Western Atlas International, Inc.

Wood Group Logging Services Holding Inc.

Wood Group Logging Services Holdings, Inc.

Than Shwe

John M Michaels

Roy Torrance

Mike Flecker

Steve Thompson

Saeed Rafie

John C Anderson

Michael Yesudas

John L Leder

A system, apparatus, and method for determining real time bubble point pressure and compressibility of a fluid originating from a subsurface earth formation during well production first permit remote collection of a sample of fluid. The sample of fluid is then remotely expanded, while the temperature, pressure, and volume of the sample of fluid are remotely monitored. The real time bubble point pressure and compressibility of the sample of fluid are extracted from a plot of sample fluid pressure versus volume, which exhibits substantially linear behavior having two different slopes.

Determining subsurface fluid properties using a downhole device

A method of determining the real time bubble point pressure of a fluid originating from a subsurface earth formation using an adjustable choke positioned downhole adjacent to the formation. The adjustable choke is placed into communication with the wellbore fluid flowing from the formation to the surface. The adjustable choke has a remotely adjustable choke opening for selectively restricting the flowrate of the fluid flowing through the choke. The adjustable choke has a pressure sensor for measuring the fluid pressure downstream of the choke opening. The method includes obtaining downstream fluid pressure data as a function of choke size for generating a plot of downstream pressure versus choke size data which exhibits substantially linear behavior having two different slopes. Extrapolating a best-fit line through the set of data having a first slope so as to intersect an extrapolation of a best-fit line through the set of data having a second slope thereby provides the bubble point pressure of the fluid as the pressure corresponding to the intersection of the two lines.

Determining fluid bubble point pressure using an adjustable choke

A method of determining an amount of dissolved gas in a fluid sample is disclosed. The method includes hydraulically confining and expanding the sample while measuring pressure and volume. A first volume and pressure are determined at which the rate of change in pressure with respect to volume deviates from a linear relationship. A second volume and pressure at which continued expansion of the fluid causes substantially no change in pressure is determined. The first pressure and volume are extrapolated by the linear relationship to intersect an extrapolation from the second volume and pressure at no change in pressure, thereby determining a bubble point comprising a bubble point pressure and a bubble point volume. A third pressure corresponding to measured pressure of the fluid sample at the bubble point volume is determined. An extrapolated sample volume is determined at the third pressure by extrapolating the linear relationship from the bubble point to a sample volume along the linear relationship corresponding to the third pressure. A volume of gas dissolved in the fluid sample is determined by linearly scaling a difference between the bubble point volume and the extrapolated sample volume with respect to a difference between the second volume and the bubble point volume. In a preferred embodiment of the invention, the sample is withdrawn into a sample chamber in an electric wireline formation test tool having a means for measuring pressure and volume of the sample chamber.

Determining fluid properties from pressure, volume and temperature

A method of determining the volume of a fluid sample withdrawn from an earth formation penetrated by a wellbore is disclosed. The method includes the step of positioning a formation testing tool adjacent to the earth formation. The tool includes a probe which can be selectively placed in hydraulic communication with the formation and excluded from hydraulic communication with the wellbore. The probe can be in hydraulic communication with a pressure transducer. The tool includes a sample chamber selectively placed in hydraulic communication with the probe. The chamber includes means for measuring the volume of the chamber and means for selectively controlling the volume of the chamber. The method further includes the steps of placing the probe in hydraulic communication with the formation, placing the sample chamber in hydraulic communication with the probe and selectively increasing the volume of the chamber while measuring the volume of the chamber and the pressure, determining the volume of the chamber when a fluid from the wellbore disposed within the probe at the start of withdrawal of the sample ceases to expand, by determining an expansion volume at which the pressure decreases less rapidly with respect to an increase in chamber volume, and determining the volume of the fluid sample by subtracting the expansion volume from a total volume of fluid withdrawn into the sample chamber.

Formation fluid flow rate determination method and apparatus for

An apparatus for withdrawing fluid from an earth formation comprising an elongated housing, a first inflatable elastomeric seal adapted to expansively fill an annular space between the housing and the wall of a wellbore. The seal includes axially spaced seal lips protruding from a surface of the seal. The seal lips circumscribe the seal and define a flow channel therebetween. The flow channel includes radially spaced filler blocks which divide the channel into radial segments. Each segment further includes a flow port. The apparatus includes means for inflating the seal. The apparatus includes valves connected to each of the flow ports for connecting selected flow ports to an intake of a fluid pump and connecting selected other flow ports to a discharge port of the pump. The pump is operable in conjunction with the valves to withdraw fluid from selected flow ports and to discharge fluid into other flow ports. The apparatus includes a fluid discharge port connected to the valves, and in hydraulic communication with the wellbore so that fluid withdrawn from the flow ports can be discharged into the wellbore, and fluid withdrawn from the wellbore can be discharged through the flow ports. The apparatus includes a pressure transducer connected to the pump intake so that a pressure of the fluid withdrawn is determined. A preferred embodiment includes a second pressure transducer connected to the pump discharge and differential pressure transducers interconnected between adjacent flow ports to measure radial differences in pressure.

Formation testing method and apparatus using multiple radially-segmented

A method and apparatus for conducting in situ tests on a subsurface earth formation of interest which is traversed by a wellbore. A wireline formation testing instrument is positioned at formation depth and a sampling probe thereof is extended into fluid communication with the formation and isolated from wellbore pressure. Utilizing a hydraulically energized double-acting bi-directional piston pump and by valve controlled selection of pumping direction testing fluid such as completion fluid may be pumped into the formation through the sampling probe either from fluid reservoirs of the instrument or from the wellbore. After reversing the operating and control valving of the pump and instrument, the piston pump is utilized to extract formation fluid from the formation and pump it to sample tanks of the instrument, pump it into the wellbore or subject it to controlled pressure for real time formation testing and for formation characterization. The pumping mechanism of the formation testing instrument includes a pump-through capability for unlimited pumping of formation fluid to permit effective removal of filtrate, sand, rocks and other debris until an uncontaminated formation fluid sample can be recovered for testing. The piston pump and valving arrangement further permits successive draw-down of minute volumes for rapidly determining formation pressure and permits bubble point pressure and fluid compressibility testing to enable bubble point pressure and fluid compressibility profile plots for formation characterization.

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Houston, TX, United States of America

Than Shwe