Solids control/waste management specialists from M-I SWACO, A Schlumberger Company, recommended the operator employ their new-generation RHE-USE† process to completely remove LGS to enhance drilling efficiency and reduce disposal costs. The patent-pending, chemically-enhanced technology had previously field-proven its capacity to optimize drilling while delivering cuttings suitable for onsite disposal. With operator approval, the process was used in a 5,049-ft (1,539 m) interval from 10,768 to 15,817 ft TD (3,282-4,821 m).
By using the RHE-USE process, the operator saved an estimated $163,282, including the recovery of 1,045 bbl of reusable oil-base drilling fluid through the use of dual MEERKAT† drying shakers. Total dilution amounted to 537 bbl of diesel, water and barite.
In comparison, at the 100% dilution rate previously required, up to 18,517 bbl would have been consumed to maintain 2.9% LGS. In addition, the 5,049-ft interval was drilled in 12 days with generated hole volume of approximately 275.2 bbl based on a 6¾ -in. bit and 10% washout. Removing the bulk of the LGS concentration also reduced friction appreciably, thereby lowering downhole mud temperature by 20 to 30°. Less abrasion meant the downhole motor and bit could drill longer without tripping for maintenance.