Numerical simulation and experimental study on the influence of novel refuelling nozzle with rectifier tube in the process of diesel refuelling

Feb 2018 / by Chang Chen, Zhi Han, Qixin Zhang, Shifu Zhang, Jikun Guo and Shiqiang Song

When applying the traditional refuelling gun in large-flow rapid refuelling process, large amount of bubbles are produced under the strong impact between the high speed oil column and the tank wall or internal oil surface, which will reduce the refuelling efficiency seriously. In this paper, a combination of CFD simulation and refuelling experiment has been conducted to analyse the effect of rectifier tube in flow field stability and diesel foam reduction when applying to the process of large-flow rapid refuelling. The simulation result has been further discussed by comparing with the refuelling experiment data. And, it has been proved that the application of rectifier tube in the refuelling nozzle can control the turbulent state of the flow field effectively and reduce foam generation significantly, so as to make contribution to improve the refuelling efficiency and operation security.
Keywords: Numerical simulation, experimental study, rectifier tube, volume of fluid model, PISO algorithm

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CFD numerical simulation of internal flow field in fuel tank during large-flow rapid refuelling process

Feb 2018 / by Chang Chen, Shifu Zhang, Zhi Han, Jikun Guo, Qixin Zhang and Dongmei Zhang

With the gradual improvement of modern social life, more and more attentions are attracted to higher efficiency of refuelling process. However, large flow rapid refuelling process may result in unexpected turbulence and violating the safety standards. Since there are a few of existing literature researches the internal flow field in fuel tank during large flow rapid refuelling process, this paper carried out numerical simulation research for the gas-liquid twophase flow in oil tank under the condition of vertical refuelling and tilting filling in that circumstance, and devoted to research characteristics of the flow field inside the fuel tank and the cause of the foam formation under different fuelling conditions by using CFD software. The result of this study was of certain reference value to solve the problems of large foam and turbulence in flow field during large flow rapid refuelling process.
Keywords: Numerical simulation, VOF model, internal flow field, large-flow rapid refuelling process, CFD

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Discussion on lithology data conversion methods in studies of seismic sedimentology

Feb 2018 / by Qilin Chen, Yutan Dou, Mingjun Su, Huaqing Liu and Mengli Zhang

Seismic sedimentology is a new interdisciplinary in oil and gas exploration, and consists of two branches: seismic lithology and seismic geomorphology. The current prevailing seismic lithology method is 90o phase conversion technology, which transforms seismic data to lithology data for the purpose of direct interpretation of seismic events, acting like interpreting logging data. Based on premise of zero-phase wavelet of seismic data, with the geological formations of thin sandstone layers and simple vertical composition of sandstone and mudstone with great impedance contrast, the results of seismic events transformed by 90o phase conversion method correspond to lithology interfaces, and have the capability of effectively distinguishing sandstone from other different lithologies. However, continental sedimentary basins face several geological difficulties, such as diversity of depositional types, fast changeable sedimentary facies, great variable sandstone thickness, complex diagenesis and diagenetic sequence. These problems result in velocity of sandstone from acoustic logging or seismic survey less than velocity of incumbent mudstone, moreover these abnormal velocity discrepancies vary with sediment types and buried depth, which bring great difficulties for utilizing seismic data to predict sedimentary lithology and identify sandstone formations especially thin layers. Therefore, 90o phase conversion technology has limited applications, and cannot guarantee its accuracy for predicting unconventional oil and gas reservoirs. In this paper, we discusses several conversion methods of seismic data to lithology data, including 90o phase conversion, trace integration, poststack inversion (for example, colour inversion and logging constrained inversion) and pre-stack inversion technology. We focused on the advantages and disadvantages of these techniques as well as their feasibility and applicable conditions, so that the optimal method matching strata slice is able to be selected to describe subsurface geomorphology. These lithology data conversion methods, can greatly improve the lithology discrimination ability and lithology data resolution, which would benefit extensive application of seismic sedimentology, especially at the areas with complex lithology and tight hydrocarbon reservoirs in continental sedimentary basin.
Keywords: Seismic sedimentology, 90o phase conversion, colour inversion, post-stack inversion, pre-stack inversion, seismic lithology

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Experimental study on foaming mechanism of diesel oil during large-flow rapid refuelling process

Feb 2018 / by Chang Chen, Zhi Han, Shifu Zhang, Jikun Guo, Qixin Zhang and Jianyong Yang

Modern social life and the needs of industrial development has put forward higher requirements for the flow and efficiency of refuelling process. However, the greater the filling flow, the bubble produced by diesel oil is more obvious which will reduce the fuel efficiency seriously. This article focus on the influence factors and mechanism of diesel oil foam during large-flow rapid refuelling process by setting different condition of filling experiments. It was found that the filling flow rate of 150 L/min ~ 180 L/min is suitable for achieving the balance with the combination of consideration of refuelling rate and bubble reduction. What is more, the way of increasing the diameter of refuelling gun has obvious influence in diesel bubbles reduction. In addition, “flare regular” refuelling gun produce more bubbles than “straight regular” refuelling gun which is mainly because the diesel oil in the pipeline is more turbulent. The developed model and experiment results are useful to researchers and engineers in the area of large-flow rapid refuelling process of diesel oil.
Keywords: Experimental study; foaming mechanism; diesel oil; large-flow rapid refuelling

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Building of monitoring indicator system of oilfield blocks and data preprocessing

Feb 2018 / by Liuli Lu, Wen Yong Yan, Xin Shi, and Ke Wang

Oilfield block development assessment, yield prediction and pre-warning are now the hot topics in the field of oilfield development. Building a monitoring indicator system is the first step to achieve this. We addressed the problem of the lack of single well production data by using the SPSS (Statistical Product and Service Solutions) Missing Value Analysis and cubic spline interpolation. The equation for calculating weights was improved and the missing values were filled based on interpolation. The oilfield block monitoring indicators were characterized by using different techniques for single well production monitoring. The former included water absorbing capacity, oil production capacity, fluid producing capacity, seepage capacity, and pressure-maintaining capacity. The latter included water injection profile, production profile, well log interpretation and pressure monitoring. Finally, a case study was performed on fault block reservoir III in No.1 district of GD oilfield. The degree of correlation between each monitoring indicator and oilfield block development indicators was calculated so as to verify the monitoring indicator system of oilfield blocks.
Keywords: Oilfield block, yield prediction, monitoring indicator system, data preprocessing

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Use of isotopic analysis technique for exploration of coal, oil and natural gas deposits

Feb 2018 / by B. K. Pal

In geochemistry isotopic effects of oxygen, carbon, sulphur and some other elements allow representing the different pattern for the formation of coal, oil and gas deposits. That is why they are considered as important exploration criterion. In this paper, results of isotopic investigations are presented as an important method for forming of models of forming systems comprising physical and chemical conditions and also mechanisms of deposits forming.

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