Hydraulic Energy Research Articles

Analysis of the Thermal–Mechanical–Hydraulic Coordination Mechanism of a Constrained Piston Hydraulic Engine

By effectively integrating traditional engines with reciprocating plunger pumps, the constrained piston hydraulic engine can simultaneously output hydraulic energy and rotational mechanical energy, which effectively solves the problems of the complex structure, long power transmission chain, and low energy conversion efficiency of traditional power sources. Based on a certain single-cylinder diesel engine, a single-cylinder axial constrained piston hydraulic engine was designed, and its thermal–mechanical–liquid coordination mechanism was studied and analyzed in-depth. A mathematical model of the thermal–mechanical–liquid coupling working process of the single-cylinder axial hydraulic engine was established, and the conversion mechanism and output of the three types of energy, thermal, mechanical, and liquid, were simulated and analyzed. The results show that under the premise of improving the overall efficiency, the constrained piston hydraulic engine can effectively output mechanical–hydraulic dual-element power, and its combustion characteristics and output power performance indicators meet the expected design requirements. The maximum amplitude difference of the output hydraulic oil flow rate reaches 248 L/min, and the flow rate fluctuates greatly, so it is necessary to adopt methods to suppress the flow rate pulsation to ensure the reliability of the output flow rate.

Technology Focus: Hydraulic Fracturing Operations (June 2023)

With the global normalization of economies over the past 2 years after the pandemic, the demand for energy has only been increasing, and all forecasts show this demand will continue to grow. In light of the current geopolitical situation globally, balancing the energy trilemma (ensuring energy security, energy equity, and environmental sustainability) is a key global challenge. With the ever-increasing energy demand, oil and gas remains a major component within the energy mix to address this challenge and to aid in satisfying the growing demand. Hydraulic fracturing continues to be the main technology differentiator that enables enhancing recovery from both green- and brownfield reservoirs globally. During the past few years, the industry has made great strides in reducing carbon emissions through the deployment of new technologies in fracturing equipment manufacturing, including electric, hybrid, and turbine-driven fracturing equipment spreads. We have also seen the application of automation and emissions monitoring being widely adopted throughout the industry in an effort to lower the operational carbon footprint. Fracture monitoring to optimize fluid volumes and designs remains a critical area of development. Research is ongoing with the focus on combining different monitoring technologies including tracers, fiber optics, downhole cameras, and microseismic monitoring. There also have been innovations in using surface data to develop cost-effective solutions to monitor fracture-geometry propagation. Nanotracers and low-cost disposable fiber-optic cables have been areas that have seen increasing deployments within the monitoring realm. Cluster efficiency and stage spacing is being optimized in basins globally by studying perforation erosion, fracture propagation, and performance between various perforation strategies using different gun configurations in both single clusters and multiple clusters including extreme-limited-entry applications. We have seen improvements in the pressure ratings of dissolvable and flow-through plugs with the aim of aiding in improving turnaround efficiency in plug-and-perf wells. Multistage hardware has seen enhancements with new completion technologies such as cemented ball-drop multistage fracturing systems and multistage openhole systems with sand-screens that require minimum intervention being developed and deployed. Globally, we have observed increasing application of lessons learned to revamp older technologies and fracturing concepts such as the use of crosslinked gels, energized fluid systems, and tip screenout designs. In addition to conventional reservoirs, we also are seeing a growing application of stimulation and fracturing technologies being considered and deployed for geothermal applications. The recent technological developments and deployments cement the fact that hydraulic fracturing will remain an important pillar to solving the world’s energy requirements in the years to come. Recommended additional reading at OnePetro: www.onepetro.org. SPE 212342 Overflush and Fracturing: Playing Poker With Your Completion by Martin Rylance, THREE60 Energy SPE 212749 Natural-Gas-Powered Direct-Drive Turbine Hydraulic Fracturing Technology Delivers High-Power Density and Energy Transfer Efficiency for Environmental, Economic, and Operational Benefits by Guillermo Rodriguez, BJ Energy Solutions, et al. SPE 212322 Combined Video and Ultrasonic Measurements for Fracture Diagnostics—Greater Than the Sum of the Parts by Tobben Tymons, EV, et al. SPE 209159 Lessons Learned From the Large-Scale CO2 Stimulation of 11 Unconventional Wells in the Williston Basin: A Practical Review of Operations, Logistics, Production Uplift, and CO2 Storage by Lionel Ribeiro, Equinor, et al.

Influence of Leading and Trailing Edge Angle on Impeller Blades of a Pump as Turbine

A pump as turbine (PAT) is a turbomachine that converts hydraulic energy into electricity. One of the study topics in PAT is the efficiency due to centrifugal pumps are not designed to operate in reverse mode. Geometric variations of the impeller have been studied in the literature. However, it was not possible to evidence the influence of the inclination of the blade leading and trailing edge. Therefore, the objective of this work is to analyze numerically and fluid dynamically the inclination angle of the blade leading and trailing edge of a centrifugal pump, in pump and turbine mode. First, the characteristic curve was validated. Then, the inclination of the leading and the trailing edge was modified, in a range of 25° to 90°, obtaining head, efficiency, and power graph. As a result, in pump mode was evidenced that an angle close to 90° on the blade trailing edge provides a higher efficiency of 50.26% and decreases until 40.77% when the angle approaches 30°, reducing the head to around 20%, while power remained constant. In turbine mode, an inverse effect was obtained, where the maximum efficiency was 60.9% and the generated power increased up to 4.76 kW in the blade leading edge. Therefore, the angular variation of the leading and the trailing edge is adequate in turbine mode, while in pump mode there is a loss of capacity.

Reducing the fluid loss in case of depressurization of tractors’ hydraulic drive

BACKGROUND:The operation of hydraulic drives of agricultural machinery is associated with the problem of leakage of fuel and lubricants, leading to contamination of water and soil. The most intense oil spill occurs when high-pressure hoses of hydraulic equipment are destroyed. The existing methods of solving the problem of oil leakage from high-pressure hoses have severe restrictions and high costs of their implementation. One of the effective methods of solving the problem is the use of hydraulic drive protection devices that disconnect the unpressurised section from the pressure source.
 AIMS:To develop an improved protection device an emergency stop device that controls a hydraulic drive with several types of hydraulic motors with a minimum number of device elements.
 MATERIALS AND METHODS:The design of a hydraulic drive emergency stop device (RUF Patent No. 2522013) installed in the hydraulic system of a tractor with single- and double-acting hydraulic cylinders has been developed. The method in use is a morphological analysis of the structure and distinctive features of existing engineering solutions.
 RESULTS:The shutdown unit and the terminal sensor of the emergency stop device compare the value of the hydraulic pump supply with the flow rate in the drain line. At the same time, the device is able to automatically adjust itself to their permissible difference, ensuring that there are no false responses when using double-cavity hydraulic cylinders with one rod. False responses when connecting a single-cavity hydraulic cylinder are prevented by using an additional flow sensor that blocks the shutdown unit. The fluid flow is throttled in the annular gaps between the pistons, sensor and shutdown unit housings; in this case, both pistons are mutually balanced.
 CONCLUSIONS:The proposed solution is aimed to eliminate significant oil throw-out form high-pressure hoses and makes it possible to use a single device for controlling the whole tractor hydraulic system. As a result, the weight and cost of the protection device reduce and the hydraulic drive scheme does not complicate significantly. The developed device does not demand additional power supply from the tractors on-board power circuit, as it operates with use of hydraulic energy. The protection device is applicable to hydraulic cylinders and hydraulic motors of various sizes thanks to ability of self-adjustment to the greatest difference in flow rate.

Optimal hydraulic energy harvesting strategy for PaT installation in Water Distribution Networks

Water Distribution Networks (WDNs) represent a noteworthy field for possible implementation of Small Hydropower (SHP), by replacing Pressure Reduction Valves (PRV) with turbomachines, in particular Pump as Turbines (PaTs), to control and regulate the pressure, while harvesting energy otherwise wasted. Different models were developed to predict the performance and select the positioning of the PaTs for the maximum energy recovery but most of them neglect practical aspect such as: power grid limitations and optimal harvesting strategy. In this framework, we intend to propose a new method to select a PaT, defining its optimal working point, by introducing an energy exploitation coefficient. The proposed methodology is based on the experimental results of a real PaT tested in the high capacity hydraulic laboratory at Polytechnic University of Bari. Firstly, the selected commercial centrifugal pump was tested in both pump and turbine modes. Then, three different approaches, for the Best Efficiency Point (BEP) selection, are described and compared in terms of energy exploitation and capacity factor for a WDN. The first consists of selecting the BEP at the average flow rate, the second one considers the probability distribution of the flow rate and the corresponding available hydraulic energy, whereas the latter is based on the highest energy harvesting. By applying energy production, economic and environmental analyses, the new proposed methodology, based on the third approach, shows a remarkable advantage in terms of exploited energy. Indeed a remarkable 60% energy recovery is achieved with 334 ton CO2/year avoided. Furthermore, the impact of the electrical motor on the maximum power generation (cut-off) is considered. Eventually, useful insights for the future PaT selection and installation are discussed.

Mine water as a source of energy: an application in a coalfield in Laciana Valley (León, NW Spain)

Mine water can be a renewable and economical source of geothermal and hydraulic energy. Nine discharges from closed and flooded coal mines in the Laciana Valley (León, NW Spain) have been studied. Various technologies for the energy use of mine water, as well as the influence of factors such as temperature, the need for water treatment, investment, potential customers and expansion capacity, have been evaluated by means of a decision-making tool. It is concluded that the most advantageous option is an open-loop geothermal system using the waters of a mountain mine, the temperature of which exceeds 14 °C and whose distance to customers is less than 2 km. A technical–economic viability study for a district heating network designed to supply heating and hot water to six public buildings in the nearby town of Villablino is presented. The proposed use of mine water might help areas that have been greatly affected socioeconomically by the closure of the mines and has other advantages compared to conventional energy systems, such as the reduction of CO2 emissions.Graphical It showing the advantages of using mine water as an energy source for district heating and a simplified layout.

Research on electro-hydraulic ratios for a novel mechanical-electro-hydraulic power coupling electric vehicle

In the context of globalization where new energy vehicles are widely used, this paper proposes a novel mechanical-electro-hydraulic power coupling system for electric vehicles (MEHV). The planetary gear mechanism (PDCM) is integrated with the accumulator, hydraulic pump/motor, battery and motor to realize the mutual conversion of mechanical energy, electric energy and hydraulic energy. Subsequently, a rule-based energy management strategy is established to distribute energy and realize smooth switching in real time. Then, further analysis is carried out on the electro-hydraulic torque distribution. The results illustrate that, the peak torque of the drive motor (DM) can be decreased, and the hydraulic energy can be fully utilized to improve the state of charge (SOC) under appropriate ratio. Simultaneously, to ensure the appropriate electro-hydraulic ratio under complicated conditions, this paper adopts the fuzzy rule-based energy management strategy of multi-parameter input. Ultimately, the actual driving conditions are established using the actual driving data and the strategy. Consequently, the peak torque is significantly lower than pure electric vehicle, the battery energy consumption is reduced by 19.06%. Therefore, the approach proposed in this paper notably improves the running state of the motor, the energy utilization rate, as well as the economy and stability of the vehicle.

The effect of diuretics on spirometric parameters in patients with ischemic heart failure

Heart failure is the failure of the cardiac pump under physiological loading conditions to impart sufficient hydraulic energy output in order to maintain a physiological circulation. A cohort study extended over a period of 14 months from the first of august 2010 to the first of November 2011. The patient was diagnosed as having heart failure according to the recommendation of the European Society of Cardiology, depending on the result of history, examination and echocardiographic conformation. Spirometric data were collected in accordance with American Thoracic Society standards. All the patients had a restrictive spirometric defect before treatment with diuretics, but after treatment all show normal spirometric pattern. The present study recommend the followings: - The use of a cheap office spirometer in rural area by general practitioner (GP) doctors and nursing staff could be useful for follow up patients with ischemic heart failure to detect early deterioration by objective mean to refer the patient for specialized care. Also, the office spirometer needs no special skills and the nursing staff can master the procedure with a 2 weeks training course.

English

Communal solar-powered irrigation systems (SPIS) have the potential for sharing the upfront costs hence encouraging farmers to adopt irrigation. Conventional methods of sizing photovoltaic water pumping (PVWP) system for irrigation consider the hydraulic energy requirement by the pump and PV generator capacity separately from the available water source capacity. As a result, the potential of the technology is not optimized, leading to over or under-sizing of the system. Consequently, there is a negative impact on acquisition cost and system performance. The study aimed to determine the optimal PVWP system configuration for communal irrigation. A comparative techno-economic and environmental performance assessment was conducted on different pumping system configurations and a multi-criteria decision analysis approach was used to select the optimal configuration. The findings show a PVWP system with storage tank as the optimal configuration for the communal irrigation. Although the initial capital cost for standalone PVWP system configurations is almost two times that of the conventional diesel pumping systems (CPS), its operation and maintenance (O&M) and lifecycle cost are respectively three times and about four times lower than the CPS cost. Furthermore, the PVWP system for communal irrigation is feasible for irrigation projects that exceed 3 years due to their high acquisition costs. Therefore, promotion of solar-powered irrigation should also focus on the communal approach as a way of improving technology adoption and upscaling. Key words: Communal irrigation system, photovoltaic water pumping system, solar powered irrigation system, design optimization.

Microbe-sediment interactions in Great Lakes recreational waters: Implications for human health risk.

Microbial assessments of recreational water have traditionally focused on culturing or DNA-based approaches of the planktonic water column, omitting influence from microbe-sediment relationships. Sediment (bed and suspended) has been shown to often harbour levels of bacteria higher than the planktonic phase. The fate of suspended sediment (SS) bacteria is extensively related to transport dynamics (e.g., deposition) of the associated sediment/floc. When hydraulic energy allows, SS will settle, introducing new (potentially pathogenic) organisms to the bed. With turbulence, including waves, currents and swimmers, the risk of human ingestion is elevated due to resuspension of bed sediment and associated microbes. This research used multiplex nanofluidic reverse transcriptase quantitative PCR on RNA of bacteria associated with bed and SS to explore the active bacteria in freshwater shorelines. Bacterial genes of human health concern regarding recreational water use were targeted, such as faecal indicator bacteria (FIB), microbial source tracking genes and virulence factors from waterborne pathogens. Results indicate avian sources (i.e., gulls, geese) to be the largest nonpoint source of FIB associated with sediment in Great Lakes shorelines. This research introduces a novel approach to microbial water quality assessments and enhances our understanding of microbe-sediment dynamics and the quality of freshwater beaches.

Correction to: Experimental Study of Natural Bed Roughness Effect on Hydraulic Condition and Energy Dissipation Over Chutes

Correction to: Experimental Study of Natural Bed Roughness Effect on Hydraulic Condition and Energy Dissipation Over Chutes

A Comprehensive Review of Energy Regeneration and Conversion Technologies Based on Mechanical–Electric–Hydraulic Hybrid Energy Storage Systems in Vehicles

The primary purpose of this paper is to investigate energy regeneration and conversion technologies based on mechanical–electric–hydraulic hybrid energy storage systems in vehicles. There has been renewed interest in hydraulic storage systems since evidence has been presented that shows that they have the distinct advantages of high energy output and energy recuperation compared to electrical energy recovery systems, which are widely applied in electric vehicles; however, they are known to be high-cost, with a complicated structure and not zero carbon. In this paper, we first review recent research on hydraulic energy regeneration and conversion technologies. Secondly, as the main part of this paper, the latest technological progress and breakthroughs of the mechanical–electric–hydraulic hybrid energy storage systems in vehicles—which are divided into four categories: passenger, minibus and bus, commercial vehicle and special vehicle—are analyzed and discussed in depth. In addition, the current research status of energy management techniques is presented and summarized. Finally, prospects and challenges are suggested and explained. It is evident from the literature review that the mechanical–electric–hydraulic hybrid systems perform excellently in vehicles. Clearly, this review will be helpful to understand, explore and define the hydraulic vehicle of the future concerning energy optimization and environmental friendliness.

Performance study of spiral Darrieus water rotor with V-shaped blades

Because of the excessive consumption of fossil fuels, the world has begun suffering from the depleting of those sources and wide environmental problems. Hydraulic energy, considered as unlimited and non-detrimental, has become the best refuge to supply world demand while protecting the planet. Above all vertical axis water turbine, for their low cost and independency on water direction, Darrieus turbine takes the advantage to be more suitable for some implementation. Thus, various studies have been carried out to improve its efficiency. This study emphasizes on the effect of the blade chord ratio on a spiral Darrieus water rotor performance which has not been two much explored. An experimental static and dynamic tests realized in an irrigation canal were performed with a 3D printed spiral Darrieus rotor. With the intention of the performances betterment, four spiral Darrieus rotors having a chord ratio equal to 0.25, 0.5, 0.75, and 1, respectively, were tested through numerical simulations using the ANSYS FLUENT 17.0 software. Based on the numerical study, it is provided that the rotor with chord ratio of 0.5 was the optimum. In fact, it gives maximum power coefficient of 0.188 at a tip speed ratio equal to 0.71. The obtained findings present an interesting data that could provide the hydrodynamic characteristics of the water flow for the engineers and designers to improve the performance of the spiral Darrieus rotor.

Integrated Smart Management in WDN: Methodology and Application

Urbanization and population growth have been responsible for a significant increase in consumption of water and energy at a global scale. A careful management of water resource and infrastructures is crucial for Energy Transition, as well as for achieving a sustainable efficiency of these systems. High pressure values along with the ageing of the systems contribute to high leakage levels of Water Distribution Networks (WDN). The simultaneous control of excess pressure and containment of water losses are mainly performed by using Pressure Reducing Valves (PRVs) in WDN, which dissipate the surplus of hydraulic energy. Instead of being dissipated, energy can be recovered by the transformation of the excess pressure into electrical energy with the use of Pump as Turbines (PAT), which results in an increased reliability, reduction of cost and an overall improvement in the efficiency of WDN. The work aims on presenting an integrated efficiency management methodology in terms of Effectiveness (E), capability (ηpi), reliability (μpi) and sustainability (χpi) with values between 47 to 98%, also associated with the pressure and leakage management, and energy recovery. This research presents a modelling of a real WDN of a District Metering Areas (DMA) of Beloura endowed with seasonal consumption variability to better show its applicability. Additionally, an economic analysis to assess the solution’s feasibility is presented concluding an annual energy recovered of 9.8 MWh and a saving of about 30% of water leakage, which correspond, in the analyzed case study, to about 3523 m3. The payback period found is around 9 or 12 years, for only one PAT or two different PATs installed, due to the small available energy of the analyzed case study. Acknowledging the synergy between water and energy efficiency and taking advantage of these integrated smart management methodology exemplification, it resulted in more efficient systems to achieve both effectiveness solutions, digital and energy transition in the water sector.

Effect of the inlet-to-outlet key width ratio of Piano Key Weir on its hydraulic behaviour

The Piano Key Weir (PKW) is an ungated type of spillway, i.e., a novel evolution over the traditional labyrinth weir. It allows the reservoirs to operate with elevated supply levels without causing any damage to the dam structures, thereby providing additional storage. It is designed to improve the hydraulic performance of linear weirs by increasing pass discharge and energy dissipation. In this study, an experimental investigation has been carried out to assess the effect of the inlet-to-outlet width ratio (Wi/Wo) on PKW hydraulic behaviours viz hydraulic efficiency and energy dissipation. To this end, nine different width proportions (1 ≤ Wi/Wo ≤ 2) type-A PKW models were tested and examined. The findings revealed that the Wi/Wo ratio significantly impacts the hydraulic performance of PKW, and the results indicate that the efficiency of the PKW increases as the width ratio increases at a certain limit and then starts decreasing. The discharge coefficient was the highest for the given discharge and head, resulting in the best hydraulic performance with a Wi/Wo ratio between 1.25 and 1.30. However, the energy dissipation across the PKW decreases as the width ratio increases. Moreover, the discharge coefficient of different width ratios (Wi/Wo) ranging between 1.28 and 1.30 is 7–17% higher than Wi/Wo = 1 and 8–13% higher than Wi/Wo = 2.0. However, the energy dissipation across the weir for Wi/Wo = 2.0 indicates 15–29% less energy dissipation than Wi/Wo = 1. It means the energy dissipation across the weir decreases as the Wi/Wo ratio increases.

The Role of Fluid Overpressure on the Fracture Slip Mechanism Based on Laboratory Tests That Stimulating Reservoir-Induced Seismicity

A critically stressed fracture will slide in response to the increase in fluid pressure inside the fracture while impounding, which will trigger induced seismicity. The mechanism of fluid overpressure is regarded as a significant factor in the reaction of the fracture slip after water diffusing. This study uses a shearing test with a cylinder of granite, with 100 mm height and 50 mm diameter, under the condition of hydraulic-mechanic (HM) coupling to figure out how fluid overpressure alters the mechanical behavior of the critically stressed fracture. The cyclic water pressurization simulates periodical impounding in the water reservoir. Results show that several slip events happen when water pressure continues to rise higher than the stable state. The change of roughness also indicates the deterioration of the fracture surface while sliding. According to the results, we conclude that the difference between inlet pressure and outlet pressure leads to an overpressure of the fracture, promoting a series of slips and induced seismicity. Hydraulic energy is introduced to explain the relationship between the input and output energy, which is also strong evidence to illustrate that fluid overpressure is a crucial mechanism in reservoir-induced seismicity.

Numerical study on the energy consumption characteristics of a novel integrated pump-motor unit for SWRO desalination system

Energy recovery device (ERD) is a critical component in seawater reverse osmosis (SWRO) desalination systems, which recovers hydraulic energy from the high-pressure brine and effectively reduces system energy consumption. In this thesis, a novel integrated seawater desalination pump-motor energy recovery device (ISPM-ERD) without the slipper/swashplate interface is proposed to further reduce energy consumption and improve system integration, which is able of concomitantly achieving seawater pressurization and energy recovery. A co-simulation multibody dynamic model with rigid-flexible coupling is applied to precisely examine the internal power loss of ISPM-ERD, especially volumetric loss and mechanical loss of the key lubricating interface. Besides, the influence of shaft rotational speed and working pressure on the power loss and overall efficiency of ISPM-ERD are comparatively investigated. In addition, a performance study of the presented ISPM-ERD is carried out based on the co-simulation model, which reveals the energy recovery efficiency and specific energy consumption (SEC) of ISPM-ERD under various operating conditions. The results indicate that the proposed ISPM-ERD is sufficient to meet the needs of the small-scale SWRO systems, whose energy recovery efficiency is more than 90.1 % in the 3.0–7.0 MPa operating pressure range and the SEC of freshwater production is 2.94 kW·h/m3 under rated working conditions.

Regenerative Braking Algorithm for Parallel Hydraulic Hybrid Vehicles Based on Fuzzy Q-Learning

The use of regenerative braking systems is an important approach for improving the travel mileage of electric vehicles, and the use of an auxiliary hydraulic braking energy recovery system can improve the efficiency of the braking energy recovery process. In this paper, we present an algorithm for optimizing the energy recovery efficiency of a hydraulic regenerative braking system (HRBS) based on fuzzy Q-Learning (FQL). First, we built a test bench, which was used to verify the accuracy of the hydraulic regenerative braking simulation model. Second, we combined the HRBS with the electric vehicle in ADVISOR. Third, we modified the regenerative braking control strategy by introducing the FQL algorithm and comparing it with a fuzzy-control-based energy recovery strategy. The simulation results showed that the power savings of the vehicle optimized by the FQL algorithm were improved by about 9.62% and 8.91% after 1015 cycles and under urban dynamometer driving schedule (UDDS) cycle conditions compared with a vehicle based on fuzzy control and the dynamic programming (DP) algorithm. The regenerative braking control strategy optimized by the fuzzy reinforcement learning method is more efficient in terms of energy recovery than the fuzzy control strategy.

A Novel Energy-Efficient Transmission System and Control Strategy for Hydraulic Machines

Each part of a hydraulic press dissipates a large amount of energy when energy or power is transmitted. Therefore, this study proposes a 3-D vertical arrangement structure for the hydraulic press to reduce their energy dissipation. In the proposed structure, the aboveground and underground spaces are comprehensively utilized, and then the hydraulic equipment are arranged three-dimensionally and set in layers according to the functional requirements. Some equipment is connected directly to minimize the use of valves and pipelines and reduce the transmission distance of hydraulic energy between the pump station and the actuator. Furthermore, a method for scheduling the drive system in the above structure is presented to share a transmission zone with no conflict and shorten their idle time. The composition of each zone is set to match the power demand of each operation to achieve the scheduling schemes. Finally, the proposed scheme is applied to a 31.5 MN hydraulic press as a case study. Results showed that the energy efficiency increased from 43.95% to 85.03%, demonstrating excellent energy-saving potential.

Improving Drilling Efficiency and Safety Based on Hydraulic Mechanical Specific Energy in the Framework of Economic Model Predictive Control

Summary The economic value of real-time optimization of the drilling process has attracted extensive attention in the period of crude oil price fluctuation. Because of the complicated bottomhole conditions and coupling relationship among subsystems, it is difficult for the driller to continuously adjust the primary manipulation variables—weight on bit (WOB), revolutions per minute (RPM), and managed pressure drilling (MPD) equipment—which leads to unsatisfactory drilling effect and increased nonproductive time. Here, we propose an integrated control strategy based on economic model predictive control with zone tracking (ZoneEMPC), nonlinear model predictive control (NMPC), and Lyapunov-based model predictive control (LMPC) to optimize hydraulic mechanical specific energy (HMSE) while stabilizing bottomhole pressure (BHP). During normal drilling, ZoneEMPC is used to minimize HMSE through operating RPM, WOB, mud pump flow, and choke-valve opening as well as its tracking performance, which ensures that the BHP is maintained within the pressure window. Moreover, the controller is switched to NMPC, which adjusts the BHP to quickly reach the new setting zone. The reason for controller switching is that the tracking accuracy of ZoneEMPC could decline when encountering high-pressure formation with gas invasion. As the BHP reaches the new pressure range, the controller is switched to ZoneEMPC again and the HMSE is reoptimized. In addition, the transmission rate of mud pulse telemetry is not enough to meet the real-time control in practical engineering. Therefore, the LMPC controller is used to ensure the closed-loop stability of the system when the downhole measurement data (e.g., BHP) delayed. This study uses the drilling data of a vertical well located in Tarim, China, to verify the control strategy. The results indicated that the proposed integrated control strategy could improve the rate of penetration (ROP), especially in a formation with high rock strength. Meanwhile, the BHP could be adjusted efficiently and stably under different conditions. This work provides a unified framework integrating multiple system models for practical engineering, which has certain theoretical guiding significance for the automation and intelligent development of the oil and gas industry.