UK Oil & Gas PLC (London AIM: UKOG) is pleased to announce that its Horse Hill-2z ("HH-2z") Portland horizontal well (UKOG 85.635% net controlling interest) has, to date, successfully drilled 2,016 ft wholly within the Portland reservoir's most oil productive zone or "sweet spot", the presence and quality of which was defined by the HH-2 pilot well's successful coring and electric logging programmes.
Following the fitting of a new rig engine, expected to be completed over the coming days, the remaining 1,200 ft of the planned circa 3,200 ft horizontal section within the "sweet-spot" will be drilled. Horizontal drilling is expected to be completed by mid-November.
Drilling data indicates that sections of possible increased reservoir quality over that seen in HH-1 and HH-2 have been encountered within the sweet-spot. Furthermore, mud weights indicate that the horizontal may lie within a reservoir zone that is less pressure depleted by HH-1 oil production than expected. A comprehensive electric logging and extended well test ("EWT") programme will further clarify these potentially positive outcomes.
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.
After cementing the 7-inch diameter casing down to 2373 ft, the well drilled ahead in 6-inch diameter hole, encountering the top Portland sandstone at a drilled depth below rig floor of 2389 ft, some 850 ft laterally southeast of the HH-2 surface location.
The well's 6-inch hole trajectory was increased from around 70° to vertical at the 7-inch casing shoe to its current 88°-90° to vertical, approximately parallel to the geological dip of the Portland. Electric logging tools close to the drilling bit together with rock cuttings have enabled the trajectory to be kept within an overall 35 ft thick section containing the highest permeability reservoir zones.
After reaching its total drilled depth, HH-2z will then be completed with production tubing and a downhole electric pump or "ESP" prior to a clean-up programme and extensive EWT campaign.
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:
"We have successfully delivered around two thirds of the planned horizontal section within the Portland reservoir's sweet-spot, a 35 ft zone containing the most productive, porous and permeable sandstones. Keeping within this zone is no mean feat and is a testament to the meticulous preparation and skill of our geologists and directional drillers. We remain on schedule to complete drilling the full trajectory around the middle of November, and will then immediately complete, clean-up and flow test the well."