Several days are spent during coring operations when Conventional Coring technology is being used, due to the multitude of trips in an out of the hole. Wireline retrievable coring is a unique technology offering capabilities to full bore core, drill and convey logs in a continuous operation without tripping out of the hole. This technology saves considerable time compared to multiple conventional coring runs.
Historically, one of the constraints with large diameter wireline coring systems is the requirement to pick up specialty drill pipe. This specialty drill pipe provides an internal diameter large enough to accommodate the retrieval of the inner components, utilized to cut 3" to 3.5" diameter core. Moreover, another constraint with large diameter wireline coring systems is the inability to run a jar within the drill string, due to internal diameter limitations.
A new wireline retrievable system capable of acquiring 3" diameter core utilizing standard 5 ½" × 4" drill pipe was designed for application on Saudi Aramco wells. In addition, custom large bore coring jars were designed and deployed to meet the operator's stuck pipe mitigation requirements. With several runs made, the newly designed wireline coring system brings a step change to coring technology, and increases its operational efficiency.
The improvement in this technology has drastically increased the efficiency of large diameter wireline retrievable coring technology and greatly improved the economics.