PREDICTION OF ASPHALTENE DEPOSITION RISK IN EP OPERATIONS

摘要

The understanding of reservoirs with fluids, which may have potential asphaltene deposition problems during oil production, is a key issue in many deepwater and onshore developments. Early prediction and development of robust flow assurance strategies often lead to savings of millions of dollars during development and operation of any given field. Fluid sample integrity is critical in order to obtain representative reliable data. Screens based on dead and live oil studies have been developed to aid in successful prediction of oil stability with respect to asphaltene precipitation. Shell has calibrated dead oil screening tests (titration, SARA, and PVT) to evaluate asphaltene stability using petroleum samples of known asphaltene stability from worldwide operations. The DBR live-oil depressurization system is routinely used for screening the onset of asphaltene precipitation. The amount of asphaltic solid precipitated is quantified with a Shell proprietary calculation approach. A laboratory technique (ADT) for screening chemicals used in prevention of asphaltene precipitation (inhibitors) has been developed and calibrated using fluids and data from various fields worldwide. Similarly efficiency of chemical dispersants is carefully evaluated using in-house developed ADST test. All of the above screens and techniques are routinely used to predict and prevent asphaltene problems potentially arising in exploration, development and production phases of the field life.