The casing scraper is designed for casingcleaning operations. The tool is run into the well with all scraper bladesfully retracted. Blade activation, by-pass downward flow-path opening, scrapingoperation, whole-well displacement, blade retraction, and retrieval preparationare controlled by sequential ball-drop and hydraulic pressure operation.
1. Run-in-Hole Condition
During run-in-hole, all scraper bladesremain fully retracted. The tool maintains its minimum running outer diameterto allow safe passage through the casing.
The internal flow path remains availablefor circulation as required during run-in-hole.
2. Activation and Downward Flow-PathOpening
After the tool reaches the target scrapingdepth, the activation ball is dropped from surface.
Once the activation ball lands on the ballseat, pump pressure is increased to the required activation pressure. Theinternal hydraulic mechanism shifts, extending the scraper blades outward intocontact with the casing inner wall.
At the same time, the downward flow path isestablished through the bypass passage. This allows fluid remain communicationthrough the tool to the lower BHA or bottom-hole section while the scraperremains in the activated condition.
3. Scraping Operation
With the scraper blades extended, casingcleaning is performed by maintaining circulation and reciprocating the stringacross the target interval.
The scraper blades remove cement residue,mud cake, rust, scale, and debris from the casing ID. The blade layout providescircumferential casing wall coverage during reciprocation.
4. Whole-Well Displacement
After scraping is completed, the downwardflow path remains available through the bypass passage.
This allows whole-well displacement to beperformed after the scraping operation, including circulation or displacementthrough the lower section as required by the job program.
5. Deactivation and Blade Retraction
After scraping and displacement arecompleted, the deactivation ball is dropped from surface.
Once the deactivation ball lands on itsseat, pump pressure is applied to shift the internal mechanism. The scraperblades retract back into the tool body, meanwhile the downward flow path isturn off, the upper circulation path is opened, which is ready for POOH.
6. Retrieval Preparation
After blade retraction, the tool returns toits retrieval condition with the blades fully retracted.
The assembly can then be prepared for safepull-out-of-hole according to the field procedure.
Ball-drop hydraulic activation
The scraper blades are activated by a drop ball and hydraulic pressure. After the scraping operation, a second ball is used to retract the blades and prepare the tool for safe retrieval.
Bypass downward flow path
The tool is designed with a bypass flow system, allowing downward fluid communication during the activated condition instead of completely isolating the lower section.
Supports post-scraping whole-well displacement
After casing scraping is completed, circulation and displacement can continue through the downward bypass flow path, supporting whole-well displacement and wellbore clean-up requirements.
Hydraulically actuated retractable blades
The scraper blades are hydraulically extended to contact the casing wall and can be retracted into the tool body before pull-out-of-hole.
Staggered blade arrangement
Multiple blade sets are circumferentially staggered to provide effective casing wall coverage during reciprocation.
Designed for drilling and clean-up combination operations
The tool is suitable for single-trip drilling, scraping, circulation, and displacement operations, helping reduce rig time and operational cost.
Customizable connections
Tool connections can be customized according to the customer’s BHA requirements, including NC, XT, TT, VX, and other high-torque connection options.
