A New Method for Predicting the Position of Gas Influx Based on PRP in Drilling Operations

Table 1

Basic parameters.

Parameter	Value
The length of drill collar (m)	200
The length of drill pipe (m)	3800
Diameter of bit (m)	0.2159
Outside diameter of drill pipe (m)	0.127
Inside diameter of drill pipe (m)	0.1086
Outside diameter of drill collar (m)	0.1778
Inside diameter of drill collar (m)	0.078
Drill pipe roughness (m)	0.0154
Flow rate for mud pump (m^3/s)	0.037
String elastic modulus (Pa)	2.07 × 10^11
Drilling mud density (kg/m^3)	1460
String Poisson's ratio	0.3
Drilling fluid compressibility (1/kPa)	5.7 × 10^−8
Surface temperature (°C)	25
The ground atmospheric pressure (MPa)	0.101
The wall roughness (m)	0.1