Patent EA-001091-B1 (EA)
Title: Method for aquiring signals representing down hole conditions of a wellbore and tool therefor
Inventor: BARRET MICHAEL PAUL
IPC: E21B17/02
Filed: 1997-07-11
Abstract: 1. Method for acquiring signals representing down hole conditions of a wellbore in a hydrocarbon reservoir, including the steps of:  - lowering an autonomous unit into the wellbore, said autonomous unit comprising locomotion means for providing a motion along said wellbore and means for detecting said down hole conditions; and logic means for controlling said unit, said logic means being capable of making decisions based on at least two input parameters; and activating said locomotion means and said detection means so as to perform measurements of the down hole conditions in at least one location of said wellbore. 2. The method of claim 1, wherein the autonomous unit is separably and re-connectably attached to a wireline unit while being lowered into the wellbore. 3. The method of claim 1 characterised in that acquiring signals is carried out in horizontal or high-angle wellbore. 4. Down hole tool for detecting down hole conditions in a wellbore in a hydrocarbon reservoir, characterised in that said tool comprises an autonomous unit having locomotion means for providing a motion along said wellbore; means for detecting said down hole conditions; and logic means for controlling said autonomous unit, said logic means being capable of making decisions based on at least two input parameters. 5. The down hole tool of claim 4, characterised in that it is designed being capable during motion in essentially annular region which is left between outer hull of the autonomous unit and the wall of the wellbore. 6. The down hole tool of claim 4, characterised in that wherein the buoyancy of the autonomous unit is controlled by releasable ballast means. 7. The down hole tool of claim 4, further comprising a wireline unit connected to the surface and connection means for providing a separable and re-connectable connection between said wireline unit and the autonomous unit. 8. The down hole tool of claim 6, wherein the connection means includes a motor unit for closing and/or breaking the connection. 9. The down hole tool of claim 4, wherein the autonomous unit comprises means for generating power inside the wellbore. 10. The down hole tool of claim 9, wherein the means for generating power is a turbine which in operation is exposed to a flow within the wellbore. 11. The down hole tool of claim 4, wherein the locomotion means are selected from a group comprising caterpillar tracks, legs, propeller, wheels or a combination thereof. 12. The down hole tool of claim 4, wherein the autonomous unit further comprises foldable parachute means for supporting a motion in direction of a flow in the wellbore. 13. The down hole tool of claim 4, wherein the autonomous unit further comprises telemetry means for communicating signals. 14. The down hole tool of claim 13, wherein the telemetry means includes means for transferring acoustic energy to a surrounding liquid or casing. 15. The down hole tool of claim 4, wherein the autonomous unit further comprises video means for collecting images from the wellbore.