Formation testing and sampling apparatus and methods
Systems and methods for downhole formation testing based on the use of one or more elongated sealing pads capable of sealing off and collecting or injecting fluids from elongated portions along the surface of a borehole. The modified sealing pads increase the flow area by collecting fluids from an extended portion along the surface of a borehole, which is likely to straddle one or more layers in laminated or fractured formations. A tester device using the elongated sealing pads can be deployed and withdrawn using an extendible element pressing the pads to the borehole. Various designs and arrangements for use with a fluid tester, which may be part of a modular fluid tool, are disclosed in accordance with different embodiments.
1. An apparatus for use with a formation tester to support an elongated sealing pad having an elongated recess and a rigid plate installed in the elongated recess, the rigid plate having an edge embedded into the elongated sealing pad and a flange some distance away from the edge, the apparatus comprising:
a rigid base for attaching to the elongated sealing pad, wherein the rigid base has an opening into the elongated recess of the elongated sealing pad;
one or more extendable supports attached to the rigid base, operable to protrude the rigid base away from the tester; and
an extendable probe assembly operable to move into contact with the rigid plate.
2. The apparatus of claim 1 wherein the elongated sealing pad is attached to the rigid base.
3. The apparatus of claim 2 , wherein the rigid base is molded to the elongated sealing pad.
4. The apparatus of claim 2 , wherein the elongated sealing pad is removably attached to the rigid base.
5. The apparatus of claim 1 , further comprising a fluid path establishing fluid communication from the opening in the rigid base into the interior of the tester.
6. The apparatus of claim 5 , wherein the fluid path establishes fluid communication through the one or more extendable supports.
7. The apparatus of claim 1 , further comprising at least one high-resolution temperature compensated gauge pressure transducer.
8. The apparatus of claim 1 , wherein the opening of the rigid base is connected to a pretest pump within the tester by a flow line.
9. The apparatus of claim 1 , wherein the one or more extendable supports comprises a hydraulic piston.
10. The apparatus of claim 1 , wherein the one or more extendable supports comprises a hydraulic ram.
11. The apparatus of claim 10 , wherein the apparatus comprises two extendable supports and each of the two extendable supports establishes a separate fluid path to the interior of the tester.
12. The apparatus of claim 1 , wherein the one or more extendable supports are operable to exert pressure on the rigid base and the extendable probe assembly is operable to exert pressure on the rigid plate.
13. The apparatus of claim 1 , wherein the rigid plate has one or more openings.
14. The apparatus of claim 13 , wherein the flange protrudes away from the rigid base.
15. The apparatus of claim 1 , wherein the elongated sealing pad has a groove and the extendable support has a tongue configured for insertion into the groove of the sealing pad.