Landing indicator for logging tools

Abstract

An apparatus for evaluating an earth formation intersected by a wellbore may include a logging tool conveyed into the wellbore through a drilling tubular, a landing indicator associated with the logging tool, and a sensor operatively associated with the logging tool. In use, the landing indicator generates a pressure pulse in the drilling tubular after contacting a travel restrictor positioned in the drilling tubular. After the logging tool is positioned at the target depth, the sensor makes at least one measurement while the logging tool is in the drilling tubular and provides an output indicative of a selected subsurface parameter.

We claim: 
     
         1 . An apparatus for use in a wellbore, comprising:
 a tool configured to be conveyed into the wellbore through a drilling tubular;   a landing indicator associated with the tool, the landing indicator being configured to generate a pressure pulse in the drilling tubular after contacting a travel restrictor positioned along the drilling tubular; and   a sensor associated with the tool and configured to estimate at least one selected subsurface parameter while the tool is in the drilling tubular.   
     
     
         2 . The apparatus of  claim 1 , wherein the landing indicator includes a flow dam that selectively restricts fluid flow along a bore of the drilling tubular. 
     
     
         3 . The apparatus of  claim 2 , wherein the flow dam is a pliant member configured to collapse from a radially expanded state when subjected to a specified fluid flow. 
     
     
         4 . The apparatus of  claim 3 , wherein the flow dam is configured to generate a pressure pulse in the bore of the drilling tubular. 
     
     
         5 . The apparatus of  claim 4 , further comprising: a mandrel on which the flow dam is disposed; and a sleeve configured to slide between an first position and a second position on the mandrel, wherein the sleeve at least partially covers the flow dam in the first position. 
     
     
         6 . The apparatus of  claim 5 , wherein the flow dam expands to the radially expanded state after the sleeve slides to the second position. 
     
     
         7 . The apparatus of  claim 2 , wherein the flow dam is configured to invert. 
     
     
         8 . The apparatus of  claim 1 , wherein the landing indicator is connected to the tool to form a drop tool. 
     
     
         9 . The apparatus of  claim 1 , wherein the sensor comprises at least one of: (i) a gamma ray detector, and (ii) a neutron detector. 
     
     
         10 . A method of using a tool in a wellbore, comprising:
 estimating at least one subsurface parameter using a sensor associated with the tool after receiving at a surface location a pressure pulse generated by a landing indicator associated with the tool, wherein the landing indicator generates the pressure pulse in response to contact with a travel restrictor in a drilling tubular.   
     
     
         11 . The method of  claim 10 , further comprising pumping a drilling fluid into the bore of the drilling tubular, wherein the landing indicator includes a flow dam that is responsive to the flow of the drilling fluid. 
     
     
         12 . The method of  claim 11 , wherein the flow dam responds to the flowing fluid by expanding to a radially expanded state, wherein the radial expansion causes a pressure increase in the flowing fluid. 
     
     
         13 . The method of  claim 12 , further comprising pumping the drilling fluid at a flow parameter selected to collapse the flow dam from the radially expanded state, wherein the collapse causes a pressure decrease in the flowing fluid. 
     
     
         14 . The method of  claim 13 , further comprising detecting at a surface location the pressure increase and the pressure decrease. 
     
     
         15 . The method of  claim 14 , wherein the landing indicator includes a mandrel on which the flow dam is disposed; and a sleeve configured to slide between a first position and a second position on the mandrel, wherein the sleeve at least partially covers the flow dam in the first position, and further comprising moving the sleeve from the first position to the second position after the landing indicator contacts the travel restrictor. 
     
     
         16 . The method of  claim 15 , further comprising circulating fluid in the drilling tubular while the landing indicator contacts the travel restrictor. 
     
     
         17 . The method of  claim 10 , further comprising: tripping the tool out of the wellbore while estimating the at least one subsurface parameter. 
     
     
         18 . An apparatus for use in a wellbore, the apparatus comprising:
 a tool configured to be conveyed into the wellbore;   a landing indicator associated with the tool, the landing indicator being configured to generate a pressure pulse in a fluid column in the wellbore after contacting a travel restrictor positioned in the wellbore.