Field Applications of a Semianalytical Model of Multilateral Wells in Multilayer Reservoirs

Abstract

Advanced drilling technology has been widely and successfully applied to construct multilateral wells in reservoirs. This paper presents several field applications of a generalized semianalytical segmented model accounting for multilateral-well systems in commingled layered reservoirs. Cases include a heavy-oil field, Al Rayyan oil field offshore Qatar, and Dos Cuadras field offshore California.The model can predict the production performance under either constant-rate or constant-pressure conditions of a well system with any number of arbitrarily oriented laterals of any length and nonuniform formation damage. The reservoir layers, with different porosities, anisotropic permeabilities, and drainage areas, are noncommunicating except through the wellbore. The solution is valid for large reservoirs and when no-flow or constant-pressure boundaries affect the pressure behavior.Results of applying this method in the field cases showed that the model enabled us to predict multilateral-well performance, to obtain information about reservoir connectivity, and to estimate well and reservoir properties in a multilayer system. Uncertainty caused by the large number of unknown parameters in such a complex system represents the main challenge in using this method. It is recommended to use other means together with pressure transient data to reduce the uncertainty.The presented model and the lessons learned from the field applications provide engineers with a tool enabling the use of transient data collected from multilateral wells in multilayer systems for reservoir characterization and performance forecast.

Dynamic Interference Behaviors of Arbitrary Multilayer Commingling Production in Heavy Oil Reservoirs with Water Flooding

“…But with an increase of oil prices, operators would like to pursue the economical recoverable reserves instead. Previously, many scholars − studied the approach to improve oil productivity and recoverable reserves. They believed that for varying multilayer permeabilities, effective conformance control is expected to result in more efficient water flood by enhancing volumetric efficiency and potentially increasing the recovery by 5%.…”