Apparatuses and methods for deploying logging tools and signalling in boreholes

摘要

In the field of tools for use in boreholes, an apparatus (10) includes a pump (11) for circulating fluid under pressure in a wellbore (12). A control device (13) controls the speed of the pump (11). A conduit (17) interconnects the pump and the wellbore (12). Within the wellbore a downhole transducer (21) that is capable of detecting changes in the pressure of fluid at a downhole location and generating signals indicative thereof. A processor (23) generates actuator commands in dependence on the generated signals. One or more actuators (24) is operable to activate at least part of a downhole tool in dependence on a said actuator command. A modulating valve (26) is capable of modulating the pressure of fluid in the conduit. A remote transducer (27) that may be eg. at a surface location, is capable of detecting pressure of fluid in the conduit at a location remote from the downhole transducer (21). The control device causes the pump to generate one or more digital acoustic signals in the fluid, the wave forms of which are detectable by the downhole transducer (21). The modulating valve (26) is capable of generating digital or analogue wave forms in the fluid. In operation the control device sends control signals via the fluid that are detected by the downhole transducer (21). Consequently the processor (23) causes actuation of one or more tools. Following correct actuation the modulating valve (26) generates signals in the form of pressure changes in the fluid. The remote transducer (17) detects and displays such signals, to indicate at a surface location whether deployment of the tool has occurred successfully.