Abstract
Precipitation, deposition and gelling of paraffins are common production chemistry challenges associated with upstream exploration and production. In this paper the different steps used to identify the wax-related issues from project to start-up and steady state are discussed. The development is a field under steam-assisted gravity drainage (SAGD). Critical to the mapping of production chemistry risks are the many specific analytical and modeling procedures employed. During the project stages, the main risks identified were: wax precipitation downhole and potential gelling of the export pipeline. Clear strategies were put in place to manage both these potential problems. During the start-up of the field, a number of wells were suffering from poor inflow performance. A downhole deposit was retrieved and analyzed. This was identified as wax, with an increase in paraffin distribution compared to the parent crude oil. Successful mitigation of wax deposition downhole was achieved for a selective number of wells using a combination of fluid treatment and extended soak time. This suggests wax deposition is occurring in the near wellbore area. Noticeable effects of SAGD drive on the wax properties of individual well samples are observed reflected in increasing pour points (for wells where heat has broken through). No effect yet is observed on the export crude oil. Long-term surveillance for wells and the facility will continue to rely on wax measurements in combination with tubing head temperatures. Mitigation options will be further developed for continuous operational improvement.
