Well Control

WELL CONTROL MANUAL

2.2 Z = Value of Gas 2.0 Mol. Wt = 23.5 SG = 0.8114 (Relative to air)
150 F
O

200 F
O

O

250 F

GAS COMPRESSIBILITY FACTOR Z

1.8

1.6

300 F

O

1.4

1.2
300 F
O

1.0

0.8 0.6 0 2 4

150 F

O

6

8

10

12

14

16

18

20

22

GAS PRESSURE 1000'S (psia)

Revision 2 October 2001

WELL CONTROL MANUAL

CONTENTSSECT 1 SECT 2 SECT 3 SECT 4 SECT 5 SECT 6 SECT 7 SECT 8 SECT 9 SECT 10 SECT 11 SECT 12 SECT 13 BASIC SCIENCE/DEFINITIONS/PRESSURE LOSS CALCULATIONS SUBSURFACE PRESSURES PORE PRESSURE PREDICTION AND EVALUATION CAUSES OF KICKS KICK INDICATORS SHUT-IN PROCEDURES STANDARD METHODS OF WELL CONTROL SPECIAL WELL CONTROL METHODS HORIZONTAL WELL CONTROL SPECIAL CONSIDERATIONS IN HPHT AND DEEP WATER WELLS DEEPWATER WELL CONTROL HPHT WELL CONTROL WELL CONTROL SYSTEMS

WELL CONTROL MANUAL

SECT 1
SECT 1.1 Basic Science / Definitions
1.1.1 Force 1.1.2 Density 1.1.3 Specific Gravity (SG) 1.1.4 Pressure 1.1.5 Hydrostatic pressure in liquid columns 1.1.6 Circulating pump pressure 1.1.7 Bottom Hole Pressure (BHP) 1.1.8 Equivalent Circulating Density (ECD) 1.1.9 Equivalent Mud Weight (EMW) 1.1.10Drilling Fluid Velocity 1.1.11 Viscosity

SECT 1.2 Pressure Loss Calculations
1.2.1 Introduction 1.2.2 Types of Flow in Pipes and Annuli 1.2.3 Rheological Models 1.2.4 Pressure Loss in the Well System 1.2.5 Procedure of Pressure Loss Calculation Using the Bingham Plastic Model 1.2.6 Summary of Pressure Loss Calculations Using the Power Law Model 1.2.7 Surface Line Pressure Losses 1.2.8 Flow throughJet Bits 1.2.9 Surge and Swab Pressures

WELL CONTROL MANUAL
SECTION 1: BASIC SCIENCE/DEFINITIONS/PRESSURE LOSSES

1.1 BASIC SCIENCE /DEFINITIONS
1.1.1 FORCE The force applied on an object is defined as the product of its mass and its acceleration: F = m.Γ Γ [1.1]

Where

m = mass, (lbm) Γ = acceleration, (ft/s/s) F = force, (lbf)

The above fundamental formula in dynamic becomes incase of force of gravity: F(gravity) = m.g = weight [1.2]

Where

g = gravitational acceleration = 32.174 ft/s/s or = 9.81 m/s/s

which means that the force of an object is simply the weight of that object expressed in pound-force or kilogram force. 1.1.2 DENSITY The density of any substance is the mass of that substance divided by it's volume: m ρ = –– V Where m = mass, lbm V = volume, usgal ρ = density lbm/gal
Rev 2 - Oct 2001
1-1

[1.3]

WELL CONTROL MANUAL
SECTION 1 : BASIC SCIENCE/DEFINITIONS/PRESSURE LOSSES

Important note: Considering the law of conservation of mass, the Drilling Engineer could assume that the mass concentration or the drilling fluid density at any point of interest in the well remains constant (Steady state conditions). In standard conditions it canbe assumed that the increase in density due to pressure increase is equal to the reduction in density due to temperature increase when the well depth increases. Thus, the hydrostatic pressure at a given depth can be written using the isothermal formula:

HP = c x ρ x TVD Where ρ = constant
TVD = True Vertical Depth (ft) 1.1.3 SPECIFIC GRAVITY (SG)

[1.4]

The specific gravity of asubstance is the density of that substance divided by the density of fresh water.

SG =

density of a substance –––––––––––––––––––– = density of freshwater

ρs ––– ρ fw

[1.5]

ρs and ρfw are expressed in the same units 1.1.4 PRESSURE The pressure is defined as the force divided by the area that force is acting on:

Pressure = Force Area (Specific case : Pressure = Weight )
Area

[1.6]1-2

Rev 2 - Oct 2001

WELL CONTROL MANUAL
SECTION 1: BASIC SCIENCE/DEFINITIONS/PRESSURE LOSSES

1.1.5 HYDROSTATIC PRESSURE IN LIQUID COLUMNS This is the pressure exerted due to the weight and vertical height of a column of liquid. The size and shape of the column do not affect the magnitude of the pressure.

TVD

Fig.1.1 Different shaped vessels

The variation of the hydrostatic...