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OutlinePore Pressure and Fracture Gradient
Drilling Fluid
Casing Design
Cement Design
Drilling Bit
Economic Analysis
Pore Pressure and Fracture Gradient
Equation used
Pff = 0.33 x [(σOB / d) + 2 x (σpore / d)]
Pore Pressure Gradient
Approximately 0.42 psi/ft
Fracture Gradient
Approximately 0.73 psi/ft
Casing DesignAPI GRADE Yield Strength Min Ultimate Strength Min Elongation
J-55 40K (min) – 80K (max) [psi] 60K psi 29.5%
[Table 7.1 from text]
Based off of the calculated yield strength: around 42,000 psi
No need for larger ultimate strength
Water Table between 500 – 2000 foot (From NE)
Conductor Casing: 50 feet
Surface Casing: 2200 feet
Intermediate Casing: 6000 feet
Production Casing: 12000 feet
50
2200
6000
12000
Casing Design cont’d Casing Diameter Casing Pressure
Conductor 23.125 in 20 in 35 psi
Surface 19.2 in 14 in 1100 psi
Intermediate 13.5 in 11.25 in 2460 psi
Production 9.4 in 8.4 in 4850 psi
• SF = 1.7
Casing Design cont’d Casing Collapse Res.
Conductor 480 psi
Surface 1875 psi
Intermediate 5500 psi
Production 10200 psi
MW = Pressure x (0.052 x TVD)
Drilling Fluid Casing Mud Weight
Conductor 13.4 ppg
Surface 8.76 ppg
Intermediate 7.58 ppg
Production 6.16 ppg
MW = Pressure x (0.052 x TVD)
Cement DesignType: Class C
High early strength properties which allows cement to be used at high water levels.
Regularly used for shallow well cementing operations through salt beds.
Density of the cement = 11.53 ppg
Cement Design cont’dAc = ( dout
2 – din
2) / 1029.4 (bbl/ft)
Volume = Ac (bbl/ft) * Depth (ft)
Casing Cement Volume
Conductor 6.5 bbl 36.498 ft3
Surface 368.9 bbl 2071.37 ft3
Intermediate 324.58 bbl 1822.52 ft3
Production 207.49 bbl 1165.07 ft3
Total cement Volume 907.47 bbl 5095.44 ft3
Drilling BitDrilling through shale and sandstone
We will use Poly diamond crystal bit (because they are faster and tend not to break as often as other bits)
Use multi pad drilling (Will use 75% less land)
DrillingHow many days to reach depth?
It will take about 14 and half days to drill to the pay zone with an average rate of penetration of 34.3 ft/hr
How much will it cost per day?
rule-of-thumb for trip-time estimations is 1 hr/1,000 ft of a well.
C= [(R=$1125)( (t=12 hrs) +(td=350hrs)+Cb
$25,000]/(F=12,000ft) = $36.02/ft
$29,652.35
How much will it cost total to drill?
$432,331.27
Economical Analysis