The Influx Management Envelope (IME) assists in identifying influx conditions which could compromise the primary well barrier and fluid handling capacity on surface. IME boundaries are influenced by changes in parameters such as mud weight, wellbore depth and geometry, pump rate, surface pressure, etc. Thus, any changes to these parameters will change the acceptable influx volume and intensity for Dynamic Influx Management. It is, therefore, critical to understand how changes in each of these variables affect IME limits so that its validity can be established within parameter ranges, rather than only for discrete values.
This work presents an in-depth discussion of how IME limits are determined, with both detailed philosophical and practical guidance on methods to calculate the surface and subsurface limits. Recent deepwater applications of the IME are used to represent baselines for presenting methods of calculating IME limits, including a basic single bubble approach, through to the most robust approach of including transient, multiphase simulations. Parameter sensitivity analyses are performed to determine reasonable ranges for which an IME is valid, with the goal of understanding the required IME update frequency during operation.