An Integrated Multi-Component Reservoir-Wellbore Thermal Model

Chao Dong


As more and more wells have been put into operation, accurate modeling of wellbore flow plays a significant role in reservoir simulation, particularly in thermal recovery processes such as Steam Assistant Gravity Drainage (SAGD) and Cyclic Steam Stimulation (CSS). The main objective of wellbore modeling is to predict heat exchange and phase behaviour in the vertical and horizontal wellbores and therefore to predict their effect on the entire simulation process. Coupled reservoir and well modeling can provide a detailed description of these thermal processes.

To model these processes, a thermal K-value multi-component reservoir model is developed. This model has the ability to simulate three-dimensional multi-component, three-phase thermal processes such as SAGD and CSS. This model has the capability to utilize different property estimation methods such as correlations or table interpolations. Both structured and unstructured grids are used in the model. Flexible time step generation depends on fluid flow conditions in the reservoir. The Gauss elimination technique is applied to the secondary variables to speed up the process. The model utilizes existing linear solver packages by using compressed storage formats as the socket. Heat loss to overburden and underburden is modeled by a semi-analytical method. Two corresponding sets of wellbore models, Sink/Source Well (SSW) and Multi-Segment Well (MSW) models, are developed and tested to achieve several results.