Chapter 9 Thermal Wells

Question 1

BOP Elastomers should have a temperature rating of ____ degrees C and a peak working rating of ____ degrees C for one hour emergency services.

Answer 1

121C

177C

Question 2

Flexible hoses should have a temperature rating of ____ degrees C and a peak working rating of ____ degrees C for one hour emergency services

Answer 2

121C

160C

Question 3

Drilling fluids usually consist of brine solution. Increase in temperature will ____ the effective brine weight.

Answer 3

Decrease

Question 4

Why are ECD’s a consideration in thermal wells?

Answer 4

ECD’s increase with measure depth, losses might occur into the pair well as the fracture gradient of the horizontal formation doesn’t change.

Question 5

The recommend reserve drilling fluid additives and volume while drilling thermal wells are ___%.

Answer 5

50%

Question 6

True or False: any well drilled into, or in close proximity to a thermally enhanced reservoir can be considered to be a Thermal well.

Answer 6

True

Question 7

True or False: While drilling a thermal well, risks are associated with drilling the vertical section as the caprock integrity might be compromised.

Answer 7

True

Question 8

Key steps in producing the drilling program for a thermal well are :

Answer 8

• Determine the outer boundaries of the production affected area.
• Communicate with nearby status of wells proximal to your operations.
• Consider the heating of wellbore fluids during trips or extended periods of downtime.
• Drilling fluid contamination.
• Create the deviation control program (this is issued for all wells including intended straight holes).
• Estimate the uncertainty in the evaluation of the pore pressure.
• Consider the lack flexibility in casing seat selection due to directional constraints and caprock.

Question 9

When drilling both the caprock & thermal sections of a well the following should be considered:

Answer 9

• Closely monitor returns and drilling fluid temperature while drilling.
• Check all drill pipe to ensure hard banding is of “flush” to minimize potential casing wear.
• Drilling operations should be suspended if the temperature of the drilling fluid return at surface could present a hazard to personal.
• When not circulating, the well should be monitored continuously and consider circulating continuously across the trip tank.
• The trip tank should be kept half full when in use. If it is not being used, the contents should be pumped out and replaced every tour.