Big oil reserves but big problems to extract them
It all depends on how you define reserves – actually how you define the 20 billion barrels proposed by Halliburton. If this huge volume includes all the heavy and extra-heavy oils that may ultimately be produced over the next 500 years or so then perhaps such numbers are realistic. However large reserves numbers relayed by ANH, Colombia’s national hydrocarbons agency, whose aim is to set out details of a Colombian licensing round, must be taken in context. Especially when the numbers are conflated with a target output hoped for over a period of just a decade. It takes many years to develop heavy oil reserves even in accessible areas.
Colombia has been producing modest volumes of heavy oil, defined as having an API gravity of 22 degrees or less, since at least 1945 and has been producing lighter oils since 1921. Output has been erratic, largely due to the remote and difficult location in which much of the oil is located, both geographically and geologically. A pronounced peak in output in 1999 was due to a combination of just three light oil fields (Cano Limon, Cusiana and Cupiaga in the Llanos Basin) all reaching maximum output at around the same time. No other light oil fields of this magnitude have ever been found, although over 200 smaller fields are also producing in the country.
Attached is a chart that provides one simple forecast for Colombian heavy and light oil production. Of course it assumes the most likely case that no new giant light oil fields will be located – perhaps that may be arguable. Also the years after 2020 are speculative, depending on many factors beyond just the geology of Colombia. The chart does show how investment in many heavy oil developments will realistically lead to increased total oil output, albeit with exceptional growth in production through the next five years. However it will be very difficult to meet a volume close to the million barrels per day target hoped for by Ecopetrol for 2020 whilst light oil production continues to decline. Furthermore most of the new oil will be much heavier than that already being produced. Perhaps a 740,000 bbls per day target for 2015, as reported by ANH elsewhere, is achievable with massive investment in drilling, but 1 million barrels per day by 2020 seems very unlikely. As a guide the volume of oil produced over the period from 2008 to 2050 in the chart below corresponds to a little over 6 billion barrels, approximately equal to the entire volume of oil produced by Colombia in the 86 years since 1921.
Dr Michael R. Smith – www.energyfiles.com