UK Oil & Gas PLC (London AIM: UKOG) is pleased to announce that, following the successful completion of the Horse Hill-2 ("HH-2") Portland pilot well, Horse Hill-2z ("HH-2z") horizontal drilling operations are now underway (UKOG 85.635% net controlling interest). HH-2z aims to deliver a circa 3,200 ft horizontal section wholly within the Portland reservoir's most oil productive zone or "sweet spot", the presence and quality of which has been further defined by the pilot well's highly successful coring and electric logging programmes.
The significant oil saturations and high permeabilities observed in HH-2 core and logs, indicate that the "sweet spot" has likely contributed the lion's share of the 29,568 barrels of Brent quality oil produced to date from Portland extended well testing ("EWT") operations at HH-1.
HH-2/2z, the first horizontal well in the field's Portland oil pool, is designed to be retained as a future production well, capable of delivering flow rates significantly higher than the previously reported 362 barrels of oil per day from the HH-1 vertical Portland discovery well. Following a planned extensive HH-2z EWT campaign, both HH-2z Portland and the HH-1 Kimmeridge well are expected to be put into long term production by the end of 2019.
HH-2z operations were initiated through the pilot well's 9⅝" casing at the planned "kick-off" point
1320 ft below rig floor, immediately above cement plugs isolating the Portland reservoir below. The well is now building angle towards the horizontal within 8½" diameter hole and will continue down to a drilled depth of around 2300 ft, just above the Portland target zone. This section will then be cased and cemented with a 7" liner.
The well's trajectory will then continue within 6" diameter hole, entering the Portland target zone approximately 850 ft to the southeast of the HH-2 surface location. HH-2z's expected total measured depth is around 5900 ft from rig floor, of which c. 3200 ft is planned within the reservoir's sweet-spot. The well is expected to reach its total depth around mid-November.
To ensure the borehole remains wholly within the Portland sweet spot, HH-2z will be actively "geo-steered" during drilling to keep within a series of core and electric log-derived diagnostic geological markers delineating the zone's upper and lower boundaries. The successful delivery of such an optimally placed horizontal trajectory is designed to optimise flow rates and oil recoveries from the Portland reservoir.
UKOG holds a controlling 85.635% interest in the Horse Hill oil field and surrounding highly prospective PEDL137 and PEDL246 licences, which are operated by UKOG's subsidiary company, Horse Hill Developments Ltd.
Stephen Sanderson, UKOG's Chief Executive, commented:
"Our confidence in the HH-2z horizontal's ability to deliver significant flow rates has been further boosted by the pilot well's better than expected geological results. Our subsurface team's focus is now firmly upon steering the well wholly within the target zone, the Portland sweet spot , demonstrably the most oil productive part of the reservoir. I have every confidence we can deliver the desired positive result."