1. Field of the Disclosure
This disclosure relates generally to apparatus for use in a wellbore that includes sensors in a module (or “sub”) for estimating parameters of interest of a system, such as a drilling system.
2. Background of the Art
Oil wells (boreholes) are usually drilled with a drill string that includes a tubular member having a drilling assembly (also referred to as the bottomhole assembly or “BHA”) with a drill bit attached to the bottom end thereof. The drill bit is rotated to disintegrate the earth formations to drill the wellbore. The BHA includes devices and sensors for providing information about a variety of parameters relating to the drilling operations (drilling parameters), behavior of the BHA (BHA parameters) and formation surrounding the wellbore being drilled (formation parameters). Drilling parameters include weight-on-bit (“WOB”), rotational speed (revolutions per minute or “RPM”) of the drill bit and BHA, rate of penetration (“ROP”) of the drill bit into the formation, and flow rate of the drilling fluid through the drill string. The BHA parameters typically include torque, whirl, vibrations, bending moments and stick-slip. Formation parameters include various formation characteristics, such as resistivity, porosity and permeability, etc.
Various sensors are utilized in the drill string to provide measurement of selected parameters on interest. Such sensors are typically placed at individual location, such as in the BHA and/or drill pipe. U.S. patent application Ser. No. 11/146,934 filed on Jun. 7, 2005, having the same assignee as the present disclosure discloses a plug-in sensor and electronics module for placement in a pin section of the drill bit. The electronics is located relatively close to the sensors and thus allows processing of signals without significant attenuation of the signals detected by the sensors in the module. The present disclosure is directed to a module containing sensors and electronics configured to estimate a variety of downhole parameters that may be disposed in the BHA and/or at one or more locations along the drillstring.
In one aspect, a removable module or sub is provided for use in drilling a wellbore, which sub in one embodiment may include: a body having a central bore therethrough; a pin end having an external thread configured to be coupled to one of another sub and a drill pipe; a box end having an internal thread configured to be coupled to one of another sub, and a drill pipe; and at least one sensor configured to make a measurement indicative of at least one of (a) a downhole condition, and (b) a property of the earth formation, wherein the sensor is disposed in a pressure-sealed chamber in at least one of the box end and the pin end.
In another aspect, a method is provided that in one embodiment may include: conveying a drill string including a tubular and a bottomhole assembly (BHA) including a drill bit at end thereof; providing a removable sub at a selected location in the drill string, wherein the sub includes a sensor module including at least one sensor configured to make measurements indicative of at least one of a downhole condition, the at least one sensor is pressure sealed in a chamber, the removable sub including a bore extending therethrough for flow of a fluid therethrough.
Examples of certain features of the apparatus and method disclosed herein are summarized rather broadly in order that the detailed description thereof that follows may be better understood. There are, of course, additional features of the apparatus and method disclosed hereinafter that will form the subject of the claims appended hereto.
For detailed understanding of the present invention, references should be made to the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein:
The drill string 118 is shown conveyed into the wellbore 110 from a rig 180 at the surface 167. The exemplary rig 180 shown in
Still referring to
Also shown in
An additional sub 141b may be provided in the BHA 130. In one embodiment of the disclosure, at least one sub, such as sub 141b, may be positioned near a stabilizer schematically represented by 181. Additional subs such as subs 141c, 141d and 141e may be placed spaced apart at various selected locations along the drillstring 118. For example, the subs may be placed every 10th pipe junction or 15th pipe junction, etc. Certain details and the use of the subs in the drilling system 100 are discussed below in reference to
Still referring to
The end-cap 370 includes a cap bore 376 formed therethrough, such that the drilling mud may flow through the end cap, through the central bore 203 of the pin end 201 into the body of the sub 200. In addition, the end-cap 370 includes a first flange 371 including a first sealing ring 372, near the lower end of the end-cap 370, and a second flange 373 including a second sealing ring 374, near the upper end of the end-cap 370.
In the exemplary embodiment shown in
An electronics module 390 configured as shown in the exemplary embodiment of
The sub 200 enables monitoring of drilling parameters at numerous locations in the BHA and along the drillstring. The measurements of drilling parameters may be used by the processor 172 to identify undesirable behavior of the BHA 130. Remedial action in the form of altering WOB, RPM and torque can be directed by either the downhole processor or from the surface based on telemetered data sent uphole by telemetry unit 188. Vibration measurements near the stabilizer can suggest alteration of the force on the stabilizer ribs.
The subs 141c, 141d, 141e along the drillstring may be battery powered. Alternatively, a wired drill-pipe may be used to power the electronics modules on the subs. These measurements are useful in analyzing the vibration of the drill string. Vibrations of a drilling tool assembly are difficult to predict because several forces may combine to produce the various modes of vibration. Models for simulating the response of an entire drilling tool assembly including a drill bit interacting with formation in a drilling environment have not been available. Drilling tool assembly vibrations are generally undesirable, not only because they are difficult to predict, but also because the vibrations can significantly affect the instantaneous force applied on the drill bit. This can result in the drill bit not operating as expected.
For example, vibrations can result in off-centered drilling, slower rates of penetration, excessive wear of the cutting elements, or premature failure of the cutting elements and the drill bit. Lateral vibration of the drilling tool assembly may be a result of radial force imbalances, mass imbalance, and drill bit/formation interaction, among other things. Lateral vibration results in poor drilling tool assembly performance, which may result in over-gage hole-drilling, out-of-round (or lobed) wellbores and premature failure of the cutting elements and drill bit bearings.
The measurements made by these distributed sensors during drilling of deviated boreholes may be used to identify nodal locations along the drillstring where vibration is minimal and antinodal locations along the drillstring where vibrations are greater than selected limits. Nodal locations may be diagnostic of sticking of the drillstring in the wellbore. Knowledge of vibration at antinodal locations enables a drilling operator to alter the drilling operation to control vibrations such that they do not exceed the desired limits. In this regard, the acceleration and/or strain measurements made by the distributed subs may be input to a suitable drillstring vibration modeling program for analysis. SPE 59235 of Heisig et al. (which is incorporated herein by reference in entirety) discloses different methods for analysis of lateral drillstring vibrations in extended reach wells. These include an analytic solution, a linear finite element model and a nonlinear finite element model. The assumption in Heisig is that the drillbit is at an antinode and vibration analysis is carried out for a fixed length of pipe, based on the assumption that the other end of the pipe is a node. The modeling program used in Heisig may be used for modeling drillstring vibrations with nodes and antinodes identified by the distributed sensors. Another modeling program that may be used for the purposes of this disclosure is discussed in SPE59236 of Schmalhorst et al, which is incorporated herein by reference in entirety. This modeling program takes the mud flow into account. The effect of changing parameters, such as WOB and RPM, may be modeled in real time, which enables an operator to initiate remedial actions in real time.
In another aspect, the measurements made using the sensors in the subs described herein may be used to identify a dysfunction of the drillstring, and to estimate the WOB and torque at specific locations along the drillstring. A dysfunction of the drillstring is defined as a drill string parameter outside a defined or selected limit and may include, but is not limited to, vibration, displacement, sticking, whirl, reverse spin, bending and strain. In addition, the measurements and processed data may be stored on a suitable memory in the electronics module and analyzed upon tripping out of the borehole.
Alternatively, the data may be processed by a downhole and/or surface processor. Implicit in the control and processing of the data is the use of a computer program implemented on a suitable machine readable medium that enables the processor to perform the control and processing. The machine-readable medium may include ROMs, EPROMs, EAROMs, flash memories and optical disks.
Thus, in one aspect an apparatus for use in a borehole is disclosed, which in one embodiment may include: a BHA configured to be conveyed on a drilling tubular into a borehole, the BHA including a drill bit configured to drill an earth formation; and at least one removable sub in the drill string that includes a body having a pin end, a box end, and at least one sensor configured to make a measurement indicative of a downhole condition (or a “characteristic,” a “parameter” or a “parameter of interest”), the at least one sensor being disposed in a pressure-sealed chamber in the body. In one aspect, the at least one sub includes a processor configured to process signals from the at least one sensor. In another aspect, the pressure-sealed chamber may be formed or disposed in the pin end or the box end. The downhole condition may relate to one or more of: (i) acceleration, (ii) rotational speed (RPM), (iii) weight-on-bit (WOB), (iv) torque, (v) vibration, (vi) oscillation, (vii) acceleration, (viii) stick-slip, (xi) whirl, (x) strain, (xi) bending, (xii) temperature, and (xiii) pressure. In another embodiment, one or more additional removable subs may be disposed at selected locations in the drill string, wherein each additional sub includes an additional sensor configured to provide measurements indicative of the downhole condition at their respective selected locations. In another aspect, each sub may include a processor configured to process measurements from the sensor or sensors using one or more computer models to determine or identify a drilling dysfunction. The processor may further be configured to alter a drilling parameter in response to the identified dysfunction. In one configuration the pin end may include external threads and the box end may include internal threads, each end configured to be coupled to at least one of a (i) drilling tubular; (ii) sub; (iii) drill bit, and (iv) tool in the BHA. Data to and/or from the sub may be sent via a suitable communication link including, but not limited to, an electromagnetic coupling, an acoustic transducer, a slip ring, and a wired pipe.
In another aspect, a method for estimating a downhole condition is provided, which in one embodiment may include: providing a removable sub at a selected location in a drilling apparatus, wherein the removable sub includes a sensor in a pressure-sealed chamber in the removable sub, the removable sub further including a bore for flow of a fluid therethrough; making measurements using the sensor indicative of the downhole condition; and processing the measurements from the sensor to estimate the downhole condition. The measurements may be made of any suitable characteristic of a drilling apparatus, borehole and/or formation, including but not limited to: (i) acceleration, (ii) rotational speed (RPM), (iii) weight-on-bit (WOB), (iv) torque, (v) vibration, (vi) oscillation, (vii) acceleration, (viii) stick-slip, (ix) whirl, (x) strain, (xi) bending, (xii) temperature, and (xiii) pressure. The method may further include: processing the measurements from the sensor using a model to identify a drilling dysfunction; and altering a drilling parameter in response to the identified dysfunction. The data to and/or from the sub may be communicated via any suitable method, including, but not limited to, using: an electromagnetic coupling; an acoustic transducer; a slip ring; and a wired pipe. The method may further include: disposing at least one additional removable sub having an additional sensor on the drilling tubular at a elected location; and identifying the downhole condition using measurements from the additional sensor. In another aspect, the method may further include altering a drilling parameter in response to the identified downhole condition. In another aspect, as removable is disclosed, which in one embodiment may include: a body having a pin end and a box end each configured for coupling to a member of a drill string, the body having a bore therethrough for flow of a fluid; a sensor disposed in a pressure-sealed chamber in one of (i) the pin end; (ii) the box end, (iii) the sensor configured to provide measurements relating to a downhole condition, (iv) vibration, (v) oscillation, (vi) acceleration, (vii) stick-slip, (viii) whirl, (xi) strain, (x) bending, (xi) temperature, and (xii) pressure.
While the foregoing disclosure is directed to specific embodiments of the invention, various modifications will be apparent to those skilled in the art. It is intended that all variations within the scope and spirit of the appended claims be embraced by the foregoing disclosure.
This application claims priority as a continuation-in-part of U.S. patent application Ser. No. 11/146,934 filed on Jun. 7, 2005, which is incorporated herein by reference in entirety.
Number | Date | Country | |
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Parent | 11146934 | Jun 2005 | US |
Child | 12559012 | US |