Methods and systems to activate downhole tools with light
The present invention comprises a system and methods to actuate downhole tools by transmitting an optical signal through an optical fiber to the downhole tool. The optical signal can comprise a specific optical signal frequency, signal, wavelength or intensity. The downhole tool can comprise packers, perforating guns, flow control valves, such as sleeve valves and ball valves, samplers, sensors, pumps, screens (such as to expand), chemical cutters, plugs, detonators, or nipples.
The invention generally relates to the activation of downhole tools. More particularly, the invention relates to methods and systems used to activate downhole tools with light.
Downhole tools are typically activated by mechanical, electrical, or hydraulic means. Each of these types of actuation have potential problems. Mechanically actuated tools normally rely on translation or torsion of the tube or cable connecting the tool to the surface. However, movement on the surface does not always translate into movement down-hole at the location of the tool. Furthermore, the movement of the tool may remove it from the position where the actuation is required. Electrically actuated tools need cables in which electrical insulation is required. The insulation is often bulky and compromises the strength of the cable. Electrical actuation is also sensitive to spurious currents and interference that could result in undesirable actuation. Hydraulically actuated tools also suffer from the risk of undesirable actuation or actuation at the wrong depth. The local pressure at the tool is difficult to control in some circumstances. All the above require complex control mechanisms to prevent undesirable activation.
Moreover, reliability and safety are important when operating downhole tools, since a faulty tool can result in a substantial increase in costs and time for an operator and can also sometimes endanger the lives of workers. These issues are heightened when they relate to perforating guns, as these tools must have a very high level of reliability and safety.
Thus, there exists a continuing need for an arrangement and/or technique that addresses one or more of the problems that are stated above.
SUMMARYThe present invention comprises a system and methods to actuate downhole tools by transmitting an optical signal through an optical fiber to the downhole tool. The optical signal can comprise a specific optical signal frequency, signal, wavelength or intensity. The downhole tool can comprise packers, perforating guns, flow control valves, such as sleeve valves and ball valves, samplers, sensors, pumps, screens (such as to expand), chemical cutters, plugs, detonators, or nipples.
Advantages and other features of the invention will become apparent from the following description, drawing and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
In
The system illustrated in
The downhole tools 2 described in the previous paragraphs may be activated by optical signals sent through the optical fiber 10. For instance, the downhole tool 2 may be functionally connected to the optical fiber 10 so that a specific optical signal frequency, signal, wavelength or intensity sent through the optical fiber 10 by the unit 20 activates the downhole tool 2. Or, the downhole tool 2 may be functionally connected to the optical fiber 10 so that the presence of a certain amount of light in the optical fiber 10 activates the downhole tool 2.
As shown in
In
The optical signal 40 of
In other embodiments, the presence of a signal (as previously disclosed) having a specific characteristic acts as the optical signal 40. The specific characteristic can comprise a specific frequency, wavelength, pulse code, or intensity. Specific wavelengths, for instance, may be keyed on by the use of at least one filter on the optical fiber 10. Alternatively, a specific intensity may be focused on by including a material on the fiber 10 that ignites or deteriorates when exposed to such particular intensity.
Also, in other embodiments, the optical signal 40 may comprise a combination of at least two of the previously disclosed signals.
To enable the transmission of such optical signals 40, the unit 20 (as seen in
To receive the optical signal 40, the downhole tool 2 includes a receptor 50 which receives the optical signal 40 from optical fiber 10. As shown in
In one embodiment as shown in
Microprocessor 54 may comprise an optical arrangement that may contain a combination of filters or lenses or other optical devices. It may comprise an analog or digital circuit. It could be a simple transistor or a complex digital microprocessor. Storage 56 may comprise a programmable computer storage unit or an analog or digital circuit. Controller 58 may comprise a mechanical trigger, a hydraulic valve, an explosive detonator, precursor chemical reaction, a thermal sensitive device, an element that bends or contracts or expands under light or light generated heat, an explosive, a pressurized vessel, a vacuum chamber, or a spring.
The pre-programmed triggering signal may be stored in storage 56 to enable microprocessor 54 to access such pre-programmed triggering signal and compare it against the obtained optical signal 40. If a match exists, the microprocessor 54 may activate controller 58 which may actuate downhole tool 2. The microprocessor 54 is, in one embodiment, powered by a downhole battery 60. In other embodiments, microprocessor 54 is powered by the optical fiber 10 or by an independent electrical line (not shown).
In another embodiment as shown in
In either embodiment of
In an alternative embodiment, the microprocessor 54 and storage 56 can be replaced with a hard-wired recognition circuit (not shown), which may consist of an electrical circuit designed to pass only a specific characteristic of the optical signal 40 to activate a corresponding tool 2. For instance, the characteristic may be a modulation frequency applied to the optical carrier.
In another embodiment as shown in
Similarly, in the embodiment shown in
The light being transmitted through the optical fiber 10 may be converted at the downhole tool 2 into electrical energy, chemical energy (including explosive energy), or mechanical energy (including hydraulic energy). Each of these types of energy may then be utilized or harnessed to activate or to result in the activation of the relevant downhole tool 2.
Optical energy may be converted to electrical energy by at least one photodiode 80 as shown in
Optical energy may be converted to chemical energy by an optically reactive chemical chamber 90 as shown in
Optical energy may be converted to mechanical energy by a piezoelectric stack 100 as shown in
Possible compositions of material 227 include particles of silicon, iron oxide, coal, charcoal, phosphorous, gun powder, or starch; alternatively insulating materials such as ceramic wool or thermite may be used. In one embodiment, the material 227 is porous thereby enabling the substance 254 to be in contact with the material 227 at as many places as possible including the area of material 227 that is being heated by the light transmitted through optical fiber 222. Possible compositions for substance 254 include air or oxygen mixed with diethyl ether, ether, carbon disulphide, or n-pentane or hydrogen. In the case where the absorber is combustible (e.g. coal or starch particles) it may be sufficient for the surrounding medium merely to be a source of oxygen.
In another embodiment, not shown, the gun assembly can include the receptor 50 illustrated and described in relation to
Use of optical signals to actuate perforating guns and other downhole tools increases safety since the optical fiber and signal will be immune to electromagnetic fields. Therefore, the detonation or activation can only occur when the light energy of the right wavelength is transmitted from a specific unit (such as a laser) from the surface. Moreover, in those embodiments in which no battery is used downhole, the method avoids the use of such potentially problematic components. As compared to mechanically activated systems, use of the optical signal to activate perforating guns avoids the use of ball or weight dropping to activate a percussion detonator and the concerns associated therewith.
It is often times important to know the depth of the downhole tool 2 as the tool 2 is deployed in a wellbore 14. This is to ensure that the tool 2 is activated at the correct depth. For instance, if tool 2 is a perforating gun, then the gun must be activated at the depth of the relevant hydrocarbon formation. Or, if the tool 2 is a packer, then the packer must be activated above or below the relevant formations as required. As shown in
The optical fiber used to transmit light for activation of downhole tool 2 may be implemented in different ways. For instance, it may be housed within a conduit, as shown in
While the invention has been disclosed with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of the invention.
Claims
1-109. (canceled)
110. A system to actuate downhole tools by light, comprising:
- a downhole tool adapted to be deployed in a wellbore;
- an optical transmitter optically connected to the downhole tool through an optical fiber;
- the optical transmitter adapted to transmit an optical signal through the optical fiber; and
- wherein the downhole tool is activated in response to reception of the optical signal.
111. The system of claim 110, wherein the optical signal comprises a specific number of optical pulses.
112. The system of claim 111, wherein the optical signal comprises at least one pulse with a specific time duration.
113. The system of claim 111, wherein the optical signal comprises at least one pulse of light at a specific intensity, frequency, wavelength, or amount.
114. The system of claim 110, wherein the downhole tool is selected from the group consisting of a packer, a perforating gun, a valve, a sampler, a sensor, a pump, a screen, a chemical cutter, a plug, a detonator, or a nipple.
115. The system of claim 110, wherein a receptor receives the optical signal, verifies the optical signal is a valid triggering signal, and subsequently enables the activation of the downhole tool.
116. The system of claim 115, wherein:
- the receptor comprises a microprocessor, storage, and a controller;
- the valid triggering signal is stored in the storage;
- the microprocessor compares the optical signal to the valid triggering signal; and
- the microprocessor activates the controller when the optical signal matches the stored valid triggering signal.
117. The system of claim 110, wherein a plurality of downhole tools are functionally connected to the optical fiber so that each of the downhole tools may be activated in response to the reception of the optical signal.
118. The system of claim 117, wherein a different optical signal activates different downhole tools.
119. The system of claim 117, further comprising at least one optical filter functionally connected to the optical fiber that allows only light at a specific wavelength to pass therethrough to activate a downhole tool.
120. The system of claim 117, further comprising at least one coupler functionally connected to the optical fiber that diverts only light at a specific wavelength towards a downhole tool to activate such downhole tool.
121. The system of claim 110, wherein:
- the optical signal is received by at least one photodiode;
- the at least one photodiode converts the optical signal into electrical energy; and
- the electrical energy is transmitted to an initiator circuit to activate the downhole tool.
122. The system of claim 110, wherein:
- the optical signal is transmitted into an optically reactive chemical chamber;
- the chamber contains an optically reactive substance that chemically reacts when subjected to light; and
- the chemical energy is transferred to activate the downhole tool.
123. The system of claim 122, wherein the chamber includes an environment conducive to chemical reaction of the substance to light.
124. The system of claim 122, wherein the reaction is one of heating, exploding, or deteriorating.
125. The system of claim 110, wherein:
- the optical signal is converted into an electrical signal and is then transmitted into a piezoelectric stack that expands when exposed to electrical energy; and
- the expansion of the stack is used to activate the downhole tool.
126. The system of claim 110, further comprising a casing collar locator used to determine the depth of the downhole tool.
127. A method to actuate downhole tools by light, comprising:
- deploying a downhole tool in a wellbore;
- optically connecting the downhole tool to an optical transmitter through an optical fiber;
- transmitting an optical signal from the optical transmitter through the optical fiber;
- activating the downhole tool in response to reception of the optical signal.
128. The method of claim 127, wherein the transmitting step comprises transmitting an optical signal including a specific number of optical pulses.
129. The method of claim 127, wherein the deploying step comprises deploying the downhole tool as part of a logging system.
130. The method of claim 127, wherein the deploying step comprises deploying the downhole tool as part of a permanent completion.
131. The method of claim 127, wherein the deploying step comprises deploying the downhole tool as part of a coiled tubing system.
132. The method of claim 127, further comprising functionally connecting a plurality of downhole tools to the optical fiber so that each of the downhole tools may be activated in response to the reception of the optical signal.
133. The method of claim 132, further comprising functionally connecting at least one optical filter to the optical fiber, the optical filter allowing only light at a specific wavelength to pass therethrough to activate a downhole tool.
134. The method of claim 132, further comprising functionally connecting at least one coupler to the optical fiber, the coupler diverting only light at a specific wavelength towards a downhole tool to activate such downhole tool.
135. The method of claim 127, further comprising:
- receiving the optical signal at an at least one photodiode, the at least one photodiode converting the optical signal into electrical energy; and
- transmitting the electrical energy to an initiator circuit to activate the downhole tool.
136. The method of claim 127, further comprising:
- transmitting the optical signal into an optically reactive chemical chamber;
- providing an optically reactive substance in the chamber that chemically reacts when subjected to light; and
- transferring the chemical energy to activate the downhole tool.
137. The method of claim 127, further comprising:
- converting the optical signal into an electrical signal;
- transmitting the electrical signal into a piezoelectric stack that expands when exposed to electrical energy; and
- utilizing the expansion of the stack to activate the downhole tool.
138. The method of claim 127, further comprising determining the depth of the downhole tool by using a casing collar locator.
Type: Application
Filed: Aug 29, 2003
Publication Date: Mar 1, 2007
Inventor: David Smith (OSAKA)
Application Number: 10/525,910
International Classification: F42C 19/00 (20060101);