RE: 6 weeks today since the 7 inch perforating guns RNS5 Jul 2023 16:21
Desree,
It is dependent upon a number of factors; with the lithology, mud & formation chemistry, pressure regime, tectonic stresses and well inclination being the main ones.
In some cases, it won't stay open for more than a few hours, in others, it can be reasonably stable for several weeks.
Given the history in the area of wells requiring side-tracks due to lost BHA's (e.g. Basur-3), this would indicate that the hole would tend to collapse sooner rather than later.
However, with respect to Pin-1, the over-riding thing is that they carried out a DST (based on smell alone!!!) inside the 9 5/8" casing because they thought there was nothing worth testing in the 8 1/2" hole section.
That means they must have plugged & abandoned (P&A'd) the 8 1/2" hole section with cement, as they need to ensure they have isolated any potentially permeable formations and that they also have pressure integrity of the casing that is being tested.
As well as being a regulatory requirement, they have to do this as the DST tools are normally cycled open & closed (and in most cases, the guns fired) using various combinations of pressure cycles on the test string and the annulus.
I haven't read through everything yet, but it seems that UKOG have dangled the carrot of there possibly being a payzone much deeper?
If that's the case, the current well architecture (and location construction) wouldn't allow them to get to the 3,000 - 4,000m that this implies.
They'd have to build a new location (to accommodate a proper Drilling Rig & the associated equipment) and start off in a larger casing size - likely 30" Conductor and 20" surface casing.