Abstract
Worldwide energy demand is continuously increasing with the current pace of development and oil continues to play a crucial role in total energy mix. It is becoming difficult to meet the demand of crude oil with existing light and medium crude oilfields as production from these fields which are mostly in matured stage, are declining. This has necessitated more attention for increasing the exploitation of heavy and extra heavy oilfields.
Estimates of recovery factors contain inherent uncertainty especially more in early stage. The range of uncertainty in estimates of reserves depends mainly on the degree of geologic complexity, the maturity of the asset, the quality and quantity of geologic and engineering data and the operating environment. Therefore, it becomes critical to understand and determine reservoir parameters which are crucial in estimation and prediction of well and field performance in heavy oilfields. Well spacing, completion techniques, operating practices and regulations can have a significant influence on ultimate recovery.
Primary recoveries from heavy and extra heavy oil fields are very low in cold production mode. Therefore, application of thermal enhanced oil recovery becomes inevitable to improve the recovery from such reservoirs. However, cold production is still favorable at early stage due to low upfront investment.
This study has reviewed and analyzed the development and performance of large number of fields of various sizes under cold production spread over different parts of the globe and developed statistical relationships between geologic-engineering parameters and deliverables like recovery and production. These empirical relations can form basis and be used as guiding principles for heavy oil asset evaluation, initiating the early primary development and their benchmarking to the established industry practices in cold production.
