Horse Hill #1 – Recommended Testing Programme

In my spare time, i.e. when I am not writing articles, I like to think of myself as a passable petroleum engineer. So I thought I would mock up the memo I would have written to Messrs Lenigas, Sanderson & Ritson if they had had the gumption to ask for my advice. I can't blame Messrs Lenigas and Sanderson for not calling me as they don't know me from Adam, but Neil, well all I can say is I'm hurt, deeply hurt.

"Neil, who's this Steve Brown?"
"No idea"

Horse Hill #1 – Recommended Testing Programme

I have reviewed all the information you made available to me on the results of the Horse Hill #1 well and herewith I offer my recommendations on a testing programme designed to maximise the possibility that the Horse Hill partnership can enter into a development programme on the Horse Hill discovery.

Of the deeper intervals (the Coraillian down to the Palaeozoic) only the lower Lias has sufficient oil in place to be of any potential commercial interest, but with a net to gross ratio of less than 6% it will certainly require a multi-stage hydraulic fracturing programme, best conducted from a horizontal sidetrack. That would be quite an expensive undertaking with a moderate chance of success. Unless the well has intersected high permeability streaks in this sequence, Stevie Brown Petroleum Consulting Ltd recommends that no tests are conducted on this interval.

The Kimmeridge section is interesting and as I mentioned in my previous memo, the Middle Kimmeridge Lower Limestone Two from 3082 feet to 3184 feet seems the most promising section of all. If you wish to demonstrate commercial flowrates, Stevie Brown Petroleum Consulting Ltd recommends a multi-stage fracturing programme in a horizontal sidetrack, in line with routine practice in the Bakken and Permian basins. Obtaining planning approval and overcoming the irrational fears whipped up by environmental activists will not take more than two or three months (sorry that was a typo, two or three years).

Alternatively, if hydraulic fracturing is ruled out, at least in the near term, Stevie Brown Petroleum Consulting Ltd recommends the drilling of a horizontal sidetrack into the Middle Kimmeridge Lower Limestone Two. This could be accomplished by mobilising a coiled tubing drilling unit at considerably less expense than bringing the drilling rig back to the site. An extended sidetrack into this zone, we would suggest 1,000 metres of horizontal section, has a reasonable chance of intersecting natural fractures and a moderate chance of success. A multi-stage hydraulic fracturing programme would almost be bound to demonstrate a commercial flow rate, but if that is ruled out on practical grounds, then the conventional sidetrack is the next best option.

If such a programme is beyond your budget, then an acid wash of the perforated zone would be the next best option. We would recommend having the capability of pumping the acid into the formation at above fracture pressure as that will maximise the possibility of a successful test. If you cannot obtain funds for a sidetrack, or cannot get approval for an acid wash programme it will probably be better to forego any testing of this zone, as absent a proper clean-up programme the likelihood of a disappointing result which might write off the prospectivity of the Kimmeridge in the Weald basin forever would be much too high.

Finally, a straightforward conventional test of the Portland sandstone is highly recommended. The flow period should last at least 48 hours and an extended build-up period should also be conducted to investigate reservoir boundaries. This zone does look positive and I am confident the partnership will be able to report a commercial flow rate from this conventional reservoir provided you have mobilised adequate downhole pumping equipment to the site. Do remember when you report the flow from the Portland sandstone not to muddle that flow rate up with the reported oil in place from the deeper zones, it would be dreadful if investors jumped to the conclusion that successfully producing oil from the Portland indicated anything at all about how productive the Kimmeridge might be.

Stevie Brown Petroleum Consulting Ltd is pleased to be of service to the Horse Hill partnership and looks forward to a prompt payment of the invoice which is on its way via the Pixie Post.