Rotary Steerable System Research Articles

Analysis of Torsional Stick-Slip Situations from Recorded Downhole Rotational Speed Measurements

Summary The use of recorded downhole rotational speed measurements with a bandwidth up to 9 Hz gives new insights into the conditions under which stick-slip torsional oscillations occur. Observations made while drilling two reservoir sections have shown that, out of all the stick-slip situations identified, 72% of them for one well and 64% for the other well occurred in off-bottom conditions. In these off-bottom conditions, stick-slip was systematically observed while starting the topdrive (TD) until a sufficiently high TD rotational velocity was requested. For these two sections, off-bottom stick-slip was either related to using TD speeds below 120 rev/min or to reaming down during reciprocation procedures. In on-bottom conditions, stick-slip events occurred predominantly when the TD speed was less than 120 rev/min (53 and 32% of the on-bottom cases) but also in association with downlinking to the rotary steerable system (RSS) (23 and 46% of the on-bottom cases), and this, even though the TD speed was larger than 120 rev/min. These on-bottom stick-slip situations did not necessarily occur at a very high weight on bit (WOB) because 98% of them for one well and 46% for the other well took place when the WOB was lower than 10 ton. Downhole measurements have shown that when the drillstring is subject to strong stick-slip conditions, the downhole rotational speed changes from stationary to more than 300 rev/min in just a fraction of a second. Direct observations of downhole rotational speed at high frequency help in discovering conditions that were not suspected to lead to large torsional oscillations. This new information can be used to improve drilling operational procedures and models of the drilling process, therefore enabling increased drilling efficiency.

Analysis of the Negative Impact of Hydraulic Fracturing Technology on the Environment

The development of the oil and gas industry around the world is connected with the development of unconventional fields, such as shale oil, using modern technologies, for example, rotary steerable systems, which allow more accurate and high-quality work on well construction, as well as multi-stage hydraulic fracturing, allowing more efficient extracting of hydrocarbons from the deposits. However, like any mining of minerals, the extraction of hydrocarbon raw materials has a harmful effect on the ecology of the area in which the extraction takes place. This occurs due to the use of a large number of chemical compounds, a small proportion of processing of rocks obtained during drilling, cleaning up territories to create infrastructure for organizing the extraction work of raw materials. The introduction of new fields into development leads to the increase in the level of industrial pollution of the environment. The impact of hydraulic fracturing technology on the environmental situation in the field is considered in the article. The author analyzes the impact of this method of increasing oil development on the environment, the experience of using this technology abroad, as well as government regulation of the use of this technology by producing companies around the world.

Domestic rotary steerable systems development potential for drilling horizontal wells

A complex of special equipment is required for the construction of high-tech wells. The basis of modern time efficient, precise and safe drilling is rotary steerable systems (RSS). For the past five years, rotary steerable systems have been using in Russia as a technical and technological solution to reduce accidents and to improve the quality of well construction with large vertical deviations of the extended drilling radius. These systems allow drilling to be oriented along the entire length of the well. Rotary steerable systems allows drilling both perfectly vertical wells with a deviation angle of not more than 0,2°, and horizontal wells more than 2 000 metres long. Implementation of rotary steerable systems allows building wells with extremely extended reach and conducting wells in 1–2 metres thick reservoirs with precision. In 2016, OktoGeo LLC carried out pilot well program with APS Technology's 172 mm RSS (with power section) at an oil field in the territory of KhantyMansiysk Autonomous Okrug — Ugra. All the rotary steerable system positioning programs were completed based on the results of that work and results of drilling 2 205 metres long directional well.

Investigation into phantom downlinks and development of a prevention algorithm in rotary steerable system

This paper investigated the failure cause of phantom downlinks of a flow rate detection mechanism in a rotary steerable system and developed a prevention algorithm. Downlinking is the process of controlling a drilling tool from the surface by sending commands to downhole. Directional drillers send downlinks to the rotary steerable system to adjust steering parameters to achieve the desired well plan. The downlink demodulation of downhole tools is achieved through the measurement of flow rate and correlation of waveform with predefined command models; downlink acceptance is based on the correlation rate. One case study revealed that phantom downlinks were due to the variation of turbine rotation speed, which was the result of alternator load changes. A prevention algorithm of conducting a signal energy check was proposed and implemented. The algorithm can successfully prevent phantom downlinks that are usually of low-level energy and only accept authentic downlinks. The work improved the downlinking reliability of the rotary steerable system. This methodology can be further applied to other downlink demodulation mechanisms using collar speed or pressure measurement.

Error reduction of tracking planned trajectory in a thin oil layer drilling using smart rotary steerable system

Directional drilling which is a controlled drilling process, has been efficiently utilized to reach oil/gas reservoirs. Shale oil/gas development and also the need for extraction from wells that are hardly accessible, have recently introduced the directional drilling process as an interesting method in the oil/gas industry. However, error reduction during tracking the planned path is a challenging issue, especially in the cases of drilling thin oil/gas layers, as they may result in significant errors. In these conditions, it is inevitable to use smart systems (e.g. RSS) for directional drilling. Hence, it is essential to develop intelligent and automated systems for directional drilling. This study aims to introduce an operational control approach for intelligentization of the push-the-bit RSS system that can improve the tracking performance of directional drilling. To describe the borehole evolution, we utilized the Perneder-Detournay's model which has been derived via combining the BHA modeling, rock/bit interaction law and kinematic relationships between them. Considering the existence of delay and uncertainty in this model, the controllers were designed in two cases (system with and without reference inputs) to prove the stability of the system. Afterward, a relatively complicated path including horizontal and sinusoidal section in a thin reservoir layer is designed and then the suggested controller is applied to this trajectory. According to the simulation outcomes, the system was well able to follow the planned trajectory with a too small error and operational RSS force.

Analysis of Distortion Mechanisms Used in Rotary Steerable Systems

Abstract Drilling with a rotary steerable system, the mechanical drilling speed increases by two times compared to drilling with a screw bottom-hole motor, which provides significant savings drilling-time. The effective length of the horizontal elbow increases, which enables to increase the production rate more than twice. It is found that in comparison with the bottom hole motor, rotary steerable system provides drilling smoother barrel, which reduces the risk of accidents to come out. The dependence between the type of the bent housing and the most rational fields of its application is revealed, recommendations on the choice of the rotary steerable system for various issues of directional drilling are developed.

Applying modern technologies when drilling directional wells with long horizontal boreholes

Introduction. Directional drilling of wells is currently carried out by a rotary steerable system and conventional equipment including a mud motor with an adjustable skew angle. Either of the two methods has particular advantages. Research aim is to analyze the technologies provided by various service companies in the field of directional and horizontal wells drilling in order to provide means of improving the utilization capacity of the conventional bottom hole assembly in long horizontal boreholes. Methodology. When drilling directional wells with a small departure from the vertical and wells with horizontal boreholes up to 500 m long, a preference is given to a mud motor as far as a change in deviation parameters is concerned. This is due to the fact that the mud motor has a significant economic advantage. However, when drilling directional well with complex planned profile or a well with a horizontal borehole of more than 500 m, the mud motor may cause a variety of problems, while a rotary steerable system will allow to avoid some of them. Results. The rotary steerable system is not always economically feasible suggesting a need for an alternative technology with a more advantageous offer on the market of services. A system of pulsed controlled drilling will allow the adjustment of the trajectory of the wellbore when drilling in a rotary mode with conventional equipment for directional drilling, reduce rig time, and improve the borehole quality. Summary. The given technology will make it possible to improve the efficiency of conventional equipment which includes the mud motor for directional wells drilling with complex planned profile and long horizontal boreholes of more than 500 m, as soon as the technology provides the possibility of adjusting the trajectory in a rotary mode. The system of pulsed controlled drilling is developed as an alternative to the rotary steerable system making it possible to significantly reduce construction expenses for wells with complex geological conditions of drilling

Review of the Development of Rotary Steerable Systems

The rotary steerable system is essential for the development of unconventional oil and gas in China, and remains the core of the current oil drilling technology development. This paper outlines the research and development history, classification, development status of the rotary steerable system, and summarizes the advantages and disadvantages of different systems. Moreover, the prospects of the intelligent RSS technology is explored, and the outlook for the future development of the steerable drilling technology is presented.

Influence of flex-sub on mechanical properties of rotary steerable drilling system

Abstract. 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.

COMPARATIVE ANALYSIS OF PENETRATION RATES USING DOWNHOLE MOTOR AND ROTARY STEERABLE SYSTEM IN AN ONSHORE DIRECTIONAL HOLE

Directional drilling is a costly method used in drilling operations, as it requires investments in special tools such as downhole motor and rotary steerable system (RSS). This paper performs a comparative study between the penetration rates achieved when using downhole motor and RSS tools. To make the study feasible, the drilling of the 8 ¾ in diameter phase of an onshore directional hole, comprised between 197 m and 957 m, was analyzed using the equipment referenced. The average penetration rates and the costs generated by each one of them were calculated as a function of the total operating time. Considering these parameters, we found that the use of downhole motor was more advantageous than using the rotary steerable system because, despite its longer operating time, it presented much lower costs.

TECHNOLOGY OF WELL TRAJECTORY CONTROL APPLYING STEM ASSEMBLY ROTATION AND ELIMINATING ROTARY CONTROLLED SYSTEMS

The article discusses the traditional stem assembly consisting of a bit, a screw downhole motor, a telemetry system and a drilling string. This system is relatively simple, however, it has significant drawbacks which are in the non-measured zone of 15 - 20 m, and in demand of a slide mode. The slide mode has significant drawbacks: increased friction forces, which makes it difficult to transfer the load on the bit, clean the wellbore and therefore form landings during the tripping down and drill pipe drag when tripping the drill string up, and contributes to the formation of oil seals. The stem assembly consisting of: a bit, a rotary steerable system, a telemetry system and then a drilling string with a top drive has a significant advantage over the above: it illuminates the non-measured zone, which increases the accuracy of hole making, the curvature of the well is controlled with constant rotation of the drill string, which helps to improve the cuttings lifting, reducing the coefficient of friction, improving the transfer of load on the bit. The complications when wells drilling can be minimized as well. However, the stem assembly with a rotary steerable system has a high cost of operation, up to half the cost of well construction. Based on the analysis of the assemblies, a fundamentally new drill string assembly is proposed, which includes an above-bit module that excludes non-measured zone, a screw downhole motor, a telemetry system, and a top drive. The rotation of the drill string is carried out «left-right» due to the spring turned by the drill string during operation of the top drive. By adjusting the magnitude of the torque, it is possible to achieve a state where the torque decays before reaching the telemetry system and the screw downhole motor. As a result, when the drill string is rotated, the screw downhole motor can control the zenith and azimuth angles in the slide mode. Moreover, the sensors (magnetometers, accelerometers and gamma ray logging) are located in the above-bit module within the distance of 1.5 - 2.0 m from the bit.

Prediction Model of Build Rate of Push-the-Bit Rotary Steerable System

The accurate prediction of build rate of rotary steerable system (RSS) is the prerequisite for the precise control of wellbore trajectory and optimal design of the steerable tool. Push-the-bit RSS refers to a steerable drilling system that controls well trajectory through adjustment of stretch length of pushing block. Based on this feature, a three-dimensional mechanical model of push-the-bit RSS is established on the basis of the conventional steerable tool mechanical model while considering pushing force. Meanwhile, the effects of bit cutting performance and formation anisotropy are considered. Next, the lateral force method, inclination trend angle method, and ultimate build rate method based on zero lateral force are analyzed and a new ultimate build rate method based on zero lateral drilling penetration is built. A conversion coefficient is introduced to reflect the ratio of actual build rate to theoretical build rate. At last, the new model is applied to a case study. The new method is superior to other previous methods, because the effects of bit-rock interaction and actual drilling process are sufficiently considered. The influence mechanism of build rate includes “leverage effect,” “pendulum effect,” and “pushing effect.” The build rate of steerable tool is a comprehensive outcome of various effects, of which the “pushing effect” plays a dominant role. With the increase of weight on bit (WOB), the proportion of “leverage effect” increases, while the proportion of “pushing effect” decreases, and therefore the build rate decreases.

Slide-Drilling Guidance System Optimizes Directional Drilling Path

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 194096, “Slide-Drilling Guidance System for Directional-Drilling Path Optimization,” by Can Pehlivanturk and John D’Angelo, The University of Texas at Austin, and Dingzhou Cao, Anadarko, et al., prepared for the 2019 SPE/IADC International Drilling Conference and Exhibition, The Hague, 5–7 March. The paper has not been peer approved. The amount of uncertainty related to directional drilling makes accurate drilling challenging, leaving much to human know-how and interpretation. Additionally, few path-planning methods in the literature consider the directional steering tool being used. The formulation of the problem of optimization varies greatly between rotary steerable systems (RSS) and mud-motor configurations. Additional cost functions and constraints exist for mud-motor use, which significantly increases the complexity of the problem. A slide-drilling-guidance system is proposed to combat this issue and to help automate directional drilling. Introduction Despite the numerous technological advancements that made directional drilling a reality, directional drilling is still viewed more as an art than as a science. The drillstring and penetrated rock formations are complex systems whose interaction makes prediction and planning highly uncertain. Analytical, geometric approaches have sought to formulate the curvature of the well path in a way that eases the planning process and ensures smooth trajectories. The literature on directional drilling is rich in well-path-optimization methodologies based on operating constraints and well-path geometry. However, few of these methods seem to consider the tool used to generate the well path, and those that do typically use RSS because these yield better results from a technical perspective. Mud motors, however, are still used extensively because of cost effectiveness. The complete paper proposes a directional-drilling guidance system targeted at downhole motors and slide drilling to generate optimal well paths and associated slide-drilling instructions. Instead of a simplistic shortest-path approach, various cost functions aimed at maximizing the value of the well are considered. For wellbore-propagation prediction, a computationally efficient and accurate model is used. The proposed methodology is built into a software package and is being developed and implemented currently for use in the real-time drilling (RTD) system of an operator. The three main modules of the software are discussed in detail in the complete paper. The wellbore-propagation model predicts the evolution of the borehole and returns the predicted 3D path given the initial condition and a slide sheet. The fitness-evaluation module calculates the fitness of the 3D path using a cost function and returns a scalar value representing the overall value of the path. The genetic-algorithm solver generates candidate slide sheets and approaches an optimal slide sheet by iterating over generations. Software Implementation Graphical User Interface (GUI). The GUI serves as a tool to visualize the well under consideration and to study the optimization results and the effectiveness of the approach. The GUI is written in MATLAB and uses the Runtime environment. Here, the data for the planned path and the actual survey data are loaded. The planned path and the surveyed path (up to the time for which such data are available) are displayed.

Annular Ledge Formation Method Allows Sidetracking in Multilateral Wells

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 19350, “Effective Annular Ledge Formation Sidetracking in Multilateral Wells in the Vostochno-Messoyakhskoye Field,” by Andrey Voronin, Messoyakhaneftegaz, and Nikolay Abaltusov, SPE, and Anton Vershinin, Weatherford, et al., prepared for the 2019 International Petroleum Technology Conference, Beijing, 26–28 March. The paper has not been peer reviewed. Copyright 2019 International Petroleum Technology Conference. Reproduced by permission. Multilateral drilling technology offers a highly effective method of enhanced oil recovery in fields characterized by complicated geological structures. This paper describes the analysis of sidetracks drilled in an open hole by an annular ledge formation method with a downhole motor in multilateral wells. Introduction Currently, industry growth requires development of fields with complicated geology. Drilling single-bore horizontal holes for these fields is insufficient, to say nothing of drilling vertical or directional wells. Multilateral wells with multiple horizontal sidetracks are drilled with increasing frequency. The competition between downhole motors and rotary steerable systems (RSS) in multilateral-well drilling is fierce. In the complete paper, the authors describe deployment of a method previously only available with RSS that provides advantages to downhole-motor use: annular ledge formation, which involves sidetracking in an open hole. In the case study described, a conventional motor is used without additional electronics. Conventional sidetracking methods in an open hole with the use of motors involve sliding. During sidetracking, the sliding is aggravated additionally by a low rate of drillstring movement. If side-tracking with the conventional method is impossible, then usually a special sidetracking bit is installed and the motor-bend angle is increased. Such measures result in additional time and financial expenditure. The annular ledge formation method allows for sidetracking in an open hole with the use of a standard bottomhole assembly (BHA) with a motor, which also will be used for drilling a lateral. The key feature of this method lies in the fact that, during sidetracking, the drillstring is constantly rotating, which allows avoidance of the problems related to sliding. When sidetracking with the use of this method, the ledge is formed over the entire circumference of the borehole, not only on the bottom wall. But, when sidetracking deeper, a trough is formed on the low side of the hole and the upper side remains unaffected. Because of this, the annular ledge formation method is described by the authors as sidetrack with rotation. The authors discuss the deployment of this method in the Vostochno-Messoyakhskoye field when drilling multilateral fishbone wells. The complete paper presents a detailed discussion of the method and different situational approaches to its use. Vostochno-Messoyakhskoye Field The field is the northernmost developed onshore oil field in Russia in the Tazovsky region 250 km from the Arctic Circle in the Arctic climatic zone. The field is developed with horizontal production and injection wells along a horizontal section length of approximately 1000 m. The geology of the reservoirs is complicated with a large gas cap. In terms of geological conditions, the PK 1-3 pay zone is irregular within the field and is represented by loose sandstones both uniform and horizontally layered. The oil-bearing formations are isolated.

Simulation and Measurement of High-Frequency Torsional Oscillation (HFTO)/High-Frequency Axial Oscillation (HFAO) and Downhole HFTO Mitigation: Knowledge Gains Continue Using Embedded High-Frequency Drilling Dynamics Sensors

Summary High-torque, low-speed drilling mud motors are typically used to drive rotary-steerable systems (RSS) to improve the rate of penetration (ROP) of the RSS bottomhole assemblies (BHA). Downhole drilling dysfunctions are common when powered RSS BHAs are pushed to the limit for maximum drilling performance. High-frequency (HF) continuous recording compact drilling dynamics sensors were embedded into the bit, bit box of the RSS, slow-rotating housing (SRH) of the RSS, bit box of the mud motor, and top subassembly (sub) of the mud motor to better understand drilling conditions in different shale plays throughout North America. Embedded sensors placed on the outer diameter of the BHA vs. centerline-mounted sensors give a different measurement response and a different vision of the actual dynamics being experienced in the BHA. The HF sensors were deployed in the in-house developed push-the-bit RSS and mud motors, allowing us to model the motor-assist RSS BHAs with analytical models and finite-element analysis models to predict the HF torsional oscillation (TO) and axial oscillation (AO) frequencies. The derivation of the high-frequency axial oscillation (HFAO) and TO analytical equations is detailed in the paper. In one of the example motor-assist RSS BHA analyses, the simulation results reveal that the fundamental high-frequency torsional oscillation (HFTO) frequency is 11.1 Hz whereas the fundamental HFAO frequency is 32.9 Hz, which is approximately three times higher than the fundamental-mode HFTO frequency. A good correlation was observed between the simulation result and the field data gathered from the HF accelerometer and gyro sensors embedded in the RSS and mud motors. Two new types of HF axial drilling dynamics with a polycrystalline diamond compact (PDC) bit—(1) the third-order-mode HFAO and (2) the harmonics of the HFTO coupled to the longitudinal axis—were discovered and reported in detail. One example in this paper shows that the dominant HFTO frequency shifts occurred in the middle of drilling a stand with no connection involved and no surface parameter changes. The examination of the time-domain signal reveals that (1) the “baseline” HFTO-induced tangential accelerations are due to the mud motor output revolutions per minute (RPM) (2) the variation of the HFTO-induced peak tangential accelerations comes from the drillstring stick/slip, which is transmitted to the drill bit through the mud motor, and (3) the 76 and 114 Hz HFTO-induced accelerations are both approximately in a sinusoidal waveform, except in the 3-second transition period, where the mixture of both frequencies is observed. The 114 Hz-HFTO-induced tangential acceleration measured at the bit box is coupled with the 0.16 Hz drillstring stick/slip oscillation. The analytical equation is provided to describe the HFTO coupled with stick/slip as an analogy to communication theory. In addition, the extensive modeling and field measurement of the HFTO and HFAO lead to the mitigation measure of the harmful HF drilling dynamics in motor-assist RSS BHAs. The proposed HFTO mitigation mechanism is modeled, simulated, and demonstrated in the paper. The latest-generation embedded HF drilling dynamics sensors are placed on the outside diameter of the BHA, as well as along the centerline of the BHA. The different responses of the sensors due to their placement are reported and analyzed. The quality of 1000 Hz continuous-sampled gyro data are discussed, comparing against low-frequency-sampled gyro data. Additionally, this paper shows the downhole HFTO-damping mechanism and lesser known drilling dynamics, such as HFAO with a PDC bit in detail. CORRECTION NOTICE: This paper has been updated from its original version to correct the provenance statement. In addition, the equation numbering on pages 567 and 568 has been corrected from Eqs. 9, 10, and 11 to Eqs. 5, 6, and 7.

Overview of the Development of Rotary Steerable Systems

Rotary steerable system remains the development focus of current drilling technology. It is essential for China’s unconventional Oil and Gas development. This paper outlines the research and development history, classification, development status of the rotary steerable system, and summarizes the advantages and disadvantages of different systems. Moreover, the prospects of the intelligent RSS technology is explored, and the outlook for the future development of the steerable drilling technology is presented.

Real-Time Data From Wired Drillpipe Leads to Improvement in Drilling Performance

This article, written by JPT Technology Editor Judy Feder, contains highlights of paper SPE/IADC 194093, “Performance Impact of Downhole Data From Wired Drillpipe and Downhole Sensors,” by Molly Giltner, Linsay Earle, and John Willis, Occidental Petroleum, et al., prepared for the 2019 SPE/IADC International Drilling Conference and Exhibition, The Hague, 5–7 March. The paper has not been peer approved. This paper shows how high-frequency, real-time drilling data from wired drillpipe has helped optimization of drilling performance and achievement of additional improvements in the New Mexico Delaware Basin. The real-time downhole data provided increased understanding of the occurrence and mitigation of common drilling dysfunctions such as torsional vibration, whirl, axial vibration, motor microstalls, and pipe buckling. Both the data explaining downhole performance and the successful practices that resulted from the data analysis are discussed in the complete paper. The data and results have contributed to improved performance in this area of high activity and are useful for other areas with similar drilling practices. Background Since 2012, on-bottom drilling performance in the New Mexico Delaware Basin has improved steadily through insights gained from downhole memory data and a series of bit and BHA design modifications. Parallel to this, in 2015, Occidental initiated a global campaign to recognize and mitigate drilling dysfunctions through the use of mechanical specific energy (MSE). Although performance has improved through these initiatives, uncertainty in rock strength, tool reliability, proper drilling parameters, and general downhole conditions makes optimization a time-consuming and sometimes ambiguous process. To accelerate the learning process and to help tailor parameters, BHAs, and bits to ensure maximum performance, more information about the downhole drilling environment was required. The intermediate sections in this area require drilling through eight formations with various rock strengths. Drilling dynamics change through the different rock types, and a configuration that works best in one formation may not work well in another. The same goes for drilling parameters and potential autodriller dysfunction. High-speed drilling-dynamics data acquired through wired drillpipe can provide real-time insight into bit and formation interactions that are not available otherwise. This information is used to determine the root cause of lower-than-expected rate of penetration (ROP) or unusual surface parameter fluctuations. Through real-time data display, rig crews can diagnose dysfunctions quickly and correct them immediately. Simultaneously, the engineering staff can plan a redesign if needed. The data allowed the team to use a deterministic approach and physics-based principles to improve performance. The learnings gained from using wired drillpipe were expanded to adjacent rigs using nonwired pipe. Furthermore, insights gained through the abundant data have been used to train the drilling team and build their confidence in the application of MSE methodology. Project Definition Wired drillpipe telemetry can transmit data at rates up to 57,600 bits per second, enabling massive amounts of data to be transferred to surface in real time. Wired drillpipe has been employed with bi-directional communication to directional tools to achieve faster measurement-while-drilling and logging-while-drilling telemetry rates and instantaneous down-linking to rotary steerable systems in land operations in California and in offshore operations in the North Sea. The telemetry has also enabled fully integrated automation, in which high- frequency downhole data feed into the control system to optimize drilling operations and ensure consistency. Other projects have validated the use of active stick/slip mitigation technologies, optimized BHA drive systems, reduced inefficiency, and identified and redesigned performance limiters to improve drilling performance.

Prospects for the Use of Technology of Rotary Steerable Systems for the Directional Drilling

In the process of gradual reorientation of the oil industry to the production of heavy hydrocarbons, inaccessible to traditional methods of production, the need arises for the application of modern technological solutions. One of these technologies is directional drilling, which poses new challenges for drilling equipment, such as facilitating sliding - changing the angle of well bore, improving the cleaning of the wellbore, reducing the risks of differential sticking, overcoming resistance during horizontal drilling, etc. A modern technological solution is rotary steerable systems (RSS) representing a new generation of downhole systems used in directional drilling. The article discusses the advantages and disadvantages of RSS technology, its modifications, gives a classification, also provides a comparative analysis of well wiring using rotary steerable systems and, the most widely used, mud motor.

Tracking Control for Directional Drilling Systems Using Robust Feedback Model Predictive Control

A rotary steerable system (RSS) is a drilling technology which has been extensively studied and used for over the last 20 years in hydrocarbon exploration and it is expected to drill complex curved borehole trajectories. RSSs are commonly treated as dynamic robotic actuator systems, driven by a reference signal and typically controlled by using a feedback loop control law. However, due to spatial delays, parametric uncertainties and the presence of disturbances in such an unpredictable working environment, designing such control laws is not a straightforward process. Furthermore, due to their inherent delayed feedback, described by delay differential equations (DDE), directional drilling systems have the potential to become unstable given the requisite conditions. This paper proposes a Robust Model Predictive Control (RMPC) scheme for industrial directional drilling, which incorporates a simplified model described by ordinary differential equations (ODE), taking into account disturbances and system uncertainties which arise from design approximations within the formulation of RMPC. The stability and computational efficiency of the scheme are improved by a state feedback strategy computed offline using Robust Positive Invariant (RPI) sets control approach and model reduction techniques. A crucial advantage of the proposed control scheme is that it computes an optimal control input considering physical and designer constraints. The control strategy is applied in an industrial directional drilling configuration represented by a DDE model and its performance is illustrated by simulations.

Determination of the Loads on the Steering Module of the Push-the-Bit Rotary Steerable System in the Context of Its Reliability

Determination of the Loads on the Steering Module of the Push-the-Bit Rotary Steerable System in the Context of Its Reliability