Formation tester with improved sample collection system
First Claim
1. A formation tester tool for retrieving a fluid from a selected formation from within a wellbore having a wellbore fluid therein, comprising:
- (a) a device for retrieving formation fluid from the selected formation;
(b) a fluid collection chamber having a first chamber for receiving the formation fluid and a second chamber in fluid communication with the wellbore for maintaining a back pressure in the second chamber;
(c) a pressure sensor associated with the first chamber for detecting the pressure in the first chamber.
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Accused Products
Abstract
This invention provides a formation evaluation tool for collecting a formation fluid in a chamber at a predetermined pressure and for maintaining the pressure of the collected fluid at a desired level during the retrieval of the chamber to the surface. The formation fluid is pumped into the chamber while a piston exposed to the hydrostatic pressure maintains the chamber pressure at the hydrostatic pressure. During retrieval of the chamber, the pressure in the chamber is maintained at a predetermined level by pumping wellbore fluid to the piston. A control unit at the surface is utilized for controlling the operation of the formation tool.
231 Citations
30 Claims
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1. A formation tester tool for retrieving a fluid from a selected formation from within a wellbore having a wellbore fluid therein, comprising:
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(a) a device for retrieving formation fluid from the selected formation; (b) a fluid collection chamber having a first chamber for receiving the formation fluid and a second chamber in fluid communication with the wellbore for maintaining a back pressure in the second chamber; (c) a pressure sensor associated with the first chamber for detecting the pressure in the first chamber. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A formation tester for testing and retrieving a formation fluid from a selected formation around a wellbore having a hydrostatic pressure due to the presence of a wellbore fluid therein, comprising:
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(a) a probe adapted for placement against the selected formation for withdrawing the formation fluid into a flow line; (b) a pump associated with the flow line for controlling the flow rate of the formation fluid into the flow line; (c) a collection chamber having a first chamber for receiving the formation fluid from the flow line and a second chamber for maintaining a predetermined pressure in the first chamber; (d) a first fluid flow control device between the flow line and the first chamber for controlling the flow of the fluid from the flow line into the first chamber; and (e) a second fluid flow control device for controlling the fluid flow from the flow line into the second chamber; and (f) a pressure sensor associated with the first chamber for detecting the pressure in the first chamber. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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23. A formation testing system for testing and retrieving a formation fluid from a selected formation around a wellbore having a wellbore fluid therein, comprising:
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(a) a downhole tool conveyable in the wellbore from a surface location, said tool having (i) a packer chamber for retrieving the formation fluid into a flow line, (ii) a pressure sensor for determining the pressure of the fluid in the flow line, and (iii) a pump associated with the flow line for controlling the flow rate of the formation fluid into the flow line; (b) a fluid collection chamber having (i) a chamber divided by a piston therein into a first chamber for receiving the formation fluid from the flow line and a second chamber for maintaining a back pressure on the piston, (ii) a first fluid flow control device between the flow line and the first chamber for controlling the flow of the fluid from the flow line into the first chamber, (iii) a pressure sensor associated with the first chamber for determining the pressure in the first chamber, and (iv) a second fluid flow control device between the flow line and the second chamber for controlling the fluid flow from the flow line into the second chamber; (c) a control circuit within the tool, said control circuit receiving signals from the pressure sensor associated with the first chamber and in response thereto controlling the fluid flow control device to control the fluid flow into the first chamber; and (d) a surface control unit for communicating with the control circuit and for providing command signals to the control circuit according to programmed instructions provided to the surface control unit. - View Dependent Claims (24, 25, 26)
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27. A method for collecting a formation fluid from a selected wellbore formation surrounding a wellbore, comprising:
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(a) conveying a formation tester in the wellbore, said formation tester having a device for retrieving the formation fluid and a chamber having a first chamber for collecting the retrieved formation fluid and a second chamber for providing a predetermined back pressure to the first chamber; (b) setting the device for retrieving the formation fluid adjacent the selected formation; (c) retrieving the formation fluid from the selected formation; (d) determining when the retrieved formation fluid is substantially free from mud filtrates; and (e) collecting the substantially mud filtrate free formation fluid into the first chamber of the chamber while maintaining a predetermined back pressure in the second chamber. - View Dependent Claims (28, 29, 30)
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Specification