Methods and means for measurement of the water-oil interface within a reservoir using an x-ray source

Abstract

An x-ray-based reservoir evaluation tool for measurement variations in formation density anticipated at the water-oil interface of a reservoir is provided, the tool including at least: an internal length comprising a sonde section, wherein said sonde section further comprises an x-ray source; radiation measuring detectors; sonde-dependent electronics; and a plurality of tool logic electronics and PSUs. A method of using an x-ray based reservoir evaluation tool for measuring variations in formation density anticipated at the water-oil interface of a reservoir is also provided, the method including at least the following steps: using x-rays to illuminate the formation surrounding the cased borehole; uses detectors to directly measure the density of the formation; using detectors to directly measure the effects on the measurement from tool stand-off or production liner attenuation; and employing techniques for compensating for the production liner and liner-annular region when computing the saturated formation density within the production interval.

1 . An x-ray based reservoir evaluation tool for measurement variations in formation density anticipated at the water-oil interface of a reservoir, wherein said tool comprises:
 an internal length comprising a sonde section, wherein said sonde section further comprises an x-ray source;   a plurality of radiation measuring detectors;   sonde-dependent electronics;   and a plurality of tool logic electronics and PSUs.   
     
     
         2 . The tool of  claim 1 , further comprising a detector used to measure casing standoff such that other detector responses are compensated for tool stand-off. 
     
     
         3 . The tool of  claim 1 , wherein said shield further comprises tungsten. 
     
     
         4 . The tool of  claim 1 , wherein the tool is configured so as to permit through-wiring. 
     
     
         5 . The tool of  claim 1 , wherein a reference detector is used to monitor an azimuthal output of the x-ray source. 
     
     
         6 . The tool in  claim 1 , wherein the tool is combinable with other measurement tools comprising one or more of neutron-porosity, natural gamma and array induction tools. 
     
     
         7 . The tool in  claim 1 , wherein the tool is used to determine the position of the water-oil interface through production liners or production casing. 
     
     
         8 . The tool in  claim 1 , wherein the tool uses additional axially-offset radiation detectors for compensating for the production liner and liner-annular region effects when computing the formation density within the production interval. 
     
     
         9 . The tool in  claim 1 , wherein the tool is integrated into a logging-while-drilling assembly. 
     
     
         10 . The tool in  claim 1 , wherein the tool is powered by mud-turbine generators. 
     
     
         11 . The tool in  claim 1 , wherein the tool is powered by batteries. 
     
     
         12 . The tool in  claim 1 , wherein the tool is combinable with other measurement tools comprising one or more of neutron-porosity, natural gamma and array induction tools. 
     
     
         13 . A method of using an x-ray based reservoir evaluation tool for measuring variations in formation density anticipated at the water-oil interface of a reservoir, wherein said method comprises:
 using x-rays to illuminate the formation surrounding the cased borehole;   using a plurality of detectors to directly measure the density of the formation;   using detectors to directly measure the effects on the measurement from tool stand-off or production liner attenuation; and   compensating for the production liner and liner-annular region when computing the saturated formation density within the production interval.   
     
     
         14 . The method of  claim 13 , further comprising using a detector that is also used for measuring casing standoff so that other detector responses may be compensated for tool stand-off. 
     
     
         15 . The method of  claim 13 , further comprising using a reference detector to monitor the azimuthal output of an x-ray source. 
     
     
         16 . The method of  claim 13 , further comprising combining other measurement methods comprising one or more of neutron-porosity, natural gamma and array induction tools. 
     
     
         17 . The method of  claim 13 , further comprising using the tool to determine the position of the water-oil interface through production liners or production casing. 
     
     
         18 . The method of  claim 13 , further comprising using additional axially-offset radiation detectors to compensate for the production liner and liner-annular region effects when computing the formation density within the production interval. 
     
     
         19 . The method of  claim 13 , further comprising integrating the tool into a logging-while-drilling assembly. 
     
     
         20 . The method of  claim 13 , further comprising powering the tool using mud-turbine generators. 
     
     
         21 . The method of  claim 13 , further comprising powering the tool using batteries.