First Conventional Coring Job with Extended Core Barrels in Mexico's Ultra Deep Water

Summary During the execution of the third well from a field in Mexico's north DW, the operator was forced to design a complex coring plan to retrieve rock samples for geological characterization, log calibration & define reservoir properties, that are impossible to define by conventional means. This coring plan aimed to retrieve 330 feet of top quality sample, mainly composed by soft, unconsolidated sand, distributed in two bodies from Eocene age. Proper characterization of both targets was critical for pay zone delimitation, and not enough data was gather from previous wells. The application design includes a heavy-duty core barrel, capable to deliver 5 ¼” OD sample, a core bit with low invasion & anti whirl features, an anti-jamming system focused in reducing risk of unplanned trips. This configuration allows increasing the core barrel to 120 feet that is twice the average length used historically in the country and will reduce in half the rig cost for the whole operation. At the well's ends, a total of 340 feet sample was catch in three runs, obtaining a 100% recovery rate. The coring job performance fulfilled the project requirements successfully and avoided a costly contingency with an estimated saving of 5 million dollars.