xSight CCL service saved rig time and reduced risks during casing-exit operation
To perform a sidetracking operation, a whipstock is typically oriented and set at a predetermined depth with a window mill attached. The window mill is then detached from the whipstock and pushed to mill a window in the casing.
Casing-exit operations are critical because they provide the only entrance into the sidetrack for all future operations, thus it is important that a high-quality window be created at the optimal depth and at the desired orientation. As well depth and complexity escalate, it becomes increasingly challenging to reliably and efficiently create the window in one trip. In a high-operating cost environment, such as deepwater and remote areas, the impact of unproductive trips is amplified. One of the challenges is milling the window through casing collars, which usually results in low rates of penetration (ROP) and excessive damage to the window mill, and can sometimes cause tool failure.
A major operator in the North Sea wanted to perform a sidetracking operation on 133 /8-in. casing and was concerned about the risks associated with milling through casing collars. Their confidence in the accuracy of the available casing tally was low. Baker Hughes, a GE company (BHGE), recommended the xSight™ smart intervention casing collar locator (CCL) service, which identifies casing collars so operators can avoid milling through them. The xSight CCL service is a component of xSight smart intervention services, which provide downhole mechanics and dynamics measurements to optimize a wide range of wellbore intervention operations. The CCL service involves acquiring magnetometer or density measurements along with measured depth, and transmits the data to surface through mud pulse telemetry. The data is then processed with a proprietary algorithm to detect and visualize the location of the casing collars in real time.
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