Dual Pumping With Five Strings of Tubing

Dual pumping, and its accompanying problems, has been a subject of continuing interest to the oil industry. From an economic standpoint, a substantial savings in drilling and equipment costs can be realized by the use of dual completions. The problems encountered in the design and installation of the dual pumping equipment in this particular field were no different from those likely to be met in any field where dual pumping might be considered. For successful installations in this field the objectives of the designers were:To utilize conventional hydraulic pumping equipment, thereby standardizing all pumping operations.To obtain high pumping efficiencies from both zones by completing the upper zone with no packer and venting the gas in the lower zone from beneath the picker to the surface.To pump each zone independently without communication between the two as required by the Oil and Gas Division of the Texas Railroad Commission. These three objectives have been accomplished and all presently-installed dual pumps of the type to be discussed are operating successfully. This type of dual pumping completion eliminates many of the problems encountered with "down the hole" trigger mechanisms. Each zone may be pumped in a conventional manner and both zones can be pumped simultaneously or individually. Well Completions Dual pump installations have been installed in the Prentice field and the Prentice 6,700-ft field located in Yoakum and Terry Counties, Tex. The pay zone in the Prentice field is the Glorietta (limestone of Permian Age), at a total depth of approximately 6,000 ft. The pay zone in the Prentice 6,700-ft field is the Clearfork (limestone of Permian Age), at a total depth of 6,700 ft. Most wells in both the Glorietta and Clearfork underwells. Prior to installation of dual pumping equipment in wells in these fields, all wells were twinned, that is a single well was drilled to each pay zone.