BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate certain embodiments and are a part of the specification.
FIG. 1 is a front view of a drilling tool that may be used with at least one vibration attenuation module according to one embodiment.
FIG. 2 is a longitudinal cross-sectional view of one vibration attenuation stage that may be used with the tool shown in FIG. 1 (or others) according to one embodiment.
FIG. 3A is a longitudinal cross-sectional view of one vibration attenuation stage that may be used with the tool shown in FIG. 1 (or others) according to another embodiment.
FIG. 3B is top cross-sectional view of the vibration attenuation stage of FIG. 3A according to one embodiment.
FIG. 4 is a cross-sectional view of one vibration attenuation stage that may be used with a drilling tool according to another embodiment.
FIG. 5 is a front view, partly in section, showing two of the vibration attenuation stages of FIG. 4 in place on a drilling tool.
Throughout the drawings, identical reference characters and descriptions indicate similar, but not necessarily identical elements. While the invention is susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents and alternatives falling within the scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION
Illustrative embodiments and aspects of the invention are described below. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, that will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.
Reference throughout the specification to “one embodiment,” “an embodiment,” “some embodiments,” “one aspect,” “an aspect,” or “some aspects” means that a particular feature, structure, method, or characteristic described in connection with the embodiment or aspect is included in at least one embodiment of the present invention. Thus, the appearance of the phrases “in one embodiment” or “in an embodiment” or “in some embodiments” (or “aspects”) in various places throughout the specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, methods, or characteristics may be combined in any suitable manner in one or more embodiments. The words “including” and “having” shall have the same meaning as the word “comprising.”
Moreover, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.
The present disclosure contemplates, among other things, methods and apparatus for attenuating vibrations of a drillstring assembly while drilling. In some embodiments, vibrations are attenuated by introducing one or more vibration attenuation modules at appropriate assembly locations. For example, vibration attenuation modules may be inserted at locations where vibration energy is expected to be high or maximal. In some embodiments, the vibration attenuation modules include one or more cavities loosely packed with particles material that may be solid, such as sand or metallic powder. In some embodiments, the solid particles of material comprise a high density material, such as tungsten or a similar heavy metal powder. In some embodiments, the particles are generally round (spherical) and comprise diameters ranging between a few microns and a few millimeters. However, any other particle size may also be used. Vibration energy is dissipated via friction and inelastic particle-particle and particle-wall collisions that occur as a result of drillstring motion. Dissipation of vibration energy by friction and inelastic particle-particle and particle-wall collisions is referred to as particle damping.
Generally speaking, particle damping refers to structural damping and involves the use of particle-filled enclosures as part of the vibrating structure, which is described, for example, in U.S. Pat. No. 5,365,842 to Panossian and which is incorporated in its entirety by this reference. The cavities are generally loosely packed with granular materials (sand, metallic powder, etc.) that absorb kinetic energy by particle-particle and particle-wall collisions.
There has been at least one application of particle damping applied to the attenuation of acoustic vibrations in logging tools. See U.S. Pat. No. 6,654,221, which is hereby incorporated in its entirety by this reference. Proposed patterns of small holes and grooves machined on collars are filled with heavy particles. However, the high frequency (typically above 3 kHz) and small amplitude (typically less than one micron) nature of the acoustic vibrations the device was intended to attenuate have made it difficult or impossible for the proposed damping to be successful.
However, the inventors discovered that drilling induced vibrations are typically much lower in frequency (usually below 100 Hz), and can exhibit large amplitudes (e.g., a drillstring impacting a borehole wall), for which particle damping may be well suited.
Turning now to the drawings, and, in particular, FIG. 1, a drillstring 100 is shown. According to the embodiment of FIG. 1, the drillstring 100 includes a bottomhole assembly 102 and drillpipe 104. The bottomhole assembly 102 may include a connector 106 to the drillpipe 104 and a check valve assembly 108. Downhole of the check valve assembly 108 may be a pressure disconnect 110. If the drillstring 100 is capable of directional drilling, the drillstring will include an orienting tool 112 which is known by one of ordinary skill in the art having the benefit of this disclosure. In some cases, the entire drillstring 100 rotates and causes rotation of a drill bit 115 to facilitate borehole drilling. However, some systems may include a mud motor 114 to drive and rotate a drill bit 115 and an adjustable bent housing 116 facilitates directional drilling. According to principles described herein, vibration attenuation of the drillstring 100 may be especially effective when the entire drillstring 110 fully rotates without any need for a mud motor or adjustable bent housing. Some embodiments may not include acoustic logging equipment, although the principles described herein are equally applicable to attenuating low frequency vibrations in drillstrings that make measurements while drilling.
As mentioned above, drilling operations with a drillstring such as the drillstring 100 shown in FIG. 1 generate heavy vibrations that reduce the life of the drilling tools. Therefore, one embodiment shown in FIG. 2 provides an apparatus comprising an oilfield drillstring vibration attenuation module 120. One or more of the oilfield drillstring vibration attenuation modules 120 may be inserted into the drillstring 100 (FIG. 1). The oilfield drillstring vibration attenuation module 120 comprises a mandrel 122. The mandrel 122 comprises an outer surface 124 and an inner surface 126. The inner surface 126 defines a passageway 128 through the mandrel 122 that allows drilling mud and other fluids to communicate therethrough between segments of drillpipe and/or other drillstring components. An annular cavity 130 is formed between the inner and outer surfaces 124, 126, and particles are packed in the annular cavity 130. In one embodiment, the particles are loosely packed in the annular cavity 130 to facilitate vibration attenuation. Volume of the annular cavity 130 may be maximized in some aspects to increase the amount of energy that can be absorbed. Maximizing the volume of the annular cavity 130 may require consideration of mechanical and mud flow constraints inherent to the drilling operations.
In the embodiment of FIG. 2, the mandrel 122 comprises first and second ends 132, 134 that are preferably, but not necessarily, threaded. The first and second ends 132, 134 allow the vibration attenuation module 120 to be inserted: between adjacent segments of drillpipe 104 (FIG. 1), between components of the bottomhole assembly 102 (FIG. 1), between a segment of drillpipe and the bottomhole assembly, or between other components.
Although the mandrel 122 may comprise a single piece, in one embodiment, the mandrel 122 comprises a first pipe 136, and a second pipe 138 threadedly attached to and disposed at least partially inside of the first pipe 136. The annular cavity 130 may be disposed between the first and second pipes 136, 138. In the embodiment shown in FIG. 2, the first pipe 136 is a cylindrical pipe, and the second pipe 138 is also cylindrical and threadedly attached to (and concentric with) the first pipe 136.
According to some aspects, the annular cavity 130 comprises an internal wall 140 that includes features that enhance the transfer of vibrational energy from the internal wall 140 to the particles. In some embodiments, the internal wall features are geometrically shaped to facilitate transfer of axial, lateral, and torsional vibration energy from the internal wall 140 to the particles. For example, the internal wall features may comprise a spiral. In another embodiment, the internal wall features comprise a plurality of grooves 142 and protrusions 144 that increase particle/wall collisions. The grooves 142 and protrusions 144 may be arranged in the spiral or zig-zag pattern shown in FIG. 2. In one embodiment, the internal wall 140 comprises a roughened surface that also facilitates wall/particle interactions. Pre-modeling may allow designing the internal wall features in a way that allows for the best tradeoff between damping in the different vibrational modes (axial, lateral, torsional) to achieve maximum overall performance.
Some embodiments include two or more vibration attenuation modules 120 spaced along the drillstring 100 (FIG. 1). Some embodiments may include three to ten vibration attenuation modules. In one embodiment, each of the vibration attenuation modules 120 is placed at anticipated maximum vibration locations of the drillstring 100 (FIG. 1). Those of ordinary skill in the art having the benefit of this disclosure will recognize that a pre-plan drill modeling study and/or experimentation will yield the likely locations of maximum vibration.
In one embodiment, the mandrel 122 comprises a stabilizer ring 150 shown in FIGS. 3A-3B. The stabilizer ring 150 of FIGS. 3A-3B may be configured for attachment about the drillstring 100 (FIG. 1). In one embodiment, the stabilizer ring 150 is attached around a collar of the drillstring 100 (FIG. 1), but other locations may also be used. The stabilizer ring 150 may include a plurality of radially protruding blades, for example the four equally spaced hollow blades 152 shown in FIGS. 3A-3B. However, any number of blades may be used. The interior of the blades 152 comprises the annular cavity 130, although the annular cavities 130 of FIGS. 3A-3B are discontinuous circumferentially. Each of the annular cavities 130 of FIGS. 3A-3B may be loosely packed with the same particles described above with reference to FIG. 2. Particle damping at drillstring stabilizers (such as stabilizer rings 150) may significantly increase the life of the drillstring 100 (FIG. 1) by absorbing much of the shock and vibration induced by drilling with the particles.
Although the vibration attenuation module 120 comprising the stabilizer ring 150 shown in FIGS. 3A-3B may be attached around the drillstring 100 (FIG. 1) as described above, other embodiments may comprise separate modules. For example, FIG. 4 illustrates a vibration attenuating module 120 comprising an insertable stabilizer 250. Similar to the embodiment of FIG. 2, the insertable stabilizer 250 may comprise first and second ends 232, 234 that are preferably, but not necessarily, threaded. The first and second threaded ends 232, 234 allow the vibration attenuation module 120 to be inserted: between adjacent segments of drillpipe 104 (FIG. 1), between components of the bottomhole assembly 102 (FIG. 1), between a segment of drillpipe and the bottomhole assembly, or between other components.
Like the stabilizer ring 150 (FIGS. 3A-3B), the insertable stabilizer 250 may include a plurality of radially protruding blades, for example four equally spaced hollow blades 252 shown in FIGS. 4-5. However, any number of blades may be used. The interior of the blades 252 comprises the annular cavity 130. Each of the annular cavities 130 of FIGS. 4-5 may be loosely packed with the same particles described above with reference to FIG. 2. Although two vibration attenuation modules 120 are illustrated in FIG. 5, any number of attenuation modules 120 comprising the insertable stabilizers 250 may be inserted into the drillstring 100. As mentioned above, particle damping at drillstring stabilizers (such as insertable stabilizers 250) may significantly increase the life of the drillstring 100 by absorbing much of the shock and vibration induced by drilling with the particles.
Each apparatus shown and described above may be used with any drillstring and is not limited to the embodiments shown in FIGS. 1 and 5. Moreover, the present specification contemplates any drillstring particle damping and is not limited to the specific embodiments shown in FIGS. 1-5. One aspect contemplates a method comprising attenuating drilling induced vibrations in an oilfield drillstring. The attenuating comprises inserting at least one particle-damping-based vibration attenuation module (such as those described above) at one or more locations of the drillstring, and absorbing vibrational energy with the at least one vibration attenuation module. In one aspect, the method further comprises strategically inserting multiple vibration attenuation modules along the drillstring to reduce drilling-induced vibration. One aspect further comprises inserting multiple vibration attenuation modules along the drillstring at locations where vibrational energy is expected to be larger or maximal.
The preceding description has been presented only to illustrate and describe certain principles. It is not intended to be exhaustive or to limit the invention to any precise form disclosed. Many modifications and variations are possible in light of the above teaching.
The embodiments shown and described were chosen and described in order to best explain the principles of the invention and its practical application. The preceding description is intended to enable others skilled in the art to best utilize the principles taught in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of this disclosure be defined by the following claims.
Patent Application
20080066965
