Re: What software would you like to see?
Sounds like an interesting topic; how are you approaching it? Are you using 3D grids and expanding heatflow from a certain point source spatially or is it a 1D approach? Have you looked into heatflow models that use salt diapirs that are able to transfer heat upwards faster, as I imagine that could sort of be a similar approach.... but I generally don't deal with this stuff.
As for the jobs, I think the main reason you're not seeing many vacancies may be due to the fact that smaller companies generally are hired to develop software or plugins. They have less budget to hire recruiters and get their applications online. Also, they generally hire from within their network; it's often all about who you know.
Furthermore, I think that it's still pretty difficult to find geologists that have expert programming skills and the industry anticipates this by targeting their job offers on pure IT specialists first. But, the need to have a geological background when developing geoscience software is paramount I believe.
I wouldn't worry about the job market, it's picking up again and the fact that you are already thinking about your future options by trying to make useful software will percolate onto your cv; I'm sure!
I can not help you with ideas for software though, but you might want too look around the Ocean store (
http://www.ocean.slb.com/Pages/category ... tegory=all) as this is a good indication of what sort of stuff is in demand (sorry, Petrel again). Also keep an eye on the BlueBack guys (
http://www.blueback-reservoir.com) as they do exciting stuff. Furthermore you can get some pretty advanced seismic interpretation and modeling software for free to play around with from DGB (
http://www.opendtect.org).
For more about maturation and basin modeling, Becip Franlab probably provides the most advanced package (
http://www.openflowsuite.com/).
Good luck, and please let us know what you come up with!