Han Li¹, Tianding Chen^{2, *}, Hualiang Teng³, Yingtao Jiang⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.118, No.2, pp. 253-274, 2019, DOI:10.31614/cmes.2019.05807

Abstract In any classical value-based reinforcement learning method, an agent, despite of its continuous interactions with the environment, is yet unable to quickly generate a complete and independent description of the entire environment, leaving the learning method to struggle with a difficult dilemma of choosing between the two tasks, namely exploration and exploitation. This problem becomes more pronounced when the agent has to deal with a dynamic environment, of which the configuration and/or parameters are constantly changing. In this paper, this problem is approached by first mapping a reinforcement learning scheme to a directed graph, and the set that contains all… More >

Ye Chen, Yonghai Gao, Guizhen Xin, Wang Yao, Dongzhi Gao, Litao Chen, Baojiang Sun^*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.4, pp. 88-89, 2019, DOI:10.32604/icces.2019.05522

Abstract Natural gas hydrate is regarded as a kind of potential alternative energy resource and attracts the attention all over the world. Geological surveys have found that most natural gas hydrates are buried at the bottom of the sea. Several development methods, such as depressurization, thermal stimulation and inhibitor injection are proposed gradually on the basis of hydrate special properties, obtaining certain trial-produce performance. It is of great significance to learn the flow rules underground for production safety guarantee and efficiency improvement. However, the special phase transition of hydrate between solid and fluid accompanied by energy and mass change makes it… More >

Na Wei^1,*, Jinzhou Zhao¹, Wantong Sun¹, Shouwei Zhou¹, Liehui Zhang¹, Qingping Li², Haitao Li¹, Qiang Fu^1,2, Xin Lv², Lijun Zheng²

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.4, pp. 84-86, 2019, DOI:10.32604/icces.2019.04533

Abstract Currently, marine natural gas hydrate has attracted people’s attention due to its huge amount of resources. As a creative way to securely and efficiently exploit metastable hydrate reservoir which is in shallow subsurface of sea floor and with weak cementing, the method of solid fluidization exploitation is to excavate and crush the marine natural gas hydrate reservoir, transport the hydrate to the sea surface platform through the airtight pipeline, and finally the methane gas is obtained after post-processing.
In the process that the hydrate solid particles are transported up, as the temperature rises and the pressure drops, the hydrate rises… More >

Lin Jiang^1,*, Na Wei^1,*, Jinzhou Zhao¹, Shouwei Zhou^1,2, Liehui Zhang¹, Qingping Li³, Guorong Wang¹, Jun Zhao¹, Kaisong Wu¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.4, pp. 81-83, 2019, DOI:10.32604/icces.2019.04515

Abstract With huge reserves, marine natural gas hydrate is one of the most potential unconventional alternative energy sources after shale gas, coalbed methane and tight gas. The research and pilot engineering of natural gas hydrate exploitation technology mainly adopts the depressurization method at home and abroad, all of which refer to the exploitation technology of conventional oil and gas.
While using the depressurization method to exploit the non-diagenetic gas hydrate, the undersea hydrate decomposes in situ, partly flows to the bottom of the well, and escapes into the seawater in large quantities, and the hydrate will face the following six risks… More >

Binbin Diao¹, Deli Gao^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.90, No.1, pp. 77-90, 2013, DOI:10.3970/cmes.2013.090.077

Abstract The measurement of the relative position of two adjacent wells is one of the key technologies in the directional drilling of twin parallel horizontal wells, and the downhole intersection of two adjacent wells. A new electromagnetic ranging system and a guidance method are introduced for determining the relative position of two adjacent wells. The system mainly consists of two solenoid assemblies, improved surveying instrument for measurement while drilling (MWD), and a computational procedure for guidance. Also, the distribution of the magnetic field of each energized solenoid assembly is discussed, by regarding the solenoid assembly as two independent oscillating magnetic dipoles.… More >