Field of the Invention

[001] This invention relates generally to the field of electric submersible pumping systems, and more particularly, but not by way of limitation, to a submersible pumping system that includes a system and method of active real-time condition monitoring using on-board data acquisition and wireless telemetry.

Background

[002] Electric submersible pumping systems are often deployed into wells to recover petroleum fluids from subterranean reservoirs. Typical electric submersible pumping systems include a number of components, including one or more fluid filled electric motors coupled to one or more high performance pumps located above the motor. In many instances, downhole components and tools are subjected to high-temperature, corrosive environments, which often lead to failure of these components. Downhole sensors are needed to provide reliable data regarding the physical, thermal and chemical properties of the components and downhole conditions.

[003] Current downhole sensors used to transmit data about the downhole components and characteristics require cable attachments and connectors connected to the various components. Typically these sensors are not able to provide information about the state of the components during operation of the submersible pumping system and attempts to measure downhole characteristics during operation often results in errors due to indirect measurements. Further, sensors are often located on large, bulky instrumentation and require intrusive methods to measure downhole characteristics. For example, lateral shaft displacements of an electric submersible pump motor is often monitored by penetrating through the stator of the motor with some type of position sensor.

[004] There is, therefore, a need for an improved wireless monitoring system to provide more accurate, real-time condition monitoring of the downhole components during operation of the submersible pumping system. It is to this and other needs that the preferred embodiments are directed.

Summary of the Invention

[005] In a preferred embodiment, the present invention includes a pumping system for use in a subterranean wellbore below a surface. The pumping system includes a motor assembly, a pump driven by the motor assembly, and one or more sensors configured to measure an operating parameter within the pumping system and output a signal representative of the measured parameter. The pumping system further includes a wireless telemetry system that is configured to transmit data representative of the measured parameter from the pumping system to the surface.

[006] In another aspect, the preferred embodiments include a method for monitoring physical parameters within a pumping system deployed in a wellbore. The method includes the steps of providing an acoustically active sensor within the pumping system, providing an interrogator in wireless communication with the acoustically active sensor, and providing a control unit in communication with the interrogator. The method continues with the steps of transmitting an incident wireless signal from the interrogator, receiving the incident wireless signal at the acoustically active sensor and reflecting from the acoustically active sensor a reflected wireless signal, where the reflected wireless signal has been affected by the physical parameter acting on the acoustically active sensor. The method concludes with the steps of receiving the reflected wireless signal with the interrogator and interpreting the differences between the incident wireless signal and the reflected wireless signal as a measurement of the physical parameter acting on the acoustically active sensor.

[007] In yet another aspect, the preferred embodiments include a method for monitoring physical parameters of a pumping system deployed in a wellbore below the surface from a control unit located on the surface. The method includes the steps of providing a sensor within the pumping system, measuring a condition within the pumping system with the sensor, providing a transmitter operably connected to the sensor and providing a receiver at a spaced apart distance from the transmitter within the pumping system. The method continues with the step of transmitting a primary wireless data signal from the transmitter to the receiver that is representative of the measured condition. The method concludes with the step of transmitting a data secondary signal to the control unit on the surface from the receiver, where the secondary signal is representative of the measured condition.

Brief Description of the Drawings

[008] FIG. 1 is a depiction of a pumping system constructed in accordance with a first preferred embodiment.

[009] FIG. 2 is a depiction of the acoustically active sensors of the pumping system 100 of FIG. 1.

[010] FIG. 3 is a partial cross-sectional view of the motor assembly of FIG. 1 with acoustically active sensors.

[011] FIG. 4 is a depiction of a pumping system with wireless telemetry system constructed in accordance with a second preferred embodiment. [012] FIG. 5 is a depiction of a pumping system with wireless telemetry system constructed in accordance with a third preferred embodiment.

Detailed Description of the Preferred Embodiment

[013] In accordance with a preferred embodiment of the present invention, FIG. 1 shows an elevational view of a pumping system 100 attached to production tubing 102. The pumping system 100 and production tubing 102 are disposed in a wellbore 104, which is drilled for the production of a fluid such as water or petroleum. As used herein, the term "petroleum" refers broadly to all mineral hydrocarbons, such as crude oil, gas and combinations of oil and gas. The production tubing 102 connects the pumping system 100 to a wellhead 106 located on the surface. Although the pumping system 100 is primarily designed to pump petroleum products, it will be understood that the present invention can also be used to move other fluids. It will also be understood that, although each of the components of the pumping system are primarily disclosed in a submersible application, some or all of these components can also be used in surface pumping operations.

[014] The pumping system 100 preferably includes a pump assembly 108, a motor assembly 110, a seal section 112, a sensor array module 114 and a wireless telemetry system 116. The motor assembly 110 is preferably an electrical motor that receives power from a surface-mounted variable speed drive 118 through a power cable 120. When energized, the motor assembly 110 drives a shaft that causes the pump assembly 108 to operate. The seal section 112 shields the motor assembly 110 from mechanical thrust produced by the pump assembly 108 and provides for the expansion of motor lubricants during operation. The seal section 112 also isolates the motor assembly 110 from the wellbore fluids passing through the pump assembly 108. The sensor array module 114 is preferably placed below the motor assembly 110 and is configured to measure and evaluate a number of parameters internal and external to the motor assembly 110. Such parameters include, for example, wellbore temperature, wellbore static pressure, gas-to-liquid ratios, internal operating temperature, vibration, radiation, motor winding conductivity, motor winding resistance and motor operating speed. It will be appreciated that the sensor array module 114 may also be connected to sensors placed in other locations within the pumping system 100. For example, the sensor array module 114 can be connected to sensors in the seal section 112 and pump 108 for monitoring intake and discharge pressures and internal operating temperatures.

[015] The wireless telemetry system 116 provides a communication system for sending and receiving information between the pumping system 100 and surface facilities using acoustic, radio or other wireless signal telemetry. In a first preferred embodiment depicted in FIG. 1, the wireless telemetry system 116 includes a surface-mounted control unit 122, an interrogator 124 and one or more acoustically active sensors 126. The control unit 122 preferably includes an onboard computer that controls the operation of the wireless telemetry system 116, stores information retrieved through the wireless telemetry system 116 and provides information to the variable speed drive 118 and other downstream computer systems and operator interfaces.

[016] In response to a command signal 128 from the control unit 122, the interrogator 124 emits an incident acoustic wave 130. The incident acoustic wave 130 is received by the acoustically active sensors 126. In response to the incident acoustic wave 130, the acoustically active sensors 126 produce a reflected acoustic wave 132 that is received by the interrogator 124. Unless otherwise limited, the term "reflected" will be used herein to refer broadly to waves that are produced directly or indirectly in response to the incident acoustic wave 130, including waves that are only reflected as well as waves that are transmitted, amplified, or otherwise transformed from the incident acoustic wave 130. The differences between the incident acoustic wave 130 and the reflected acoustic wave 132 present information about the measurement taken by the acoustically active sensor. The interrogator 124 can be configured to interpret the reflected acoustic wave 132 and provide an interpreted result to the control unit 122 or simply relay the reflected acoustic wave 132 to the control unit 122 for interpretation. It will be appreciated that the interrogator 124 can be placed in the wellbore 104, on the pumping system 100 or on the surface. It will be further appreciated that the command signal 128 can be transmitted to the interrogator 124 from the control unit 122 through a wired or wireless transmission.

[017] As illustrated in FIG. 1, the signal between the acoustically active sensor 126 and the interrogator 124 passes through the wellbore 104 or surrounding reservoir. In an alternate preferred embodiment, the signal connection between the acoustically active sensor 126 and interrogator 124 can be configured to pass through the pumping system 100 and production tubing 102 by adjusting the frequency, wavelength, energy and other characteristics of the acoustic signal. Non-signal noise created by other components within the pumping system 100 can be filtered out at the interrogator 124 or at the control unit 122 on the surface.

[018] Turning to FIGS. 2 and 3, shown therein is a particularly preferred embodiment of an acoustically active sensor 126 and a cross-sectional depiction of the motor assembly 110. The acoustically active sensor 126 is preferably a surface acoustic wave (SAW) sensor that includes an input transducer 134, a delay field 136 and an output transducer 138. Each acoustically active sensor 126 is a micro-electromechanical system that relies on the modulation of surface acoustic waves to sense and measure a physical parameter such as temperature, stress and strain, ultraviolet radiation, current, magnetic fields and voltage. The input transducer 134 receives the incident acoustic wave 130 and directs the wave energy along the delay field 136. As the acoustic wave passes along the delay field 136, the measured parameter (e.g., temperature, strain, radiation, current, magnetism, or voltage) affects the wave travel. The affected acoustic wave is then passed to the output transducer 138, which sends the reflected acoustic wave 132 back to the interrogator 124. The effect of the measured parameter on the passage of the transduced wave through the delay field 136 can be interpreted as a measurement of the underlying physical parameter. Although the presently preferred embodiments employ the use of an incident acoustic wave 130 and a reflected acoustic wave 132, it will be appreciated that in alternate embodiments of the present invention the acoustically active sensors 126 are configured to receive and transmit waves of electromagnetic radiation. Such waves of electromagnetic radiation may include, for example, radio and microwave radiation.

[019] FIG. 3 illustrates the placement of the acoustically active sensors 126 in the motor assembly 110. The motor assembly 110 preferably includes a housing 140, a stator 142, a rotor 144 and a shaft 146. In response to the passage of multiphase alternating electrical current through windings in the stator 142, the rotor 144 and shaft 146 rotate in accordance with well-established electromotive principles.

[020] In the presently preferred embodiments, the acoustically active sensor 126a is placed on the shaft 146 in a way that the delay field 136 measures strain on the shaft 122. Acoustically active sensor 126b is secured to the rotor 144 and configured to measure bar-to-bar conductance within the rotor 144. Acoustically active sensor 126c is placed in the housing 140 and configured to measure the external temperature of the wellbore 104 around the motor 110. Acoustically active sensor 126d is secured within the stator 142 and configured to measure winding-to-winding electrical current. Acoustically active sensor 126e is secured within the base of the motor 110 and configured to measure the temperature of the motor lubricant circulating through the motor 110. Acoustically active sensor 126f is secured within the stator 142 and is configured to measure vibration within the motor assembly 110. It will be appreciated the motor assembly 110 may include additional acoustically active sensors 126 in alternative locations and in configurations designed to evaluate additional physical parameters. Furthermore, the acoustically active sensors 126 can be placed in the wellbore 104, the production tubing 102, on surface facilities and in other components within the pumping system 100.

[021] The interrogator 124 preferably polls the acoustically active sensors 126 on a high-frequency basis. In a first preferred embodiment, the interrogator 124 uses frequency domain protocols for differentiating signals sent and received from individual acoustically active sensors 126. In a second preferred embodiment, the interrogator 124 uses time domain protocols for differentiating signals sent and received from individual acoustically active sensors 126. The interrogator 124 can be configured to poll multiple acoustically active sensors 126 simultaneously or multiple interrogators 124 can be used in concert to communicate with multiple acoustically active sensors 126.

[022] The use of the acoustically active sensors 126 and the remote interrogator 124 provides an enhanced monitoring system that is non-intrusive and makes possible the real-time, high-resolution monitoring of components within the pumping system 100 and wellbore 104.

[023] Turning to FIG. 4, shown therein is an alternate preferred embodiment of the pumping system 100 in which the wireless telemetry system 116 includes a transmitter 148, a receiver 150 and one or more repeaters 152. The transmitter 148 is operably connected to the sensor array module 114. Data collected by sensors within the pumping system 100 is aggregated at the array module 114 and passed to the transmitter 148. The transmitter 148 converts the measurement data into a primary data signal 154 that is transmitted to the receiver 150. In preferred embodiments, the receiver 150 is positioned at or near the top of the pumping system 100. The receiver 150 converts the primary data signal 154 into a secondary data signal 156 that is transmitted by the receiver 150 directly to the surface control unit 122 or indirectly through the one or more repeaters 152. The surface control unit 122 interprets the secondary data signal 156 and provides the variable speed drive 118 or operator with information about the measurements taken from the wellbore 104 and pumping system 100.

[024] As illustrated in FIG. 4, the signal between the transmitter 148 and the receiver 150 passes through the wellbore 104 or surrounding reservoir. In an alternate preferred embodiment, the signal connection between the transmitter 148 and the receiver 150 can be configured to pass through the pumping system 100 and production tubing 102 by adjusting the frequency, wavelength, energy and other characteristics of the acoustic signal. Non-signal noise created by other components within the pumping system 100 can be filtered out at the interrogator 124 or at the control unit 122 on the surface. [025] In a particularly preferred embodiment, the transmitter 148, receiver 150 and repeaters 152 are configured to send and receive radio signals and the primary and secondary data signals 154, 156 constitute radio signals. In an alternate preferred embodiment, the transmitter 148, receiver 150 and repeaters 152 are configured to send and receive acoustic signals and the primary and secondary data signals 154, 156 constitutes acoustic signals. In yet another preferred embodiment, the primary data signal 154 is an acoustic signal and the secondary data signal 156 is a radio signal. In yet another preferred embodiment, the primary data signal 154 is a radio signal and the secondary data signal 156 is a radio signal.

[026] Turning to FIG. 5, shown therein is an additional preferred embodiment of the pumping system 100 and wireless telemetry system 116. In the embodiment depicted in FIG. 5, the transmitter 148 sends the primary wireless data signal 154 that is representative of data collected by the pumping system 100 to the receiver 150. The receiver 150 is preferably positioned above the pumping system 100 in the wellbore 104. The receiver 150 converts the primary wireless data signal 154 to a wired secondary data signal 158 that is transmitted to the surface control unit 122 through a data cable 160. Thus, in the alternate embodiment depicted in FIG. 5, the wireless telemetry system 116 provides a primary wireless data signal 154 around the pumping system 100 and relies on a wired secondary data signal 158 to the surface. This embodiment realizes the benefit of avoiding data cabling in the restricted space between the wellbore 104 and the pumping system 100, but employs a wired data cable 160 to the receiver 150. In certain applications, the use of a wired data cable 160 may be more cost effective than the use of multiple repeaters 152 positioned throughout the wellbore 104. [027] As illustrated in FIG. 5, the signal between the transmitter 148 and the receiver 150 passes through the wellbore 104 or surrounding reservoir. In an alternate preferred embodiment, the signal connection between the transmitter 148 and the receiver 150 can be configured to pass through the pumping system 100 and production tubing 102 by adjusting the frequency, wavelength, energy and other characteristics of the acoustic signal. Non-signal noise created by other components within the pumping system 100 can be filtered out at the interrogator 124 or at the control unit 122 on the surface.

[028] It is to be understood that even though numerous characteristics and advantages of various embodiments of the present invention have been set forth in the foregoing description, together with details of the structure and functions of various embodiments of the invention, this disclosure is illustrative only, and changes may be made in detail, especially in matters of structure and arrangement of parts within the principles of the present invention to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed. It will be appreciated by those skilled in the art that the teachings of the present invention can be applied to other systems without departing from the scope and spirit of the present invention.