Measuring and testing – Borehole or drilling
Reexamination Certificate
1999-07-12
2001-05-15
Williams, Hezron (Department: 2856)
Measuring and testing
Borehole or drilling
C073S152030, C073S152170, C073S152460, C166S100000, C166S250160, C175S050000
Reexamination Certificate
active
06230557
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to the determination of various parameters in a subsurface formation penetrated by a wellbore while drilling the wellbore. More particularly, this invention relates to the determination of formation parameters such as formation pressure through the use of a non-rotating drill string stabilizer.
2. Description of the Related Art
Present day oil well operation and production involves continuous monitoring of various subsurface formation parameters. One aspect of standard formation evaluation is concerned with the parameters of reservoir pressure and the permeability of the reservoir rock formation. Continuous monitoring of parameters such as reservoir pressure and permeability indicate the formation pressure change over a period of time, and is essential to predict the production capacity and lifetime of a subsurface formation. Present day operations typically obtain these parameters either through wireline logging via a “formation tester” tool. This type of measurement requires a supplemental “trip”, in other words, removing the drill string from the wellbore, running a formation tester into the wellbore to acquire the formation data and, after retrieving the formation tester, running the drill string back into the wellbore for further drilling. Thus, it is typical for formation parameters, including pressure, to be monitored with wireline formation testing tools, such as those tools described in U.S. Pat. Nos.: 3,934,468; 4,860,581; 4,893,505; 4,936,139; and 5,622,223.
Each of the aforementioned patents is therefore limited in that the formation testing tools described therein are only capable of acquiring formation data as long as the wireline tools are disposed in the wellbore and in physical contact with the formation zone of interest. Since “tripping the well” to use such formation testers consumes significant amounts of expensive rig time, it is typically done under circumstances where the formation data is absolutely needed or it is done when tripping of the drill string is done for a drill bit change or for other reasons.
The availability of reservoir formation data on a “real time” basis during well drilling activities is a valuable asset. Real time formation pressure obtained while drilling will allow a drilling engineer or driller to make decisions concerning changes in drilling mud weight and composition as well as penetration parameters at a much earlier time to thus promote the safety aspects of drilling. The availability of real time reservoir formation data is also desirable to enable precision control of drill bit weight in relation to formation pressure changes and changes in permeability so that the drilling operation can be carried out at its maximum efficiency.
It is desirable therefore to provide a method and apparatus for well drilling that enable the acquisition of various formation data from a subsurface zone of interest while the drill string with its drill collars, drill bit and other drilling components are present within the well bore, thus eliminating or minimizing the need for tripping the well drilling equipment for the sole purpose of running formation testers into the wellbore for identification of these formation parameters.
To address these shortcomings, it is a principal object of the present invention to utilize at least one of the drill string components for obtaining such formation parameter data.
More particularly, it is an object of the present invention to utilize a non-rotating stabilizer tool on the drill string for engaging the formation to gather information therefrom.
SUMMARY OF THE INVENTION
The objects described above, as well as various other objects and advantages, are achieved by downhole tool for collecting data from a subsurface formation, including a tubular mandrel adapted for axial connection in a drill string positioned in a wellbore penetrating the subsurface formation and a stabilizer element positioned about the tubular mandrel for relative rotation between the stabilizer element and the tubular mandrel. A plurality of elongated ribs are connected to the stabilizer element. A means is connected to the stabilizer element for frictional engagement with a wall of the wellbore so as to prevent the stabilizer element from rotating relative to the wellbore wall. An actuator system is carried at least partially by the stabilizer element, and a probe is carried by at least one of the elongated ribs and adapted for movement by the actuator system between a retracted position within the one rib and an extended position engaging the wellbore wall such that the probe collects data from the formation.
The elongated ribs are preferably radially spaced apart, and oriented either axially or helically along the stabilizer element.
The frictional engagement means may be provided in the form of various structures, including the plurality of elongated ribs, a plurality of stabilizer blades, or some combination thereof. When the stabilizer blades are selected for providing frictional engagement with the wellbore, it is preferred that each of the blades be positioned between two of the elongated ribs.
The frictional engagement means may further include a spring system for urging the frictional engagement means into contact with the wellbore wall to prevent rotation of the frictional engagement means relative to the wellbore wall. It is preferred that the spring system include a plurality of bow-spring blades each having an inherent spring stiffness.
The probe includes in a preferred embodiment a resilient packer positioned in a substantially cylindrical opening in one of the ribs of the stabilizer element. The packer has a central opening therein. A conduit having an open end is positioned for fluid communication with the central opening in the packer. A filter valve is positioned in the central opening of the packer about the open end of the conduit, and the filter valve is movable between a first position closing the open end of the conduit and a second position permitted filtered formation fluid flow between the formation and the conduit.
The actuator system includes in a preferred embodiment a hydraulic fluid system, and means for selectively pressurizing hydraulic fluid in the hydraulic fluid system. An expandable vessel is placed in fluid communication with the hydraulic fluid system, and the vessel is expanded with increased pressure in the hydraulic fluid and contracted with decreased pressure in the hydraulic fluid. The vessel is preferably a bellows connected to the packer of the probe, such that expansion of the bellows under increased pressure in the hydraulic fluid moves the packer into sealed engagement with the wellbore wall.
The actuator system further includes in a preferred embodiment a sequence valve, operable upon sensing a predetermined pressure in the hydraulic fluid resulting from maximum expansion of the vessel, to move the filter valve of the probe to the second position whereby fluid in the formation can flow into the open end of the conduit.
It is also preferred that the downhole tool of the present invention includes a sensor placed in fluid communication with the probe conduit for measuring a property of the formation fluid. In a preferred embodiment, the sensor is a pressure sensor adapted for sensing the pressure of the formation fluid.
The present invention includes, in another aspect, a method for measuring a property of fluid present in a subsurface formation. The method includes the positioning of a drill string in a wellbore penetrating the subsurface formation. A non-rotating element of a tool positioned in the drill string is placed in engagement with a wall of the wellbore such that the non-rotating element does not move relative to the wellbore wall. A probe carried by the non-rotating element is moved into sealed engagement with the wellbore wall to establish fluid communication between the formation and the non-rotating element.
In a preferred embodiment, fluid is introduced from the formation to a sensor, such
Ciglenec Reinhart
Dorel Alain P.
Christian Steven L.
Schlumberger Technology Corporation
Wiggins David J.
Williams Hezron
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