Wireline formation test tool with jet perforator for positively establishing fluidic communication with subsurface formation to be tested
First Claim
1. In a wireline formation test tool for suspension via a cable from the surface into a fluid filled wellbore for testing a low permeability subsurface formation wherein there is includeda body,a passageway into the body which is communicated with a pressure gage, and at least one sample chamber for testing the flow rate of connate fluids introduced into the passageway from the subsurface formation, andmeans for affixing and stabilizing the tool body in the wellbore at the level of the subsurface formation to be tested, which includes an extensible packer assembly, inclusive of a packer pad with openings, adapted for sealing engagement by projection of the pad of the packer assembly against a wall of the formation to be tested, and alignment of the pad opening with said passageway for isolation of said passageway of the tool body from wellbore fluids to establish a path for fluid communication between said passageway and the subsurface formation,the improvement comprisinga jet perforator assembly, inclusive of a housing containing an open end firing chamber within which an explosive charge can be placed, the open end of the firing chamber being aligned upon and facing the wall of the formation to be tested, a fluid-fillable chamber in front of the firing chamber with one or more pistons mounted therein for applying pressure upon a fluid placed therein, and the volume thereof is substantially equal to that of the firing chamber, such that detonation of the explosive charge within the firing chamber will perforate the wall, penetrate said fluid-filled chamber, perforate said formation and connect the formation with said fluid-filled chamber, the fluid will fill the firing chamber, and establish a positive flow of connate fluids from the subsurface formation through said passageway into the body of the tool, for testing.
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Accused Products
Abstract
A wireline tool, and process for its use, for lowering into wellbores for testing the gas pressure, and connate fluid flow rates, in low permeability oil or gas producing subsurface formations. The tool features a jet charge perforator for detonation to perforate through the wall and positively establish fluidic communication with the non damaged portion of the subsurface formation to be tested. It also includes, in the combination, a mechanism for affixing and stabilizing the tool in the wellbore at the wall of the subsurface formation to be tested, inclusive of a packer assembly for isolating from wellbore fluids the opening between the subsurface formation, created by the jet perforator, and tool test components. On blasting into the wall of the subsurface formation, the pressure in the flowline is maintained at formation pressure, avoiding formation damage. The pressure is recorded during the flow of gas and connate fluids from the subsurface formation, and analysis is made of a specimen taken into a chamber of the test tool.
93 Citations
17 Claims
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1. In a wireline formation test tool for suspension via a cable from the surface into a fluid filled wellbore for testing a low permeability subsurface formation wherein there is included
a body, a passageway into the body which is communicated with a pressure gage, and at least one sample chamber for testing the flow rate of connate fluids introduced into the passageway from the subsurface formation, and means for affixing and stabilizing the tool body in the wellbore at the level of the subsurface formation to be tested, which includes an extensible packer assembly, inclusive of a packer pad with openings, adapted for sealing engagement by projection of the pad of the packer assembly against a wall of the formation to be tested, and alignment of the pad opening with said passageway for isolation of said passageway of the tool body from wellbore fluids to establish a path for fluid communication between said passageway and the subsurface formation, the improvement comprising a jet perforator assembly, inclusive of a housing containing an open end firing chamber within which an explosive charge can be placed, the open end of the firing chamber being aligned upon and facing the wall of the formation to be tested, a fluid-fillable chamber in front of the firing chamber with one or more pistons mounted therein for applying pressure upon a fluid placed therein, and the volume thereof is substantially equal to that of the firing chamber, such that detonation of the explosive charge within the firing chamber will perforate the wall, penetrate said fluid-filled chamber, perforate said formation and connect the formation with said fluid-filled chamber, the fluid will fill the firing chamber, and establish a positive flow of connate fluids from the subsurface formation through said passageway into the body of the tool, for testing.
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10. A wireline formation test tool for suspension via a cable from the surface into a fluid-filled wellbore for testing a low permeability subsurface formation which comprises
an elongate body, a passageway into the body which is communicated with a pressure gage, and at least one sample chamber for testing the flow rate of connate fluids introduced into the passageway from the subsurface formation, a packer assembly constituted of a pad and pad support, each provided with concentric openings, mounted on the projecting ends of and extensible with a pair of spaced-apart pistons located on one side of the elongate body, adapted for sealing engagement by projection of the pad of the packer assembly against a wall of the formation to be tested, and alignment of the pad opening with said passageway for isolation of said passageway of the tool body from wellbore fluids, and for stabilizing and affixing the tool body in the wellbore at the level of the subsurface formation to be tested, and a jet perforator assembly, inclusive of a housing containing an open end firing chamber within which an explosive charge can be placed, and chamber provided with pistons, communicable with said passageway, located in front of the firing chamber for containing a fluid compatible with the connate fluids of said subsurface formation upon which pressure can be applied by said pistons, the housing being extended through the opening of the packer pad of said packer assembly, with the open end of the firing chamber aligned upon and facing the fluid-fillable chamber and wall of the subsurface formation to be tested, such that detonation of the explosive charge will open the fluid-filled chamber in front of the firing chamber to permit fluid to flow from said chamber into the firing chamber, and perforate the formation to establish a positive flow of connate fluids from the subsurface formation through said fluid-filled chamber and passageway into the body of the tool for testing.
Specification