New CBM field test.

[nonAPI]

Hey zdas04 and anyone else who has a thought on the subject.

I am preparing to drill some coal exploration holes that are going to be permitted as gas wells just in case the gas content warrants a pilot project. This is a new field test a couple of hundred miles from the nearest CBM production. The coal is in the Dakota at roughly 1,275'. We will be retrieving 2.495" cores on wireline using an HQ coring system. Any advice or snakes in the grass I should be looking for?

Thanks for any input.

Cliff

 

[zdas04]

Cliff,
The one thing that I've always wished we'd done better in the early days of the San Juan Coal is collect and organize data. Getting P(i) with a bomb, BHT, and initial gas content would have made my life so much easier as I tried to figure out how to produce the wells. One key data point that everyone misses is in-situ CO2 (or N2 or whatever problem inert you'll find there). Out of all the wells we drilled here I can only find two places where a gas sample was analyzed prior to sales - both cases were around 18% and the first sales-gas analysis on both wells was under 5%. Knowing what the gas is before you disturb it too much is really useful for predicting peak CO2 for facility sizing (our current CO2 is over 25%).

I'm a flangehead and I'm not very familiar with the driller's tools - does the HQ coring system deal well with keeping an unconsolidated core pressurized until it gets to the lab? We got some really meaningless data from unpressurized cores that rattled around for a few weeks before anyone tried to do the gas content, vitrinite reflectance, etc. calcs. Everyone also tries to do perm calcs on the core, but I've found that data to be useless (coal is a pretty good cap rock after all and all of the flow to sales is through the modified cleat system not pore-to-pore).

Can you share where you're drilling these wells? If you need any help with the facilities and infrastructure give me a call.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com

 

[nonAPI]

zdaso4,

The HQ coring system allows for continuous coring with the cores being wireline retrievable. We will have the cannisters and testing trailer onsite and the core will go into the cannisters as they are removed from the core sleeve.
I had not thought ahead far enough to run a pressure/temperature bomb and I will have the opportunity to do so prior to running casing and after coring. Good suggestion. We will have the gas from the core analyzed for inerts also. We are allso going to collect a water sample prior to running casing. Who knows maybe it will be able to be surface discharged.
I have read several articles which mention a permeability calculation and have wondered (not being an engineer myself) how in the world they could come up with that figure and actually have it mean anything.
A little later in the permitting process I'll be able to talk.

Cliff