Compared with conventional mode of operation, the coiled tubing acidification could facilitate the implementation of uniform acidification technology like fixing points, layering, steering, etc., distribute the acidizing fluid in long well sections, construct repeatedly and in multiple layers, conduct stimulation operations directly without well killing and flow back the reacted acid rapidly by gas lift after acidification so as to avoid the wellhead facilities, completion pipe string as well as the Christmas tree from contacting with the acidizing fluid and prevent corrosion, which is featured with high operation efficiency, cost-saving, convenience and time-saving, safety and reliability, etc.
This technology is applicable to acid pickling, acidification, organic plug removal and other stimulation operations for carbonate rocks and sandstone reservoirs.
This technique is primarily used in carbonate reservoirs to realize acidizing fluid at fixed points in long horizontal section, and complete the dragging and acidizing operation by coiled tubing in open-hole horizontal well.
Well Name | Length of acidized well section (m) | Mode of completion | Yield before operations (cubic meter/day) | Yield after operations (cubic meter/day) |
X-44H | 164.5 | Open-hole completion (with perforated pipe, but the perforated pipe are not run to place) | Shut down | 579 |
Y-44H | 160.28 | Shut down | 268 | |
Y-29H | 600.2 | Open-hole completion | Shut down | 596 |
X-46H | 599.4 | Shut down | 577 | |
X-57H | 530.2 | Shut down | 655 |