Tubular Material Selection for HTHP Well with Example Calculation

This article demonstrates how to select material that will be suitable for high pressure, high pressure and corrosive environment. The material chart is based on the Sumitomo tubular chart.

Well conditions are as follows;

Reservoir: High pressure & high temperature gas reservoir

Reservoir Temperature: 420 F (216 C)

CO₂ content: 2.9% mol

H₂S:40 ppm

Chloride Ion Content in Produced Water: 150,000 ppm

Fluid saturation pressure: 10,000 psig

Solution

1. Determine Partial Pressure

 Partial pressure = fraction of gas × fluid saturation pressure (psia)

 Fluid saturation pressure (psia) = Fluid saturation pressure (psig) + 14.7 psi

Fluid saturation pressure (psia) = 10,000 + 14.7 =10,014.7 psia

CO₂ partial pressure (psia) = 10,014.7 × (2.9/100) = 290 psia

CO₂ partial pressure (atm) = 290 ÷ 14.7 = 19.8 atm

H₂S content = 100ppm = 40 ÷ 1,000,000 = 0.00004

H₂S partial pressure (psia) = 10,014.7 × 0.00005 = 0.4 psia

H₂S partial pressure (atm) = 0.5 ÷ 14.7 = 0.027 atm

2. Check with the tubular chart. For this exercise, Sumitomo steel is used.

Look up at the chart to check.

The chart suggests SM 13CSR-80, 90.

For the corrosion stand point, SM 13CSR-80, 90 will work, but this material will safely operate under temperature below 175 C and chloride content below 50,000 ppm.

The given reservoir conditions are too harsh for this material.

Reservoir Temperature: 420 F (216 C)

Chloride Ion Content in Produced Water: 150,000 ppm

Fluid saturation pressure: 10,000 psig

The better grade must be selected for this reservoir environment. Some pipe grades that can be chosen are as follows;

• SM 25CRW-110, 125
• SM 25CR-110, 125
• SM 25CR-110, 125

References

Jonathan Bellarby, 2009. Well Completion Design, Volume 56 (Developments in Petroleum Science). 1 Edition. Elsevier Science.

Wan Renpu, 2011. Advanced Well Completion Engineering, Third Edition. 3 Edition. Gulf Professional Publishing.

Ted G. Byrom, 2014. Casing and Liners for Drilling and Completion, Second Edition: Design and Application (Gulf Drilling Guides). 2 Edition. Gulf Professional Publishing.