초록 ▼

A tool with a switch is inserted and moved down the inside of tubular-shaped and electrically conductive casing in the well. Spaced apart contacts on the tool are connected between upper and lower electrically conductive casings located on opposite sides of a high impedance separation in the casing.

A tool with a switch is inserted and moved down the inside of tubular-shaped and electrically conductive casing in the well. Spaced apart contacts on the tool are connected between upper and lower electrically conductive casings located on opposite sides of a high impedance separation in the casing. The switch is operated for creating a changing electrical conductance between the upper and lower casings representative of data. The electrical conductance across the high impedance separation is interrogated with an alternating current signal to retrieve the data.

대표청구항 ▼

A data communication system for data in a well comprising: electrically conductive and annular casing cemented in the well and comprising a ring-shaped high impedance separation, separating the casing into an upper casing portion and lower casing portion; means for applying an alternating current si

A data communication system for data in a well comprising: electrically conductive and annular casing cemented in the well and comprising a ring-shaped high impedance separation, separating the casing into an upper casing portion and lower casing portion; means for applying an alternating current signal between the upper casing portion and the surrounding earth causing a flow of current along the casing; a tool insertable inside of the casing to the separation and comprising switch means, for sequentially changing electrical conductance for such flow of current across the separation between the upper and lower casing portions, for causing a changing signal at the upper case representative of the data; and means coupled to the upper casing portion and responsive to the changing signal for forming a representation of the data.