Gas Gathering Station Research Articles

Multi-objective site selection optimization of the gas-gathering station using NSGA-II

Abstract The gas-gathering station (GGS) is a key component in the gas field, and its site selection is an important issue for designers. Since the diffusion of gas from the station may pollute the surrounding environment, it is a trend to consider the environmental and economic factors in the site selection of GGSs. In this study, a model is developed with the objective functions of minimal construction costs and environmental impact. We apply NSGA-II to search for the Pareto frontier and couple A* algorithm to find the optimal routes, and we use the Monte Carlo method to sample the uncertain wind data and evaluate the environmental impact. The effectiveness of the proposed method is demonstrated in a design problem in a gas field. The optimal construction site for the GGS is solved by the proposed method. The results show that this work can serve as a decision-support tool for the design of GGS.

Development of cleaning methods complex of industrial gas pipelines based on the analysis of their hydraulic efficiency

The majority of gas and gas condensate fields of Ukraine are developed by pressure depletion, which makes it possible to stabilize production only in conditions of low working pressures at the wellhead. In turn, the working pressure values significantly depend on the pressure at the inlet to the gas gathering stations and pressure loss in the gas gathering and transportation process. Consequently, their reduction will lead to an increase in natural gas production from depleted fields. The main idea of the work is to offer continuous monitoring of the gas gathering system in order to detect changes in the thermobaric operation mode. Such changes can signal the high probability of liquid accumulation, which will produce additional friction. The results of monitoring changes in pressure, temperature, dew points and natural gas composition allow carrying out their complex analysis and evaluating the possibility of liquid mass formation in certain areas of the gas pipeline system with an acceptable accuracy, which at once excludes a more detailed recording of their presence by means of instrument equipment and human resources, as well as reduces the time of non-response to a problem. The works may be fully executed by the operations technician or the dispatch service. After detecting potentially hazardous places, they are analyzed for confirmation of the presence of liquid and the decision to clean them with one of the proposed methods is made. This approach will be very interesting to large international companies, since natural gas reserves are constantly exhausted, and withdrawal of the remaining gas from depleted fields is an attractive target for producing companies. In addition, the use of simple pigging methods based on the analysis of the hydraulic efficiency of pipelines can significantly reduce both time and material resources.

Stable isotopic composition of coal bed gas and associated formation water samples from Raniganj Basin, West Bengal, India

This study was carried out to document the source and stable isotopic characteristics of coal bed gas and associated coal bed water samples of the Raniganj Basin, West Bengal, India. The Raniganj Basin is one of the largest coal bed gas-producing sites in India. However, the gas isotopic composition of this basin was not well investigated until now. The exploration has been focused on mature coals with a high content of assumed thermogenic methane. Interestingly, the present study has revealed that although the gas is thermogenic, there is a significant effect of microbial activities in gas generation. The gas explored from this Basin contains almost 98–99% methane (CH4) in general with very little portions of other hydrocarbons and thus, this gas can be considered as “dry gas”. It is consistent also with late-stage microbial alteration of thermogenic gases. The δ13C and δD values of CH4 range from −47.4 to −49.7‰ and −207 to −211‰ respectively across the three wells as well as from −48.8 to −50.1‰ and −209 to −211‰ respectively in the gas samples collected from gas gathering station. The Whiticar style cross plot of these two parameters reveals that the gas samples have mixed thermogenic and biogenic sources and the microbial gas was generated through the CO2 reduction pathway rather than the acetate fermentation pathway. The difference in δD values of water and methane samples [δD (H2O-CH4)], that varies from 173 to 175‰, may also exhibit that the biogenic methane was produced through reduction of CO2. The stable hydrogen and oxygen isotopic signatures of formation water samples (δD and δ18O-H2O) stand with the mixed origin of the gas. The cross-plot of these two parameters reveals that the water samples lie almost along the Global Meteoric Water Line (GMWL), which may suggest the combined effect of methanogenesis due to mixing of coal seam formation water with modern meteoric water. In summary, the produced coal bed gas from the Raniganj Basin, although being largely thermogenic in origin, has been influenced by secondary microbial alteration.

Fatigue life analysis of cracked gas receiver of emergency cut-off system in gas gathering station

Small-scale air compressor and gas receiver are used as the driving gas of the emergency cut-off system in gas gathering station. Operation of block valve is ensured by starting and stopping compressor automatically. The frequent start-stop of compressor and the pressure fluctuation pose a threat to the service life of gas receiver, and then affect normal operation of the emergency cut-off system and security of gas gathering station. In this paper, the fatigue life of a pressure vessel with axial semi-elliptical surface crack in the inner wall is analyzed under the varying pressure by means of the theory of fracture mechanics. The influences of the amplitude of pressure fluctuation and the initial crack size on the residual life of gas receiver are discussed. It provides a basis for setting the working parameters of gas receiver of emergency cut-off system and determining the maintenance cycle.

OIL: Installation of a Central Gas Gathering Station at Madhuban, Assam

This case deals with several types of uncertainties faced by project team in an oil company north east in India. These challenges and uncertainties are in the areas drawing approval, supply chain, critical equipment availability, soll type, control room, soil type, employee availability, environmental clearances, safety and wildlife clearances. This project demonstrates the ownership issues, why it is difficult to complete a project on time in the Northeast of India or why public sector project gets delayed.

A Systematic Approach to Source-sink Matching for CO2 EOR and Sequestration in South Sumatera

Abstract Carbon dioxide for enhanced oil recovery (CO 2 EOR) can magnify oil production substantially while a consistent amount of the CO 2 injected remains sequestrated in the reservoir, which is beneficial for reducing the greenhouse gas (GHG) emission. The success of CO 2 EOR sequestration depends on the proper sources-sinks integration. This paper presents a systematic approach to pairing the CO 2 captured from industrial activities with oil reservoirs in South Sumatra basin for pilot project. Inventories of CO 2 sources and oil reservoirs were done through survey and data questionnaires. The process of sources-sinks matching was preceded by scoring and ranking of sources and sinks using criteria specifically developed for CO 2 EOR and sequestration. The top candidate of CO 2 sources are matched to several best sinks that correspond to added value, timing, injectivity, containment, and proximity. Two possible scenarios emerge for the initial pilot where the CO 2 will be supplied from the gas gathering station (GGS) while the H3 and F21 oil fields as the sinks. The pilot is intended to facilitate further commercial deployment of CO 2 EOR sequestration in the South Sumatera basin that was confirmed has abundant EOR and storage sinks as well as industrial CO 2 sources.

Dynamic accident modeling for high-sulfur natural gas gathering station

Dynamic accident modeling for a gas gathering station is implemented to prevent high-sulfur natural gas leakage and develop equipment inspection strategy. The progress of abnormal event occurring in the gas gathering station is modeled by the combination of fault tree and event sequence diagram, based on accident causal chain theory, i.e. the progress is depicted as sequential failure of safety barriers, then, the occurrence probability of the consequence of abnormal event is predicted. Consequences of abnormal events are divided into accidents and accident precursors which include incidents, near misses and so on. The Bayesian theory updates failure probability of safety barrier when a new observation (i.e. accident precursors or accidents data) arrives. Bayesian network then correspondingly updates failure probabilities of basic events of the safety barriers with the ability of abductive reasoning. Consequence occurrence probability is also updated. The results show that occurrence probability trend of different consequences and failure probability trend of safety barriers and basic events of the safety barriers can be obtained using this method. In addition, the critical basic events which play an important role in accidents occurrence are also identified. All of these provide useful information for the maintenance and inspection of the gas gathering station.

Electric Heating Power Optimization of Natural Gas Pipeline

After the analysis of gas flow, energy consumption is mainly in the process of heating gas pipeline and natural gas throttle. For this problem, this paper, heat transfer, thermodynamics, computational fluid dynamics are used, the pipeline throttling, convection of natural gas in the pipe and the heat transfer between the gas, wall panels, heating cable, insulation, soil and the atmosphere are all considered, thermal analysis model between the wellhead and the gas gathering station is established, the electric heating power on the gas pipeline is optimized, the optimal electric heating power can be calculated when the temperature of wellhead and gas gathering station is expected to reach are known. The effect of tube diameter, gas volume, surface temperature on the heating power is analyzed.

Quantitative risk analysis of toxic gas release caused poisoning—A CFD and dose–response model combined approach

Some major toxic gas release accidents demonstrate the urgent need of a systematic risk analysis method for individuals exposed to toxic gases. A CFD numerical simulation and dose–response model combined approach has been proposed for quantitative analysis of acute toxic gas exposure threats. This method contains four steps: firstly, set up a CFD model and monitor points; secondly, solve CFD equations and predict the real-time concentration field of toxic gas releases and dispersions; thirdly, calculate the toxic dose according to gas concentration and exposure time; lastly, estimate expected fatalities using dose–response model. A case study of hydrogen sulfide releases from a gas gathering station has been carried out using a three dimension FLUENT model. Acute exposure fatalities have been evaluated firstly with a simplified ideal model which assumes workers stay at original exposure location without moving. Then a comparison has been made with a more realistic model which assumes workers start evacuating according to a prearranged course as soon as hydrogen sulfide detection system alarms. These two models represent the worst and best emergency response effects, respectively, and the analysis results demonstrate significant differences. Results indicate that the CFD and dose–response combined approach is a good way for estimating fatalities of individuals exposed to accidental toxic gas releases.