OA12136A

OA12136A - Wellbore logging system.

Info

Publication number: OA12136A
Application number: OA1200200208A
Authority: OA
Inventors: Douwe Johannes Runia
Original assignee: Shell Int Research
Priority date: 2000-01-14
Filing date: 2001-01-12
Publication date: 2006-05-05
Also published as: US20010035289A1; AR027206A1; EP1247002B1; BR0107569A; NO20023365D0; EA200200757A1; WO2001051768A2; CA2396168C; AU2516701A; NO323060B1; CA2396168A1; NO20023365L; EA003565B1; EP1247002A2; EG22609A; WO2001051768A3; MXPA02006779A; CN1401046A

Abstract

A logging system for use in a borehole formed in an earth formation, comprising a tubular element to be installed in the borehole, and a logging member including a conduit having an inlet opening and being movable in radial direction of the tubular element between a retracted position in which the logging member is substantially arranged within the tubular element and an extended position in which the logging member extends beyond the tubular element so that said inlet opening is in fluid communication with the earth formation when the tubular element is installed in the borehole, the logging system further comprising an activating device for moving the logging member between the retracted position and the extended position thereof.

Description

1 12136

The invention relates to a logging System for use ina borehole formed in an earth formation.

Generally, in the practice of wellbore drilling eachfurther section of a wellbore is drilled after thepreviously drilled wellbore sections are cased withwellbore casing. After completing drilling of the furthersection, a logging tool is lowered by wireline throughthe previously installed casing and into the newlydrilled section so as to conduct a measurement of adownhole parameter. An example of such logging tool is aformation pressure test/sampling tool for measuring thepressure or composition Of fluid présent in the earthformation. Such tool is provided with a conduit which ispushed into the borehole wall a short distance so as tocreate fluid communication between the earth formationfluid and a fluid chamber of the tool. A drawback of such wireline logging method is therequired additional drilling rig time during lowering andoperating the logging tool. A further drawback is thatthere is a danger that the logging tool gets blocked inthe open wellbore section. Moreover, it may not bepossible to insert the logging tool into a significantpart of the newly drilled wellbore section, for examplein case of a highly inclined or horizontal boreholesections. As a conséquence valuable information on thesurrounding formation cannot be obtained.

It is an object of the invention to provide animproved logging system which overcomes the drawbacks ofthe conventional system.

In accordance with the invention there is provided alogging system for use in a borehole formed in an earthformation, comprising a tubular element to be installed 12136 in the borehole, and a logging member including a conduithaving an inlet opening and being movable in radialdirection of the tubular element between a retractedposition in which the logging member is substantiallyarranged within the tubular element and an extendedposition in which the logging member extends beyond thetubular element so that said inlet opening is in fluidcommunication with the earth formation when the tubularelement is installed in the borehole, the logging Systemfurther comprising an activating device for moving thelogging member between the retracted position and theextended position thereof.

It is thereby achieved that that valuable drillingrig time is saved since the tubular element forms anintégral part of the logging System and is to be loweredinto the borehole anyway. Thus there is no need toseparately lower a logging tool into the borehole bywireline during periods between lowering/installing thetubular element and drilling the further wellboresection. Also, lowering of the tubular element intohighly inclined or horizontal wellbore sections can bedone more easily than lowering of a wireline into suchsections. A further advantage of the logging Systemaccording to the invention is that by moving the loggingmember to its retracted position the tubular element canbe lowered into the borehole without being hampered bythe logging System and without the risk of damage to thelogging member. Further, by moving the logging member toits extended position after the tubular element isinstalled in the borehole, a characteristic of the earthformation fluid (e.g. pressure or composition) can bedetermined in a logging run.

Suitably the activating device is removably arrangedwithin the tubular element. Thus, after lowering of thetubular element into the borehole and détermination of 3 12136 the fluid characteristic, the activating device can beremoved from the tubular element and retrieved to surfaceso that the interior of the tubular element is free fromobstacles in order to allow passage of wellbore tools orselected fluids through the tubular element.

Preferably the tubular element is one of a wellborecasing, a wellbore liner and a drill string.

The invention will be further described in moredetail and by way of example with reference to theaccompanying drawings in which

Fig. 1 schematically shows an embodiment of thelogging system of the invention in a first mode ofoperation thereof; and

Fig. 2 schematically shows the embodiment of Fig. 1in a second mode of operation thereof.

Referring to Figs. 1 and 2 there is shown a wellborecasing 1 arranged in a borehole 2 formed in an earthformation 4, which casing 1 has not yet been cemented inthe borehole 2 but is suspended from a drilling rig (notshow) at surface. The casing 1 includes an upper casingsection 6, an intermediate casing section 8 connected tothe upper casing section 1 by connector 9, and a lowercasing section 10 connected to the intermediate casingsection by connector 11. The intermediate casingsection 8 is provided with an opening 12 in which aprimary pad 14 and a telescoping member 16 are arranged.The pad 14 is of cylindrical shape and has an outersurface 14a facing the borehole wall and an inner surface14b facing the interior of the casing section 8. At leastan end part of the primary pad at the side of the outersurface 14a is made of elastomeric material.

The telescoping member 16 connects the primary pad 14to the casing section 8, and is arranged to perform atelescoping movement in radial direction (of thecasing 1) so as to move the primary pad 14 between a 12136 retracted position wherein the primary pad 14 is locatedsubstantially within the outer radius of the casingsection 8 and an extended position wherein the primarypad 14 extends beyond the outer radius of casingsection 8 and the outer surface 14a contacts the wall ofthe borehole 2. Furthermore, the telescoping member 16seals the primary pad 14 relative to the casingsection 18.

The primary pad 14 is provided with a bore 18extending in radial direction of the casing section 8, inwhich a conduit 22 is arranged in a manner allowing theconduit 22 to slide through the bore 18 a selectedstroke. The conduit 22 has at its inner end a shoulder 24which, when in contact with the inner surface 14a,prevents further outward sliding of the conduit 22. Acompression spring 25, arranged between the shoulder 24and the inner surface 14b of the primary pad 14, biasesthe conduit 22 to a radially inward position thereof. Theconduit 22 is internally provided with a bail valve 26including a bail 28 biased against a valve seat 30 by aspring 32. The bail valve 26 prevents flow of fluid fromthe exterior of the casing section 8 to the interiorthereof when the bail 28 is biased against the valveseat 30.

The primary pad 14 is biased to its retractedposition by a leaf spring 29 extending along the outersurface of the casing section 8 and being connected atopposite ends thereof to the casing section 8. The leafspring 8 is provided with an opening (not shown) forpassage of the conduit 22 therethrough as the conduit 22slides outwardly through the bore 18.

An activating device 34 is removably arranged withinthe casing section 8 and latched to the casing wall by alatching assembly (not shown). The activating device 34includes a secondary pad 36 of cylindrical shape and made 5 12136 of elastomeric material, which secondary pad 36 isarranged concentrically relative to the primary pad 14and a jack 38 arranged to bias the secondary pad 36against the primary pad 14 so as to move the primary 5 pad 14 between the retracted position thereof and the extended position thereof. The activating device 34furthermore includes a support member 40 for supportingthe jack 38 against the inner surface of the casingsection 8, an electric motor 42 for operating the 10 jack 38, a fluid chamber 44 provided with a fluid pressure gauge (not shown), an electronic control/memoryunit (not shown) for controlling the electric motor 42and the pressure gauge and for storing pressure readingsof the pressure gauge, and a battery (not shown) for 15 powering the control/memory unit and the electric motor 42. The secondary pad 36 is provided with a tube 46extending concentrically through the secondary pad 36 andarranged to bias the bail 28 away from the valve seat 30and to provide fluid communication between the conduit 22 20 and the fluid chamber 44 when the secondary pad is biased against the primary pad 14.

The primary pad 14, the secondary pad 36, and theconduit 22 are dimensioned such that, upon movement ofthe secondary pad 36 against the primary pad 14, the 25 secondary pad 36 pushes against the conduit 22 which thereby slides in radially outward direction through thebore 18 and the opening of the leaf spring 29 until theshoulder 24 contacts the inner surface 14b of the primarypad 14. 30 Normal operation of the assembly referred to in

Figs. 1 and 2 is hereinafter described, whereby Fig. 1shows the primary pad 14 in the retracted position andFig. 2 shows the primary pad in the extended position.

During normal operation the activating device 34 is 35 latched into the casing section 8 by means of the 12136 latching assembly, and the casing sections 6 and 10 areconnected to casing section 8 by the respectiveconnectors 9, 11. Then the casing 1, with the primarypad 14 in the retracted position, is lowered into theborehole 2. Lowering is stopped when the primary pad 14arrives at a selected depth in the borehole where it isdesired to conduct a pressure measurement of earthformation fluid such as oil or water. A wireless controlSystem (not shown) at surface is then operated so as toinduce the control/memory unit to operate the electricmotor 42 so that the motor 42 induces the jack 38 to biasthe secondary pad 36 against the primary pad 14. Theprimary pad 14 thereby moves from the retracted positionto the extended position in which the outer surface 14aof the primary pad 14 is biased against the borehole wall(Fig. 2). Simultaneously the secondary pad 36 pushesagainst the conduit 22 so that the latter protrudesthrough the opening of the leaf spring 29 and extends ashort distance into the borehole wall, and the tube 46biases the bail 28 away from the valve seat 30 andthereby provides fluid communication between theconduit 22 and the fluid chamber 44. As a resuit thefluid chamber 44 communicates with fluid présent in theearth formation. The control/memory unit then opérâtesthe fluid pressure gauge so as to measure the pressure ofthe formation fluid and to store the resulting pressuredata in the electronic memory.

The electric motor 42 is then induced to retract thejack 34 so as to move the secondary pad 36 radiallyinward. As a resuit the primary pad 14 also movesradially inward due to the biasing force from the leafspring 29. The primary pad 14 and secondary pad 36 remainin contact until the primary pad 14 reaches its retractedposition. Further radially inward movement of thesecondary pad 36 causes secondary pad 36 to become 12136 displaced from the primary pad 14, and the tube 46 tobecome displaced from the bail 28 so that the spring 18biases the bail 28 against the valve seat 30 therebyclosing the bail valve 26.

If further earth formation fluid pressuremeasurements at different borehole depths are desired,the casing 1 is raised or lowered through the borehole 2so as to relocate the primary pad 14 in the borehole 1 atthe desired depths. The procedure as describedhereinbefore is then repeated.

After completing the desired pressure measurements, asuitable retrieving device (not shown) is lowered throughthe casing 1 to the activating device 34 in order tounlatch the activating device 34 from the casingsection 8 and to retrieve the activating device 34 tosurface. The pressure data is then read out from theelectronic memory at surface.

If no further earth formation fluid pressuremeasurements are to be conducted the casing 1 is cementedin the borehole 1. In case the borehole 2 is to befurther drilled, the latching assembly is drilled out ofthe casing 1 before commencement of further drilling.

Instead of reading the pressure data from theelectronic memory after retrieval of the activatingdevice 34 to surface, the pressure can alternatively beread by extending a data transfer line (e.g. an electricconductor) from surface to the activating device 34 andtransferring the data in the form of electric signaisthrough the data transfer line to surface while theactivating device 34 is still latched to the casing 1.

Claims

8 1 2 7 3 6

1. A logging System for use in a borehole formed in anearth formation, comprising a tubular element to beinstalled in the borehole, and a logging member includinga conduit having an inlet opening and being movable inradial direction of the tubular element between aretracted position in which the logging member issubstantially arranged within the tubular element and anextended position in which the logging member extendsbeyond the tubular element so that said inlet opening isin fluid communication with the earth formation when thetubular element is installed in the borehole, the loggingSystem further comprising an activating device for movingthe logging member between the retracted position and theextended position thereof, wherein the tubular elementforms one of a wellbore casing, a wellbore liner and adrill string.
2. The logging System of claim 1, wherein the loggingmember includes a pad which extends against the boreholewall when the tubular element is installed in theborehole and the logging member is in its extendedposition.
3. The logging System of claim 2, further comprising atelescoping member interconnecting the pad and thetubular element and being arranged to perform atelescoping movement so as to move the logging memberbetween the retracted position and the extended positionthereof.
4. The logging System of claim 2 or 3, wherein the padforms a primary pad and the activating device includes a 9 12136 secondary pad arranged to bias the logging member fromthe retracted position to the extended position thereof.
5. The logging System of claim 4, wherein the activatingdevice is provided with a fluid chamber, and thesecondary pad is provided with a tube arranged to providefluid communication between said conduit and the fluidchamber when the secondary pad is biased against thelogging member.
6. The logging system of claim 4 or 5, wherein saidconduit is provided with a valve preventing flow of earthformation fluid into the tubular element when the valveis in the closed position, and wherein the secondary padis arranged to open the valve when the secondary padbiases against the logging member.
7. The logging system of any one of daims 1-6, whereinthe activating device is removably arranged within thetubular element.
8. The logging system of any one of daims 1-7, whereinthe activating device is provided with means fordetermining a characteristic of earth formation fluidentering the conduit when said inlet opening is in fluidcommunication with the earth formation.
9. The logging system of claim 8, wherein said characteristic includes a pressure of the earth formationfluid entering the conduit.
10. The logging system of any one of daims 1-9, whereinat least one of the logging member and the activatingdevice forms an RFT logging tool.
11. The logging system of any one of daims 1-10, whereinthe tubular element is internally provided with alatching assembly for latching the activating device tothe tubular element. 12136 - 9a -
12. The logging System substantially as describedhereinbefore with reference to the accompanying drawings