When evaluating artificial-lift requirements, sometimes data present uncertainties at the initial planning stage. This is the case for a field that had 10 wells drilled but only four of them producing after 6 years, at which point operations were suspended. The high-level plan was to exploit and abandon the reservoir as soon as possible. This paper presents the integrated and structured methodology that was used to deal with the high-uncertainty conditions.
ABC is a small field that has 10 wells, out of which only four produced from 1993 to 1999 while the remaining six were shut in after few months of production. Subsequently, the operations in ABC were suspended and the surface facilities were mothballed. Because of attractive remaining reserves along with high reservoir pressure, and considering that this field is in an urbanized area, a plan was requested that would deplete and abandon the reservoir as quickly as possible. Because of the adjusted time frame for the project, developing and planning this task required a preliminary analysis using the available data acquired during the 6 years of operation and some complementary reservoir studies. Because ABC is a complex reservoir with natural fractures and varying condensate composition, the reservoir-model uncertainties were difficult to minimize with data from only four wells and 6 years of history.
Typically, artificial-lift evaluation comes after the reservoir has a good model and a defined exploitation scheme. In this case, the selection of the artificial-lift method dealt with high data uncertainty associated with reservoir pressure, gas/oil ratio (GOR), and water-cut profiles because of the reservoir’s complexity and pressure/volume/temperature (PVT) properties. To overcome the uncertainty and advance the study concurrently with an ongoing reservoir-simulation study, the following approach was adopted:
Methodology Evaluates Artificial-Lift Requirements Amid High Uncertainty
20 June 2016