泥浆流速,空隙率的超声波检测算法。同时提出了一个先利用流速,空隙率变化来对气侵进行初步判定,然后根据接收信号频谱形状识别流型变化来进行气侵检测的两级气侵预警检测方法。最后通过泥浆中的固相岩石碎屑与气泡在超声波反射特性,密度,形变特性上的不同进行了总结,对固相与气相进行区分的可行性进行了分析,提出以基于气泡与固相颗粒在形变特性上的区别,从而通过流型变化来进行区分的检测方法。在检测应用方案上,提出了分别基于单检测设备以及多检测设备的一套完整的气侵检测综合应用方案。该方案包括了检测装置安装方法,通信方式,气侵分级报警检测算法,硬件设计与软件设计等各个方面。其中气侵分级检测算法综合了流速,空隙率以及流体流型检测三方面的检测结果,并且在逻辑上依据气侵过程对检测结果进行了分级验证。通过不同的报警级别,将检测算法在实时性与准确性上进行了很好地平衡。在实验验证方面,本文设计了清水以及泥浆两套气侵模拟实验平台。其中清水实验平台设计有透明观察窗口,用于对本文所提出的基础理论与方法进行了验证。在清水实验平台中,本文设计了空管实验,检测位置以及塑料小球等实验,验证了板波的存在性,以及其频谱与管内流体中反射体速度,大小之间的确定性关系。同时也间接验证了本文所提出的检测模型的正确性。而泥浆模拟实验平台能够实现定量加气以及压力的精确控制。在泥浆实验平台上本文设计了流速实验,空隙率实验,以及对甲烷气侵过程进行模拟的溶解与析出实验。其中流速实验结果显示,本文所提出的流速检测方法能够对泥浆流速进行精确检测,测量结果与靶式流量计(介入式)的最大相对误差10%,而空隙率实验结果显示本文所提出的检测方法能够有效检测空隙率在3%以上的气侵情况。溶解与析出实验中首先向循环管道中流量定量天然气,然而再通过精确的加压与降压控制,对气侵过程中甲烷气体在泥浆中溶解与析出,气体体压缩与膨胀过程进行了真实的模拟。通过在模拟过程中,检测信号的幅度以及流型变化对本文所提出的气侵检测方法的有效性进行了验证。最后对本项目实验过程中的一些特殊现象进行了阐述与说明,并对实验过程中所存在的问题与不足提出了未来研究的研究方向与解决思路。
[Abstract]:Gas invasion detection is an important part of the safety of oil drilling, and it is also a hot spot in the field of well control safety in oil and gas mining. The traditional gas invasion detection method is based on the change of the flow velocity of well drilling fluid, and the delay of detection results is high, while the latest gas intrusion detection method based on the number of underground parameters needs the old drill. The well process equipment is updated with high cost and difficult to be applied quickly. For deep sea drilling, the method of gas invasion detection by non intrusive flowmeter at the mud line is a feasible scheme with low cost and strong real time. On this basis, the theory and prescription of non-invasive gas invasion detection using ultrasonic wave at the mud line are carried out on this basis. According to the different level of research, this paper mainly includes three aspects of gas invasion detection theory, detection application and verification experiment. In the detection theory and method, this paper proposes a complete set of theories and methods based on continuous ultrasonic velocity, voidage and gas invasion detection. The characteristics of the propagation, reflection and Doppler effect of continuous ultrasonic wave in the mud and methane multiphase flow in the annular tube are analyzed. Then the reflection of the reflector in the mud in the annular tube is theoretically derived according to the theory of wave conversion and the theory of plate wave correlation. The ultrasonic signal can generate the plate wave at the incident tube wall, and the amplitude of the plate wave is related to the reflection angle of the ultrasonic wave. Based on the results of these theoretical analysis, the distribution of the particle velocity component in the fluid in different flow pattern States, the distribution of the velocity component of the particle in the fluid, the reception of the ultrasonic signal and the hyper acoustic incident, the reflection angle, the distance, attenuation characteristic and so on. A continuous ultrasonic reflection model based on uniform distribution is constructed by the surface factor. Through this model, the amplitude of the reflected signal, the frequency spectrum is determined by the flow velocity, the void rate and the flow pattern in the annular tube, and the corresponding mathematical expressions are derived. Finally, a set of plate wave detection based on these theoretical bases is proposed. In the process of deep sea drilling, the ultrasonic detection algorithm of mud flow velocity and void fraction in the mud and gas-liquid two phase fluid at the mud line at the mud line is also proposed. At the same time, a preliminary determination of the gas invasion is made by using the flow velocity and the change of air gap rate, and then the two stage gas invasion early warning of gas invasion detection is carried out according to the spectrum shape of the received signal to identify the gas invasion. In the end, the difference between solid phase rock debris and bubbles in the ultrasonic reflection characteristics, density and deformation characteristics is summarized. The feasibility of separating solid phase from gas phase is analyzed, and the difference between bubble and solid particle based on the deformation characteristics is proposed, and the difference between the flow pattern and the flow pattern will be distinguished. In the detection application, a comprehensive application scheme of gas intrusion detection based on single detection equipment and multiple detection equipment is proposed. The scheme includes the installation method of the detection device, the communication mode, the gas invasion classification alarm detection algorithm, the hardware design and the software design, among which the gas invasion classification test is carried out. The measurement method combines the detection results of three aspects of flow velocity, void ratio and fluid flow pattern detection, and logically according to the gas invasion process, the detection results are graded and verified. Through different alarm levels, the detection algorithm is well balanced in real time and accuracy. In the experimental verification, this paper designs clear water. Two sets of simulation experimental platform for gas invasion are designed and the clear observation window is designed for the clear water test platform, which is used to verify the basic theory and method proposed in this paper. In the experiment platform of clean water, the experiment of the air tube experiment, the detection position and the plastic ball are designed in this paper. The existence of the plate wave and its spectrum and tube are verified. The definite relationship between the velocity and size of the reflector in the internal fluid. It also indirectly validates the correctness of the detection model proposed in this paper. The mud simulation experiment platform can achieve the accurate control of the gas flow and the pressure. In the mud experiment platform, the flow velocity testing, the air gap experiment, and the methane gas invasion are designed. The experimental results show that the flow velocity detection method proposed in this paper can accurately detect the flow velocity of the mud, and the maximum relative error between the measurement results and the target flowmeter is 10%, and the gap rate experiment results show that the proposed method can effectively detect the gap. In the dissolution and precipitation experiment, the flow rate of natural gas in the circulating pipeline is first, but the process of gas compression and expansion is simulated by the accurate pressure and pressure control, and the process of gas compression and expansion is simulated. The signal is detected by the simulation process. The validity of the method of gas intrusion detection proposed in this paper is verified by the amplitude and flow pattern changes. Finally, some special phenomena in the process of the project are expounded and explained, and the future research directions and solutions are put forward for the problems and shortcomings in the experiment process.

【学位授予单位】：电子科技大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TE52;TB559

【参考文献】