Patent Application
20160245076
This disclosure relates generally to a downhole measurement-while-drilling (MWD) tool including a spectrometer, and methods of operating such MWD tools.
The recovery of hydrocarbons from subterranean zones relies on the process of drilling wellbores. The process includes drilling equipment situated at surface, and a drill string extending from the surface equipment to a below-surface formation or subterranean zone of interest. The terminal end of the drill string includes a drill bit for drilling (or extending) the wellbore. The process also involves a drilling fluid system, which in most cases uses a drilling “mud” that is pumped through the inside of piping of the drill string to cool and lubricate the drill bit. The mud exits the drill string via the drill bit and returns to surface carrying rock cuttings produced by the drilling operation. The mud also helps control bottom hole pressure and prevent hydrocarbon influx from the formation into the wellbore, which can potentially cause a blow out at surface.
Directional drilling is the process of steering a well from vertical to intersect a target endpoint or follow a prescribed path. At the terminal end of the drill string is a bottom-hole-assembly (“BHA”) which comprises 1) the drill bit; 2) a steerable downhole mud motor of a rotary steerable system; 3) sensors of survey equipment used in logging-while-drilling (“LWD”) and/or measurement-while-drilling (“MWD”) to evaluate downhole conditions as drilling progresses; 4) means for telemetering data to surface; and 5) other control equipment such as stabilizers or heavy weight grounding subs. The BHA is conveyed into the wellbore by a string of metallic tubulars (i.e. drill pipe).
MWD equipment is used while drilling to provide downhole sensor and status information to surface in a near real-time mode. This information is used by a rig operator to make decisions about controlling and steering the well to optimize the drilling speed and trajectory based on numerous factors, including lease boundaries, existing wells, formation properties, and hydrocarbon size and location. The rig operator can make intentional deviations from the planned wellbore path as necessary based on the information gathered from the downhole sensors during the drilling process. The ability to obtain real-time MWD data allows for a relatively more economical and more efficient drilling operation.
Known MWD tools contain essentially the same sensor package to survey the well bore; however the data may be sent back to surface by various telemetry methods. Such telemetry methods include, but are not limited to, the use of hardwired drill pipe, acoustic telemetry, use of fibre optic cable, Mud Pulse (MP) telemetry and Electromagnetic (EM) telemetry. The sensors are usually located in an electronics probe or instrumentation assembly contained in a cylindrical cover or housing, located near the drill bit.
MP telemetry involves creating pressure waves (“pulses”) in the drill mud circulating through the drill string. Mud is circulated from surface to downhole using positive displacement pumps. The resulting flow rate of mud is typically constant. The pressure pulses are achieved by changing the flow area and/or path of the mud as it passes the MWD tool in a timed, coded sequence, thereby creating pressure differentials in the mud. The pressure differentials or pulses may be either negative pulses or positive pulses. Valves that open and close a bypass mud stream from inside the drill pipe to the wellbore annulus create a negative pressure pulse. Valves that use a controlled restriction within the circulating mud stream create a positive pressure pulse. Pulse frequency is typically governed by pulse generator motor speed changes. The pulse generator motor requires electrical connectivity with the other elements of the MWD tool.
The pulse generating motor driveline system is subjected to extreme pressure differentials of up to approximately 20,000 psi between the external and internal aspects of the MWD tool when the MWD tool is downhole. To accommodate this large pressure differential, the mud is allowed access to areas of the MWD tool which are positioned on one side of a compensation mechanism. Pressure is equalized on the other side of the pressure compensation mechanism within the tool using clean lubrication liquid, such as hydraulic fluid or silicon oil. Various systems are used to provide pressure compensation including metallic bellows, rubber compensation membranes, and piston compensations with springs.
According to a first aspect there is provided a pulser assembly for a downhole measurement-while-drilling tool comprising a motor subassembly and an electronics subassembly electrically coupled to the motor subassembly. The motor subassembly comprises a motor, a motor subassembly housing that houses the motor, a spectrometer inside the motor subassembly housing comprising an optical sensor for optical communication with a lubrication liquid when the lubrication liquid is sealed inside the motor subassembly housing, and a driveshaft extending from the motor out of the motor subassembly housing for coupling with a rotor of a fluid pressure pulse generator. The electronics subassembly comprises electronics equipment and an electronics subassembly housing that houses the electronics equipment.
The electronics equipment may comprise a controller operative to read optical measurement data from the spectrometer and compare the optical measurement data to an onboard database to determine a molecular composition of the lubrication liquid. The controller may be further operative to determine when the molecular composition of the lubrication liquid has changed beyond a threshold level. The controller may be further operative to log a unique flag when the molecular composition of the lubrication liquid has changed beyond the threshold level. The controller may be further operative to transmit a unique signal when the molecular composition of the lubrication liquid has changed beyond the threshold level. The controller may be further operative to deactivate one or more operations of the measurement-while-drilling tool when the molecular composition of the lubrication liquid has changed beyond the threshold level.
The pulser assembly may further comprise a feed through connector located between the motor subassembly and electronics subassembly such that a fluid seal is established therebetween. The feed through connector may comprise: a body with a first end and an opposite second end; a receptacle in the first end which receives the spectrometer with the spectrometer facing the motor; at least one motor electrical interconnection extending axially through the body and out of the first and second ends to electrically connect the electronics equipment and the motor; and at least one spectrometer electrical interconnection extending from the spectrometer through the body and out of the second end to electrically connect the spectrometer and the electronics equipment.
The motor subassembly housing may further comprise an end with an annular shoulder in which the feed through connector is seated. A feed through seal may extend between the body and the annular shoulder such that a fluid seal is established therebetween. A receptacle seal may extend between the spectrometer and the receptacle establishing a fluid seal therebetween.
The spectrometer may be removeably mounted in the receptacle and the feed through connector may further comprise a retention clip removeably mounted in the receptacle for securing the spectrometer in place when seated in the receptacle.
The motor subassembly may further comprise a printed circuit board electrically coupled to the electronics equipment, and the spectrometer may be mounted on the printed circuit board. The motor subassembly may further comprise a motor connection block comprising at least one interconnection which extends from the motor connection block to the electronics subassembly, and the printed circuit board may be electrically coupled to the motor connection block.
According to another aspect, there is provided a motor subassembly for a pulser assembly of a downhole measurement-while-drilling tool, comprising: a housing; a motor inside the housing; a driveshaft extending from the motor and out of a driveshaft end of the housing, the driveshaft for coupling to a rotor of a fluid pressure pulse generator; and a spectrometer inside the housing and comprising an optical sensor for optical communication with a lubrication liquid when the lubrication liquid is sealed inside the housing.
The motor subassembly may further comprise a feed through connector located at an electronics end of the housing opposed to the driveshaft end of the housing. The feed through connector may comprise: a body with a first end and an opposite second end; a receptacle in the first end which receives the spectrometer with the spectrometer facing the motor; at least one motor electrical interconnection extending axially through the body and out of the first and second ends to electrically connect the motor to electronics equipment of the pulser assembly; and at least one spectrometer electrical interconnection extending from the spectrometer through the body and out of the second end to electrically connect the spectrometer and the electronics equipment. The electronics end of the housing may further comprise an annular shoulder in which the feed through connector is seated. A feed through seal may extend between the feed through connector body and the annular shoulder such that a fluid seal is established therebetween. A receptacle seal may extend between the spectrometer and the receptacle establishing a fluid seal therebetween. The spectrometer may be removeably mounted in the receptacle and the feed through connector may further comprise a retention clip removeably mounted in the receptacle for securing the spectrometer in place when seated in the receptacle.
The motor subassembly may further comprise a printed circuit board inside the housing and the spectrometer may be mounted on the printed circuit board. The motor subassembly may further comprise a motor connection block for electrical communication with electronics equipment of the pulser assembly. The motor connection block may be electrically coupled to the printed circuit board.
According to another aspect, there is provided an apparatus for a downhole measurement-while-drilling tool comprising a spectrometer and a feed through connector. The feed through connector comprises: a body with a first end and an opposite second end; a receptacle in the first end which receives the spectrometer; at least one motor electrical interconnection extending axially through the body and out of the first and second ends to electrically connect a motor to electronics equipment of the downhole measurement-while-drilling tool; and at least one spectrometer electrical interconnection extending from the spectrometer through the body and out of the second end to electrically connect the spectrometer and the electronics equipment.
A receptacle seal may extend between the spectrometer and the receptacle establishing a fluid seal therebetween.
The spectrometer may be removeably mounted in the receptacle and the feed through connector may further comprise a retention clip removeably mounted in the receptacle for securing the spectrometer in place when seated in the receptacle.
According to another aspect, there is provided a method of determining a molecular composition of a lubrication liquid in a downhole measurement-while-drilling tool having: a motor subassembly comprising a motor, a housing that houses the motor with the lubrication liquid sealed within the housing, a spectrometer inside the housing and comprising an optical sensor in optical communication with the lubrication liquid, and a driveshaft extending from the motor out of the housing for coupling with a rotor of a fluid pressure pulse generator; and electronics equipment electrically coupled to the motor subassembly. The method comprises: reading optical measurements from the spectrometer; and comparing the optical measurement from the spectrometer to an onboard database to determine the molecular composition of the lubrication liquid.
The method may further comprise determining when the molecular composition of the lubrication liquid has changed beyond a threshold level. The method may further comprise logging a unique flag in the electronics equipment when the molecular composition of the lubrication liquid has changed beyond the threshold level. The method may further comprise transmitting a unique signal when the molecular composition of the lubrication liquid has changed beyond the threshold level. The method may further comprise deactivating one or more operations of the measurement-while-drilling tool when the molecular composition of the lubrication liquid has changed beyond the threshold level.
According to another aspect, there is provided a downhole measurement-while-drilling tool comprising: the pulser assembly of the first aspect and a fluid pressure pulse generator comprising a rotor and a stator. The rotor is coupled with the driveshaft of the pulser assembly and is rotatable by the motor relative to the stator to generate fluid pressure pulses.
This summary does not necessarily describe the entire scope of all aspects. Other aspects, features and advantages will be apparent to those of ordinary skill in the art upon review of the following description of specific embodiments.
Directional terms such as “uphole” and “downhole” are used in the following description for the purpose of providing relative reference only, and are not intended to suggest any limitations on how any apparatus is to be positioned during use, or to be mounted in an assembly or relative to an environment.
The embodiments described herein relate generally to a downhole measurement-while-drilling (MWD) tool including a spectrometer, and methods of operating such MWD tools.
Referring to the drawings and specifically to
The MWD tool 20 generally comprises the fluid pressure pulse generator 30 and a pulser assembly which takes measurements while drilling and which drives the fluid pressure pulse generator 30. The fluid pressure pulse generator 30 and pulser assembly are axially located inside a drill collar with an annular gap therebetween to allow mud to flow through the gap. The fluid pressure pulse generator generally comprises a stator and a rotor. The pulser assembly and stator are fixed to the drill collar, and the rotor is rotated by the pulser assembly relative to the stator to generate fluid pressure pulses 6.
Referring to
The motor subassembly 25 is filled with a lubrication liquid such as hydraulic oil or silicon oil, and the lubrication liquid is contained inside the motor subassembly housing 49 by a rotary seal 54 which provides a fluid seal between the driveshaft 24 and the motor subassembly housing 49. The pressure compensation device 48 comprises a flexible membrane 51 in fluid communication with the lubrication liquid on one side and with the mud on the other side via ports 50 in the motor subassembly housing 49. As is known in the art, the membrane 51 can flex to compensate for pressure changes in the mud and allow the pressure of the lubrication liquid to substantially equalize with the pressure of the mud. Without pressure compensation, the torque required to rotate the driveshaft 24 would need high current draw with excessive battery consumption resulting in increased costs. In alternative embodiments (not shown), the pressure compensation device 48 may be any pressure compensation device known in the art, such as pressure compensation devices that utilize pistons, metal membranes, or a bellows style pressure compensation mechanism.
As will be described in more detail below, a spectrometer 34 is seated inside the feed through connector 29 (collectively “spectrometer and feed through subassembly 29, 34”) and faces the inside of the motor subassembly 25. The spectrometer 34 can thus have optical access to the lubrication liquid inside the motor subassembly housing 49, and can monitor the molecular composition and condition of the lubrication liquid.
Referring now to
The D&I sensor module 100 comprises three axis accelerometers, three axis magnetometers and associated data acquisition and processing circuitry. Such D&I sensor modules are well known in the art and thus are not described in detail here.
The drilling conditions sensor module 102 includes sensors mounted on a circuit board for taking various measurements of borehole parameters and conditions such as temperature, pressure, shock, vibration, rotation and directional parameters. Such sensor modules 102 are also well known in the art and thus are not described in detail here.
The main circuit board 104 can be a printed circuit board with electronic components soldered on the surface of the board. The main circuit board 104 and the sensor modules 100, 102 may be secured on a carrier device (not shown) which is fixed inside the electronics subassembly housing 33 by end cap structures (not shown). The sensor modules 100, 102 are each electrically communicative with the main circuit board 104 and send measurement data to the controller 106. The spectrometer 34 is also electrically communicative with the main circuit board 104 and sends measurement data to the controller 106. The controller 106 processes the measurement data and the encoder 105 is programmed to encode the processed measurement data into a carrier wave using known modulation techniques. The controller 106 then sends control signals to the motor of the motor and gearbox assembly 23 to rotate the driveshaft 24 to generate pressure pulses corresponding to the carrier wave determined by the encoder 105.
The feed through connector 29 is located between and electrically interconnects and fluidly separates the motor subassembly 25 and the electronics subassembly 28. Such feed through connectors 29 are known in the art and can be adapted for use as the spectrometer and feed through subassembly 29, 34. A suitable feed through connector 29 may therefore be custom designed or adapted from commercially available products. An embodiment of the spectrometer and feed through subassembly 29, 34 will now be described in detail with reference to
The high pressure end of the body 80 includes a receptacle in which the spectrometer 34 is seated. The receptacle is located centrally in the high pressure end and has a depth that allows the spectrometer 34 to be slightly recessed in the high pressure end of the body 80 with its detection surface facing outwardly from the high pressure end of the body 80. The spectrometer 34 includes an optical sensor (not shown) which is in optical communication with the lubrication liquid in the motor subassembly 25 through the detection surface. A receptacle O-ring seal 84 and parbak ring 86 surround the spectrometer 34 and provide a fluid seal between the receptacle and the spectrometer 34. At least one spectrometer electrical interconnection extends from the spectrometer 34 through the body 80 and out of the low pressure end of the body 80 to transmit data from the spectrometer 34 to the electronics equipment in the electronics subassembly 28. In the embodiment shown in
As can be seen in
Referring now to
In alternative embodiments, the spectrometer 34 may be mounted anywhere within the motor subassembly housing 49 where the spectrometer's optical sensor has optical access to the lubrication liquid sealed within the motor subassembly housing 49.
The spectrometer 34 includes a light source which emits light with a wavelength from gamma to far infrared to illuminate the lubrication liquid surrounding the spectrometer 34. An optical sensor in the spectrometer 34 collects reflected light and electrically transmits this data to the controller 106 to be processed. The spectrometer 34 may be a near infrared (NIR) spectrometer as are known in the art, such as a SCiO™ sensor, which emits light in the near-infrared region of the electromagnetic spectrum (generally from about 800 nm to 2500 nm). In alternative embodiments, the light source may be a separate device and spaced from the optical sensor. In these alternative embodiments, the light source and optical sensor comprise the spectrometer 34. Without being bound by science, it is thought that molecules present in the lubrication liquid vibrate and these vibrations interact with light to create a unique optical signature. By comparing the light being emitted and the light collected the molecular content of the lubrication liquid can be analyzed.
The optical measurement data sent to the controller 106 from the spectrometer 34 will typically be too complex to transmit to the surface by telemetry. The memory 108 therefore contains program code that is executed by the controller 106 to analyze the optical measurement data received from the spectrometer 34 and compare it with an onboard database stored in the memory 108 to determine the molecular composition of the lubrication liquid. The memory 108 also contains program code that is executed by the controller 106 to utilize the determined molecular composition information to provide information on the composition and condition of the lubrication liquid. For example, the controller 106 uses the determined molecular composition information to predict the life percentage of the lubrication liquid or to determine if there are foreign particles in the lubrication liquid as described below in more detail.
Over time, the lubrication liquid will oxidize, burn or otherwise degrade to a point where the lubrication liquid is no longer effective. The spectrometer measurement data may therefore be used to predict the life percentage of the lubrication liquid to determine when the lubrication liquid needs replacing. According to an embodiment, and referring to
There may be a build up of foreign particles in the lubrication liquid over time which can affect the quality of the lubrication liquid. Such foreign particles may, for example, include excessive carbon build up as the lubrication liquid becomes carburized due to high electrical currents present in the motor subassembly 25. Other foreign particles which may be present in the lubrication liquid include metal filings or drilling mud that has seeped into the lubrication liquid through failure of the seal 54 or the pressure compensation device 48. According to an embodiment, and referring to
While particular embodiments have been described in the foregoing, it is to be understood that other embodiments are possible and are intended to be included herein. It will be clear to any person skilled in the art that modifications of and adjustments to the foregoing embodiments, not shown, are possible. For example, in alternative embodiments (not shown), the fluid pressure pulse generator 30 may be positioned at the uphole end of the MWD tool 20.
This application claims benefit to Patent Application No. 62/115,429 filed Feb. 12, 2015, the contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62115429 | Feb 2015 | US |
