报告一：ANALYTICAL AND NUMERICAL ANALYSES OF WELLBORE DRILLING PROBLEM IN POROELASTOPLASTIC ROCK FORMATIONS

报告人: Prof. Shengli Chen
Department of Civil & Environmental Engineering, Louisiana State University

内容简介：

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The cavity theory has wide applications in the areas of underground excavations and tunnel constructions in soil and rock as well as the wellbore instability in the oil and gas industry. In this research, a class of exact analytical solutions have been developed for the wellbore drilling/tunnel excavation problems in elastoplastic soil/rock masses subjected to non-isotropic initial stresses, using the cavity contraction method and under both drained and undrained conditions. To provide realistic predictions of the soil/rock behaviour, a variety of elastoplastic constitutive models including the critical state based modified Cam Clay and bounding surface models have been adopted in the analyses. Numerical simulations were also conducted with the use of ABAQUS software. A user defined material subroutine (UMAT) has been developed and implemented into ABAQUS for the bounding surface model. The proposed analytical solutions have been further validated with the available experimental data for the responses of borehole during drilling.

报告人简介：

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Dr. Chen, Shengli is currently an Assistant Professor in the Department of Civil & Environmental Engineering at Louisiana State University (LSU). He received his Ph.D. degree in Petroleum Engineering from the University of Oklahoma (OU) in December 2012, and was a Research Petroleum Engineer with Aramco Research Center at Houston before joining LSU in August of 2014. Prior to that, Dr. Chen had been an Assistant/Associate Professor in the Department of Civil Engineering at Shanghai Jiao Tong University, and received his B.S. and Ph.D. degrees in Civil Engineering both from Zhejiang University. Dr. Chen’s main areas of expertise are analytical and computational geomechanics, pile engineering, poromechanics and hydraulic fracturing modelling, and wellbore stability drilling through shale/salt formations. His current research is funded by American Chemical Society, Board of Regents, Louisiana, and Louisiana Transportation Research Center. Dr. Chen has published 20 plus international journal papers in the areas of geomechanics and geotechnical/petroleum engineering, and he has been serving as an Associate Editor of SPE Journal since 2014.
 
报告二：MODELING WATER INJECTION IN LAND-FACIES KARAMAY OIL SAND RESERVOIRS
报告人: Prof. Botao Lin
Department of Oil and Gas Well Engineering, College of Petroleum Engineering, China University of Petroleum (Beijing)
时  间：7月19日（周二）上午10点

内容简介：

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At present, steam assisted gravity drainage (SAGD) adopts a stimulation process through water injection to a pair of horizontal wells, in order to save both cost and time in preheating. Two deformation mechanisms named shear dilation and tensile parting occur in this process. The land-facies Karamay oil sand has grains that are loosely packed and isolated by a mixed matrix of bitumen, sand and clay. Triaxial tests confirmed that the sand exhibited dilation behavior under shear and substantial plastic volumetric expansion upon hydrostatic unloading. However, numerical analysis disclosed that the oil sand reservoir showed only elastic behavior upon water injection. This research aims at providing a comprehensive analysis on the injected water propagation across land-facies oil sand reservoirs. The analysis fulfills three technical aspects: (1) adoption of a poroelasticity framework regarding anisotropic rigidity; (2) application of strain-dependent hydraulic flow anisotropy; and (3) consideration of petrophysical heterogeneity along the wellbores. A finite element (FE) approach was used to simulate the water propagation using laboratory calibrated data, based on which the case study of a field injection project was analyzed to predict the configuration of propagation fronts along the wellbores, the development of dilation zone across the reservoir; and to compare the predicted and observed injection volume with time.

报告人简介：

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Dr. Lin, Botao graduated from Sun Yat-sen (Zhongshan) University, China, with bachelor in geology and master in geotechnical engineering in 2005 and 2007, respectively. He gained his PhD degree in civil engineering from the University of Oklahoma, USA, in 2012, prior to joining China University of Petroleum at Beijing in 2013. He currently worked as associate professor in petroleum engineering affiliated with Department of Oil and Gas Well Engineering, College of Petroleum Engineering, as well as State Key Laboratory of Petroleum Resources and Prospecting, both at China University of Petroleum (Beijing). His major research interests have been focused on geomechanics in heavy oil recovery, permeation in shale gas reservoirs, and mechanical interaction of marine mud with surface conductors. Dr. Lin has published 23 papers in the areas of geomechanics and petroleum engineering, and he has been serving as reviewer for many international journals in those areas.
 
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