Pore Pressure and Methods of Analysis Section 3 PPFG Modeling Principles Part 7 Model Calculations Reference

Part 7.???Model Calculations Reference Height

???????????????All pressure gradient calculations are equivalent to the density of the height of a fluid from the reference height of the model to the depth of the calculation. Given the height of the fluid column, the pressure generated will be determined by the density of the fluid.

Pressure gradient units are usually the density of the hypothetical fluid (ppg, sg, etc.), but sometimes are expressed in change in pressure given a change in depth (psi/ft, pa/m, etc.). To convert from sg and g/cc to ppg, 1.0 sg is equal to 8.3454 ppg. The most common reference heights used are the surface elevation, mean sea level, and the elevation at the drill floor (RKB).

Figure 21.???????????Model Reference Heights of MSL and RKB

Figure 22.???????????MSL and RKB Model Calculations: Water Depth of 700 feet and RKB Height of 100 feet

Figure 23.???????????MSL and RKB Model Calculations: Onshore