Model for Inclusive Pressure Distribution of Horizontal Well in a Two-Layered Bounded Extended Reservoir

Growing applications ofhorizontal well technology warrant attempts towards modelling for more realistic phenomena. In the study ofperformance ofhorizontal wells in layeredreservoirs, particular issues have been dealt with; however, existing models restrict the number offlow regimes. In this research, the pressure distribution of horizontal wells in layered reservoirs was presented in the form of dimensionless pressure and dimensionless pressure derivative functions of reservoir system properties andfluidproperties without restriction on the number andtype offlow regimes. The model consideredthe effect ofthe interface on pressure response andthe effect ofcrossflow. From the results obtained, dimensionless pressure depends on the type ofinterface, degree ofcrossflow, dimension oflayer, regional well parameters, and regional rock and fluid properties. Dimensionless pressure was found to increase as the degree ofcrossflow reduces. Dimensionless pressure decreases as layer thickness increases. The type, interval ofsubsistence, andnumber ofexisting flow regimes dependlargely on the reservoir system parameter, the location ofthe interface relative to the well, and the degree ofcrossflow. A horizontal well in a bound layered reservoir experiences a minimum ofeleven (11) flow regimes, including some transition periods at full flow, i.e., when all the external boundaries are felt. During a flow period, the type and number offlow regimes that may occur, as well as the duration ofexistence, are determined by the values ofparameters, the geometry ofthe reservoir, the fluid properties and the well architecture selected. The model was seen to produce a series ofradial and linear flows along the individual principal axes or combinations ofany ofthe three principal axes. Each flow regime could be recognisedby its characteristic signature in the log-log graph plots ofthe pressure andpressure derivative versus time. Flexibility ofthe model in this article allows for an easy switch ofreservoir features between isotropy andanisotropy, single compartment andlayered, andhomogeneity andheterogeneity