Real-Time Interpretation Model of Reservoir Characteristics While Underbalanced Drilling Based on UKF

Table 1

Basic parameters for well X.

Parameters	Value	Parameters	Value
Well depth (m)	3000	Yield point (Pa)	3.84
Casing shoe depth (m)	2200	Surface temperature (°C)	20
Casing ID (mm)	228.47	Geothermal gradient (°C/m)	0.0266
Bit diameter (mm)	215.9	Casing pressure (MPa)	1
Drill pipe OD (mm)	127	Gas injection rate (Nm^3/s)	0.5
Drill pipe ID (mm)	108.6	ROP (m/h)	16
Bit nozzle area (mm^2)	660	Oil density (kg/m^3)	850
Pump rate (L/s)	30	Oil viscosity (mPa·s)	30
Mud density (kg/m^3)	1180	Compressibility of liquid (Pa^-1)
Consistency index (Pa·s^n)	0.37	Reservoir porosity	0.15
Flow behavior index	0.68	Skin factor	0.013