Deltic was lined up for a takeover approach last year, only for acquisitive interest to be fended off by a management team that has the support of its shareholders.
The latest buying interest meanwhile comes amidst professional stake building.
Richard Sneller, former Baillie Gifford fund manager and notable AIM investor, shareholding in the company increased above 10% from around 9% according to a regulatory announcement on the London Stock Exchange.
It is the latest update of its kind. Sneller has been buying up shares for a number of months.
In November, Shell confirmed its commitment to the drilling the planned gas exploration well.
At that time the operator was given a short licence extension, to the end of March, to allow an analysis of seismic data ahead of a formal drill decision. Shell continues to carry 100% of Deltic's costs until the well investment decision is made.
Deltic shares ended the trading day at 1.61p, up 5.9%.