19 December 2017
I was wondering if any of the esteemed members of the forum could share 'best practices' (or perhaps the not so best practices) to drill coal beds.
I am aware that Statoil has a method called Low Energy Drilling, but have no details on this.
Many thanks in advance.
Late response, but I would recommend reviewing the following published work by ExxonMobil 2008-2010 for 'best practices' mitigating borehole instability due to coal cleat pressurization (and resulting inability to maintain hoop stress) along with associated directional and drilling dynamics observations and strategies when drilling the transitions to the coal along with the formation itself.
SPE 125246 - Practices Implemented to Achieve Record Performance in Narrow Margin Drilling in Bass Strait Extended Reach
SPE 128712 - Utilizing an Engineered Particle Drilling Fluid to Overcome Coal Drilling Challenges
This may lead you down the rabbit hole to reading SPE 163481 - Practical Guide to Lost Returns Treatment Selection Based on a Holistic Model of the State of Near Wellbore Stresses which is worth more than a casual read in its own right.