Deep wells in the Delaware Basin, just as in other areas, complicate wireline operations. As compared with shallow well operations, increased depths, temperatures, and pressures place greater demands on equipment and operating techniques.
Temperature, although high in the deeper Basin wells, is less a problem than in other regions of large geothermal gradient. All modern logging equipment is designed and maintained to perform properly at temperatures as high as 340°F. Some instruments, such as the Gamma-Ray Neutron, operate at temperatures up to 500°F. Perforating, formerly a problem in high temperature wells, is now accomplished at temperatures up to 470°F through the use of special high temperature shaped charge components. Thus, although temperatures in deep Basin wells require careful preparation, they do not preclude effective logging and perforating operations.
Relatively light muds are used in the Delaware Basin to increase the efficiency of drilling operations. These low density muds create problems that are more or less unique to this area. First, all operations, both logging and perforating, are normally run using blowout preventers. A properly installed pressure control system enables efficient and safe logging operations. Second, the relatively light muds for such deep wells lead to high cable tension during wireline operations. Winch drums and cables must be engineered to operate safely under these unusually high tensions. A special powered sheave wheel has been introduced in the Delaware Basin to reduce cable tension at the drum and to further reduce possibilities of winch drum collapse, or of cable "cutting in" to lower layers on the drum.
Deep wells in the Delaware Basin are not the easiest wells to log and perforate. In addition to the usual complications at extreme depths - such as elevated temperatures and pressures, and greater margin for error in depth measurements - these wells offer special problems.
