Comparative Solution Project

Hi,

In the description for 11C the top of the grid is given as approximately 2000m but the write-up says temperature at top of grid is 36-40C (Page 23-24). Why is the temperature not much higher? I would estimate it to be around 70+2000*0.025 = 120C.

Anyone can clarify?

Thanks,

Ichiro

Hi Ichiro,

My team had a similar discussion yesterday. My interpretation is that 70 degC is the temperature at the bottom of the grid where Z is defined as 0. Z is increasing upwards from the bottom of the grid, so the temperature at the top of the grid becomes at the front becomes 70-1200*0.025=40 degC and at the top of the arch is 70-(1200+150)*0.025=36.215 degC.

Regards,

Hi Ichiro, 

Thanks for posting your question. 

The origin of the coordinate system is at the "lower left" corner of the domain, with the vertical coordinate being positive upwards (see Section 4.1, bullet point 2, and similar descriptions in section 2 and 3). I.e., the relevant point for your question is that the datum for the vertical coordinate is the lowest point of the reservoir. Thus T=70 at the lowest point of the reservoir, and decreasing upwards according to 25C per km. 

The temperatures are motivated with reservoirs below the North Sea, where the temperature at the sea floor is a few degrees C, thus mean temperature of around 55C is consistent with reservoir at about 2km depth below the sea floor. 

Hope this clarifies your question, 

Jan

I am sure Jan will clarify this, but it depends on where your origin is and what is the z-direction. I believe the intention is to have 70C as the temperature at the origin in the coordinates used for the description, with a reservoir thickness around 1200m. Part of the challenge is to convert the mathematical description to simulator coordinates, which may be different. The initiative for this model started in Northern Europe, where surface temperatures are quite low :)