The Surprise-1 well was re-entered on 18 November 2011 using Hunt Rig #3 and on 29 November 2011 the well reached a depth of 2,672m RKB in the Pacoota Sandstone.
The results of electric log analysis, coring and visual observations of cuttings and mud flow indicated a prospective oil flow from the well. The Company proceeded to drill an approximately 230m lateral which it then tested.
A number of dip changes were encountered during the horizontal drilling but the drill bit remained in sandstone throughout and with continuous oil shows. Of the 230m section drilled,approximately 10m rated less than good to excellent oil shows.
The first flow rates from testing were released to the market on 11 January 2012 with a maximum sustained flow rate of 300 barrels of oil per day (B OPD) over a four-hour test period, with a 7.5% drilling fluid cut.
The oil quality encountered had an API gravity averaging 40 degrees-light sweet crude and low gas oil ratios.
On 13 January 2012 the Company advised that further initial flow testing had concluded after recording a sustained flow rate via a 32/64” choke of 380 BOPD with a low 4.4% drilling fluid and/or water cut. The final PBU (Pressure Build Up) was 523 PSI. Independent consultants RPS Energy Pty Ltd (“RPS”) concluded that the well may access Stock TankOil Initially In Place (STOIIP) in the range of 0.5 to 2 million barrels in an area proximal to the well.
RPS based their calculations on a 105m section of the horizontal well bore placed in the lower half of an 8m thick sandstone reservoir section with an average permeability of 50 millidarcies and a vertical to horizontal permeability ratio of 10%.
RPS used a vertical wellbore model; further definition may be available by using horizontal wellbore modelling.
CTP Price at posting:
46.0¢ Sentiment: LT Buy Disclosure: Held
