Method and apparatus for testing wells

Claim 1

A method of testing a formation intersected by a well bore, said method comprising: maintaining pressure in a body of fluid in a well bore, disposed adjacent a conduit means, at one level while maintaining said body of fluid isolated from a submerged formation to be tested and the interior of said conduit means; in response to said one level of pressure in said body of fluid, maintaining a flow path leading from said formation through said conduit means in said well bore in a closed condition; changing the pressure of said fluid body while isolating said change in pressure of said fluid body from said formation; in response to said change in pressure, permitting fluid to flow from said formation through said conduit means; further changing the pressure of fluid in said fluid body while isolating said further change in pressure from said formation and the interior of said conduit means; in response to said further change of pressure of said fluid body, entrapping within said conduit means a sample of fluid from said formation.

Claim 2

A method of testing a formation intersected by a well bore, said method comprising: maintaining pressure in a body of fluid in a well bore, disposed adjacent a conduit means, at one level while maintaining said body of fluid isolated from a submerged formation to be tested and the interior of said conduit means; in response to said one level of pressure in said body of fluid, maintaining a flow path leading from said formation through said conduit means in said well bore in a closed condition; changing the pressure of said fluid body while isolating said change in pressure of said fluid body from said formation; in response to said change in pressure, permitting fluid to flow from said formation through said conduit means; further changing the pressure of fluid in said fluid body while isolating said further change in pressure from said formation and the interior of said conduit means; in response to said further change of pressure of said fluid body, entrapping within said conduit means a sample of fluid from said formation.

Claim 3

A method of testing a submerged formation from an offshore test site, said method comprising: maintaining pressure in a body of fluid in a submerged well bore, disposed adjacent a conduit means, at a relatively low level while maintaining said body of fluid isolated from a submerged formation to be tested; in response to said relatively low level of pressure in said body of fluid, maintaining a flow path leading from said formation through said conduit means in said well bore in a closed condition; increasing the pressure of said fluid body while isolating said increase in pressure of said fluid body from said formation; in response to said increase in pressure, permitting fluid to flow from said formation through said conduit means; further decreasing the pressure of fluid in said fluid body while isolating said further decRease in pressure from said formation; and in response to said further decrease of pressure of said fluid body, entrapping within said conduit means a sample of fluid from said formation.

Claim 4

A method of testing a submerged formation from an offshore test site, said method comprising: maintaining pressure in a body of fluid in a submerged well bore, disposed adjacent a conduit means, at a relatively low level while maintaining said body of fluid isolated from a submerged formation to be tested; in response to said relatively low level of pressure in said body of fluid, maintaining a flow path leading from said formation through said conduit means in said well bore in a closed condition; increasing the pressure of said fluid body while isolating said increase in pressure of said fluid body from said formation; in response to said increase in pressure, permitting fluid to flow from said formation through said conduit means; further decreasing the pressure of fluid in said fluid body while isolating said further decRease in pressure from said formation; and in response to said further decrease of pressure of said fluid body, entrapping within said conduit means a sample of fluid from said formation.

Claim 5

A method of testing a submerged formation from an offshore test site, said method comprising: disposing a test string including tester valve controlled conduit means between a floating vessel and a submerged formation; maintaining pressure in a body of liquid in a submerged well bore, disposed adjacent said conduit means, at a relatively low level while maintaining said body of liquid isolated form a submerged formation to be tested; in response to said relatively low level of pressure in said body of liquid, maintaining a flow path leading from said formation through said conduit means in said well bore in a closed condition; increasing the pressure of said liquid body while isolating said increase in pressure of said liquid body from said formation; in response to said increase in pressure, permitting fluid to flow from said formation through said conduit means; further decreasing the pressure of liquid in said liquid body while isolating said further decrease in pressure from said formation; in response to said further decrease of pressure of said liquid body, entrapping within said conduit means a sample of fluid from said formation; maintaining a confined body of pressurized gas in said conduit means operable to determine the pressure level in said liquid body operable to permit said liquid to flow from said formation through said conduit means; and maintaining yieldable means in said conduit means operable to determine the pressure level in said liquid body operable to cause said entrapping.

Claim 6

A method of testing a submerged formation from an offshore test site, said method comprising: disposing a test string including tester valve controlled conduit means between a floating vessel and a submerged formation; maintaining pressure in a body of liquid in a submerged well bore, disposed adjacent said conduit means, at a relatively low level while maintaining said body of liquid isolated form a submerged formation to be tested; in response to said relatively low level of pressure in said body of liquid, maintaining a flow path leading from said formation through said conduit means in said well bore in a closed condition; increasing the pressure of said liquid body while isolating said increase in pressure of said liquid body from said formation; in response to said increase in pressure, permitting fluid to flow from said formation through said conduit means; further decreasing the pressure of liquid in said liquid body while isolating said further decrease in pressure from said formation; in response to said further decrease of pressure of said liquid body, entrapping within said conduit means a sample of fluid from said formation; maintaining a confined body of pressurized gas in said conduit means operable to determine the pressure level in said liquid body operable to permit said liquid to flow from said formation through said conduit means; and maintaining yieldable means in said conduit means operable to determine the pressure level in said liquid body operable to cause said entrapping.

Claim 8

A method of testing a formation, intersected by a well bore site, said method comprising: providing a well testing assembly including: conduit means communicating with a formation to be tested, with said conduit means being disposed in a well bore and selectively removable therefrom, wall means encircling at least a portion of said conduit means, and selectively releasable sealing means extending between said conduit means and said wall means and cooperating with said conduit means and said wall means to provide a well annulus isolated from the interior of said conduit means; regulating flow from said formation through said conduit means with an assembly including: first, valve seat means carried by a wall portion of said conduit means, second, valve seat means carried by another interior wall portion of said conduit means, and spaced longitudinally of and above said first valve seat means, slidable sample chamber side wall means mounted on said first and second valve seat means for sliding movement longitudinally of said conduit means, first valve means carried by a lower portion of said slidable sample chamber side wall means and disposed in valving cooperation with said first valve seat means, second valve means carried by an upper portion of said slidable sample chamber side wall means and disposed in valving cooperation with said second valve seat means, formation fluid inlet passage means operable to transmit formation fluid from said formation to the interior of said slidable sample chamber side wall means under valving control of said first sleeve valve means, formation fluid outlet passage means operable to transmit formation fluid from the interior of said slidable sample chamber side wall means to the interior of said conduit means under valving control of said second sleeve valve means, said first and second sleeve valve means being concurrently operable in response to movement of said slidaBle sample chamber side wall means, said first and second sleeve valve means being sequentially movable from a first position closing said inlet and outlet passage means, to a second position opening said inlet and outlet passage means, and to a third position closing said inlet and outlet passage means; providing a formation sample trapping chamber means including: wall means cooperating with said first and second valve seat means and said slidable sample chamber side wall means to define a sample receiving cavity; providing formation testing actuating means including: pressurizing means selectively operable to increase the pressure of fluid in said well annulus, with said sealing means isolating said well annulus from said formation, piston means carried by said sample chamber side wall means, cylinder means defined by a portion of said conduit means with said piston means being slidably mounted therein, first expansible and contractible cavity means included in said cylinder means and containing a body of expansible and contractible pressurized fluid yieldably biasing said piston means and slidable sample chamber side wall means in one direction, second expansible and contractible cavity means included in said cylinder means operable to receive formation fluid to bias said piston means in another direction opposite to said one direction, communicating means providing pressure-change transmitting fluid communication between said second expansible and contractible cavity means and said well annulus; and testing said formation by: imparting the pressure of said pressurized fluid to said piston means to urge said slidable sample chamber side wall means in said one direction and hold said first and second sleeve valve means in said first, position to prevent a flow of formation fluid through said sample trapping chamber means from said formation, while maintaining said relatively low pressure level in said well annulus, operating said pressurizing means to increase the pressure of fluid in said well annulus, with said increase in pressure being operable to provide said relatively intermediate pressure in said well annulus and effect movement of said sample chamber side wall means in said opposite direction and move said first and second valve means from said first position to said second position to permit a flow of fluid consecutively through said inlet passage means, interior of said sample trapping chamber means, and outlet passage means, and operating said pressurizing means to provide said relatively high pressure level in said well annulus to cause said first and second valve means to move in said opposite direction from said second position to said third position and entrap a sample of formation fluid in said sample trapping chamber means.

Claim 9

A method of testing a formation, intersected by a well bore site, said method comprising: providing a well testing assembly including: conduit means communicating with a formation to be tested, with said conduit means being disposed in a well bore and selectively removable therefrom, wall means encircling at least a portion of said conduit means, and selectively releasable sealing means extending between said conduit means and said wall means and cooperating with said conduit means and said wall means to provide a well annulus isolated from the interior of said conduit means; regulating flow from said formation through said conduit means with an assembly including: first, valve seat means carried by a wall portion of said conduit means, second, valve seat means carried by another interior wall portion of said conduit means, and spaced longitudinally of and above said first valve seat means, slidable sample chamber side wall means mounted on said first and second valve seat means for sliding movement longitudinally of said conduit means, first valve means carried by a lower portion of said slidable sample chamber side wall means and disposed in valving cooperation with said first valve seat means, second valve means carried by an upper portion of said slidable sample chamber side wall means and disposed in valving cooperation with said second valve seat means, formation fluid inlet passage means operable to transmit formation fluid from said formation to the interior of said slidable sample chamber side wall means under valving control of said first sleeve valve means, formation fluid outlet passage means operable to transmit formation fluid from the interior of said slidable sample chamber side wall means to the interior of said conduit means under valving control of said second sleeve valve means, said first and second sleeve valve means being concurrently operable in response to movement of said slidaBle sample chamber side wall means, said first and second sleeve valve means being sequentially movable from a first position closing said inlet and outlet passage means, to a second position opening said inlet and outlet passage means, and to a third position closing said inlet and outlet passage means; providing a formation sample trapping chamber means including: wall means cooperating with said first and second valve seat means and said slidable sample chamber side wall means to define a sample receiving cavity; providing formation testing actuating means including: pressurizing means selectively operable to increase the pressure of fluid in said well annulus, with said sealing means isolating said well annulus from said formation, piston means carried by said sample chamber side wall means, cylinder means defined by a portion of said conduit means with said piston means being slidably mounted therein, first expansible and contractible cavity means included in said cylinder means and containing a body of expansible and contractible pressurized fluid yieldably biasing said piston means and slidable sample chamber side wall means in one direction, second expansible and contractible cavity means included in said cylinder means operable to receive formation fluid to bias said piston means in another direction opposite to said one direction, communicating means providing pressure-change transmitting fluid communication between said second expansible and contractible cavity means and said well annulus; and testing said formation by: imparting the pressure of said pressurized fluid to said piston means to urge said slidable sample chamber side wall means in said one direction and hold said first and second sleeve valve means in said first, position to prevent a flow of formation fluid through said sample trapping chamber means from said formation, while maintaining said relatively low pressure level in said well annulus, operating said pressurizing means to increase the pressure of fluid in said well annulus, with said increase in pressure being operable to provide said relatively intermediate pressure in said well annulus and effect movement of said sample chamber side wall means in said opposite direction and move said first and second valve means from said first position to said second position to permit a flow of fluid consecutively through said inlet passage means, interior of said sample trapping chamber means, and outlet passage means, and operating said pressurizing means to provide said relatively high pressure level in said well annulus to cause said first and second valve means to move in said opposite direction from said second position to said third position and entrap a sample of formation fluid in said sample trapping chamber means.

Claim 11

A method of testing a submerged formation from an offshore test site, said method comprising: providing a well testing assembly including: tubular conduit means communicating with a formation to be tested with said conduit means being disposed in a well bore and selectively removable therefrom to a floating work station, wall means encircling at least a portion of said conduit means, and selectively releasable sealing means extending between said conduit means and said wall means and cooperating with said conduit means and said wall means to provide a well annulus isolated from the interior of said conduit means; regulating flow from said formation through said conduit means with an assembly including: first, generally tubular valve seat means carried by and spaced inwardly from an interior wall portion of said conduit means and mounted concentrically therewith, second, generally tubular valve seat means carried by and spaced inwardly from another interior wall portion of said conduit means, mounted concentrically therewith, and spaced longitudinally of and above said first valve seat means, slidable sample chamber side wall means mounted on said first and second valve seat means for sliding movement longitudinally of said conduit means, first sleeve valve means carried by a lower portion of said slidable sample chamber side wall means and disposed in valving cooperating with said first valve seat means, second sleeve valve means carried by an upper portion of said slidable sample chamber side wall means and disposed in valving cooperation with said second valve seat means, formation fluid inlet passage means carried by said first valve seat means, and operable to transmit formation fluid from said formation to the interior of said slidable sample chamber side wall means under valving control of said first sleeve valve means, formation fluid outlet passage means carried by said first valve seat means, and operable to transmit formation fluid from the interior of said slidable sample chamber side wall means to the interior of said conduit means under valving control of said second sleeve valve means, said first and second sleeve valve means being concurrently operable in response to movement of said slidable sample cHamber side wall means, said first and second sleeve valve means being sequentially movable from a first, lower position closing said inlet and outlet passage means, to a second, intermediate position above said first position opening said inlet and outlet passage means, and to a third, upper position above said second position closing said inlet and outlet passage means; providing a formation sample trapping chamber means including: first barrier means closing a lower portion of said first valve seat means, second barrier means closing an upper portion of said second valve seat means, said first and second barrier means cooperating with said first and second valve seat means to provide sample entrapping closures at upper and lower ends, respectively, of said slidable sample chamber side wall means; providing formation testing actuating means including: pump means selectively operable from said floating work station to increase the pressure of fluid in said well annulus, with said sealing means isolating said well annulus from said formation, annular piston means carried on the exterior of said sample chamber side wall means and mounted coaxially thereof, cylinder means defined by a portion of said conduit means with said piston means being slidably mounted therein, first expansible and contractible cavity means included in said cylinder means above said piston means and containing a body of expansible and contractible pressurized fluid yieldably biasing said piston means and slidable sample chamber side wall means downwardly, second expansible and contractible cavity means included in said cylinder means below said piston means, communicating means provide pressure-change transmitting fluid communication between said second expansible and contractible cavity means and said well annulus; testing said formation by: imparting the pressure of said pressurized fluid to said piston means to urge said slidable sample chamber side wall means downwardly and hold said first and second sleeve valve means in said first, lower position to prevent a flow of formation fluid through said sample trapping chamber means from said formation, while maintaining said relatively low pressure level in said well annulus, operating said pump means at said floating work station to increase the pressure of fluid in said well annulus, with said increase in pressure being operable to provide said relatively intermediate pressure in said well annulus and effect upward movement of said sample chamber side wall means and move said first and second valve means from said first lower position to said second, intermediate position to permit a flow of fluid consecutively through said inlet passage means, interior of said sample trapping chamber means, and outlet passage means, operating said pump means at said floating work station to provide said relatively high pressure level in said well annulus to cause said restraining means to yield, and move said first and second valve means from said second intermediate position to said third, upper position and entrap a sample of formation fluid in said sample trapping chamber means, after said testing of said formation, releasing said sealing means from said wall means, and raising said conduit means to said floating work station; and effecting said testing while concurrently substantially preventing wave action induced forces from being transmitted from said floating work station to said conduit means.

Claim 12

A method of testing a submerged formation from an offshore test site, said method comprising: providing a well testing assembly including: tubular conduit means communicating with a formation to be tested with said conduit means being disposed in a well bore and selectively removable therefrom to a floating work station, wall means encircling at least a portion of said conduit means, and selectively releasable sealing means extending between said conduit means and said wall means and cooperating with said conduit means and said wall means to provide a well annulus isolated from the interior of said conduit means; regulating flow from said formation through said conduit means with an assembly including: first, generally tubular valve seat means carried by and spaced inwardly from an interior wall portion of said conduit means and mounted concentrically therewith, second, generally tubular valve seat means carried by and spaced inwardly from another interior wall portion of said conduit means, mounted concentrically therewith, and spaced longitudinally of and above said first valve seat means, slidable sample chamber side wall means mounted on said first and second valve seat means for sliding movement longitudinally of said conduit means, first sleeve valve means carried by a lower portion of said slidable sample chamber side wall means and disposed in valving cooperating with said first valve seat means, second sleeve valve means carried by an upper portion of said slidable sample chamber side wall means and disposed in valving cooperation with said second valve seat means, formation fluid inlet passage means carried by said first valve seat means, and operable to transmit formation fluid from said formation to the interior of said slidable sample chamber side wall means under valving control of said first sleeve valve means, formation fluid outlet passage means carried by said first valve seat means, and operable to transmit formation fluid from the interior of said slidable sample chamber side wall means to the interior of said conduit means under valving control of said second sleeve valve means, said first and second sleeve valve means being concurrently operable in response to movement of said slidable sample cHamber side wall means, said first and second sleeve valve means being sequentially movable from a first, lower position closing said inlet and outlet passage means, to a second, intermediate position above said first position opening said inlet and outlet passage means, and to a third, upper position above said second position closing said inlet and outlet passage means; providing a formation sample trapping chamber means including: first barrier means closing a lower portion of said first valve seat means, second barrier means closing an upper portion of said second valve seat means, said first and second barrier means cooperating with said first and second valve seat means to provide sample entrapping closures at upper and lower ends, respectively, of said slidable sample chamber side wall means; providing formation testing actuating means including: pump means selectively operable from said floating work station to increase the pressure of fluid in said well annulus, with said sealing means isolating said well annulus from said formation, annular piston means carried on the exterior of said sample chamber side wall means and mounted coaxially thereof, cylinder means defined by a portion of said conduit means with said piston means being slidably mounted therein, first expansible and contractible cavity means included in said cylinder means above said piston means and containing a body of expansible and contractible pressurized fluid yieldably biasing said piston means and slidable sample chamber side wall means downwardly, second expansible and contractible cavity means included in said cylinder means below said piston means, communicating means provide pressure-change transmitting fluid communication between said second expansible and contractible cavity means and said well annulus; testing said formation by: imparting the pressure of said pressurized fluid to said piston means to urge said slidable sample chamber side wall means downwardly and hold said first and second sleeve valve means in said first, lower position to prevent a flow of formation fluid through said sample trapping chamber means from said formation, while maintaining said relatively low pressure level in said well annulus, operating said pump means at said floating work station to increase the pressure of fluid in said well annulus, with said increase in pressure being operable to provide said relatively intermediate pressure in said well annulus and effect upward movement of said sample chamber side wall means and move said first and second valve means from said first lower position to said second, intermediate position to permit a flow of fluid consecutively through said inlet passage means, interior of said sample trapping chamber means, and outlet passage means, operating said pump means at said floating work station to provide said relatively high pressure level in said well annulus to cause said restraining means to yield, and move said first and second valve means from said second intermediate position to said third, upper position and entrap a sample of formation fluid in said sample trapping chamber means, after said testing of said formation, releasing said sealing means from said wall means, and raising said conduit means to said floating work station; and effecting said testing while concurrently substantially preventing wave action induced forces from being transmitted from said floating work station to said conduit means.

Claim 13

A method of testing a submerged formation from an offshore test site, said method comprising: providing a well testing assembly including: tubular conduit means communicating with a formation to be tested with said conduit means being disposed in a well bore and selectively removable therefrom to a floating work station, wall means encircling at least a portion of said conduit means, and selectively releasable sealing means extending betweEn said conduit means and said wall means and cooperating with said conduit means and said wall means to provide a well annulus isolated from the interior of said conduit means; regulating flow from said formation through said conduit means with an assembly including: first, generally tubular valve seat means carried by and spaced inwardly from an interior wall portion of said conduit means and mounted concentrically therewith, second, generally tubular valve seat means carried by and spaced inwardly from another interior wall portion of said conduit means, mounted concentrically therewith, and spaced longitudinally of and above said first valve seat means, slidable sample chamber side wall means mounted on said first and second valve seat means for sliding movement longitudinally of said conduit means, first sleeve valve means carried by a lower portion of said slidable sample chamber side wall means and disposed in valving cooperation with said first valve seat means, second sleeve valve means carried by an upper portion of said slidable sample chamber side wall means and disposed in valving cooperation with said second valve seat means, formation fluid inlet passage means carried by said first valve seat means, and operable to transmit formation fluid from said formation to the interior of said slidable sample chamber side wall means under valving control of said first sleeve valve means, formation fluid outlet passage means carried by said first valve seat means, and operable to transmit formation fluid from the interior of said slidable sample chamber side wall means to the interior of said conduit means under valving control of said second sleeve valve means, said first and second sleeve valve means being concurrently operable in response to movement of said slidable sample chamber side wall means, said first and second sleeve valve means being sequentially movable from a first, lower position closing said inlet and outlet passage means, to a second, intermediate position above said first position opening said inlet and outlet passage means, and to a third, upper position above said second position closing said inlet and outlet passage means, first valve shielding means defined by a first wall portion of said conduit means, spaced outwardly of said inlet passage means and first valve seat means, and cooperating with said first valve seat means to define a first annular passage leading to said inlet passage means, second valve shielding means defined by a second wall portion of said conduit means, spaced outwardly of said outlet passage means and second valve seat means and cooperating with said second valve seat means to define a second annular passage leading from said outlet passage means; providing a formation sample trapping chamber means including: first barrier means closing a lower portion of said first valve seat means, second barrier means closing an upper portion of said second valve seat means, said first and second barrier means cooperating with said first and second valve seat means to provide sample entrapping closures at upper and lower ends, respectively, of said slidable sample chamber side wall means, first, passage means carried by said first barrier means and disposed axially thereof, first plug valve means valvingly mounted in said first passage means, second, passage means carried by said second barrier means and disposed axially thereof, and second plug valve means valvingly mounted in said second passage means, said first valve shielding means being removable from said conduit means to provide access to said first plug valve means, and said second valve shielding means being removable from said conduit means to provide access to said second plug valve means; providing formation testing actuating means including: pump means selectively operable from said floating work station to increase the pressure oF fluid in said well annulus, with said sealing means isolating said well annulus from said formation, annular piston means carried on the exterior of said sample chamber side wall means and mounted coaxially thereof, cylinder means defined by a portion of said conduit means with said piston means being slidably mounted therein, first expansible and contractible cavity means included in said cylinder means above said piston means and containing a body of expansible and contractible pressurized nitrogen yieldably biasing said piston means and slidable sample chamber side wall means downwardly, second expansible and contractible cavity means included in said cylinder means below said piston means, communicating means provide pressure-change transmitting fluid communication between said second expansible and contractible cavity means and said well annulus; providing valve latching means including: first latching means carried by said sample trapping chamber means, and second latching means carried by said slidable sample chamber side wall means and operable to engage said first latching means and latch said sample chamber side wall means with said sample trapping chamber means and secure said first and second sleeve valve means in said third, upper position; providing venting valve means in said conduit means below said first valve means and operable to vent pressurized fluid from the interior of said conduit means to the exterior thereof in response to a decrease in pressure of fluid adjacent the exterior of said conduit means; providing yieldable restraining means carried by said sample chamber side wall means, said restraining means being operable to yieldably prevent movement of said first and second sleeve valve means from said second, intermediate position to said third upper position, said restraining means being further operable to position said first and second sleeve valve means at said first, lower position in response to a relatively low pressure level in said well annulus, at said second, intermediate position in response to a relatively intermediate pressure level in said well annulus, and at said third, upper position in response to a relatively high pressure level in said well annulus; providing yieldable movement impedance means operable to relatively impede initial upward movement of said piston means in said cylinder means and permit relatively unimpeded downward movement of said piston means in said cylinder means, said impedance means including disabling means operable to substantially vitiate the movement impeding operation of said impedance means after said yieldable restraining means has yielded to permit said first and second sleeve valve means to move from said second, intermediate position toward said third, upper position; supporting said conduit means at said floating work station while providing: collapsible and extensible coupling means between said conduit means and said floating work station; and testing said formation by: imparting the pressure of said pressurized nitrogen to said piston means to urge said slidable sample chamber side wall means downwardly and hold said first and second sleeve valve means in said first, lower position to prevent a flow of formation fluid through said sample trapping chamber means from said formation, while maintaining said relatively low pressure level in said well annulus, operating said pump means at said floating work station to increase the pressure of fluid in said well annulus, with said increase in pressure being operable to provide said relatively intermediate pressure in

Claim 14

A method of testing a submerged formation from an offshore test site, said method comprising: providing a well testing assembly including: tubular conduit means communicating with a formation to be tested with said conduit means being disposed in a well bore and selectively removable therefrom to a floating work station, wall means encircling at least a portion of said conduit means, and selectively releasable sealing means extending betweEn said conduit means and said wall means and cooperating with said conduit means and said wall means to provide a well annulus isolated from the interior of said conduit means; regulating flow from said formation through said conduit means with an assembly including: first, generally tubular valve seat means carried by and spaced inwardly from an interior wall portion of said conduit means and mounted concentrically therewith, second, generally tubular valve seat means carried by and spaced inwardly from another interior wall portion of said conduit means, mounted concentrically therewith, and spaced longitudinally of and above said first valve seat means, slidable sample chamber side wall means mounted on said first and second valve seat means for sliding movement longitudinally of said conduit means, first sleeve valve means carried by a lower portion of said slidable sample chamber side wall means and disposed in valving cooperation with said first valve seat means, second sleeve valve means carried by an upper portion of said slidable sample chamber side wall means and disposed in valving cooperation with said second valve seat means, formation fluid inlet passage means carried by said first valve seat means, and operable to transmit formation fluid from said formation to the interior of said slidable sample chamber side wall means under valving control of said first sleeve valve means, formation fluid outlet passage means carried by said first valve seat means, and operable to transmit formation fluid from the interior of said slidable sample chamber side wall means to the interior of said conduit means under valving control of said second sleeve valve means, said first and second sleeve valve means being concurrently operable in response to movement of said slidable sample chamber side wall means, said first and second sleeve valve means being sequentially movable from a first, lower position closing said inlet and outlet passage means, to a second, intermediate position above said first position opening said inlet and outlet passage means, and to a third, upper position above said second position closing said inlet and outlet passage means, first valve shielding means defined by a first wall portion of said conduit means, spaced outwardly of said inlet passage means and first valve seat means, and cooperating with said first valve seat means to define a first annular passage leading to said inlet passage means, second valve shielding means defined by a second wall portion of said conduit means, spaced outwardly of said outlet passage means and second valve seat means and cooperating with said second valve seat means to define a second annular passage leading from said outlet passage means; providing a formation sample trapping chamber means including: first barrier means closing a lower portion of said first valve seat means, second barrier means closing an upper portion of said second valve seat means, said first and second barrier means cooperating with said first and second valve seat means to provide sample entrapping closures at upper and lower ends, respectively, of said slidable sample chamber side wall means, first, passage means carried by said first barrier means and disposed axially thereof, first plug valve means valvingly mounted in said first passage means, second, passage means carried by said second barrier means and disposed axially thereof, and second plug valve means valvingly mounted in said second passage means, said first valve shielding means being removable from said conduit means to provide access to said first plug valve means, and said second valve shielding means being removable from said conduit means to provide access to said second plug valve means; providing formation testing actuating means including: pump means selectively operable from said floating work station to increase the pressure oF fluid in said well annulus, with said sealing means isolating said well annulus from said formation, annular piston means carried on the exterior of said sample chamber side wall means and mounted coaxially thereof, cylinder means defined by a portion of said conduit means with said piston means being slidably mounted therein, first expansible and contractible cavity means included in said cylinder means above said piston means and containing a body of expansible and contractible pressurized nitrogen yieldably biasing said piston means and slidable sample chamber side wall means downwardly, second expansible and contractible cavity means included in said cylinder means below said piston means, communicating means provide pressure-change transmitting fluid communication between said second expansible and contractible cavity means and said well annulus; providing valve latching means including: first latching means carried by said sample trapping chamber means, and second latching means carried by said slidable sample chamber side wall means and operable to engage said first latching means and latch said sample chamber side wall means with said sample trapping chamber means and secure said first and second sleeve valve means in said third, upper position; providing venting valve means in said conduit means below said first valve means and operable to vent pressurized fluid from the interior of said conduit means to the exterior thereof in response to a decrease in pressure of fluid adjacent the exterior of said conduit means; providing yieldable restraining means carried by said sample chamber side wall means, said restraining means being operable to yieldably prevent movement of said first and second sleeve valve means from said second, intermediate position to said third upper position, said restraining means being further operable to position said first and second sleeve valve means at said first, lower position in response to a relatively low pressure level in said well annulus, at said second, intermediate position in response to a relatively intermediate pressure level in said well annulus, and at said third, upper position in response to a relatively high pressure level in said well annulus; providing yieldable movement impedance means operable to relatively impede initial upward movement of said piston means in said cylinder means and permit relatively unimpeded downward movement of said piston means in said cylinder means, said impedance means including disabling means operable to substantially vitiate the movement impeding operation of said impedance means after said yieldable restraining means has yielded to permit said first and second sleeve valve means to move from said second, intermediate position toward said third, upper position; supporting said conduit means at said floating work station while providing: collapsible and extensible coupling means between said conduit means and said floating work station; and testing said formation by: imparting the pressure of said pressurized nitrogen to said piston means to urge said slidable sample chamber side wall means downwardly and hold said first and second sleeve valve means in said first, lower position to prevent a flow of formation fluid through said sample trapping chamber means from said formation, while maintaining said relatively low pressure level in said well annulus, operating said pump means at said floating work station to increase the pressure of fluid in said well annulus, with said increase in pressure being operable to provide said relatively intermediate pressure in