Release tool for downhole operations

Abstract

A downhole tool for connecting and releasing portions of a tool string includes a housing; an electronics assembly; an activation mechanism; a valve assembly and a set of retainer dogs to connect and release a neck of another tool. The downhole tool may also include one or more measurement sensors for measuring a parameter and transferring one or more measured parameter values to the surface of the well.

What is claimed is: 
     
         1 . An apparatus for connecting and releasing a downhole tool located within a wellbore comprising:
 a housing having an axial bore;   an electronics assembly configured to communicate with the surface of the wellbore;   an activation mechanism configured to receive an electrical current from the electronics assembly;   a valve assembly in operative communication with the activation mechanism and having a first piston configured to open a port in the housing to wellbore fluid;   a second piston slidably engaged with the housing and held in an initial downward state by a spring;   plural retainer dogs each having an engagement recess disposed on an inner radial surface thereon configured for clamping a neck of a tool; and   wherein said second piston further comprises a cavity configured to retain said plural retainer dogs in a clamped state until said second piston is acted upon by the wellbore fluid.   
     
     
         2 . The apparatus of  claim 1  wherein the housing is comprised of an upper section and a lower section connected by a main sub. 
     
     
         3 . The apparatus of  claim 2 , wherein the activation mechanism is located within the main sub. 
     
     
         4 . The apparatus of  claim 2 , wherein the valve assembly is located within the main sub. 
     
     
         5 . The apparatus of  claim 1 , wherein the valve assembly further comprises a burst disk. 
     
     
         6 . The apparatus of  claim 1 , wherein valve assembly is further configured to activate a switch to communicate a state of the valve to the electronics assembly. 
     
     
         7 . An apparatus for connecting and releasing a downhole tool located within a wellbore comprising:
 a housing having an axial bore;   a burst disk located within the housing and configured to open a passageway to wellbore fluid upon breakage at a predetermined pressure;   a piston located within the housing and held in an initial downward state by a spring;   plural retainer dogs having an engagement recess disposed on an inner radial surface thereon configured for clamping a neck of a tool; and   wherein said piston further comprises a cavity configured to retain said plural retainer dogs in a clamped state until said piston is acted upon by wellbore fluid.   
     
     
         8 . The apparatus of  claim 7 , wherein the housing is comprised of an upper section and a lower section connected by a main sub. 
     
     
         9 . The apparatus of  claim 8 , wherein the burst disk is disposed within the main sub. 
     
     
         10 . A wireline release tool and measurement system, the system comprising: a wireline for lowering a tool string into a wellbore;
 a housing attached to the wireline and having an axial bore; an electronics assembly configured to communicate with the surface of the wellbore via the wireline;   a release assembly comprising plural retainer dogs each having an engagement recess disposed on an inner radial surface thereon configured for clamping and releasing a neck of a tool; and   a measurement sensor disposed within the main sub and configured to measure a parameter and communicate a measured value to the electronics assembly.   
     
     
         11 . The system of  claim 10 , wherein the housing is comprised of an upper section and a lower section connected by a main sub. 
     
     
         12 . The system of  claim 10 , wherein the release assembly further comprises a valve assembly located in the main sub configured to open a passageway to wellbore fluid. 
     
     
         13 . The system of  claim 10 , wherein the release assembly further comprises a piston having a cavity configured to retain said plural retainer dogs in a clamped state until said piston is acted upon by wellbore fluid. 
     
     
         14 . The system of  claim 10 , wherein the measurement sensor is a temperature sensor for measuring wellbore temperature. 
     
     
         15 . The system of  claim 10 , wherein the measurement sensor is a pressure transducer for measuring wellbore pressure. 
     
     
         16 . The system of  claim 10 , wherein the measurement sensor is a tension transducer for measuring tension of the tool string. 
     
     
         17 . The system of  claim 16 , wherein the tension measurement further comprises a pressure compensation chamber to compensate for the pressure driven compression of the tension transducer. 
     
     
         18 . The system of  claim 17 , wherein the pressure compensation chamber is further comprised of more than one sealing surface with varying cross-sectional area to pressure balance the transducer relative to the wellbore exterior pressure. 
     
     
         19 . The system of  claim 17 , wherein the pressure compensation chamber is disposed within a second sub separate from the main sub. 
     
     
         20 . The system of  claim 10 , wherein the electronics assembly comprises:
 a housing;   a processor that is electrically connected to both the release assembly and the at least one measurement sensor; and   wherein the processor is configured to receive a signal from the surface of the wellbore to initiate the release assembly and transmit a measured parameter measured by the measurement sensor to the wellbore surface via the wireline.