Definition - What does Slimhole Well mean?
A Slimhole Well is a type of a gas or an oil well whose borehole size is significantly smaller than the usual borehole size. It is generally less than 6 inches in diameter and 4 ¾ inches or less deep. It is drilled by E&P organizations. The Slimhole Well sets a perfect correlation between the well cost and the volume of rock drilled out. It goes with a notation that the cost of developing a gas or an oil well will reduce when less rock is extracted.
Petropedia explains Slimhole Well
- Drilling Slimhole Wells is the most commonly accepted engineering criteria these days within the E&P industry space because it is estimated that the well development cost is reduced by 30% after following this drilling criteria. The small size diameter and shallow deepness has the following advantages:
- Uses less material in well preparation.
- Uses less rig hold time.
- Increases the number of drillings at the same time.
- Reduces waste mud volumes.
- Uses less manpower.
- Saves time in location preparation and many more advantages.
Some of the disadvantages of Slimhole Wells include:
- ECD (Equivalent Circulating Density) is high which can limit mud weight.
- It eliminates contingencies.
- Geophysical information is limited.
- Production will be for small rates.
- It limits potential for sidetrack option.
Production rates of up to 50 mmscfd gas, 4000 bpd oil are achievable in many cases through 4 1/8 inch size borehole and 3 ½ inch liner. There are two technologies commonly used for drilling Slimhole Wells, i.e., downsized conventional drilling and continuous coring method