Apparatus and method for obtaining formation samples

Abstract

An apparatus and method for collecting a fluid from a subterranean formation are disclosed. A fluid sample container has an elongated body. The elongated body includes an internal cavity, a first end having a first opening for receiving the downhole fluid into the internal cavity, a second end axially displaced from the first end, the second end having a second opening for expelling at least a portion of the downhole fluid from the internal cavity. Fluid collecting includes establishing fluid communication with a formation of interest and the fluid sample container receiving the downhole fluid into the internal cavity through the first opening and expelling at least a portion of the downhole fluid from the internal cavity through the second opening.

1 . An apparatus for collecting a downhole fluid, the apparatus comprising:
 a fluid sample container having an elongated body, the elongated body including an internal cavity, a first end having a first opening for receiving the downhole fluid into the internal cavity, a second end axially displaced from the first end, the second end having a second opening for expelling at least a portion of the downhole fluid from the internal cavity.   
   
   
       2 . An apparatus according to  claim 1 , wherein the internal cavity is defined in part by a wall having a curvilinear cross section profile for fluid sticking, fluid resistance or a combination thereof within the internal cavity. 
   
   
       3 . An apparatus according to  claim 2 , wherein the wall curvilinear cross section profile approximates at least a portion of one or more of a circle and an oval. 
   
   
       4 . An apparatus according to  claim 1 , wherein the internal cavity is defined in part by a wall having a surface treatment that reduces fluid sticking, fluid resistance or a combination thereof. 
   
   
       5 . An apparatus according to  claim 4 , wherein the surface treatment is selected from one or more of a coating, a polished surface and an insert. 
   
   
       6 . An apparatus according to  claim 1  further comprising a flow control device that is controllable to cease downhole fluid expulsion from the second opening when a predetermined parameter is met for the downhole fluid. 
   
   
       7 . An apparatus according to  claim 1 , further comprising a pressure control device for controlling fluid pressure within the internal cavity. 
   
   
       8 . An apparatus according to  claim 7 , wherein the pressure control device includes a pump for controlling pressure in the internal cavity. 
   
   
       9 . An apparatus according to  claim 7 , wherein the pressure control device includes a member disposed within the internal cavity for controlling pressure in the internal cavity. 
   
   
       10 . An apparatus according to  claim 9 , wherein the member includes a piston that moves in the internal cavity to control pressure in the internal cavity. 
   
   
       11 . An apparatus according to  claim 9  further comprising a check valve coupled to the pressure control device to allow fluid flow through a central opening of the pressure control device. 
   
   
       12 . An apparatus according to  claim 1  further comprising a fluid monitoring device for estimating a property of the downhole fluid. 
   
   
       13 . An apparatus according to  claim 12 , wherein the property of the downhole fluid includes a level of contamination. 
   
   
       14 . A method for collecting a downhole fluid, the method comprising:
 establishing fluid communication with a formation of interest and a fluid sample container having an elongated body, the elongated body including an internal cavity, a first end having a first opening, a second end axially displaced from the first end, the second end having a second opening;   receiving the downhole fluid into the internal cavity through the first opening; and   expelling at least a portion of the downhole fluid from the internal cavity through the second opening.   
   
   
       15 . A method according to  claim 14  further comprising reducing fluid perturbations within the internal cavity using a wall having a curvilinear cross section profile defining at least in part the internal cavity. 
   
   
       16 . A method according to  claim 15 , wherein the wall curvilinear cross section profile approximates at least a portion of one or more of a circle and an oval. 
   
   
       17 . A method according to  claim 14 , wherein reducing fluid perturbations includes using a wall having a surface treatment that reduces fluid sticking, fluid resistance or a combination thereof. 
   
   
       18 . A method according to  claim 17 , wherein the surface treatment is selected from one or more of a coating, a polished surface and an insert. 
   
   
       19 . A method according to  claim 14  further comprising ceasing the downhole fluid expulsion when a predetermined parameter is met for the downhole fluid using a flow control device that is controllable to cease downhole fluid expulsion from the second opening. 
   
   
       20 . A method according to  claim 14  further comprising controlling fluid pressure within the internal cavity using a pressure control device. 
   
   
       21 . A method according to  claim 20 , wherein controlling fluid pressure within the internal cavity includes using a pump as part of the pressure control device. 
   
   
       22 . A method according to  claim 20 , wherein controlling fluid pressure within the internal cavity includes controllably changing a volume within the internal cavity using a member disposed within the internal cavity. 
   
   
       23 . A method according to  claim 22 , wherein the member includes a piston and controllably changing a volume within the internal cavity includes moving the piston to control pressure within the internal cavity. 
   
   
       24 . A method according to  claim 22  further comprising, flowing the downhole fluid through a check valve in the member. 
   
   
       25 . A method according to  claim 14  further comprising estimating a property of the downhole fluid using a monitoring device. 
   
   
       26 . A method according to  claim 25 , wherein the property of the downhole fluid includes a level of contamination.