| Existence of wall inflow or outflow is the major difference between regular pipe flow and fluid flow along a wellbore. Wall inflow or outflow has a significant effect on wall friction, acceleration, and flow pattern transition. It is found that under practical flow conditions, wall inflow increases the wall friction for laminar flow though it decreases the friction for turbulent flow. The opposite is true for wall outflow.; A new single phase wellbore flow model, which incorporates frictional, accelerational and gravitational pressure drops, and the influence of wall inflow or outflow, is presented. New wall friction factor correlations for wellbore flow have been developed.; Many factors play a role in gas-liquid flow along a wellbore. The influences of different parameters on the wellbore flow behavior are interrelated and depend upon specific flow conditions. For gas-liquid flow in a wellbore, both homogeneous and mechanistic models are proposed. Flow models for individual flow patterns are developed. New criteria for transition among different flow patterns occurring in a wellbore are proposed.; Transient flow models for separated and dispersed gas-liquid flows along a wellbore are also developed. The transient flow equations are solved numerically by using a SCM (split coefficient matrix) finite difference approach.; Occurrence of multiple solution in separated gas-liquid wellbore flow depends on fluid properties, pipe geometry, flow rates, empirical correlations, and wall inflow or outflow rates. Regions of multiple solutions are identified. The impact of wall inflow or outflow on the occurrence of multiple solutions and on the regions of multiple solutions is investigated. Physical consideration and numerical simulation of the transient process for separated gas-liquid flow are employed to determine the physically realistic solution wherever multiple solutions exist.; Predictions by the new wellbore flow models are compared with experimental data. Excellent agreement is observed between model prediction and measurements. The mechanistic model also makes reasonable flow pattern predictions.; A simplified transient coupling model is proposed for parallelpiped reservoirs containing wells or laterals of arbitrary configurations. The coupling model can be used to determine well productivity index, well indices, wellbore potential and pressure profile, and wall inflow or outflow rate distribution. |
