How to Calculate and Solve for Gas Recovery Factor (Production) | Reservoir Fluid Flow

The image above represents a gas recovery factor (G).

To compute for a gas recovery factor (production), two essential parameters are needed and these parameters are cumulative gas production (GP) and initial gas in place (G).

The formula for calculating the gas recovery factor (G):

RFG = Gp / G

Where:

RFG = Gas Recovery Factor (G)
GP = Cumulative Gas Production
G = Initial Gas in Place

Let’s solve an example;
Find the gas recovery factor (G) when the cumulative gas production is 13 and the initial gas in place is 17.

This implies that;

GP = Cumulative Gas Production = 13
G = Initial Gas in Place = 17

RFG = Gp / G
RFG = 13 / 17
RFG = 0.764

Therefore, the gas recovery factor (G) is 0.764.

Calculating the Cumulative Gas Production when the Gas Recovery Factor (G) and the Initial Gas in Place is Given.

GP = RFG x G

Where;

GP = Cumulative Gas Production
RFG = Gas Recovery Factor (G)
G = Initial Gas in Place

Let’s solve an example;
Find the cumulative gas production when the gas recovery factor (G) is 24 and the initial gas in place is 6.

This implies that;

RFG = Gas Recovery Factor (G) = 24
G = Initial Gas in Place = 6

GP = RFG x G
GP = 24 x 6
GP = 144

Therefore, the cumulative gas production is 144.

How to Calculate and Solve for Gas Recovery Factor of a Reservoir Fluid Flow | The Calculator Encyclopedia

The image above represents a gas recovery factor.

To compute for the gas recovery factor, three essential parameters are needed and these parameters are initial pressure(Pi), initial compressibility factor (Ziand P/Z Ratio (P/Z).

The formula for calculating the gas recovery factor:

RFG = 1 – P/Z.Pi / Zi

Where;

RFG = Gas Recovery Factor (P, Z)
Pi = Initial Pressure
Zi = Initial Compressibility Factor
P/Z = P/Z Ratio

Let’s solve an example;
Find the gas recovery factor when the initial pressure is 12, the initial compressibility factor is 7 and the P/Z ratio is 36.

This implies that;

Pi = Initial Pressure = 12
Zi = Initial Compressibility Factor = 7
P/Z = P/Z Ratio = 36

RFG = 1 – P / Z.Pi / Zi
RFG = 1 – 36[12 / 7]
RFG = 1 – 36[1.714]
RFG = 1 – 61.714
RFG = -60.714

Therefore, the gas recovery factor is -60.714.

How to Calculate and Solve for Pressure and Initial Compressibility Factor Ratio of a Reservoir Fluid Flow | The Calculator Encyclopedia

The image above represents pressure and initial compressibility factor ratio (P/Z Ratio).

To compute for the pressure and initial compressibility factor ratio, four essential parameters are needed and these parameters are initial pressure (Pi), Initial Compressibility Factor (Zi), Cumulative Gas Production (GP) and initial gas in place (G).

The formula for calculating the P/Z Ratio:

P/Z = Pi / Zi (1 – Gp / G)

Where;

P/Z = P/Z Ratio
Pi = Initial Pressure
Zi = Initial Compressibility Factor
GP = Cumulative Gas Production
G = Initial Gas in Place

Let’s solve an example;
Given that the initial pressure is 20, the initial compressibility factor is 28, the cumulative gas production is 30 and the initial gas in place is 34.
Find the pressure and initial compressibility factor ratio (P/Z Ratio)?

This implies that;

Pi = Initial Pressure = 20
Zi = Initial Compressibility Factor = 28
GP = Cumulative Gas Production  = 30
G = Initial Gas in Place = 34

P/Z = Pi / Zi (1 – Gp / G)
P/Z = 20 / 28 (1 – 30 / 34)
P/Z = 20 / 28 (1 – 0.88)
P/Z = 20 / 28 (0.117)
P/Z = 0.714(0.117)
P/Z = 0.084

Therefore, the P/Z Ratio is 0.084.

Calculating for Initial Pressure when P/Z Ratio, Initial Compressibility Factor, Cumulative Gas Pressure and Initial Gas In Place is Given.

Pi = P/Z x Zi / (1 – Gp / G)

Where;

Pi = Initial Pressure
P/Z = P/Z Ratio
Zi = Initial Compressibility Factor
GP = Cumulative Gas Production
G = Initial Gas in Place

Let’s solve an example;
Given that the P/Z Ratio is 50, the initial compressibility factor is 18, the cumulative gas production is 25 and the initial gas in place is 32.
Find the initial pressure ?

This implies that;

P/Z = P/Z Ratio = 50
Zi = Initial Compressibility Factor = 18
GP = Cumulative Gas Production = 25
G = Initial Gas in Place = 32

Pi = P/Z x Zi / (1 – Gp / G)
Pi = 50 x 18 / (1 – 25 / 32)
Pi = 900 / (1 – 0.78125)
Pi = 900 / (0.21875)
Pi = 4114.28

Therefore, the Initial Pressure is 4114.28.

Calculating for Initial Compressibility Factor when P/Z Ratio, Initial Pressure, Cumulative Gas Pressure and Initial Gas In Place is Given.

Zi = Pi (1 – Gp / G) / P/Z

Where;

Zi = Initial Compressibility Factor
Pi = Initial Pressure
P/Z = P/Z Ratio
GP = Cumulative Gas Production
G = Initial Gas in Place

Let’s solve an example;
Given that the P/Z Ratio is 40, the initial pressure is 18, the cumulative gas production is 15 and the initial gas in place is 22.
Find the initial compressibility factor ?

This implies that;

Pi = Initial Pressure = 18
P/Z = P/Z Ratio = 40
GP = Cumulative Gas Production = 15
G = Initial Gas in Place = 22

Zi = Pi (1 – Gp / G) / P/Z
Zi = 18 (1 – 15 / 22) / 40
Zi = 18 (1 – 0.681) / 40
Zi = 18 (0.319) / 40
Zi = 5.742 / 40
Zi = 0.1435

Therefore, the initial compressibility factor is  0.1435.

How to Calculate and Solve for Gas Initially in Place of a Reservoir Fluid Flow | The Calculator Encyclopedia

The image above represents gas initially in place.

To compute for gas initially in place, five essential parameters are needed and these parameters are drainage area (A), initial gas FVF (Bgi), initial water saturation (Swi), porosity (φ) and thickness (h).

The formula for calculating gas initially in place:

G = 43560Ah φ (1 – Swi) / Bgi

Where;

G = Gas Initially in Place
A = Drainage Area
Bgi = Initial Gas FVF
Swi = Initial Water Saturation
φ = Porosity
h = Thickness

Let’s solve an example;
Find the gas initially in place with a drainage area of 44, initial gas FVF of 23, initial water saturation of 32, porosity of 18 and exponent of 14.

This implies that;

A = Drainage Area = 44
Bgi = Initial Gas FVF = 23
Swi = Initial Water Saturation = 32
φ = Porosity = 18
h = Thickness = 14

G = 43560Ah φ (1 – Swi) / Bgi
G = 43560 x 44 x 14 x 18 (1 – 32) / 23
G = 43560 x 44 x 14 x 18 (-31) / 23
G = -14972791680 / 23
G = -650990942.6

Therefore, the gas initially in place is -650990942.6

How to Calculate and Solve for Gas Flow of Reservoir Fluid Flow | The Calculator Encyclopedia

The image above represents gas flow.

To compute for the gas flow, four essential parameters are needed and these parameters are Performance Co-efficient (C), Average Reservoir Pressure (Pr*), Flowing Bore Hole Pressure (Pwf*) and Exponent (n).

The formula for calculating the gas flow:

Qg = C(Pr*² – Pwf*²)n

Where;

Qg = Gas Flow
C = Performance Co-efficient
Pr* = Average Reservoir Pressure
Pwf* = Flowing Bore Hole Pressure
n = Exponent

Let’s solve an example;
Find the gas flow when a performance Co-efficient is 9, average reservoir pressure is 10, flowing bore hole pressure is 5 and an exponent of 20 is given.

This implies that;

C = Performance Co-efficient = 9
Pr* = Average Reservoir Pressure = 10
Pwf* = Flowing Bore Hole Pressure = 5
n = Exponent = 20

Qg = C(Pr*² – Pwf*²)n
Qg = 9(10² – 5²)20
Qg = 9(100 – 25)20
Qg = 9(75)20
Qg = 9(3.17e+37)
Qg = 2.85e+38

Therefore, the gas flow is 2.85e+38.

How to Calculate and Solve for Total Compressibility of a Reservoir Fluid Flow | The Calculator Encyclopedia

The image above represents the total compressibility.

To compute for the total compressibility, seven essential parameters are needed and these parameters are Water compressibility (Cw), Oil compressibility (Co), Gas compressibility (Cg), Rock compressibility (Cr), water saturation (Sw), Oil saturation (So) and Gas saturation (Sg).

The formula for calculating the total compressibility:

CT = CoSo + CgSg + CwSw + Cr

Where;

CT = Total Compressibility
Cw = Water Compressibility
Co = Oil Compressibility
Cg = Gas Compressibility
Cr = Rock Compressibility
Sw = Water Saturation
So = Oil Saturation
Sg = Gas Saturation

Let’s solve an example;
With a given value of 13 as water compressibility, 17 as oil compressibility, 19 as gas compressibility, 25 as rock compressibility, 24 as water saturation, 29 as oil saturation and 21 as gas saturation.
Find the total compressibility?

This implies that;

Cw = Water Compressibility = 13
Co = Oil Compressibility = 17
Cg = Gas Compressibility = 19
Cr = Rock Compressibility = 25
Sw = Water Saturation = 24
So = Oil Saturation = 29
Sg = Gas Saturation = 21

CT = CoSo + CgSg + CwSw + Cr
CT = (17 x 29) + (19 x 21) + (13 x 24) + 25
CT = 493 + 399 + 312 + 25
CT = 1229

Therefore, the total compressibility is 1229 psi.

How to Calculate and Solve for Solution Gas – Oil Ratio of a Reservoir Fluid Flow | The Calculator Encyclopedia

The image above represents a Gas – Oil Ratio.

To compute for the gas – oil ratio, seven essential parameters are needed and these parameters are Solution Gas (Rs), Oil Viscosity (μo), Gas Viscosity (μg), Relative Permeability to Gas (krg), Relative Permeability to Oil (kro), Gas Formation Volume Factor (Bg) and Oil Formation Volume Factor (Bo).

The formula for calculating the gas – oil ratio:

GOR = Rs + [krg /  kro] [μoBo / μgBg]

Where;

GOR = Solution Gas-Oil Ratio
Rs = Solution Gas
μo = Oil Viscosity
μg = Gas Viscosity
krg = Relative Permeability to Gas
kro = Relative Permeability to Oil
Bg = Gas Formation Volume Factor
Bo = Oil Formation Volume Factor

Let’s solve an example;
Find the Gas – Oil Ratio with a solution gas of 11, oil viscosity of 7, gas viscosity of 9, relative permeability to gas of 12, relative permeability to oil of 16, gas formation volume factor of 22 and oil formation volume factor of 18.

This implies that;

Rs = Solution Gas = 11
μo = Oil Viscosity = 7
μg = Gas Viscosity = 9
krg = Relative Permeability to Gas = 12
kro = Relative Permeability to Oil = 16
Bg = Gas Formation Volume Factor = 22
Bo = Oil Formation Volume Factor = 18

GOR = Rs + [krg /  kro] [μoBo / μgBg]
GOR = 11 + [12/16] [7 x 18 /9 x 22]
GOR = 11 + [12/16] [126/198]
GOR = 11 + [12/16] [0.63]
GOR = 11 + [0.75] [0.63]
GOR = 11 + 0.477
GOR = 11.477

Therefore, the Gas – Oil Ratio is 11.477.

How to Calculate and Solve for the Water – Oil Ratio of a Reservoir Fluid Flow | The Calculator Encyclopedia

The above image represents Water – Oil Ratio.

To compute for the water – oil ratio, six essential parameters are needed and these parameters are o)Oil Viscosity, (μw)Water Viscosity, (krw)Relative Permeability to Water, (kro)Relative Permeability to Oil, (Bw)Water Formation Volume Factor and (Bo)Oil Formation Volume Factor.

The formula for calculating the water – oil ratio:

WOR = [krw / kro] [μoBo  / μwBw ]

Where;

WOR = Water Oil Ratio
μo = Oil Viscosity
μw = Water Viscosity
krw = Relative Permeability to Water
kro = Relative Permeability to Oil
Bw = Water Formation Volume Factor
Bo = Oil Formation Volume Factor

Let’s solve an example;
Find the water – oil ratio when the oil viscosity is 9, water viscosity is 11 with a relative permeability to water of 21, relative permeability to oil of 7 and a water formation volume factor of 14 with oil formation volume factor of 27.

This implies that;

μo = Oil Viscosity = 9
μw = Water Viscosity = 11
krw = Relative Permeability to Water = 21
kro = Relative Permeability to Oil = 7
Bw = Water Formation Volume Factor = 14
Bo = Oil Formation Volume Factor = 27

WOR = [krw / kro] [μoBo  / μwBw ]
WOR = [21/7] [9 x 27 /11 x 14]
WOR = [21/7] [243/154]
WOR = [21/7] [1.5779]
WOR = [3] [1.5779]
WOR = 4.73

Therefore, the Water – Oil Ratio is 4.73.

How to Calculate and Solve for the Average Pressure of a Reservoir Fluid Flow | The Calculator Encyclopedia

The above image represents the reservoir fluid.

To compute for the reservoir fluid, two essential parameters are needed and these parameters are External pressure (Peand Flowing Bottom-Hole Pressure (Pwf).

The formula for calculating the average pressure of the reservoir fluid:

P* = √[Pe² + Pwf² / 2]

Where;

P* = Average Pressure
Pe = External Pressure
Pwf = Flowing Bottom-Hole Pressure

Let’s solve an example;
Find the average pressure of a reservoir fluid with an external pressure of 19 and Flowing bottom-hole pressure is 15.

This implies that;

Pe = External Pressure = 19
Pwf = Flowing Bottom-Hole Pressure = 15

P* = √[Pe² + Pwf² / 2]
P* = √[19² + 15² / 2]
P* = √[361 + 225 / 2]
P* = √[586 / 2]
P* = √[293]
P* = 17.117

Therefore, the average pressure is 17.117 psi;.

Calculating the External Pressure when the Average Pressure and the Flowing Button-Hole Pressure is Given.

Pe = √[[P* x 2]² – Pwf²]

Where;

Pe = External Pressure
P* = Average Pressure
Pwf = Flowing Bottom-Hole Pressure

Let’s solve an example;
Find the external pressure of a reservoir fluid with an average pressure of 24 and Flowing bottom-hole pressure is 16.

This implies that;

P* = Average Pressure = 24
Pwf = Flowing Bottom-Hole Pressure = 16

Pe = √[[P* x 2]² – Pwf²]
Pe = √[[24 x 2]² – 16²]
Pe = √[2048]
Pe = 45.25

Therefore, the external pressure is 45.25.

How to Calculate and Solve for a Well Drainage Area | Nickzom Calculator

The image above represents well drainage area.

To compute for the well drainage area, three essential param xeters are needed and these parameters are Total Area of Field (AT), Well Flow Rate (qwand Field Flow Rate (qr).

The formula for calculating the well drainage area:

Aw = Ar[qw / qr]

Where;

Aw = Well Drainage Area
AT = Total Area of Field
qw = Well Flow Rate
qr = Field Flow Rate

Let’s solve an example;
Find the well drainage area when the total area of field is 11, well flow rate is 9 and the field flow rate is 6.

This implies that;

AT = Total Area of Field = 11
qw = Well Flow Rate = 9
qr = Field Flow Rate = 6

Aw = AT[qw / qr]
Aw = 11[9/6]
Aw = 11[1.5]
Aw = 16.5

Therefore, the well drainage area is 16.5 ft².

Calculating the Total Area of Field when Well Drainage Area, Well Flow Rate and Field Flow Rate is Given.

AT = Aw (qr / qw)

Where;
AT = Total Area of Field
Aw = Well Drainage Area
qw = Well Flow Rate
qr = Field Flow Rate

Let’s solve an example;
Find the total area of field when the well drainage area is 32, well flow rate is 11 and the field flow rate is 14.

This implies that;
Aw = Well Drainage Area = 32
qw = Well Flow Rate = 11
qr = Field Flow Rate = 14

AT = Aw (qr / qw)
AT = 32 (14 / 11)
AT = 32 (1.272)
AT = 40.704

Therefore, the total area of field is 40.704.

Calculating the Field Flow Rate when Well Drainage Area, Total Area of Field and Well Flow Rate is Given.

qr = qw (Ar / Aw)

Where;
qr = Field Flow Rate
AT = Total Area of Field
Aw = Well Drainage Area
qw = Well Flow Rate

Let’s solve an example;
Find the field flow rate when the well drainage area is 42, total area of field is 32 and the well flow rate is 24.

This implies that;
Aw = Well Drainage Area = 42
AT = Total Area of Field = 32
qw = Well Flow Rate = 24

qr = qw (AT / Aw)
qr = 24 (32 / 42)
qr = 24 (0.7619)
qr = 18.285

Therefore, the Field Flow Rate is 18.285.