Eco-Friendly Electric-Powered Hydraulic Fracturing Towards Shale-Gas Recovery: Efficiency, Economics and Field Application

The recovery of unconventional gas fields especially the shale gas is of great significance to clean energy supply. High productivity of shale gas is attributed to the large-scale hydraulic fracturing with high operating pressure (80-100MPa) and discharging rate (14-18m3/min). More high-horsepower fracturing vehicles driven by diesel engines result in higher CAPEX. The low operation efficiency and unexpected maintenance negatively affected the economics performance of operators due to unacceptable OPEX. The fully electric-powered hydraulic fracturing solution was proposed as the alternative to the diesel-engine fracturing vehicles in this article. The skid-based electric pumping units were newly developed with advantages of high power density (6000HP per unit), Variable Frequency Drive (VFD) modules integration, fuel cost saving, low maintenance expenditure and eco-friendly operation. The field application was conducted in one pad of N209 in shale gas field, Sichuan, China. The electric-powered system, consisting of pumping units and blenders with other facilities, was deployed on the operation site. One large-capacity electric power grid (35kV and 30000kVA) was constructed for both drilling and massive multistage fracturing. The operation team successfully performed all hydraulic fracturing jobs as required with 7.4×105 kWh of total power consumption. The system functioned reliably without large faults occurred. The electric-powered solution was comprehensively evaluated and compared to the diesel-engine fracturing solution in terms of CAPEX, operational efficiency, power consumption, maintenance and fleet crew cost. The novelty of the technology is the fully electric-powered hydraulic fracturing system with large-capacity electric power grid. It is concluded from the field application that the electric-powered fracturing technology is qualified for unconventional reservoirs development.

Overview of electric pump units for spacecraft thermal control systems

The paper reports a brief description of spacecraft operating conditions, the main reasons of heating and thermal gradient appearance and need to reassign the thermal energy. Active thermal control systems and their advantages are considered, spacecraft for which the use of this type of thermal control systems is a priority. The electric pumping unit is pointed as a key unit of active thermal control systems. The electric pump unit is considered from the as the electromechanical system, its key elements are pointed. A description of the preferred pump types is reported and the types of active thermal control systems are briefly discussed. The foreign and domestic operating experience of spacecraft electric pumping units, the features of their designs are considered, the most common types of key elements are determined. Based on the results of the review, it is concluded that the most relevant layout of the electric pump unit is a centrifugal electrical pump with a brushless DC motor and hydrodynamic bearings. It is also indicated that the electric pump unit is a product with a long lifetime, which complicates the task of monitoring the technical condition in order to prevent failure.

Submersible pumps - application practice, technical requirements, development paths

Проанализировано применение погружных (плавающих) насосов в насосно-рукавных комплексах. Рассмотрены их преимущества перед центробежными насосами, устанавливаемыми в мобильной пожарной технике. На основе практики применения и технических характеристик погружных насосов, производимых ведущими зарубежными фирмами, сформулированы технические требования для разработки отечественного погружного насоса. Кроме того, технические требования могут стать основой разработки национального стандарта для этого типа пожарно-технической продукции. The article analyzes the results of operation of a relatively new type of centrifugal pump - a submersible (floating) centrifugal pump with a hydraulic drive. These pumps have a number of significant advantages over centrifugal pumps installed on mobile fire fighting equipment - they can be used to pump liquid from a mark up to minus 30 m. Since the suction pipe of such a pump is located directly in the pumped liquid (below the liquid mirror level), the phenomenon of cavitation is practically excluded. Submersible pumps are used to supply water in case of fire and for water disposal during the elimination of hazardous hydrological phenomena, both independently and in conjunction with centrifugal pumps installed on mobile fire fighting equipment (supply to pumping). All submersible pumps included in the set of hose-pumping complexes are of foreign production. The demand for such pumping units causes the need to develop domestic samples in order to get away from import dependence in the manufacture of pumping and hose systems and their operation. Based on the practice of using submersible pumps and the technical characteristics of submersible pumps produced by leading foreign companies, the following technical requirements for the development of a domestic submersible pump have been formulated. Pump delivery is 170-180 l ∙ s from the mark to minus 30 m. Water intake is possible both in equipped (adapted) and unequipped (unsuitable) places. In addition, the requirements for the hydraulic drive, weight and size characteristics, and some components have been formulated. In conclusion, some directions for the further development of pumping and hose systems and submersible pumping stations are considered.

Principles of Imitation for the Loading of the Test Bench for Gas Turbines of Gas Pumping Units, Adequate to Real Conditions

The purpose of the study is to analyze the prospects for the development of loading methods for gas turbines as well as to develop a mathematical model that adequately describes the real operating conditions of the loading system at various loads and rotation speeds. A comparative analysis of the most common methods and technical means of loading the shafts of a free turbine at gas turbine plants intended for operation as part of gas pumping units is presented. Based on the results of the analysis, the expediency of using the loading model “Free Power Turbine Rotor–Hydraulic Brake” as a load simulation is shown. Recommendations for the creation of an automation system for the load testing of power plants have been developed. Mathematical models and Hardware-in-the-Loop simulation models of power plants have been developed and tested. One of the most important factors that predetermine the effectiveness of the loading principle is the possibility of software implementation of the loading means using software control systems that provide the specified loading parameters of the gas turbine.

Calculation of specific rates of the electric energy consumption at frequency regulation of electric drives: A case study of pumping stations

The issues of developing a methodology for calculating the specific rates of electrical energy consumption during frequency regulation of electric drives of pumping stations are considered. When calculating specific consumption rates, experimental studies were carried out at the Chirchik pumping station. When developing the methodology, technological, design parameters, water consumption, as well as the total capacity of pumping units based on frequency-controlled electric drives are taken into account. At the same time, the characteristics of the main parameters that must be taken into account when choosing variable frequency drives for pumping units are determined.

Research of transition processes in the operation of reclamation pumping stations

This paper presents the results of field studies carried out on existing pressure systems with pumping stations. The considered field experiments were carried out on a closed irrigation system, which includes a pumping station with a water intake, a closed irrigation pipeline network and sprinklers. On this system, field studies of transient processes were carried out with the simultaneous shutdown of all pumping units simulating emergency power outages of the motors, and with shutdown of one of the units simulating the automatic operation of the station. The presented results make it possible to carry out practical calculations of transient processes for pumping stations with different water supplies, heads, capacities, diameters and lengths of pressure pipelines and shockproof devices.

Improving the Efficiency of Distributed Water Supply Systems by Means of an Adjustable Electric Drive

The water supply of the pumping station must meet the needs of the consumer which change during the day. Therefore, its performance needs to be adjusted. Any deviation of the pump unit’s performance from the nominal value leads to additional energy costs. Under such conditions, great importance is paid to optimising the operation of electric drives of the water supply pumping station. To regulate the performance of a pumping station, it is often resorted to changing the number of operating pumping units, the engines of which are started directly from the electrical network. Medium-and high-power engines are subject to technical restrictions for a direct start, which are supplemented by the need to maintain pauses between starts. Therefore, when ensuring the desired value of pumping station performance, it is very important to consider the features of starting pump engines. Control systems are widely used in the field of electric drive and water supply. It is in these areas that the efficiency of the control system depends on the amount of electricity that will be consumed by the technological process or the reliability of its operation. It is known that pumps account for about half of all energy produced. Therefore, the issue of effective control systems is particularly relevant in the field of water supply. The purpose of this study is to increase the reliability and efficiency of the water supply system by considering the distribution properties of the pipeline network when controlling electric pump drives, which will allow coordinating the operation of the pumping station, the pipeline network, and the consumer. To achieve this purpose, the study was conducted to assess the impact of the distribution and length of the pipeline network. The system of water supply and distribution is analysed, what criteria affect the correct performance of work and what problems may arise during operation for a long period of time are investigated. Ways to optimise the operation of pumping stations to increase their energy efficiency and cost-effectiveness of installations are investigated. The main reasons for the expediency of using an adjustable electric drive to control pumping units are considered

VIBRATION PROCESSES AND THEIR RELATIONSHIP WITH DEFECTS

ABSTRACT The article is devoted to vibration diagnostics, an effective method for assessing the parameters of the mechanical state of centrifugal pumping units. The use of vibration diagnostics allows, due to early detection of malfunctions, to improve target operation, increase the turnaround time and reduce the likelihood of emergency destruction of pumping unit elements. Diagnostic signs of the presence of defects in various elements of the pumping unit are presented. During the development of diagnostic methods, the character stages of the development of injuries are selected. These stages are the formation of the injury, the accumulation of injuries, collapse, and so on. consists of stages. Dynamic forces are considered to be the main cause of vibration in machine parts. It is under the influence of dynamic forces that fatigue breaks down in machine parts. The use of vibrodiagnostics in machine parts allows to accurately assess the degree of damage to its individual nodes. This, in turn, leads to improved operating conditions. In conclusion, it should be noted that vibrodiagnostics not only detects malfunctions in machines, but also reveals the causes of its formation. Keywords: vibrodiagnostics, improvement of operational conditions, determination of defects, probability of emergency destruction, repair, assessment.