Service of Plugging Removal by Acidizing

After nearly a dozen years of continuous development, the acidizing technology has developed from the analysis on reservoir pollution, the optimization of product system, design of process operation to site all-dimensional acidizing operation capacity. The construction of acidizing experiment is promoted simultaneously with the process design, and by now five fundamental research orientations have been established, including the study on reservoir rocks, the study on physical simulation, the study on acidizing fluid system, the study on the cause analysis of formation pollution and the study on reservoir fluid, with more than 40 sets of specialized supporting instruments configured. We uphold the attitude of technological innovation, and continuously promote the application of "new process, new technology and new material" in the oilfield acidizing.

Relying on the science and technology planning, COSL has completed nearly 15 scientific research and production projects as well as 28 key technological acidizing operations at the Company level and the Division level. Depending on the promotion in the equipment capacity, the Company has completed more than 1,400 well-times of acidizing operations during 10 years, opened up several overseas markets, and made contributions to the development of acidizing technology.

Process Introduction

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.

Technical Indicators

Well Type: Horizontal well, highly-deviated well, vertical well with long production section
Reservoir Lithology: Carbonate rocks or sandstone, with strong heterogeneity
Dragging Capacity: 20m~40m/section
Dragging Speed of Coiled Tubing:<25/mmin

Technical Applicability

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 NameLength of acidized well section (m)Mode of completionYield before operations (cubic meter/day)Yield after operations (cubic meter/day)
X-44H164.5Open-hole completion (with perforated pipe, but the perforated pipe are not run to place)Shut down579
Y-44H160.28Shut down268
Y-29H600.2Open-hole completionShut down596
X-46H599.4Shut down577
X-57H530.2Shut down655