Coring in unconventional reservoirs with typical unconsolidated formations has introduced additional challenges requiring more innovative concepts to be developed. These requirements, economic issues of unconventional reservoirs, and also issues of conventional coring particularly in regard to excessive trip times incurred have recently led to widespread attention to wireline continuous coring (WCC) modified from mining industry to petroleum industry applications. This coring method has contributed to coring deep formations, long core sections, multiple zones, jam prone formations, exploration zones or areas with unknown core points. Currently, WCC is suffering from several drawbacks while some recent attempts have been made to remove them. In this accordance, this work is missioned to remove some existing defects by adding some innovative concepts to be applied to the ordinary WCC. Therefore, a more efficient continuous coring method is aimed which includes enhanced coring key performance indicators.

Therefore, several identified challenges of WCC are considered to be removed or alleviated by innovative concepts to be added. The challenges consist of un-flushed inner tube while run in hole, limited retrievable core size, in-situ/pressure coring hazards (i.e. safety issues, complex sealing, etc.), slick line issues (rig time, torque, rupture, etc.), untimely and inefficient decision making while coring/drilling, non-optimized coring/drilling and tripping induced core damage in WCC.

In order to address these issues, as novelty measures, first an inner tube flushing system is proposed for flushing inner tubes prior to commencing coring. Second, casing drilling coring is recommended in order to obtain larger core sizes contributing to improved core analysis. Third, in-situ downhole measurement and sampling systems are proposed to measure properties of in-situ fluids in order to complete or replace pressure/in-situ coring systems and ensure safety. Fourth, an innovative mode conversion system is proposed to mitigate slick line issues. Fifth, a less complex logging while coring system has also been proposed in special cases to enhance and expedite real time decision making process in regard to proceeding to core cutting or not. Sixth, an innovative mode conversion system contributing to partial elimination of wireline jobs will also be proposed to substitute slick line/ wireline retrievals. Seventh, optimum tripping schedules have been characterized as crucial to match formation rock and fluid properties and type of WCC applied and also to prevent coring induced damage.

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