Abstract
Inflow Control Devices (ICD) were developed in response to early water break-through from the heel of prolific horizontal wells. In their initial applications, the design of ICD installations was based on equalizing flux (flow rate per unit length) along the length of a horizontal well, which required "choking" of flux in the heel region. In practice, these tools are often installed along the entire length of a horizontal well, with the logic that since choking level is proportional to flow, the tool will automatically produce a more uniform flow profile.
In this paper we will re-examine the technical validity of attempting to achieve equal flux along the length of the horizontal well. We will show that in reservoirs with uniform permeability the flux from the toe and heel regions should in fact be larger than the mid-section. We will also show that delaying water or gas breakthrough is not a sufficient reason for use of ICDs. We will discuss the benefits of a new design philosophy whereby each well segment is choked at a level that regulates its flux to a level that produces an outcome more suitable for optimum reservoir management. This gives the operator the flexibility to design ICD layout to optimize various flow parameters, including time or cumulative production at water/gas breakthrough, location of first water/gas breakthrough, etc. This will be especially valuable for wells in variable permeability reservoirs. A new design simulator developed based on above concept will be presented and its benefits demonstrated through a case history.
