Patent Application
20160040526
Not applicable.
Not applicable.
Not applicable.
1. Field of the Invention
The present invention relates to a system and method for transmitting downhole information to a surface location. More particularly, the present invention relates to a system and method for communicating downhole information from multiple orientations of a downhole tool through pressure release encoding. The present invention also relates to a system and method with a means to detect vertical and lateral orientation of a downhole tool. More particularly, the present invention relates to adjusting interpretation of data from the sensors measuring downhole conditions, according to the detected orientation of the downhole tool.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
Natural resources, such as ground water, natural gas, and petroleum, are deposited underground. Drilling is part of a process for extracting those resources from their remote location. A well or borehole can be created by use of a drilling rig to rotate a drill string, which has a drill bit attached at its end in order to bore into the ground to a desired depth. Drill collars and drill pipe sections add length, weight and support along the drill string as the borehole deepens, and different types of drill bits cut into all types of rock formations and soil combinations. In rotary drilling, the drill bit is rotated by rotating the drill string at the surface. Rotary drilling can be efficient for boring vertically into the ground, because there is only one direction of the drill bit. In directional drilling, the drill bit can be rotated by a downhole mud motor or other device, including types of rotary assemblies, coupled to the drill bit. The drill bit can deviate from vertical, so as to slant the borehole or even angle the borehole towards horizontal. In a steerable drill string, the mud motor is bent at a slight angle to the centerline of the drill bit so as to create a side force that directs the path of the drill bit away from a straight line.
Drilling fluid or drilling mud pumps through the inside of the drill string, out of the drill bit by nozzles or jets, and up the annulus to the surface, in order to create the proper physical and hydrostatic conditions to safely drill the well. Additionally, the rock cuttings are removed from the borehole in the drilling mud circulation flowing to the surface.
The distal end of a drill string is the bottom hole assembly (BHA), which includes the drill bit, the drilling sub and drill collars. In “measurement while drilling” (MWD) or “logging while drilling” (LWD) applications, sensing modules in the BHA, or other downhole tools, provide information concerning the downhole conditions, such as direction of the drilling. The actual sensors may include devices to measure angle of inclination, azimuth and toolface direction, including magnetometers and accelerometers. This information can be used, for example, to control the direction in which the drill bit should adjust, during directional drilling or as steerable drilling.
Sensing modules can also provide useful downhole information in real-time with regard to other aspects of the drilling operation. For example, ultrasonic transducers monitor resistivity of high frequency wavelength signals bounced back from the rock formation downhole so that characteristics of the formation can be determined. Water or hydrocarbons or rock at the downhole depth can be mapped in real time. Other sensing modules can include magnetic resonance imaging (MRI), gamma scintillators, and nuclear detectors. Radioactivity, porosity, and density can be other downhole conditions detected by some of these other sensing modules.
The downhole information collected by the sensing modules is transmitted to the surface for analysis. Mud pulse telemetry receives data from the sensing modules, digitally encodes the data, and actuates a pulser to send pressure pulses within the flow of drilling mud. A receiver at the surface interprets the pressure pulses to collect the encoded data. Conventional mud pulsers require a large amount of power to actuate the valve and modulate the drilling mud sufficient for detection at the surface. Oscillating drilling mud for a pressure transducer to detect at the surface is difficult to power and control. More recent developments in mud pulse telemetry include a pressure release encoding system to reduce the power requirements and to increase efficiency for generating pulses through the drilling mud. In particular, only a small amount of power is needed because the mud pump becomes the primary energy source of the pressure release encoding system. A valve means restricts mud flow, and a brake means progressively releases the valve means to create the pressure drop. The pressure drop is generated by setting an equilibrium pressure gradient across the valve means based on the mud pump energy, releasing the brake means to a second position, and resetting the equilibrium pressure gradient across the valve means based on the mud pump energy again. No additional modulation or actuation of the drilling mud is required by this pressure release encoding system. There is no additional manipulation of the originating mud pump delivering the drilling mud to the borehole at a set rate and pressure.
For pressure release encoding systems, additional information must be encoded when the downhole tool, such as a BHA, changes orientation. The actual sensors of a sensing module measure the same properties in any orientation. However, a change in orientation of the downhole tool affects how these measured properties relate to downhole conditions. For example, an accelerometer measures inclination angle. The deviation from vertical is detected so that the slant of the borehole can be monitored for directional drilling. If the orientation changes toward lateral or horizontal, then the accelerometer can no longer measure deviation from vertical. Some inclination sensors have a range of 0 to 20 degrees, such that more than 20 degrees of slant exceeds the range of the inclinations sensor. There is no more useful information from the inclinations sensor past 20 degrees from vertical. Measurements past 20 degrees of slant would show no changes, but that lack of change does not mean that the downhole condition is vertical anymore.
In another example, a magnetometer measures azimuth. The direction of slant from vertical is detected, not just the slant itself, can be monitored for directional drilling. When the orientation changes toward lateral or horizontal, then the magnetometer measures direction from horizontal, not vertical. The directional data is no longer direction of slant, but rather direction of the toolface. The tool face can be moving up, down or side to side through the formation, not just deviating from vertical. The same measurements and readings are being produced from the magnetometer, but the downhole condition has changed from direction of slant from vertical to direction of the toolface.
It is an object of the present invention to provide an embodiment of a system and method for communicating downhole information through pressure release encoding to the surface.
It is an object of the present invention to provide an embodiment of a system and method for communicating downhole information collected from a sensing module on a downhole tool, such as a BHA, in different orientations.
It is another object of the present invention to provide an embodiment of a system and method for communicating downhole information collected from a sensing module in vertical and lateral orientations.
It is still another object of the present invention to provide an embodiment of a system and method for communicating downhole information collected from a sensing module measuring properties in vertical and lateral orientations.
It is an object of the present invention to provide an embodiment of a system and method for communicating downhole information with a means to detect vertical and lateral orientation of a downhole tool.
It is another object of the present invention to provide an embodiment of a system and method for communicating downhole information, according to detected orientation of the downhole tool.
It is still another object of the present invention to provide an embodiment of a system and method for communicating downhole information according to detected orientation of the downhole tool through pressure release encoding.
It is an object of the present invention to provide an embodiment of a system and method for communicating downhole information from a complex sensing module through pressure release encoding to the surface.
These and other objectives and advantages of the present invention will become apparent from a reading of the attached specifications and appended claims.
Embodiments of the system for communicating downhole information through a wellbore to a surface location include communicating complex downhole information dependent upon orientation. Prior art systems convey simple downhole information easily, such as the angle of inclination of the drilling sub in a wellbore. However, the same sensors for angle of inclination no longer measure that same downhole information, when the orientation of the downhole tool changes too much. The direction can be changed, such that the sensor no longer functions or the calibration no longer corresponds to the new orientation. For directional drilling beyond straight vertical drilling, the orientation of the downhole changes frequently. Embodiments of the system and method of the present invention accommodate the changes in orientation and communication of this more complex downhole information through a pressure releasing encoding system.
The system of the present invention includes a drill string with a downhole tool at an end thereof, a pumping means for pumping drilling mud through the wellbore, the drill string, and the downhole tool, a valve means for providing a flow restriction to the drilling mud passing through the downhole tool, a sensing module positioned in the downhole tool, an actuator means cooperative with the valve means, and a detector means at the surface location. The drilling mud is fluid and circulates through the wellbore, drill string, and downhole tool to the surface location. The wellbore, drill string, and downhole tool are in fluid connection. The pump means can be located at the surface location. The valve means controls flow of the drilling mud through the downhole tool. The actuator means fixes the valve means in at least two static positions. The actuator means can be a hydraulic brake that releases the valve to move between the static positions. The time between pressure changes at the static positions relate to downhole information from the sensing module. The detector means is cooperative with the drilling mud passing through the downhole tool, such that the time between pressure changes at the downhole tool can be measured at the surface location. The measurement value of the detector means at the surface location is the communication of downhole information to the surface location. The changes of pressure of the drilling mud convey the downhole conditions measured by the sensing module.
The downhole tool has a first orientation and a second orientation. The downhole tool can be a drilling sub, drilling collar, stabilizer or other attachment to the drill string. The first orientation is different from the second orientation. The first orientation can be vertical, while the second orientation is lateral. Alternatively, the first orientation can be vertical, while the second orientation is more than twenty degrees from vertical. As long as the first and second orientations are different, the sensing module on the downhole tool measures different downhole conditions with the same sensors. The more complex downhole conditions can be encoded for communication to the surface location, instead of the only simple downhole conditions.
Embodiments of the sensing module include a first sensor means for measuring a first downhole condition in the first orientation, and a second sensor means for measuring a second downhole condition in the second orientation. The sensor means and the orientation determines the downhole condition, such that the downhole condition is now more complex. When the first orientation is generally vertical and the second orientation is generally lateral, the first sensor means can be an inclination sensor and the second sensor means can be an inclination sensor. Thus, the first downhole condition is angle of inclination, while the sensing module and downhole tool are in the vertical orientation. The second downhole condition is toolface inclination, while the sensing module and downhole tool are in the lateral orientation.
Embodiments of the sensing module also include a sensor means for measuring a first downhole condition in the first orientation and for measuring a second downhole condition in the second orientation. The same sensor measures the same property in different orientations, such that the data relates to different downhole conditions. Measurements in one orientation relate to a different downhole condition in another orientation. The sensor means and the orientation determines the downhole condition, such that the downhole condition remains complex. When the sensor means is comprised of an azimuth sensor, such as a magnetometer, the first downhole condition is the direction of slant from vertical, and the second downhole condition is direction of toolface. The directional measurement of the azimuth is the same, but the added information of orientation makes the downhole condition information more complex. This additional information can also be communicated to the surface location with the changes in pressure according to the actuator means. Other sensors, including an azimuth sensor, a magnetometer, a transducer, a gamma scintillator, nuclear detectors, an accelerometer, and a magnetic resonance imaging device can incorporate the orientation information for more complex downhole conditions too.
A switch and logic means can be incorporated in some embodiments to encode the downhole condition with the complexity of orientation data. The switch can activate either the first sensor means or second sensor means, according to position of the downhole tool. For example, if both the first sensor means and the second sensor means are inclination sensors, the system can alternate between sensing the slant of vertical drilling and the direction of the toolface for lateral drilling. Alternatively, if the inclination sensor is an accelerometer with a range of twenty degrees from vertical in the first orientation, the switch deactivates the inclination sensor above twenty degrees from vertical, while activating another inclination sensor to cover the range remaining above twenty degrees from vertical.
There is a drilling mud circulation system, defined by the drilling mud flowing through the drill string, the downhole tool, and the wellbore. Embodiments of the method for communicating the complex downhole information through the wellbore to the surface location include positioning the valve means in a fluid passageway of the downhole tool, positioning the actuator means cooperative with the valve means for fixing the valve means in at least two static positions, and forming a flow restriction within the circulation system at the downhole tool, the flow restriction being comprised of the valve means and the actuator means. A quantified pressure of drilling mud in the circulation system is applied against the flow restriction for a stable pressure powered by the originating mud pump.
Next, the first downhole condition in the first orientation is measured. A first percentage of pressure within the flow restriction is released at a first time, and the valve means moves to another static position. A pressure drop in the drilling mud is created. A second percentage of pressure within the flow restriction is released at a second time, and the valve means moves to another status position. Another pressure drop in the drilling mud is created. The time between the first pressure drop at the first time and the second pressure drop at the second time is correlative to the first downhole condition in the first orientation. The method further includes determining the first downhole condition at a surface location by sensing the time between the first pressure drop at the first time and the second pressure drop at the second time, according to orientation of the downhole tool. Repeating releases of percentages of pressure, within the flow restriction at additional times, communicates additional downhole conditions, such as the second downhole condition in the second orientation.
In other embodiments of the method, a single sensor can measure the first downhole condition in the first orientation and the second downhole condition in the second orientation. These sensors do not deactivate or require re-calibration to take measurements again, such as inclination sensors. These sensors can be an azimuth sensor, a magnetometer, a transducer, a gamma scintillator, nuclear detectors, or a magnetic resonance imaging device. The method of the present invention detects orientation of the downhole tool, and correlating a sensed time between controlled static pressure drops across the valve means to first and second downhole conditions, according to orientation of the downhole tool. Complex downhole conditions, including orientation data, are conveyed to the surface location by a pressure release encoding system.
Referring to
The present invention is a system 10 for communicating complex downhole information dependent upon orientation of the downhole tool 28.
Embodiments of the system 10 of the present invention include a drill string 16 with a downhole tool 28 at an end thereof, a pumping means 40 for pumping drilling mud through the wellbore 12, the drill string 16, and the downhole tool 28, a valve means 34 for providing a flow restriction to the drilling mud passing through the downhole tool 28, a sensing module 32 positioned in the downhole tool 28, an actuator means 36 cooperative with the valve means 34, and a detector means 42 at the surface location 14.
At the surface location 14, embodiments of the present invention have the detector means 42 cooperative with the drilling mud passing through the downhole tool 28, such that the time between pressure changes at the downhole tool 28 can be measured at the surface location 14.
The measurement value of the detector means 42 at the surface location is the communication of downhole information to the surface location 14. The changes of pressure of the drilling mud convey the downhole conditions measured by the sensing module 32.
Embodiments of the system 10 of the present invention show the downhole tool 28 having a first orientation and a second orientation. The first orientation is different from the second orientation. The first orientation can be vertical as shown in
The embodiments of
The system 10 further includes a switch means to deactivate the first sensor means 50, when the orientation changes. For example, when the orientation passes twenty degrees from vertical, the inclination sensor of the first sensor means 50 can be deactivated because no more useful information is being measured. The system 10 will now active the second sensor means 52 to begin collecting data, since the orientation is now in the second orientation of the downhole tool 28. The switch means moves back and forth, as the downhole tool 28 can move in all directions. The downhole tool 28 may return to a generally vertical orientation, returning to the first orientation, so that the first sensor means 50 can collect relevant deviation from vertical data again.
Embodiments of the system 10 include the computer 46 with the logic means and display means for the encoded data from the drilling mud. The complex downhole conditions are interpreted from the encoded data, including the detected orientation of the downhole tool. Any means to detect the orientation of the downhole tool contributes to the encoded data from the sensing module 32. The means for detecting may be compass or bubble devices on inclination sensors as either the first or second sensor means 50, 52 or a device separate from the first and second sensor means 50, 52.
An alternate embodiment of the sensing module 32′ is shown in
The present invention also includes the method for communicating the complex downhole information through a pressure releasing encoding system. With the drilling mud circulation, defined by the drilling mud flowing through the drill string 16, the downhole tool 28, and the wellbore 12, embodiments of the method for communicating the complex downhole information through the wellbore 12 to the surface location 14 include positioning the valve means 34 in a fluid passageway 44 of the downhole tool 28, positioning the actuator means 36 cooperative with the valve means 34 for fixing the valve means 34 in at least two static positions, and forming a flow restriction within the circulation system at the downhole tool 28. The flow restriction is comprised of the valve means 34 and the actuator means 36. A quantified pressure of drilling mud in the circulation system is applied against the flow restriction for a stable pressure powered by the originating mud pump means 40. The energy from the originating pump 40 supplies the energy for the pulse through the drilling mud, instead of requiring power for modulating the drilling mud. The pressure release encoding of the present invention is based on setting an equilibrium pressure by the pump means 40 across the valve means 34 and then releasing the valve means 34 by the actuator means 36 to a new position, where the equilibrium pressure re-establishes. The change is pressure is the pulse receivable at the surface location 14.
In embodiments of the method, the time between the pressure changes is encoded data related to the downhole information. In the present invention, it is the complex downhole information that is communicated to the surface location 14. In the method, the first downhole condition in the first orientation is measured. For example, the sensing module 32 measures the deviation from vertical by an inclination sensor as the first sensor means 50. A first percentage of pressure within the flow restriction is released at a first time, and the valve means 34 moves to another static position. A pressure drop in the drilling mud is created. A second percentage of pressure within the flow restriction is released at a second time, and the valve means 34 moves to another static position. Another pressure drop in the drilling mud is created. The time between the first pressure drop at the first time and the second pressure drop at the second time is correlative to the first downhole condition in the first orientation. The measurement is communicated to the surface location along with the orientation information, as complex downhole information.
The method further includes determining the second downhole condition at a surface location by sensing the time between another set of pressure drops, according to orientation of the downhole tool. Repeating releases of percentages of pressure, within the flow restriction at additional times, communicates additional downhole conditions, such as the second downhole condition from a second sensor means 52 in the second orientation. The complex downhole information can now be communicated with the same pressure releasing encoding.
Various embodiments of the method include gathering the complex downhole information from other sensing modules 32 and 32′. For one embodiment, a single sensor measures the first downhole condition in the first orientation and the second downhole condition in the second orientation. The azimuth sensor is one type of sensor that provides both first and second downhole conditions. Other sensors that do not deactivate nor require re-calibration to take measurements again, may also be single sensors providing the complex downhole information. Again, the method of the present invention, detects orientation of the downhole tool and the measurement from the sensor to correlate the sensed time between controlled static pressure drops across the valve means to the first and second downhole conditions, according to orientation of the downhole tool. Complex downhole conditions, including orientation data, are conveyed to the surface location by a pressure release encoding system.
The present invention provides a system and method for communicating downhole information through pressure release encoding to the surface. The pressure release encoding based on the originating mud pump powers the transmission through the drilling mud. The changes in pressure communicate complex downhole information gathered from a sensing module at the downhole location. The sensing module can be placed in any downhole tool, including a BHA or drill sub, specifically. Alternate drill collar or stabilizers may also contain the valve, actuator, and sensing module required. There is also a means for detecting orientation of the downhole tool, so that the orientations of the sensors of the sensing module are known. Known bubble or compass devices can detect vertical and lateral orientations. Other sensors may, themselves, be calibrated for certain orientations, such as an inclination sensor with a range of zero to twenty degrees from vertical or another range. The present invention address the orientation as a complicating factor in the interpretation of the plain measurement data previously conveyed. The sensing module in vertical and lateral orientations is now applied to a pressure releasing encoding so that pressure releasing encoding communicates more useful information, especially for directional and steering drilling operations. A drill bit can be more accurately steered through a formation with the MWD or real time data supplied by the complex downhole information of the present invention. Pressure releasing encoding and advanced sensing modules of the present invention allow for more relevant downhole data to be conveyed through drilling mud to the surface.
The foregoing disclosure and description of the invention is illustrative and explanatory thereof. Various changes in the details of the illustrated structures, construction and method can be made without departing from the true spirit of the invention.
