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In drilling engineering, the cost of drilling tool fracture is enormous, and studying the fatigue failure process of drilling tools has practical significance. This paper uses metal magnetic memory detection technology to design and conduct fatigue damage tests on typical drilling tool material 42CrMo specimens under tensile, torsional, compressive, tensile, compressive, and torsional dynamic loading conditions. By analyzing the changes in the tangential component Hp(x) and gradient value K of the magnetic memory signal under different load conditions with the number of loading times, the process of fatigue failure of the specimens and the trend of changes in the magnetic memory signal in local stress concentration areas are explored. The characteristic parameters of fatigue damage based on magnetic memory detection were extracted and the critical point at which fatigue damage leads to crack initiation was inferred. This confirms that metal magnetic memory testing technology is an effective means of analyzing the fatigue damage process of drilling tools and provides a certain reference for formulating judgment standards for drilling tool maintenance on site.

An online machine learning system based on X-ray nondestructive quality evaluation technique was developed to detect internal defects of boat-fruited sterculia seed. The X-ray images of boat-fruited sterculia seed were first acquired by the detection system. Then, a boat-fruited sterculia seed net (BSSNet) was trained to identify the defective boat-fruited sterculia seeds based on the X-ray images. The BSSNet was evaluated with the accuracy, precision, specificity, and sensitivity as 94.64%, 93.51%, 92.37%, and 96.64%, respectively. Further, three classical CNN models including VGG16, Resnet, and Inception were trained on the same dataset with accuracy of 95.71%, 94.29%, and 94.64%, respectively. Compared with the classical CNN models, the BSSNet achieved similar or higher accuracy in X-ray images classification. Finally, an independent dataset containing 200 X-ray images was used to validate the performance of the BSSNet and obtained an accuracy of 96.5%. The results presented above demonstrated that this classification method has a great potential for industrial applications. PRACTICAL APPLICATION: An X-ray online detection system integrated with a machine vision model was used to evaluate the quality of boat-fruited sterculia seed. A low-power x-ray detection system can detect internal defects of the object and ensure safety in the production process. The developed machine vision can sort the boat-fruited sterculia seed with an accuracy of 96.5%. The proposed nondestructive detection system showed a good potential to be used in industrial applications.

Rotating plane flow distributing pairs have been widely used in engineering. It is very important to reduce the frictional resistance between the pairs to improve the sensitivity and prolong service life. In this paper, the traditional rotating plane flow pair is improved, and the boss is introduced to keep the rotor and the stator in incomplete contact, and then a gap is formed between the flow pairs. The relationship between the pressure distribution and the friction resistance of the flow pairs is established. The theoretical mathematical model of the fluid movement between the gaps of the structure is built. Given the complexity of model analysis, the numerical analysis method is used to analyze the fluid motion in the structure. The height of the boss is proved to be the most important parameter of the structure, the increase of the boss’s height causes the pressure between the flow pairs to increase, and the pressure difference between regions gradually decreases, so the friction between the flow pairs will gradually decrease until reaching a stable value. The change of the boss’s diameter has little influence on the pressure distribution of the clearance, but as the diameter increases, the friction between the flow pairs will increase linearly. Once the opening width of the waist hole on the upper rotor is smaller than the radius of the discharge hole on the lower stator, the smaller the width, the higher the pressure, but when the opening width is larger than the radius of the discharge holes, the change of the width has no obvious influence on the pressure distribution and the friction.

Annular drilling fluid between the drillstring and borehole wall has a great influence on lateral vibration of drillstring and the influence involves the added mass. Assuming the drilling fluid is incompressible, we derive the added mass coefficient that annular drilling fluid influences on lateral vibration of drillstring in the case of axial flow of drilling fluid. When the axial flow of drilling fluid is considered, the added mass coefficient is difficult to solve. We apply CFD method and dynamic mesh technique to establish the calculation model for the flow in the annulus caused by the vibration of drillstring in the annulus. The pressure distribution and velocity distribution of annular drilling fluid are obtained. The added mass force of the drilling fluid acting on the drillstring along the direction of the drillstring is obtained from the pressure distribution, and the added mass coefficient of the lateral vibration of the drillstring is obtained. This paper provides the basis to solve the added mass coefficient of the lateral vibration of drillstring considering axial flow of drilling fluid.

Drillstring vibration is an important cause of precocious failure of drilling, and torsional vibration is a particular important phenomenon. Stick/slip is a severe type of torsional drillstring oscillation that affects the efficiency of the drilling process and can cause bit damage as well as drillstring failure. In an automatic vertical drilling system (VDS), frictional force between the pads and borehole wall will reduce the drill bit instantaneous rotational speed. The pads of the implementing agencies in VDS constantly pushed against the borehole wall, making bottom hole by a cycle of nonlinear damping force, which lead to chaotic and disorder motion to the bottom drilling tool. Here, the stick–slip vibration is modeled to understand the large amplitude torsional oscillation of the drillstring. Based on the model, the causes for torsional vibrations in VDS and torsional vibrations with and without stick–slip will be evaluated. We show that pushing the borehole wall will cause the drill bit torsional vibration more serious. The results contribute to the better understanding of the dynamics of the push-the-bit VDS. The results obtained can also be applied to the same type of rotary steerable system.

For the increasing well plugging in oilfield development, a new unplugging technology is presented in this paper for the downhole plugging by using high voltage pulse wave. Based on the mechanism analysis, the circuit resistance model and the empirical calculation formula of the pressure shock wave are obtained, and the influence of the same current waveform on the pressure shock wave generated by the wire explosion is preliminarily studied in laboratory experiments under different energy conditions. A corresponding unplugging evaluation test device was designed to simulate the approximate downhole reservoir conditions in the places where the shock wave occurs to test the approximate downhole stress conditions of the core, and to test the permeability changes after different shock waves acted on the core. The results show that the peak value of the pressure shock wave is proportional to the effect of well unplugging, which verifies the feasibility of the unplugging and increasing permeability technology of the electric explosion-controlled shock wave. This technology can quickly dredge the oil seepage channel, increase well permeability, thus increasing the well productivity, which has a broad application prospect and important practical significance.

In this paper we analysis of the dynamic model of the Rotary Steerable System (RSS) with a single stabilizer and flex-sub. The drill collar and joint are simplified to obtain suitable bottom-hole assembly (BHA) model of mechanical analysis and finite element analysis. Using the BHA uniform stiffness assumption (ignoring the influence of variable section and variable stiffness of drill collar in BHA), the paper takes a method of the longitudinal and transverse bending continuous beam method to analyse the stress of BHA with RSS with the flex-sub under different inclination angles and curvature conditions. In addition, a dynamic analysis model is proposed, and the dynamic stress of drilling tools with RSS is analysed. Through the software of ANSYS, the finite element analysis of the RSS with the flex-sub is carried out to verify the theoretical results. The influence of flex-sub on the steering drilling performance of RSS is studied, and the optimized parameters of flex-sub design are obtained, which provides useful suggestions for the design of RSS.

Seismic While Drilling (SWD) is a well seismic method developed in recent years which is based on reverse vertical seismic logging. It is a newly-developed well seismic technology which combines the seismic exploration technology with petroleum drilling engineering technology. Compared to conventional VSP, SWD has its own characteristics and unique advantages in that it uses bit vibration in the process of drilling as the source for seismic measurement, without interfering with the drilling or occupying drilling time, and without any risk to the hole, especially the bit can be predicted in real-time structure details of the formation in front of the bit through the field seismic imaging processing, with the main purpose of reducing drilling risks. The key of this technology is how to collect and recover the weak bit reflection signal under strong disturbance noise and make it the equivalent formation impulse response.

The random noise of the sensor is the main cause of the error in navigation accuracy. In addition, strong downhole vibration will generate greater random noise of fiber-optic gyroscope and accelerometer during MWD operation. The random noise in vibration features concerning time series mutation, slowness and periodicity in its varying. The results show a wide internal noise band and the changing of the noise over time. Considering all these features, this section explores with the dynamic Allan variance method the dynamic characteristics of the random noise produced by fiber-optic gyroscope and accelerometer in vibration, to offer theoretical guidance for improving the environmental adaptability of sensors in vibration and offer theoretical support for noise modeling.

The big data is often called the petroleum in the information era, but the connection between petroleum and big data is not limited to it. The big data technology and petroleum and natural gas industry are closely related. In the economic environmental background where the global energy market is gloomy, the petroleum and natural gas companies increasingly obviously pay close attention to the big data. Not merely the big data technology will generate influences on the oil & gas industry. The progresses obtained in computing technology, Internet of Things, cloud computing, mobile communication technology, robot technology and artificial intelligence bring new innovations for the oil & gas industry. Integrating the traditional production mode in the oil & gas industry with the rapidly developing Internet industry will definitely make the oil & gas industry glow the new vitality.

We introduced five types of information transmission method for Measurement While Drilling (MWD): cable method, drilling fluid pulse method, acoustic method and electromagnetic wave method and the latest technology of intelligent drill pipe at present. With the application of advanced drilling technologies such as rotary steering drilling and geosteering drilling, the real-time measurement and transmission of a large number of downhole parameters put forward higher requirements on the information transmission rate. Lower transmission rate has become the bottleneck of parameter expansion for measurement. Intelligent drill pipe (Intelli Pipe) is now the latest downhole signal transmission technology with the highest transmission rate. The communication rate can reach up to 2Mbps, and the stable communication rate can reach 56 kbps, which is too much higher than the current electromagnetic wave or mud pulse transmission applied in MWD, but high manufacturing costs are the main factors that constrain its development.

Logging while drilling (LWD) technology can be roughly divided into three generations. Correlation with construction and formation evaluation; logging while drilling ensures that the logging data required to determine capacity and economy and reduce drilling risks can be collected. The target location is found in conjunction with wellbore imaging, formation dip and density data. These advances have led to high success rates for drilling of many types of wells, especially high-angle, super-long and horizontal wells. So far, serialized and complete sets of logging while drilling equipment have been developed, including electric logging while drilling, sonic logging while drilling, nuclear logging while drilling, formation pressure logging while drilling, NMR logging while drilling and seismic logging while drilling, etc.

Digitalization will reshape the oil industry has become the industry consensus, data have become a torrent flowing into every area of the global economy. This book is mainly for data processing and mining in drilling engineering, and is committed to build a bridge between drilling engineers and signal processing scientists. The technical development of drilling engineering focuses on commercial operations, so the final presentation of any kind of data processing theory is software and some kind of instrument, Many oil companies only give the results of the test, more is used for advertising, however, we need to get to the bottom of its theoretical basis.

We shown that drilling dynamics is a crucial problem must be attached great importance to. Our innovation lies in combining actual measurement with theoretical modeling. Two evaluation methods are compared systematically, such as theoretical and measurement methods. In this chapter, our investigations concern the dynamics of drilling, unveiling a chaotic regime and suggesting practical ways of improving current drilling techniques. The reveal of chaos provides a new way to detect early fatigue cracks as weak signals in a noisy environment to reduce engineering cost and the possibility of disaster. Data from all nine fields in China are used in our studies. Proposes a theoretical model for drilling dynamics, and a real drilling system is developed to validate the theoretical dynamical behaviour. The existence of chaos in drilling may open a new concept of drilling chaos in the solid flow mechanics that will benefit to both the physicists and the drilling engineers.

Drillstring vibrations are an important cause of premature failure of drillstring components and drilling inefficiency, in particular, torsional vibration is more important. A large amount of research on torsional drillstring vibrations has been conducted in the last few decades. Stick/slip is a severe type of torsional drillstring oscillation that affects the efficiency of the drilling process and can cause bit damage as well as drillstring failure. For rotary steerable system (RSS), the stick-slip vibration is introduced as a new mechanism to explain the large amplitude torsional oscillation of the drillstring. we aim for an improved understanding of the causes for torsional vibrations in RSS and torsional vibrations with and without stick-slip are observed. We show that the RSS implementing agencies pushing the borehole wall caused the drill bit torsional vibration more serious. The results contribute to the better understanding of the dynamics of the push-the-bit RSS. Chaotic vibration is mainly caused by elasticity of the drillstring and changing frictional forces at the bottom tool, static frictional forces are higher than the kinetic frictional forces which make the bit act in a manner where it sticks and then slips, and presents complex dynamic behavior, which makes down-hole dynamic responses difficult to predict. In the Rotary Steerable System (RSS), frictional force between the pads and borehole wall will make the drill bit instantaneous rotational speed reduces. The pads of the implementing agencies in RSS constantly pushed against the borehole wall, making bottom hole by a cycle of nonlinear damping force, which is lead to the bottom drilling tool movement of chaos and disorder.

Rotary-steerable drilling provides unique features such as an extended reach and accurate well trajectory control. These characteristics can notably increase drilling efficiency and safety. One of the main technical difficulties of rotary-steerable drilling is dynamically measuring the spatial attitude at the bottom of the rotating drillstring as the drillstring rotates. We developed a strap-down measurement system, with a triaxial accelerometer and triaxial magnetometers installed near the bit. The inclination and azimuth can be measured in real time even as the drillstring rotates. Although the magnetic system is the norm, we can use this system to achieve continuous measurement while drilling; to achieve this, a novel state-space model is proposed here and the Kalman filter is used to estimate the states. Simulation and experiments show that a continuous-survey system with a Kalman filter approach can improve measurement precision and reduce errors produced by drillstring vibration.

As a kind of superhard material, the polycrystalline diamond compact (PDC) has been extensively used in engineering with its high strength and high wear resistance. Meanwhile, PDC has been increasingly used in bearing design to improve bearing capacity and service life. However, as a bearing material, its friction coefficient under different working conditions is not clear although it is a very important parameter. In this paper, the authors proposed a theoretical model of friction measurement and design a set of measurement rig to investigate the friction characteristics of the PDC bearing. The measurement equipment is developed based on the Coulomb friction model, with the three measurement environments taken into consideration: dry, water and drilling mud. A pair of thrust ball bearing was used in the measurement equipment to equilibrium axial load. But the friction coefficient of thrust ball bearing is proved far less than that of the PDC bearing in the experiment. The frictional coefficient of PDC bearings can be stabilized at about 0.12 under dry friction or water lubrication conditions and increase to 0.2 when tested under drilling fluid environment. Measuring the friction coefficient of PDC bearing -especially under drilling fluid environment can not only provide support for the design of the downhole tool where the bearing friction coefficient obviously affects the feasibility and agility of the tool but also help people to deepen the understanding of PDC materials.

Automatic vertical drilling tools are the key technologies to achieve vertical drilling in deep & super-deep wells, and are also the core for deviation control and well straightening. Based on a self-development automatic vertical drilling tool with electronic closed loop control system (EVDT) designed by the research team, straightening behavior is analyzed in this paper. The mechanical analysis model of the BHA (bottom hole assembly) equipped with the EVDT is developed by using the beam-column theory. The formulas are deduced for calculating the bit lateral forces, bit tilt angle and trend angle of deviation. The influence laws of the push-out force, WOB (weight on bit), deviation angle and wellbore curvature on the straightening behavior of drilling tools are discussed. The results show that when the counterforce of the push-out force is pointing to the low side of borehole wall, the bit lateral force is inclination-drop force and the drilling tendency is straightening. The absolute values of bit lateral force and trend angle of deviation decrease with the increase of WOB but increase with the increase of push-out force, deviation angle and wellbore curvature. The push-out force and wellbore curvature have great influence on both bit lateral force and trend angle of deviation. WOB has major influence on trend angle of deviation, but minor influence on bit lateral force. The deviation angle has little influence on both bit lateral force and trend angle of deviation. This provides basis for predicting and controlling wellbore trajectory.

In the study of drilling dynamics, many investigations are limited to laboratory systems and simple mathematical models. Using field measurement data and a new dynamical model in a rotary steerable drilling system, we demonstrate the existence of low-dimensional chaos in drilling. The behaviors of the mathematical model and actual measurement are shown to be consistent. The revealing of chaos provides a new way to detect early fatigue cracks as weak signals in a noisy environment to reduce engineering cost and the possibility of disaster.

Ordinary drillstring torsional vibration is a very common phenomenon that has been attracted great interesting. Through Measurement data, a series of studies and analysis of torsional vibration characteristics of the bottom hole assembly (BHA) have been developed. However, for rotary steerable system (RSS), especially push-the-bit mode, its drill torsional vibration phenomenon will demonstrate the new properties, because that the underground implementing agencies will generate cycle torque and drag to the BHA in the orientation process. This process is completely different to the previous. A set of “strap-down” measurement system was developed in this paper, and the triaxial accelerometer and triaxial fluxgate were installed near the bit. Proposed a method of solver drill bit rotation speed using real-time downhole measurement data (sampling frequency 100 Hz), and the torsional vibration mathematical model of push-the-bit RSS was established. We found that the torsional vibration phenomenon of push-the-bit RSS is more serious than the ordinary drilling system by downhole measurement data analysis, even in most cases manifested as stick-slip. The torsional vibration was divided into five different modes, which showing different statistical regularities. Corresponding analysis of the angular displacement and speed, we found that the drill bit always appears low-speed in the position of oriented. This is a strong proof of that the RSS implementing agencies pushing the BHA caused the drill bit torsional vibration more serious. This work is supplemented and development of the drill string torsional vibration studies. Contribute to the better understanding of the dynamics of the push-the-bit RSS. Put forward a new way of analysis the rotary steerable drillstring fatigue damage predicted, steering ability and the torsional vibration control.

In present, the drilling industry have to face the reality of low oil and gas prices, fully mechanical vertical drilling tool is likely to become the best choice for vertical drilling in the future. Without electric measurement and control system, the mechanical vertical drilling tool has a mechanically stable platform with gravity sensitivity. The stable platform included an eccentric block which is not only sensitive to gravity but also severely affected by torsional vibration. In this article, we reveal the dynamics of eccentric block under the effect of torsional vibration, which is the key element of the well deviation control accuracy in mechanical vertical drilling tool. The dynamic model of eccentric block is established using Lagrangian equation and Coulomb friction, and the law of dynamic characteristics under the effect of different amplitudes and period of torsional vibration is found. The results show that, with the deviation angle and eccentric torsion moment of eccentric block is increased, the resistance to torsional vibration increases. While the frequency of torsional vibration decreases, a subordinate period gradually appears after the rotation speed value of ω is less than 1 rad/s, the torsional vibration with large amplitude and high frequency is detrimental to the stability of the eccentric block. In addition, the largest Lyapunov exponent is estimated using the time series of simulation, the dynamics of eccentric block under the effect of torsional vibration can be switched four types, and the maximum and minimum values of largest Lyapunov exponent are 3.99 × 10 −2 and −2.98 × 10 −2 , which means with the state of torsional vibration changes and the response of eccentric block would be transformed to chaos.

In the oil and gas drilling engineering, measurement-while-drilling (MWD) system is usually used to provide real-time monitoring of the position and orientation of the bottom hole. Particularly in the rotary steerable drilling technology and application, it is a challenge to measure the spatial attitude of the bottom drillstring accurately in real time while the drillstring is rotating. A set of “strap-down” measurement system was developed in this paper. The triaxial accelerometer and triaxial fluxgate were installed near the bit, and real-time inclination and azimuth can be measured while the drillstring is rotating. Furthermore, the mathematical model of the continuous measurement was established during drilling. The real-time signals of the accelerometer and the fluxgate sensors are processed and analyzed in a time window, and the movement patterns of the drilling bit will be observed, such as stationary, uniform rotation, and stick–slip. Different signal processing methods will be used for different movement patterns. Additionally, a scientific approach was put forward to improve the solver accuracy benefit from the use of stick–slip vibration phenomenon. We also developed the Kalman filter (KF) to improve the solver accuracy. The actual measurement data through drilling process verify that the algorithm proposed in this paper is reliable and effective and the dynamic measurement errors of inclination and azimuth are effectively reduced.

In the oil drilling process, measurement-while-drilling (MWD) system is usually used to provide real-time monitoring of the position and orientation of the bottom hole. Particularly, in rotary steerable drilling technology and application, how to accurately measure the spatial attitude (inclination, azimuth, tool face) of the bottom drilling tool in real time while the drill string rotating is a challenging problem. Current MWD surveying is performed along the well path at stationary survey stations, because of that the bottom drilling tool shows complex characteristics while rotating due to combined effect of their randomly nonlinear moving state, such as vertical vibration, horizontal vibration, and stick-slip. The effects of complex characteristics cause sensors to generate a great dynamic error which will accumulate gradually during attitude resolving, so ultimately measuring spatial attitude deviates seriously from the true value. This is a huge challenge for signal processing. In this paper, a set of "strap-down" measurement system was developed, the triaxial accelerometer and triaxial fluxgate were installed near the bit, and real-time well deviation and azimuth can been measured even when the drill string was rotating. However, according to the drilling field tests, playback analysis on storage data of the underground measurement indicates that drill string vibration is the main reason for measurement errors. So this paper proposed dynamic solution approach to the bottom of the rotating drill string attitude. By setting a time window, the real-time measurement of the accelerometer and the flux gate signal are processed and analyzed, the movement patterns of the rotary drilling tool at the bottom were judged within the time window.utilizing stick-slip vibration to improve measurement accuracy, reducing the impact of vibration on the measurement results at the same time. Although the stick-slip vibration should be avoided point of view the life of the drill string, we can still take advantage of it because of it cannot be avoided entirely. A continuous measurement while drilling system was developed and a large number of field test data were also analyzed. Simulation results in Matlab showed that recommended dynamic survey approach could effectively enhance measurement precision, and deduce effect of vibration on resolve results.