RIASSUNTO
SPE Members
Abstract
The Dome Polycrystalline Diamond Compact (PDC) is a relatively new development in PDC technology. The Dome PDC has a radius of curvature across the diamond table rather than being flat. Previous studies have shown the new design reduces torque and dissipates heat better than the conventional PDC. The dome design also offers a more impact resistant structure which in turn has potential for harder rock applications.
This paper addresses the application of the Dome PDC cutter in slim hole operations (3 1/4"" to 4 3/4"" diameters) in the Permian Basin. The new cutter has been tested and applied in dolomitic formations where conventional PDC's have failed in the past. The 3/8"" diameter Dome PDC has been utilized on bits as well as underreamers. The use of Dome PDC bits has proven successful in the 3500'-4500' Grayburg/San Andres formation of Lea County, New Mexico. The increased ROP's and dependability of the fixed cutter in this area offer an economic advantage over roller cone technology . The Dome PDC bits have proven a fast economical way to deepen through 4"" and 5"" liners. The subsequent underreaming of wellbores with the Dome PDC in West Texas and New Mexico have shown savings in excess of 70% over roller cone tools. These savings are reflected by an increase of penetration rates from 10 FPH to over 30 FPH.
The performance of the Dome PDC in the Permian Basin greatly enhances opportunities for utilization of old producing wells for deepening and recompletions.
Introduction
Many wells in the Permian Basin, having been drilled and completed in the 1930's and 40's, are experiencing some magnitude of restoration or transition. With many formations depleted, it has been found profitable in many cases to unitize with other operators and implement an organized water flood. A large portion of the wells acquired for this task have to be cleaned out and deepened through the potential flood interval. Federal and State guidelines on injection wells and zonal isolation are just two of the reasons a competent production casing is required. However, the age and usually corrosive environment surrounding these wells usually provides a highly corroded, leaking production casing.
The typical wellbore configuration is 5 1/2"" production casing with an open hole completion as seen in Figure 1. Occasionally 4' liners have already been installed for wellbore isolation or repair. The deepening and setting of 4"" Flush Joint liners has been a remedial process that although practiced widely has resulted in many poor cement jobs. Experience has revealed a high percentage of the 4"" liner installations suffer from zonal communication. Underreaming prior to running liner equipment has shown to be effective in improving cement bonding and isolation.
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