The EM telemetry system 40 can be similar to Weatherford's EMpulse electromagnetic (EM) measurement-while-drilling (MWD) system. Overall, the EM telemetry system 40 allows operators to drill and survey the borehole 12 independent of the rig hydraulics. For example, by using EM telemetry rather than mud pulse telemetry, the pumps at the rig 22 do not need to be cycled to communicate with the MWD tool 50 in the borehole 12. This can make the drilling operation more efficient.
The downhole transceiver 45 of the EM telemetry system 40 is a sonde-based design configured for use in non-magnetic drillstring tubulars to provide two-way communication between the surface and the MWD tool 50 downhole. Operators can communicate instructions to the downhole instrumentation while drilling proceeds, and both uplink and downlink communications are completely independent of rig or drilling activity. Survey data can be obtained with the MWD tool 50 while the drillstring 22 is stationary for a short period of time to reduce the possibility of differential sticking or hole sloughing that can result from extended periods without circulation or pipe movement. Because the system 40 is independent of drilling hydraulics, there is no lag time or need to cycle the pumps for synchronization purposes when survey data is being transmitted.
In some implementations, the system's antenna 60 along with the electronics of the MWD tool 50 can be retrieved from the bottom hole assembly 30 using fishing and other techniques. In other implementations, these components may not be retrievable via wireline or the like.
During use, the MWD tool 50 and the downhole transceiver 45 are typically powered by batteries. To uplink information, the downhole transceiver 45 uses the emitting antenna 60 to inject signals into the formation 10. The signals propagate to the surface, and the surface transceiver 44 receives the signal for decoding by data acquisition systems. As shown, the transceiver 44 can be coupled to the wellhead at the rig 22 and coupled to a ground antenna 42, creating two electrodes of a dipole antenna.
Various types of measurement equipment can be used on the MWD tool 50. For example, the tool 50 can include a gamma ray probe to measure gamma radiation in the borehole. The tool 50 can include an annular pressure sensor to measure downhole pressure conditions. The gamma ray probe and the pressure sensor can be mounted directly above the bit on the bottom hole assembly 30 to provide real-time inclination and gamma ray data near the bit. The oriented gamma ray sensor provides high-side and low-side gamma measurements while rotating. An inclination sonde can measure inclination close to the bit and can measure inclination-on-the-fly while sliding and rotating.
Given the various forms of measurements that can be obtained, various types of information can be transmitted from the MWD tool 50 to the surface in real-time, including: directional surveys, annulus pressure, total gamma ray, oriented gamma ray, inclination closer to the bit, inclination and gamma at bit, etc. For example, the EM telemetry system 40 can transmit the toolface, inclination, azimuth, gamma ray, and annulus-pressure data while drilling sections of the borehole 12. Because the rig's mud system does not interfere with the functioning of the MWD tool 50, the MWD tool 50 can operate continuously during all drilling activities, even when the rig 22 makes drill pipe connections.
The MWD tool 50 can mount in the bottom hole assembly 30 in a number of ways. For example,
In
Although existing configurations of MWD tools and antennas for EM telemetry system are effective, operators seek to use EM telemetry in harsher drilling conditions and in more diverse drilling operations. The subject matter of the present disclosure is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
A measurement-while-drilling apparatus has a bottom hole assembly, a tool string, and an antenna. The tool string is engaged in a first end or downhole portion of the bottomhole assembly. The tool string has at least one sensor and has an electromagnetic telemetry device in electrical communication with the at least one sensor.
The at least one sensor of the tool string can be a vibration sensor, a gamma ray sensor, a bore/annular pressure sensor, a directional sensor, etc. The electromagnetic telemetry device is preferably an electromagnetic telemetry transceiver configured to send and receive electromagnetic telemetry signals. The first end or downhole portion of the bottomhole assembly can include a tool carrier having a muleshoe sub disposed thereon. A downhole component, such as a stinger on the tool string, can engage in the muleshoe sub and can be held therein using a fastener, a pin, a key, a lock, or the like.
The antenna extends in the bottom hole assembly from the tool string and is in electrical communication with the electromagnetic telemetry device. A conductive landing affixed to the antenna is engaged in a second end or uphole portion of the bottomhole assembly. The landing in conjunction with the downhole component holds the tool string and the antenna in tension inside the bottomhole assembly.
In one implementation, the antenna includes a conductive rod in electrical communication with the electromagnetic telemetry device. The conductive landing is disposed on an uphole threaded end of the antenna and is held in place against the second end with one or more threaded fasteners.
The bottomhole assembly can include an emitter sub at least partially holding the antenna therein. The conductive landing can engage against a shoulder in the emitter sub. The conductive rod can have non-conductive centralizers disposed thereon and centralizing the conductive rod inside the bottomhole assembly. The conductive rod can also have a plurality of non-conductive sleeves disposed thereon.
The foregoing summary is not intended to summarize each potential embodiment or every aspect of the present disclosure.
The air hammer 101 couples to the drilling motor 102 that is adapted for air drilling, and the drilling motor 102 couples with a shock sub 103 to the MWD assembly 104. A non-magnetic pony collar (not shown) may be used to connect the MWD assembly 104 to the shock sub 103. The MWD assembly 104 includes a mule shoe sub 110, such as a universal bottom hole orientation (UBHO) sub for supporting the MWD tool 150. A double pin connector 105 connects a tool carrier 120 to the UBHO sub 110, and an emitter sub 130 is coupled to the tool carrier 120. As best shown in
Disposed above the emitter sub 130, the drilling assembly 100 includes a non-magnetic drill collar 106 followed by conventional drill collars 107a and cross-over subs 107b. Finally, the assembly 100 includes the jet sub 108 coupled above the drilling collars 107a, and a heavy weight drillpipe (HWPD) section 109 connects the jet sub 108 to a length of drillpipe 22. In general, the jet sub 108 can be positioned practically any distance from the other downhole components and still achieve its purposes.
The drilling assembly 100 can be used in directional drilling. To do this, directional measurements and other information obtained with the MWD tool 150 can be used to direct the drilling. The mud motor 102 can impart rotation to the air hammer 101 and can include a bent sub or housing with a preconfiguring bend. In this way, a combination of rotation and sliding of the drilling assembly 100 can be used in conjunction with the bent sub of the mud motor 102 to achieve directional drilling.
Drilling with air requires a number of considerations because vibration and air surging issues can cause damage and may cause the MWD tool 105, the antenna 170, or other components to fail. Therefore, the drilling assembly 100 and the process employed during drilling attempt to reduce vibration and prevent over-spinning of the motor 102. During the drilling operations, for example, staging the drilling air “on” and “off” for the string is necessary, and all air must be turned off if the drilling assembly 100 is “off bottom” for extended amounts of time. The motor 102 is kept “on bottom” as much as possible to reduce vibration and to reduce over-spinning of the hammer 101. String floats can be used to keep pressure trapped within drillstring 22 to reduce surge effects against the MWD tool 150 and the motor 102. String floats can also reduce blow down time while bleeding air off when making connections between sections of the drillstring.
To reduce the motor speed, the jet sub 108 disposed above the motor 102 diverts drilling air to the borehole. Not only does this aid in moving material in the annulus away from the drilling assembly 100, but the jet sub 108 is configured to limit the air delivered to the drilling motor 102. (In general, the drilling motor 102 preferably rotates at less than 120 RPM.) These considerations help reduce excessive vibration and over spinning of the motor 102.
As shown in
To properly support the assembly 104, the MWD tool 150 and the antenna 170 are seated within tight tolerances and configured with suitable tension. To configure the tension, consideration is given to any axial changes, such as the compression, experienced by the drilling assembly 100 during drilling operations. In general, the axial distance between the support of the stinger 158 in the UBHO sub 110 and the support of the landing 180 in the emitter sub 110 may change during operation so that the static length of the MWD tool 150 and the antenna 170 and the fixation of the stinger 158 and the landing 180 are configured to accommodate or account for expected changes in the axial distance during operations.
Turning to
As already indicated, the MWD tool 150 positions in the tool carrier 120. As shown in
As already indicated, the antenna 170 positions in the emitter sub 130 of the MWD assembly 104 and is supported by several centralizers 178a-c. The antenna 170 extends from the MWD tool 150 inside the assembly 104 and is in electrical communication with the EM telemetry device 152. As shown and if necessary, the extension 160 can connect to the uphole end (151:
The tool's stinger 158 affixes in the UBHO sub 110 with one or more fasteners, such as stinger bolts, to hold the MWD tool 150 at the downhole end. On the opposite end of the assembly 104, the conductive landing 180 on the uphole end of the antenna 170 secures firmly in the emitter sub 130. Securing the MWD tool 150 and the EM antenna 170 with the stinger 158 at one end and with the landing 180 at the opposite end allows the entire configuration to be held in tension inside the MWD assembly 104. Being held secure in tension inside the MWD assembly 104 allows the MWD tool 150 and the antenna 170 to be used in harsher environments than conventionally permitted.
For example, the MWD assembly 104 can be used with the percussion air hammer (101:
In addition to being held in tension, the MWD tool 150 and the antenna 170 can be centralized in the MWD assembly 104 to protect the MWD tool 150 and the antenna 170 from damage. For example, the sections (e.g., battery, gamma, and CDS/BTR) of the MWD tool 150 can be supported with centralizers 155, which are preferably composed of rubber or the like for electrical isolation. Similarly, sections of the antenna 170 can be supported with centralizers, as discussed below.
As noted above, the stinger 158 of the MWD tool 150 stings into the UBHO sub 110 and affixes in the UBHO sub 110 with one or more fasteners (e.g., stinger bolts), locks, keys, or the like. For example,
One or more stinger bolts 118 affix the stinger 158 in the UBHO sub 110. The bolts 118 can be positioned just about anywhere on the stinger 158. Preferably, a stinger bolt insert 159 is used with the stinger bolt 118.
Discussion now turns to more details of the hard-mounted antenna 170 and related components. In particular,
As best shown in
In general, the extension 160 can be about 36-in. long. As will be discussed below, the extension 160 allows operators to perform pre-job testing, and other configurations may not require the use of such an extension 160. Either way, the extension 160 in its assembled state can be transported to a field location in one piece.
As best shown in
To assemble the antenna 170, the bottom centralizer 178a attaches to the downhole end 174a of the rod 172. Support components 176a-b are joined together and are threaded on the inside to connect to the threaded end 174a of the rod 172. The bottom centralizer 178a is slipped over the support components 176a-b and is retained by an insulating nut 179a. (
After installing the bottom centralizer 178a, the lower protector 175a (e.g., fiberglass sleeve) is positioned on the rod 172, and the mid span centralizer 178b is installed. In particular, the mid-span support components 176a-b are assembled in a similar fashion to the bottom support components, but they are not threaded to the rod 172. Instead, the support components 176a-b slide on the rod 172, and the mid span centralizer 178b is positioned on the support components 176a-b and is held by a nut 179a.
The second protector 175b is installed on the rod 172 and can be secured with an epoxy. Finally, the top centralizer 178c is then installed on the rod 172. (
In the field, the drilling assembly 100 is assembled for use. Initially, the MWD tool 150 has the extension 160 installed thereon, and operators test and program the MWD tool 150 for use. Once the downhole components (air hammer 101, motor 102, UBHO sub 110, and tool carrier 120) of the drilling assembly 100 are installed at the rig, the MWD tool 150, the extension 160, and the antenna 170 can be installed. Then, the remainder of the drilling assembly 100 can be assembled.
With the UBHO sub 110 and the tool carrier 120 held at the rig, the MWD tool 150 is picked up and stabbed into the tool carrier 120 by positioning the tool's stinger 158 in the UHBO sub 110 and securing it with a stinger bolt 118. At this point, the extension 160 extends beyond the tool carrier 120 and allows operators to continue testing and programming as needed.
Once these steps are completed, the threaded end 174b of the antenna 170 inserts into the emitter sub 130, and the emitter sub 130 is lifted and positioned over the tool carrier 120. The connection between the antenna 170 and the extension 160 is then made.
The top centralizer 178c is installed on the antenna's rod 172 and tightened down with a retaining nut. All the other centralizers 178a-b have been previously installed. The emitter sub 130 is then made up to the tool carrier 120. Once the emitter sub 130 is screwed to the tool carrier 120, the assembly is lowered, and slips are set on the emitter sub 130 to hold it at the rig.
At the uphole end of the emitter sub 130, operators slip the conductive landing 180 over the threaded end 174b of the rod 172 and seat the landing 180 flush within the emitter sub's bore back. A first nut 189a threads onto the threaded end 174b of the rod 172 and tightens against the landing 180. Then, a second nut 189b threads on the rod 172 and is tighten against the first nut 189a. A buffer 190 then installs above of the landing 180 and will abut against the pin end of the non-magnetic collar 106 when made up to the end of the emitter sub 106.
Once assembly is complete, the MWD tool 150 is held firmly at its downhole end at the UHBO sub 110 (e.g., by means of the locking pin 118 attached to the stinger 158). At the uphole end, the antenna 170 affixed to the MWD tool 150 by the extension 160 is held by the conductive landing 180 firmly screwed to the contact rod 172 connected to the MWD tool 150. The landing 180 contacts a shoulder in the emitter sub 130. This setup allows for EM telemetry to be conducted under the most adverse drilling conditions, including air/mist operations when the air hammer (101) and the motor (102) are used on the end of the drilling assembly 100 for drilling.
One or more cross members 184 connect the tubular body 182 to the surrounding outer ring 186 and form gaps or passages for the flow of fluid (e.g., air) through the landing 180 to other parts of the drilling assembly. The end 188 of the outer ring 186 is preferably beveled or contoured so that the landing 180 centers against the emitter sub's landing shoulder 138, which is also preferably beveled or contoured in a complementary manner.
The MWD tool 150 can be stabilized in the tool carrier 120 using conventional types of centralizers. Alternatively, the MWD tool 150 can be stabilized using another form of centralizer. Turning to
As best shown in
Features of the centralizer 200 of
The mud motor 102 has a number of modifications adapting it for use with air. As shown in
Additionally, the disclosed motor 102 is configured with a number of multiple lobes that would make the motor 102 more suited for high speed and low torque applications. However, other controls are used to achieve the motor speeds desired during drilling operations. In general, the ratio of lobes for rotor and stator of a drilling motor that uses drilling fluid is expected to be ⅞. According to the modifications disclosed herein, the ratio of lobes for the rotor 300 and the stator 302 are configured to also be ⅞, but the stages of the power section determine use for air. For instance, a ⅞ lobed, 3 stage motor can be used for 6¾-in motor operations using air. Alternatively, a ⅞ lobed, 2.5 stage motor can be used for 8″ motor operations using air. A stage is defined as a 360-degree wrap of the lobes along the rotor 300. A smaller number of stages on the rotor 300 means the rotor 300 has low pitched lobes for the air to push against. This gives a slower revolutions per min at a given flow rate compared to a rotor with a higher number of stages above 3.
Finally, the motor 102 has bearing clearances that help cool the bearings and flush the bearings of debris using the air. For instance,
As shown in
Conventionally, the radial bearings on a mud motor operated with drilling mud have a clearance of about 0.008 to 0.015-in. To allow the upper and lower radial bearings 310 and 312 to be cooled with lower injection rates on the disclosed motor 102, the radial clearances between the static and dynamic bearings are “opened” up as specified in the Table below. This additional radial clearance can be achieved by grinding bearings to desired sizes.
The MWD tool 150, extension 160, the antenna, and other disclosed components can be used with any suitable downhole assembly, including the air drilling assembly disclosed herein. Moreover, although the disclosure has referenced the use of “air” for drilling, other fluids can be used, including conventional drilling fluids provided a suitable drill bit and motor are coupled to the MWD assembly. Moreover, reference herein to use of “air” is meant to apply to the use of any suitable gas, foam, mist, aerated mud, and the like.
The foregoing description of preferred and other embodiments is not intended to limit or restrict the scope or applicability of the inventive concepts conceived of by the Applicants. It will be appreciated with the benefit of the present disclosure that features described above in accordance with any embodiment or aspect of the disclosed subject matter can be utilized, either alone or in combination, with any other described feature, in any other embodiment or aspect of the disclosed subject matter.
In exchange for disclosing the inventive concepts contained herein, the Applicants desire all patent rights afforded by the appended claims. Therefore, it is intended that the appended claims include all modifications and alterations to the full extent that they come within the scope of the following claims or the equivalents thereof.