Depending the size of your data, this may be performance prohibitive,
but I think you could try joining against a single-columned table of all possible weeks of interest,
as far into the future as you would like, and then use the cross-join method described here:
I've put together a starting framework for you to develop your requirements.
The first 2 vizzes are exploring the difference between 'Worked' and 'Open'. I presumed that 'Worked' meant closed jobs ? I would probably rearranged the vizzes if this is not the case.
In the 3rd viz, I have created a gantt duration chart to show the halflife of each ticket, again I presumed that this was simply the duration of the ticket from Open to Closed.
In all 3 vizzes, the only calculated field that is running behind the scenes is a calculation to find the duration between the created and worked date;
HTH 10.5 attached
Ticket Backlog_v10.5.twbx 20.5 KB