We've all seen endless speculation as to reasons why Wahoo, Bobcat and Raptor are taking so long. We know for sure that drilling diffficulties have been a major reason, if not the only reason. Wahoo is proof of that. In the announcement on that on Wahoo, Hession said that testing the gas filled shale, which he believes is just above a productive reservoir, could be an "option."
Reservoir engineering is not my specific role, but I've worked with the best ones in my company and learned a few things along the way. Production testing conducted by IOC to date amazed me at the brevity and limited amount of gas produced in the process. Because of that I was concerned whether the test results would provide sufficiently reliable information as to the reservoir size, generally referred to as areal extent. A short test proves productivity index, i.e., how much flow rate you get per psi of drawdown. You get permeability and thickness data. But you don't know how big the box is. Reservoir engineers use pressure transient testing to determine that. For a highly permeable, well connected reservoir that test may take only days. For something of poorer quality, a much longer test period may be required. In some extreme cases where the cost to develop is very high, and the uncertainties/risks are high, an extended production test is conducted. This may exceed a month in terms of flowing days and shutin/pressure buildups. Generally, these limestones and dolomite rocks, referred to as hard rock, in many places do not have high permeability and porosity as does sandstone. Natural fractures present in the rock are what makes the best reservoirs highly productive and hold large HC volumes. A view of IOCs published test results in consultant reports confirms that thiers is more typical of hard rock.
Secondly, wells often penetrate multiple productive horizons. Each of these can be separate reservoirs. Most regulators prohibit commingling of these reservoirs (i.e., flowing both at the same time up the same production tubing) without proper permits and technical justification for doing so. E.g., if it is uneconomic to produce both separately, then commingling may be allowed. So if IOC is seeing multiple, substantial productive horizons, then they would need to, and definitely want to, test each separately to fully interpret what they have. The better the data set for each zone tested, which means longer testing, then the greater the confidence anyone will have about developing and investing. Better data can eliminate the need for e.g., additional appraisal wells. Who knows, longer testing at E/A might have secured a better bid sooner, and more bidders the first time around.
So we know they are having drilling problems, but they may be in a new phase as we speak (or type). Hopefully they are. Also these new operations can run into their own problems, causing additional delay and cost. But if they have more than just 1 zone to test per well, that in general is not bad news, especially if each zone is big. But in general you'd rather have one humongously thick, totally connected zone per well. That would mean fewer wells to drill in development which equates to less captial and more profit.
