Wellbore Hydraulics and Well Performance

GASMAN wells may be operated in either production or injection mode. GASMAN allows simulation of well inflow performance for both vertical and horizontal wells. Inflow performance may be modeled from first principles (permeability, reservoir thickness, drainage radius and skins etc.) or by IPR (for example, forecheimer using darcy/non-darcy coefficients).

Where liquids are present (for example in condensate reservoirs), the critical gas rate required to avoid slugging is indicated.

In instances where the client has more data relating to well performance at the tubing head, GASMAN can be configured to model well performance via tubing head forcheimer coefficients. When required, these can be linked to reservoir pressure to allow representation of changing tubing head performance with reservoir depletion.

The change in gas pressure through the tubing (due to static head and friction) is rigorously modeled in GASMAN through friction-factor correlations applied to each well tubing segment.

Whichever well inflow performance technique is applied, GASMAN produces tubing-head pressure vs. flow curves for each well. The individual well operating points resulting from the interaction between subsurface and topsides facilities can be readily interrogated - allowing identification of unproductive alignment of well and machinery capabilities.

Where a gathering system is present, the fully integrated GASMAN model readily reconciles well and pipeline pressures and flows.