Backpropagation neural network method in data processing of ultrasonic imaging logging-while-drilling

The existing methods for extracting the arrival time and amplitude of ultrasonic echo cannot eff ectively avoid the local interference of ultrasonic signals while drilling,which leads to poor accuracy of the echo arrival time and amplitude extracted by an ultrasonic imaging logging-while-drilling tool.In this study,a demodulation algorithm is used to preprocess the ultrasonic simulation signals while drilling,and we design a backpropagation neural network model to fit the relationship between the waveform data and time and amplitude.An ultrasonic imaging logging model is established,and the finite element simulation software is used for forward modeling.The response under diff erent measurement conditions is simulated by changing the model parameters,which are used as the input layer of the neural network model;The ultrasonic echo signal is considered as a low-frequency signal modulated by a high-frequency carrier signal,and a low-pass fi lter is designed to remove the high-frequency signal and obtain the low-frequency envelope signal.Then the amplitude of the envelope signal and its corresponding time are extracted as an output layer of the neural network model.By comparing the application eff ects of the various training methods,we fi nd that the conjugate gradient descent method is the most suitable method for solving the neural network model.The performance of the neural network model is tested using 11 groups of simulation test data,which verify the eff ectiveness of the model and lay the foundation for further practical application.

Self-adaptive inversion method of electromagnetic-propagation resistivity logging while drilling data

Because of the constraint mode of the inversion objective function in the traditional resistivity-inversion method of electromagnetic-propagation resistivity logging while drilling(EPR-LWD),obvious differences appear in the radial and vertical investigation characteristics between the amplitude-ratio and phase difference,which affect the practical application of EPR-LWD data.In this paper,according to the EPR-LWD data,a self-adaptive constraint resistivity-inversion method,which adopts a self-adaptive constraint weighted expression in the objective function to balance the contributions of the phase difference and amplitude attenuation,is proposed.A particle swarm optimization algorithm is also introduced to eliminate the dependence of the accuracy and convergence on the initial value of the inversion.According to the inversion results of multiple classical formation models for EPR-LWD,the differences between the adaptive constraint inversion-resistivity logs with the traditional amplitude-ratio and the phase difference of the resistivity logs are discussed in detail.The results demonstrate that the adaptive resistivity logs take into account the advantages of the amplitude-ratio logs in the radial investigation and phase difference logs in the vertical resolution.Further,it is superior in thin-layer identification and invasion-effect appraisal compared with the single-amplitude-ratio and phase difference logs.The inversion results can provide a theoretical reference for research on the resistivity-inversion method of electromagnetic wave LWD.

钻井液油气半透膜分离技术试验与分析

现有气测录井技术所使用的烃类气体来源主要是使用电动脱气器分离钻井液中的烃类组分,将其混入空气送入气相色谱检测,主要得到的是C1—C5气态烃组分。这种方式一方面受钻井液的影响,另一方面由于空气含量的不确定性,只能定性地评价油气显示。半透膜对烃类组分具有一定的分离选择性,可以直接插入钻井液进行油气分离,能得到气态和常温呈液态的烃类组分,相对于电动脱气器具有受影响因素少,能定量评价油气含量的优点。因此,在气测录井技术中,为了提供定量烃类气体来源,通过对半透膜气体分离技术的研究,研制了适合要求的半透膜以及基于半透膜的油气分离装置。对这种分离装置的响应时间、分离效率、衰减检测、C1—C8(包括苯、甲苯)组分响应等性能的试验结果证明,其适用于钻井现场的油气检测,扩展了油气检测内容,丰富了油气评价信息。

控压钻井地质适应性评价技术

控压钻井(MPD)技术是解决具有窄安全密度窗口、易漏易喷地层安全钻井的一项关键技术。控压钻井的适应性评价技术是控压钻井科学选井选层、安全实施的关键。目前国内外还没有成熟的控压钻井适应性评价体系。首先对控压钻井应用类别分类和国际钻井承包商协会(IADC)分类进行了对比,选用IADC颁布的5种流体类型、6个风险等级、3种应用形式的分类方法。然后从地质、工程和经济角度建立了控压钻井地质适应性评价方法,即"三步法"评价体系,主要包括必要性评价、可行性评价、技术经济性评价,在此基础上提出了控压钻井地质适应性评价的关键技术,即地质环境因素描述、精细水力学计算、设备配套与优选、压力控制方法、经济性评价。最后在缅甸D区块进行了应用,结果表明所建立的分类方法和地质适应性评价技术具有很强的实用性。

缅甸D区块非渗透性防塌钻井液研究

针对缅甸D区块钻井过程中存在的井壁失稳问题,系统分析了缅甸D区块易塌井段泥页岩黏土矿物组分、岩石微观结构、泥页岩水化性能,结合现场实际对前期钻井液存在的问题进行分析,优化出适宜缅甸D区块特点的非渗透性防塌钻井液配方。室内性能评价表明,该非渗透性防塌钻井液具有较强的抗污染能力、抗温能力,泥页岩抑制能力以及封堵能力。在现场应用4口井过程中,该钻井液取得了较好的井眼稳定效果,可有效解决缅甸D区块井眼坍塌和井径扩大率的问题,显著降低了井下复杂事故的发生。

沙特高温高压低渗凝析气井全过程欠平衡设计与应用

沙特B区块属于高温高压低渗凝析气田,储层为致密砂岩地层,在前期的勘探作业中,钻井中显示良好而测试时产量不高,室内实验表明油锁和水锁是引起储层伤害的主要原因。本文采用一种新型全过程欠平衡设计方法,在设计时充分考虑了井控安全、油锁、水锁、井壁稳定对井底负压值的影响、在水力参数计算过程中高温高压对钻井液密度和黏度的影响;在施工过程中考虑了在钻进、接立柱、取心、起下钻等整个作业过程中保持井底负压所需要的设备和工艺。通过现场M-0001井试验表明,该方法能有效释放油气井产能,避免储层伤害,测试后显示该井表皮系数为-3.44,钻井过程中储层没有污染。