Method and Apparatus for Characterizing Gas Production

Abstract

A method of characterizing the productivity of open hole gas well involves characterizing the chemical and/or isotopic composition of the gas contributing strata from a series of discrete samples by degassing the mud during drilling This data is then used to de-convolute the combined or mixed gas during well production after drilling is complete to determine the relative contributions of the now characterized strata.

1 . A process for characterizing production from an open bore gas well, the process comprising steps of:
 a) drilling an open bore well,   b) extracting gas samples characteristic of the well depth,   c) characterizing the gas isotope composition of the extracted gas samples,   d) defining the gas isotope compositions characteristic of two or more strata penetrated by the well,   e) extracting commingled production gas samples from the producing open bore well,   f) characterizing the gas isotope composition of the extracted production gas samples,   g) determining with mathematical un-mixing algorithms the contribution to the production gas sample from the gas isotope compositions characteristic of two or more strata.   
   
   
       2 . A process for characterizing production from an open bore gas well according to  claim 1  wherein said step of extracting gas sample comprises the step by extracting gas samples from the drilling mud at the surface of a well. 
   
   
       3 . A process for characterizing production from an open bore gas well according to  claim 1  wherein said step of extracting gas sample occurs while the well is being drilled. 
   
   
       4 . A process for characterizing production from an open bore gas well according to  claim 1  further comprising the step of lowering a sampling device in the bore hole after the well is drilled. 
   
   
       5 . A process for characterizing production from an open bore gas well according to  claim 4  further wherein the gas is sample from isolated fracks by sealing the portion of the bore hole above and below the frack. 
   
   
       6 . A device for collecting of gas samples from discrete depth of the bore hole for chemical and isotopic analysis, the device comprising:
 a) an upper packing layer,   b) an lower packing layer disposed below and coupled to said upper packing materials so as to form a cavity for receiving gas there between, wherein both said upper and lower packing layer are substantially impermeable to gases,   c) a gas sampling device in fluid communication with the cavity between said upper and lower packing layer.   
   
   
       7 . A device according to  claim 6  that further comprises a gas flow meter in fluid communication with the cavity between said upper and lower packing layer. 
   
   
       8 . A device according to  claim 7  wherein said flow meter and said gas sampling device are disposed between the packing. 
   
   
       9 . A device according to  claim 7  wherein said flow meter and said gas sampling device are disposed above said upper packing and further comprising a conduit through said upper packing to provide fluid communication with the cavity between said upper and lower packing layer. 
   
   
       10 . A device according to  claim 7  wherein the gas sampling devices comprises a plurality of isolatable sample tubes connected at the top by a common upper gas manifold and the bottom by a common lower gas manifold. 
   
   
       11 . A device according to  claim 10  wherein a plurality of the isolatable sample tubes are each isolated from the common upper gas manifold by a valves and from the common lower gas manifold by a second valve. 
   
   
       12 . A method of gas sampling in a gas well, the method comprising the steps of:
 a) providing the sampling device having a gas sampling inlet disposed between an upper and lower packer member,   b) lowering the sampling device in the well bore,   c) positioning the sampling device to capture gas samples at a fixed location,   d) activating the upper and lower packer member to isolate the gas sampling inlet from the region of the gas well above and below the fixed location,   e) acquiring gas samples,   f) removing the gas samples.   
   
   
       13 . A method according to  claim 12  that further comprises the steps of:
 a) characterizing the gas isotope composition of the extracted gas samples,   b) defining the gas isotope compositions characteristic of two or more strata penetrated by the well,   c) extracting commingled production gas samples from the producing open bore well,   d) characterizing the gas isotope composition of the extracted production gas samples,   e) determining with mathematical un-mixing algorithms the contribution to the production gas sample from the gas isotope compositions characteristic of two or more strata.   
   
   
       14 . A method according to  claim 12  that further comprises the step of:
 a) fracking the geological deposit at the fixed location prior to positioning the sampling device.   
   
   
       15 . A method according to  claim 12  that further comprises multiple step of fracking different fixed location or geological deposits surrounding the well bore and sampling the gas at two or more frack locations. 
   
   
       16 . A method according to  claim 12  wherein the well has an open bore. 
   
   
       17 . A method according to  claim 12  wherein the well has a casing.