Published: 08/30/2012
Published: 08/30/2012
Over the years, a southern Mexico well went from producing 1,700 bbl/d to just 290 bbl/d. The water cut, which had increased from 0% to 70%, was reducing oil production and negatively impacting well economics.
A production logging tool (PLT) showed three producing intervals—with the majority of the well’s oil production coming from the 5,030–5,050 m interval. Due to rising oil-water contact, the two deeper intervals and the lower portion of the third interval were invaded by water. The PLT also showed a leak in the casing at 4,975 m that was producing massive amounts of water.
To save the well, the operator needed to selectively plug the water-producing zones as quickly as possible. Schlumberger recommended the WaterSEEKER system, a miscible solvent slurry squeeze treatment designed to control water production reliably, efficiently, and cost-effectively.
The WaterSEEKER system, composed of microcement suspended in miscible solvent, rapidly hydrates and sets only when in contact with water. But, when the slurry comes in contact with oil, it remains liquid and flows back up after treatment—leaving oil-producing zones undamaged.
To prevent the water-control system from activating in the tubing, solvent and oil-base spacers were pumped before and after the treatment. First, Schlumberger thoroughly cleaned the intervals by performing an injection test using 10 m3 of xylene and 25 m3 of diesel. Once the wellbore was completely free of water, the intervention team pumped 7 m3 of the WaterSEEKER selective slurry followed by another 20 m3 of diesel. Lastly, to ensure adequate compressive strength development, the well was shut in for 36 hours.
The WaterSEEKER selective slurry plugged all the water-producing zones with minimal downtime. After the water control treatment, the operator realized a 65% decrease in water cut and a 244% increase in oil production.
Challenge: Increase oil production and decrease water cut, which had gone from 1,700 bbl/d to 290 bbl/d and 0% to 70%, respectively.
Solution: Plug water-producing zones with the WaterSEEKER selective slurry system.
Results: Increased net oil production to 1,000 bbl/d and reduced water cut to just 5%.
