| dc.description.abstract | In this dissertation, we develop a compositional multiphase wellbore-reservoir simulator, GURU-MSW. The compositional reservoir simulator GURU serves as the starting point of this work. GURU-MSW fully implicit couples a multi-segment wellbore (MSW) model with the reservoir simulator GURU. Although taking the most developing effort, the fully implicit coupling mechanism is considered to be unconditionally stable and fast.
After developing the general framework of the simulator, the coupled MSW-reservoir simulator is tested in two application scenarios, both being the first attempt in the literature. The first application is to analyze the well interference phenomenon. Well interference, introduced by the inter-well fracture hits, is a major production issue in shale reservoir development. When fracture hits occur, GURU-MSW can capture the sudden production rate jump caused by the wellbore crossflow. We also apply GURU-MSW to model a case with three wells under well group control.
The second application of GURU-MSW is the simulation of liquid loading phenomenon. Liquid loading is an inevitable production issue in mature gas fields, which occurs when the producing gas rate is not high enough to carry all the liquids to wellbore surface. This is a phenomenon that can neither be comprehensively simulated by a single wellbore simulator nor a single reservoir simulator because of the dynamic interaction between wellbore and reservoir. GURU-MSW successfully characterizes the dynamic interaction between wellbore multiphase flow and reservoir multiphase flow. We systematically analyze a cyclical production phenomenon, which was only reported as field observations previously.
Two new gas-liquid drift-flux models are proposed in this dissertation. The first model incorporates the flow regime transition criteria from annular flow to churn or slug flow for vertical, slanted and horizontal pipes. The model is specially designed for the application of liquid loading modeling in horizontal gas wells.
The second model is a unified model for all pipe inclinations. The new model is tested against 5805 experimental measured data points from 22 sources as well as 13440 data points from the OLGA-S library. The numerical stability of the model is tested with GURU-MSW. The drift-flux model commonly applied in MSW simulation only covers a pipe inclination range from 2 degrees (nearly horizontal) to 90 degrees (vertical upward). The proposed model has a potential in filling in the gap left by the existing drift-flux model. | en |
