RE: RNS14 Mar 2019 14:09
Alan2017
Both well worth reading in full to form your own conclusions but highlights.
http://www.ukogplc.com/page.php?pID=115
Consequently, neither the drilling fluid nor drilling and coring methodology appears to have “damaged” the reservoir (i.e. blocked or plugged fractures surrounding the well bore). As to whether these fractures remained fully or partly open during the necessary pressure draw-downs following acidisation used during testing is currently under investigation.
This has now been updated with the following
http://www.ukogplc.com/page.php?pID=115
Similarly, we have no intention to use this process, known as matrix acidisation, in the future at Horse Hill, Broadford Bridge or other Weald Basin wells with the same targets. Recent studies of our nearby Broadford Bridge-1 well show that, because of the chemical composition of the rocks, the acidisation process can have a significantly detrimental effect on the ability of oil and gas to flow into the well. However, we reiterate that this process, which was fully permitted and approved by the Environment Agency, has been used safely and widely for over 100 years to improve the fluid flow from wells in limestone rocks (“lime” rich rocks made primarily from calcium carbonate) that produce public drinking water and hydrocarbons. The process, which attempts to enlarge flow pathways in limestones by dissolving lime, utilises exactly the same chemistry as household lime scale removal from sinks, baths, showers and toilets, using similar acid concentrations of up to 15%. The lime and acid is converted into water, carbon dioxide and highly soluble calcium chloride, a naturally occurring significant constituent of the fossil salt water already present within the Weald’s underground sedimentary rock sequence. Crucially, the Portland and Kimmeridge rocks also contain significant amounts of microscopic clay particles bound within the rock. Consequently, as the lime dissolves, some of these clay particles arereleased into flow paths within the rock. The “free” clay particles then migrate towards the well and combine, forming a clay “sludge”, restricting or blocking some of the flow pathways, which can significantly reduce the well’s performance. Once blocked the flow pathways cannot be reopened. It makes neither commercial or technical sense for UKOG to utilise this acidisation process, as its future use could seriously reduce the significant natural flow potential and the good flows of hydrocarbons we expect. 0
Sign In
Follow the stocks
