RE: Easy Peasy12 Apr 2019 13:32
Post from 4th March 2019
“Scallywag - to be fair to Angus if the water zone is right at the very bottom of the well then the Ultrawave Tool sensors would not have logged this section due to the sensor offset (distance from the drill bit back to where the tool is positioned in the drilling assembly....may be 30-80ft behind.”
I would say due to the profile / angle of the well that the water zone is at the very bottom of the perforations (deepest part of the well), as that tends to be the case as Oil and Gas is lighter than water. In simplistic terms all you need to do is run a bridge plug and squeeze some cement.
So that means you only lose maximum of 80ft out of 656ft of perforations.
Previous post;
https://www.peloton.com/products/wellview/data-analysis/#group-23
You can see in the above link in this scenario the bridge plug (black and yellow triangles) is postioned above the lower perforations (red spikes denote perforations). Above the bridge plug is a small cement plug (grey) to act as the 2nd barrier to the bridge plug (2 barrier plug is required hence HSE involvement). So substitute the lower perforations and replace it with a water zone. That is what you see in the Angus well schematic with the production tubing (blue) positioned above your perforations with a production packer to isolate the rest of the well.
http://www.angusenergy.co.uk/wp-content/uploads/2019/04/Angus-BROCKHAM-WORK-PROGRAMME.pdf
I posted this link before, but this is how you would isolate the water zone at the bottom of the well.
https://www.youtube.com/watch?v=_yklTlzh7FU
Carrying out slickline runs(s) will pinpoint the zone that requires to be sealed off using packer. Resistivity tool can determine whether its oil, water or gas. These measured depths from surface are required so the packer is positioned and set at the correct depths.
In the following link, scroll down to the very last chart and you will see the middle column in the header saying Resistivity. You can see how as you move deeper in the well how the resistivity curve changes when it encounters oil, water or gas. This is how Angus will pinpoint the water zone.
https://www.spec2000.net/14-contacts.htm
You only need a bridge plug smaller than a person. The easiest way to think of it is picture a bath full of water with a plug in…..the plug is there to stop the water draining away.
Now turn the bath upside down. The bath is still full of water and the plug is now at the top. This is the oil reservoir scenario with the Bridge Plug (bath plug) stopping the water from entering the well Angus drilled.