Content of PetroWiki is intended for personal use only and to supplement, not replace, engineering judgment. SPE disclaims any and all liability for your use of such content. More information
Wellbore hydraulic simulation
While many fluid mechanics applications can be done as hand calculations, more complex problems, especially involving temperature changes, require a hydraulic simulator. To address the wellbore operations of interest, a wellbore simulator should have a wide range of capabilities. These fall into four categories:
- Transient effects
- Fluid models
- Wellbore geometry
- Flow types
Many applications for operational design involve highly transient behavior where temperatures are changing rapidly. Transient operations where fluid temperatures can change on the order of 100°F or more in a matter of minutes during flow in the well include:
- Production startup
Fully transient thermal response should be modeled in the flowing stream, the wellbore assembly, and the formation. The model should handle changing flow conditions, including:
- Changes in flow rate
- Inlet temperature and pressure
- Fluid type
- Flow direction
Oil and gas well operations involve fluids of many different types. The heat transfer characteristics and temperature-pressure coupling vary with fluid type. Oil- and water-based liquids and polymers behave differently from compressible systems. Multiple fluids in the wellbore, including spacers and displacement fluids, are an important consideration. Temperature dependent properties must be updated as temperatures and rheological properties change with time and depth. Even with drilling muds, the viscosity changes with temperature during the mud’s circuit down the drillpipe and up the annulus, affecting the overall hydraulics of the system.
Flexibility in wellbore geometry is needed to accommodate different configurations such as deviated wells, liners, dual completions, and offshore risers. The geometry determines the cross-sectional flow area and the fluid velocity, which, in turn, governs the heat transfer. Temperatures during liner cementing are strongly influenced by the size of the liner and the annular clearance.
Flow types include:
- Forward circulation
- Reverse circulation
Drilling is a special case of forward circulation, in which the depth of circulation and the wellbore thermal resistance change as the well is drilled and casing is set.
Noteworthy papers in OnePetro
G. Robello Samuel, Glenn McColpin, Landmark Graphics-Drilling & Well Services: Wellbore Hydraulic Optimization With Positive Displacement Motor and Bit 72320-MS http://dx.doi.org/10.2118/72320-MS.
Chemerinski, Bill, Imperial Oil Resources, Ltd.; Robinson, Leon, OGCI: Hydraulic Wellbore Erosion While Drilling. 30497-MS. http://dx.doi.org/10.2118/30497-MS.