Geoff Stafford and Robert McNaughton, Whiting Petroleum Corporation
When evaluating artificial lift in a CO2 flood, certain factors must be taken into special consideration. This statement is especially true if the reservoir is a sandstone without H2S. Such conditions exist at Postle Field in the panhandle of Oklahoma, making it a field of unique nature. Under normal considerations, when CO2 is injected, it mixes with water and produces a weak carbonic acid. If the reservoir is a carbonate, the rock will buffer the acid. If H2S gas is present, it also offers benefit and provides further buffer to the acid. At Postle Field, however, neither is
present. This field produces out of the Upper Morrow Sandstone which contains no carbonic cementation. In addition, it is an extremely corrosive field, which makes artificial lift very complex and dangerous. Postle Field has a robust number of wells that have either been lost or in danger of being lost, due to problems created by corrosion. This paper will discuss what is taken into consideration when designing artificial lift for the corrosive nature of Postle Field.