Over 250 wells are currently affected by scale and asphaltene in ADCO’s fields. This number is expected to increase in the future due to fields maturing and implementation of artificial lift and EOR techniques. ADCO’s approach has been reactive in the past using mechanical (jetting and milling) & chemical cleaning methods (organic solvent and acid) to address this issue. Using these remedial treatment methods, US$ 100s million per year could be required in the future to alleviate this problem. Studies have now been concluded to determine a proactive method to solve these issues & their recommendations are in the implementation phase. Improvement of remedial treatments is underway, new solvents are being tested, field trials of inhibitors are underway and new technologies for scale/asphaltene prevention are being tested. Future efforts are also planned on scale/asphaltene modeling for all fields, improving lab capabilities and improving monitoring of scale/asphaltene in the fields.
Formation Damage & Mud Systems (TRL 4-9):
A formation damage study was carried out on cores to assess formation damage (skin) for a range of drilling muds and overbalance. Results clearly suggest that better mud design is required to form a better filter cake that can prevent leak-off to the formation and subsequent damage. Different acid systems were tested for damage removal and it was shown that typical HCl will create wormholes that by-pass damaged zones but will not remove the damage; weaker acids however are much more effective. These results have highlighted the need for a further study to establish the way forward.
The next phase of the study (Phase II) will be to design proper mud systems for each of ADCO’s formations and is planned to start mid 2016.
Downhole Chemical Injection for Asphaltene Inhibition (TRL 4-9):
A novel injection technology for continuous chemical injection of asphaltene inhibitors has been been piloted by ADCO. The chemical delivery system worked very well, however there were challenges associated with chemical selection. During the initial trial, chemical “gunking” was observed in the injection line. As a result, a new line had to be installed. More chemicals are now being tested at different doses to select the best one for field trials in Q1 2017.
Combined Asphaltene & Corrosion Inhibition for CO2 Injection Projects (TRL 7-9):
A number of hybrid and combined asphaltene and corrosion inhibition chemicals have been qualified in the lab and are planned to be piloted for continuous injection in producer wells to proactively mitigate these problems following Carbon Dioxide breakthrough in EOR applications.
Scale Inhibitor Squeeze (TRL 4-9):
Chemicals have been qualified for scale inhibitor squeeze application to prevent scale build-up in the near wellbore area & the production tubulars.
This is due for field trial in 2016.
Produced Water Re-Injection (TRL 4-9):
Water production in ADCO is expected to increase by an order of magnitude over the next 20 years. Managing these increased water volumes will require a truly integrated effort as reservoir management will become more challenging, larger facilities will be required and operations will become more complex. Produced Water Re-injection (PWRI) pilots have already been undertaken and any knowledge gaps are being addressed. ADCO is developing a comprehensive understanding of the filtering and treatment requirements for re-injection of produced water in our reservoirs. Pilots are still ongoing to determine the sustainability of this type of development but results are very encouraging. This experience has provided ADCO with the confidence to continue with PWRI in the future and to include it in our development plans. The required infrastructure for these projects is currently being evaluated.