The text does not explicitly mention a specific year when the Dreguen oilfield will reach its end of life but based on other information provided in the passage it can be deduced as follows:

1) Initially, Shell expected the field to run out of oil by 2010.

2) However, due to increased production and higher recovery rates than initially anticipated, this date was extended twice.

3) First extension: The new estimated end-of-life date for the Dreguen oilfield is now mentioned as being in or around 2013.

4) Second Extension: According to recent reports from Shell, it appears that authorities have granted another extension beyond its original expected closure year of 2036 because they still believe there are sufficient reserves left within this field. If these projections prove correct then we could see continued operations well into the mid-2040s at least before finally ceasing production altogether.

Therefore, based on available information provided in the passage it can be inferred that Dreguen oilfield will likely reach its end of life sometime between 2036 and early/mid-2040s.

Shell north sea draugen platform