Browsing by Author "Xiong, Wanqiang"

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    ItemOpen Access
    Development of a Standalone Compositional Simulator for Modelling Multiphase Flow and Temperature Distribution Along Wellbore
    (2019-12) Xiong, Wanqiang; Chen, Zhangxing; Azaiez, Jalel; Chen, Shengnan; Qin, Guan; Swishchuk, A. V.
    Well modeling of multiphase flow and temperature flow along a wellbore has wide applications in the petroleum industry especially in unconventional oil and gas recovery processes. Also, wellbore modeling can be applied in a geothermal well for optimizing production parameters. The main research works completed in this study include building mathematical equations for wellbore modeling and development of a standalone wellbore simulator. At first, a series of mathematical equations are built for wellbore modeling of fluid flow in tubing or annulus, heat loss to a surrounding formation and heat transfer in the formation. Then methods and workflows are determined for key steps in wellbore simulator development including discretization, a grid system, a solution method and a liner equation solver. A standalone compositional wellbore simulator is developed. Validation works against CMG SAM, CMG Flexwell and Eclipse Multi-Segment Well are conducted afterwards. Different scenarios have been modeled by the wellbore simulator that include hot water injection, steam injection, SAGD circulation, SAGD injection, multiphase well production, steam-solvent co-injection, liquid CO2 injection for a shale gas reservoir and geothermal well production. Different well trajectories and structures are handled such as vertical, deviated and horizontal wells, and the wells consisted of one or dual tubing strings. New correlations for more accurate heat loss calculations are regressed in this study based on CFD Fluent simulation and they can better estimate the convection heat transfer in annuli space with single tubing or dual-tubing strings. Also, a semi-numerical method and a fully numerical method for heat loss calculations are proposed. The semi-numerical method consists of heat loss through wellbore components calculated by correlations and heat loss in a surrounding formation numerically simulated, and the fully numerical method performs simulation for heat transfer both in wellbore components and the surrounding formation.
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    ItemOpen Access
    Development of a Thermal Wellbore Simulator with Focus on Improving Heat Loss Calculations for SAGD Steam Injection
    (SPE Reservoir Evaluation & Engineering, 2016) Chen, Zhangxing (John); Xiong, Wanqiang; Bahonar, Mehdi; Dong, Chao
    Typical thermal processes involve sophisticated wellbore configurations, complex fluid flow and heat transfer in tubing, annulus, wellbore completion, and surrounding formation. Despite notable advancements made in wellbore modeling, accurate heat loss modeling is still a challenge using the existing wellbore simulators. This challenge becomes even greater when complex but common wellbore configurations such as multi-parallel or multi-concentric tubings are used in thermal processes such as Steam Assisted Gravity Drainage (SAGD). To improve heat loss estimation, a standalone fully-implicit thermal wellbore simulator is developed that can handle several different wellbore configurations and completions. This simulator uses a fully implicit method to model heat loss from tubing walls to the surrounding formation. Instead of implementing the common Ramey method (1962) for heat loss calculations that has been shown to be a source of large errors, a series of computational fluid dynamical (CFD) models are run for the buoyancy driven flow for different annulus sizes and lengths and numbers of tubings. Based on these CFD models, correlations are derived that can conveniently be used for the more accurate heat loss estimation from the wellbore to the surrounding formation for SAGD injection wells with single or multiple tubing strings. These correlations are embedded in the developed wellbore simulator and results are compared with other heat loss modeling methods to demonstrate its improvements. A series of validations against commercial simulators and field data are presented in this paper.