GB2331971A - Control devices for controlling the position of a marine seismic streamer - Google Patents
Control devices for controlling the position of a marine seismic streamer Download PDFInfo
- Publication number
- GB2331971A GB2331971A GB9726974A GB9726974A GB2331971A GB 2331971 A GB2331971 A GB 2331971A GB 9726974 A GB9726974 A GB 9726974A GB 9726974 A GB9726974 A GB 9726974A GB 2331971 A GB2331971 A GB 2331971A
- Authority
- GB
- United Kingdom
- Prior art keywords
- streamer
- control
- control device
- bird
- depth
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000007246 mechanism Effects 0.000 abstract 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 238000006243 chemical reaction Methods 0.000 description 2
- 229920002430 Fibre-reinforced plastic Polymers 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000004411 aluminium Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 238000003491 array Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 239000011151 fibre-reinforced plastic Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/38—Seismology; Seismic or acoustic prospecting or detecting specially adapted for water-covered areas
- G01V1/3817—Positioning of seismic devices
- G01V1/3826—Positioning of seismic devices dynamic steering, e.g. by paravanes or birds
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Physics & Mathematics (AREA)
- Oceanography (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Environmental & Geological Engineering (AREA)
- Geology (AREA)
- Remote Sensing (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Physics & Mathematics (AREA)
- Geophysics (AREA)
- Catching Or Destruction (AREA)
Abstract
A control device (or "bird") 10 for controlling the position of a marine seismic streamer 14 is provided with an elongate, partly flexible, body 12 which is designed to be connected electrically and mechanically in series with the streamer 14. In its preferred form, the bird has two opposed wings 24, which are independently controllable in order to control the streamer's lateral position, as well as its depth. The device is connectible in series between two adjacent sections 14a,14b of the streamer and comprises electrical control means 26 which, in response to detected position and depth signals, drives motors to rotate the control surfaces to bring the streamer to a predetermined fixed or programmed depth and/or lateral position. The control surfaces 24 may be attached by quick release mechanisms, facilitating their removal before the streamer with attached control devices is wound onto a drum.
Description
2331971 CONTROL DEVICES FOR CONTROLLING TRE POSITION OF A MARINE SEISMIC
STREAMER This invention relates to control devices for controfling the position of a marine seismic streamer.
A marine seisn-dc streamer is an elongate cable-like structure, typicany up to several thousand metres long, which contains arrays of hydrophones and associated electronic equipment along its length, and which is used in marine seismic surveying. In order to perform a 3D marine seismIc survey, a plurality of such streamers are towed at about 5 knots behind a seismic survey vessel, which also tows one or more seismic sources, typically air guns. Acoustic signals produced by the seisn-dc sources are directed down through the water into the earth beneath, where they are reflected from the various strata. The reflected signals are received by the hydrophones, and then digitised and processed to build up a representation of the earth strata in the area being surveyed.
The streamers are typicafly towed at a constant depth of about ten metres, in order to facilitate the removal of undesired "ghosC reflections from the surface of the water. To keep the streamers at this constant depth, control devices known as "birds", attached to each streamer at intervals of 200 to 300 metres, are used.
Current designs of birds are battery-powered, and comprise a relatively heavy body which is suspended beneath the streamer, and which has a pair of laterally projecting wings (hence the name "bird"), one on each side. The combination of streamer and birds is arranged to be neutrally buoyant, and the angle of attack of both wings is adjusted in unison from time to time to control the depth of the streamer.
Birds in accordance with these current designs suffer from a number of disadvantages. Because they are battery-powered, the batteries can run out before the survey is completed, necessitating either retrieval of the streamer for battery replacement, or deployment of a work boat to replace the battery in the water. The former operation is very time consuming, while the latter can be haza dous. Further, because the birds hang beneath the streamer, they produce considerable noise as they are towed through the water, which noise interferes with the reflected signals detected by the hydrophones in the streamers. The hanging of the birds from the streamers also means that the birds need to be detached each time the streamer is retrieved and re-attached each time it is re-deployed, which is again rather time consuming.
During the seismic survey, the streamers are intended to remain straight, parallel to each other and equally spaced. However, after deploying the streamers, it is typicafly necessary for the vessel to cruise in a straight line for at least three streamer lengths before the streamer distribution approximates to this ideal arrangement and the survey can begin. This increases the time taken to carry out the survey, and therefore increases the cost of the survey. But because of sea currents, the streamers frequently fail to accurately foRow the path of the seisrrc survey vessel, sometimes deviating from this path by an angle, known as the feathering angle, of up to 10. This can adversely affect the coverage of the survey, frequently requiring that certain parts of the survey be repeated. In really bad circumstances, the streamers can actually become entangled, which though rare, causes great damage and considerable financial loss. Current designs of birds can do nothing to alleviate any of these lateral streamer positioning problems.
It is therefore an object of the present invention to provide novel streamer control devices which alleviate at least some of the disadvantages of the current designs, and/or which possess more functionality than the current designs.
According to the present invention, there is provided a control device for controlling the position of a marine seismic streamer, the device comprising a body mechanically connected in series between two adjacent sections of the streamer, sensor means in the body for determining its angular position in a plane perpendicular to the longitudinal axis of the streamer, two opposed control surfaces projecting outwardly from the body, each control surface being rotatable about an axis which in use extends transversely of the streamer, and control means responsive to control signals and the sensor means for independently adjusting the respective angular positions of said two control surfaces so as to control the lateral position of the streamer as well as its depth.
1 In a preferred embodiment of the invention, for use with a multi-section streamer which includes an electric power line, the control means is at least partly electrical and arranged in use to receive electric power from said electric power line.
When the streamer also includes a control line, the control means is preferably arranged in use to receive control signals from the control line.
The control means preferably includes at least one electrical motor, and may also include means for sensing the respective angular positions of the two control surfaces.
Conveniently, said two control surfaces rotate about a common axis.
Advantageously, each of the two control surfaces comprises a respective wing-Eke member which is swept back with respect to the direction of tow of the streamer.
Preferably, said control surfaces are releasably secured to the body, which may be adapted to be non-rotatably coupled to the streamer.
The invention will now be described, by way of example only, with reference to the accompanying drawings, of which:
Figure 1 is a somewhat schematic representation of a preferred embodiment of a streamer control device in accordance with the present invention; Figure 2 is a simple schematic of a control system forming part of the streamer control device of Figure 1; and Figures 3 to 5 illustrate the operation of the streamer control device of Figure 1.
The streamer control device, or "bird", of Figure 1 is indicated generally at 10, and comprises an elongate streamlined body 12 adapted to be mechanically and electrically connected in series in a multi-section marine seisrnic streamer 14 of the kind which is towed by -3 - a seismic survey vessel and which is used, in conjunction with a seismic source also towed by the vessel, to conduct seisrnic surveys, as briefly described hereinbefore. To permit such connection, each end of the body 12 is provided with a respective mechanical and electrical connector 16, 18, these connectors being complementary to, and designed to interconnect with, streamer end connectors 20, 22 respectively which are normally used to join together adjacent sections 14a and 14b of the streamer 14.
The bird 10 is provided with two opposed control surfaces, or wings, 24, typicaBy moulded from a fibre-reinforced plastics material, which project horizontally outwardly from the body 12 and which are independently rotatable about a common axis extending substantially perpendicularly through the longitudinal axis of the body. Rotation of the wings 24 is effected under the control of a control system 26 sealingly housed within the body 12. The wings 24 are generally ogival (ie rounded) and swept back with respect to the direction of tow of the streamer 14 (which direction is indicated by the arrow 28), in order to reduce the possibility of debris becoming hooked on them. To facilitate their rapid removal and reattachment, the wings 24 are secured to body 12 by a quick- release attachment 30.
As mentioned hereinbefore, the streamer 14 includes hydrophones distributed along its length; it also includes control and conversion circuitry for converting the outputs of the hydrophones into digital data signals, longitudinally extending control and data lines for conducting control and data signals to and from the control and conversion circuitry, and electrical power supply lines for supplying electrical power from the vessel to the circuitry. All these lines are coupled together from the streamer section 14a to the streamer section 14b via respective corresponding lines 32 which extend through the body 12 of the bird 10 between the connectors 16, 18. Additionally, the control system 26 is connected to receive control signals and electric power from respective ones of the fines 32.
The greater part of the length of the body 12 of the bird 10 is flexible, the only rigid parts being the connectors 20, 22, and a short central section which houses the control system 26 and from which the wings 24 project. This central section, which is made of aluminium or titanium and has holes passing longitudinally therethrough for the passage of Keviar or other stress members which bear the longitudinal loads on the body 12, is kept as short as possible, -4- I typically around 40 cm, so that once the wings 24 have been detached from the body 12, the streamer 14 can be wound onto and unwound from the large drum used for storing the streamer, with the body 12 still connected in the streamer. The quick-release attachment 30 permits the removal and attachment of the wings 24 to be at least partly automated as the streamer 14 is reeled in and out during the survey.
The reason for providing the elongate flexible parts of the body 12 is to provide enough length for the inclusion of one or more hydrophones, or hydrophone groups, should this be necessary to preserve a desired uniform hydrophone spacing along the length of streamer 14. If no hydrophones need to be included, the flexible parts of the body 12 can be omitted altogether, along with the aforementioned stress members.
The control system 26 is schematically illustrated in Figure 2, and comprises a microprocessor-based control circuit 34 having respective inputs 35 to 39 to receive control signals representative of desired depth, actual depth, desired lateral position, actual lateral position and roll angle of the bird 10 (ie the angular position of the body 12 in a plane perpendicular to the longitudinal axis of the streamer 14). The desired depth signal can be either a fixed signal corresponding to the aforementioned 10 metres, or an adjustable signal, while the actual depth signal is typically produced by a depth sensor 40 mounted in or on the bird 10. The lateral position signals are typically derived from a position determining system of the kind described in our US Patent No 4, 992,990 or our International Patent Application No W09621163. The roll angle signal is produced by an inclinometer 42 mounted within the bird 10.
The control circuit 34 has two control outputs 44, 46, connected to control respective electrical stepper motors 48, 50, each of which is drivingly connected to a respective one of the wings 24. The stepper motors 48, 50 have respective outputs at which they produce signals representative of their respective current angular positions (and therefore of the current angular positions of the wings 24), which outputs are connected to respective control inputs 52, 54 of the control circuit 34.
In operation, the control circuit 34 receives between its inputs 35 and 36 a signal indicative of the difference between the actual and desired depths of the bird 10, and receives between its inputs 37 and 38 a signal indicative of the difference between the actual and desired lateral positions of the bird 10. These two difference signals are used by the control circuit 34 to calculate the roll angle of the bird 10 and the respective angular positions of the wings 24 which together will produce the necessary combination of vertical force (upwardly or downwardly) and lateral force (left or right) required to move the bird 10 to the desired depth and lateral position. The control circuit 34 then adjusts each of the wings 24 independently by means of the stepper motors 48, 50, so as to start to achieve the calculated bird roll angle and wing angular positions.
Figures 3 to 5 illustrate the operation of the bird 10 in the case where the streamer 14 is slightly heavy (slightly negative buoyancy), and the bird 10 thus needs to produce lift to maintain the streamer at the desired depth. This lift is produced by the flow of the water over the wings 24 of the bird 10, resulting from the 5 knot towing speed of the streamer 14 through the water, and can be changed by changing the angle of attack of the wings with respect to the flow. The magnitude of the lift required for the situation envisaged by Figure 3 is indicated by the length of the arrows 60.
If the streamer 14 now needs to be moved laterally to the right (as viewed in Figures 3 to 5), the angular position of the left wing 24 of the bird 10 is first adjusted to increase its Eft, while the angular position of the right wing is adjusted to decrease its lift, as represented by the length of the arrows 64 in Figure 4, thus causing the bird 10 to roll clockwise from the position shown in Figure 3 to the position shown in Figure 4. This clockwise roll continues until the bird 10 reaches the steady state condition shown in Figure 5, where it can be seen that the vertical component of the lift produced by the wings 24, indicated by the arrows 66, is equal to the lift represented by the arrows 60 of Figure 3 required to maintain the streamer 14 at the desired depth, while the much larger horizontal component, represented by the arrows 68, moves the streamer 14 to the right.
While adjusting the angular positions of the wings 24 of the bird 10, the control circuit 34 continuously receives signals representative of the actual angular positions of the wings -6- 1 1 from the stepper motors 48, 50, as well as a signal representative of the actual roll angle of the bird from the inclinometer 42, to enable it to determine when the calculated wing angular positions and bird roll angle have been reached. And as the aforementioned difference signals at the inputs 35 to 38 of the control circuit 34 reduce, the control circuit repeatedly recalculates the progressively changing values of the roll angle of the bird 10 and the angular positions of the wings 24 required for the bird and streamer reach the desired depth and lateral position, until the bird and streamer actually reach the desired depth and lateral position.
The body of the bird 10 does not rotate with respect to the streamer 14, and thus twists the streamer as it rolls. The streamer 14 resists this twisting motion, so acting as a kind of torsion spring which tends to return the bird 10 to its normal position (ie with the wings 24 extending horizontally). However, this spring returning action, though beneficial, is not essential, and the bird 10 can if desired be designed to rotate to a certain extent with respect to the axis of the streamer 14.
It will be appreciated that the bird 10 has several important advantages with respect to prior art birds. Its in-line connection in the streamer 14 not only reduces the noise it generates as the streamer is towed through the water, but also enables it to derive power and control signals via the streamer and so obviates the need for batteries (although they may still be provided if desired for back-up purposes). But most importantly, it enables the horizontal or lateral position of the streamer 14 to be controlled, and not just its depth.
Another significant advantage of the bird 10 is that by virtue of the shortness of the stiff parts of the respective body 12 and the easily detachable wings 24, it does not need to be removed from the streamer 14 during winding and unwinding. This saves a considerable amount of time when carrying out the seismic survey.
Many modifications can be made to the bird 10. For example, the wings 24 can be staggered slightly along the length of the body 12, in order to provide slightly more room for their respective drive trains. Additionally, the electric motors 48, 50 can be replaced by hydraulic actuators.
Claims (13)
1. A control device for controlling the position of a marine seismic streamer, the device comprising a body mechanically connected in series between two adjacent sections of the streamer, sensor means in the body for determining its angular position in a plane perpendicular to the longitudinal axis of the streamer, two opposed control surfaces projecting outwardly from the body, each control surface being rotatable about an axis which in use extends transversely of the streamer, and control means responsive to control signals and the sensor means for independently adjusting the respective angular positions of said two control surfaces so as to control the lateral position of the streamer as weU as its depth.
2. A control device as claimed in claim 1, for use with a multi-section streamer which includes an electric power line, wherein the control means is at least partly electrical and arranged in use to receive electric power from said electric power be.
3. A control device as claimed in claim 1 or claim 2, for use with a streamer which also includes a control line, wherein the control means is arranged in use to receive control signals from the control line.
4. A control device as claimed in any one of claims 1 to 3, wherein said two control surfaces are releasably secured to the body.
5. A control device as claimed in claim 4, wherein the body is adapted to be wound onto a streamer drum while still connected in the streamer.
6. A control device as claimed in claim 5, wherein the body is at least partly flexible.
7. A control device as claimed in claim 5 or claim 6, wherein the body is of approximately the same diameter as the streamer.
8. A control device as claimed in any preceding claim, wherein said control means includes at least one electrical motor.
1
9. A control device as claimed in any preceding claim, wherein the control means includes means for sensing the angular position of each of the two control surfaces.
10. A control device as claimed in any preceding claim, wherein the two control surfaces rotate about a common axis.
11. A control device as claimed in any preceding claim, wherein each of the two control surfaces comprises a respective wing-Eke member which is swept back with respect to the direction of tow of the streamer.
12. A control device as claimed in any preceding claim, wherein the body is adapted to be non-rotatably coupled in the streamer.
13. A control device for controlling the position of a streamer, the device being substantially as herein described with respect of Figures 1 to 5 of the accompanying drawings.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB9619699.3A GB9619699D0 (en) | 1996-09-20 | 1996-09-20 | Seismic sensor units |
GBGB9626442.9A GB9626442D0 (en) | 1996-12-20 | 1996-12-20 | Control devices for controlling the position of a marine seismic streamer |
Publications (4)
Publication Number | Publication Date |
---|---|
GB2331971A9 GB2331971A9 (en) | |
GB9726974D0 GB9726974D0 (en) | 1998-02-18 |
GB2331971A true GB2331971A (en) | 1999-06-09 |
GB2331971B GB2331971B (en) | 1999-11-17 |
Family
ID=26310075
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
GB9726974A Expired - Lifetime GB2331971B (en) | 1996-09-20 | 1997-12-19 | Control devices for controlling the position of a marine seismic streamer |
Country Status (1)
Country | Link |
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GB (1) | GB2331971B (en) |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2001037002A1 (en) * | 1999-10-29 | 2001-05-25 | Schlumberger Holdings Limited | Seismic surveying with steerable propulsion devices secured to seismic cable |
US6671223B2 (en) * | 1996-12-20 | 2003-12-30 | Westerngeco, L.L.C. | Control devices for controlling the position of a marine seismic streamer |
US7080607B2 (en) | 1998-10-01 | 2006-07-25 | Westerngeco, L.L.C. | Seismic data acquisiton equipment control system |
GB2443843A (en) * | 2006-11-14 | 2008-05-21 | Statoil Asa | Towing a seismic streamer close to the seafloor |
US7450467B2 (en) | 2005-04-08 | 2008-11-11 | Westerngeco L.L.C. | Apparatus and methods for seismic streamer positioning |
WO2011120832A3 (en) * | 2010-03-30 | 2012-06-28 | Pgs Geophysical As | Noise suppression by adaptive speed regulation of towed marine geophysical streamer |
US8442770B2 (en) | 2007-11-16 | 2013-05-14 | Statoil Asa | Forming a geological model |
US8498176B2 (en) | 2005-08-15 | 2013-07-30 | Statoil Asa | Seismic exploration |
GB2499397A (en) * | 2012-02-14 | 2013-08-21 | Statoil Petroleum As | Positioning towed underwater survey apparatus |
RU2516591C2 (en) * | 2008-11-07 | 2014-05-20 | Ион Геофизикал Корпорейшн | Method and system for controlling seismic cables |
US8757270B2 (en) | 2010-05-28 | 2014-06-24 | Statoil Petroleum As | Subsea hydrocarbon production system |
US8797549B2 (en) | 2008-02-28 | 2014-08-05 | Statoil Petroleum As | Interferometric methods and apparatus for seismic exploration |
US9423519B2 (en) | 2013-03-14 | 2016-08-23 | Pgs Geophysical As | Automated lateral control of seismic streamers |
US9663192B2 (en) | 2010-03-30 | 2017-05-30 | Pgs Geophysical As | Noise suppression by adaptive speed regulations of towed marine geophysical streamer |
US9851464B2 (en) | 2010-07-02 | 2017-12-26 | Pgs Geophysical As | Methods for gathering marine geophysical data |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB0724847D0 (en) | 2007-12-20 | 2008-01-30 | Statoilhydro | Method of and apparatus for exploring a region below a surface of the earth |
GB2479200A (en) | 2010-04-01 | 2011-10-05 | Statoil Asa | Interpolating pressure and/or vertical particle velocity data from multi-component marine seismic data including horizontal derivatives |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995031735A1 (en) * | 1994-05-13 | 1995-11-23 | Petroleum Geo-Services A/S | Depth control apparatus |
WO1997030361A1 (en) * | 1996-02-13 | 1997-08-21 | Thomson-Csf | Method for controlling the navigation of a towed linear acoustic antenna, and devices therefor |
-
1997
- 1997-12-19 GB GB9726974A patent/GB2331971B/en not_active Expired - Lifetime
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995031735A1 (en) * | 1994-05-13 | 1995-11-23 | Petroleum Geo-Services A/S | Depth control apparatus |
WO1997030361A1 (en) * | 1996-02-13 | 1997-08-21 | Thomson-Csf | Method for controlling the navigation of a towed linear acoustic antenna, and devices therefor |
Cited By (33)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7822552B2 (en) | 1996-12-20 | 2010-10-26 | Westerngeco L.L.C. | Control devices for controlling the position of a marine seismic streamer |
US6671223B2 (en) * | 1996-12-20 | 2003-12-30 | Westerngeco, L.L.C. | Control devices for controlling the position of a marine seismic streamer |
US9395458B2 (en) | 1996-12-20 | 2016-07-19 | Westerngeco, L.L.C. | Control devices for controlling the position of a marine seismic streamer |
US9395459B2 (en) * | 1996-12-20 | 2016-07-19 | Westerngeco, L.L.C. | Control devices for controlling the position of a marine seismic streamer |
US8743655B2 (en) | 1998-01-10 | 2014-06-03 | Oyvind Hillesund | Control system for positioning of marine seismic streamers |
US8230801B2 (en) | 1998-01-10 | 2012-07-31 | Westerngeco L.L.C. | Control system for positioning of marine seismic streamers |
US7293520B2 (en) | 1998-10-01 | 2007-11-13 | Westerngeco, L.L.C. | Control system for positioning of a marine seismic streamers |
US7222579B2 (en) | 1998-10-01 | 2007-05-29 | Westerngeco, L.L.C. | Control system for positioning of marine seismic streamers |
US7080607B2 (en) | 1998-10-01 | 2006-07-25 | Westerngeco, L.L.C. | Seismic data acquisiton equipment control system |
WO2001037002A1 (en) * | 1999-10-29 | 2001-05-25 | Schlumberger Holdings Limited | Seismic surveying with steerable propulsion devices secured to seismic cable |
US7450467B2 (en) | 2005-04-08 | 2008-11-11 | Westerngeco L.L.C. | Apparatus and methods for seismic streamer positioning |
US8498176B2 (en) | 2005-08-15 | 2013-07-30 | Statoil Asa | Seismic exploration |
WO2008059243A3 (en) * | 2006-11-14 | 2009-04-16 | Statoil Asa | Seafloor-following streamer |
WO2008059243A2 (en) * | 2006-11-14 | 2008-05-22 | Statoil Asa | Seafloor-following streamer |
GB2443843B (en) * | 2006-11-14 | 2011-05-25 | Statoil Asa | Seafloor-following streamer |
RU2451309C2 (en) * | 2006-11-14 | 2012-05-20 | Статоил Аса | Seabed monitoring seismic cable |
GB2443843A (en) * | 2006-11-14 | 2008-05-21 | Statoil Asa | Towing a seismic streamer close to the seafloor |
US8400871B2 (en) | 2006-11-14 | 2013-03-19 | Statoil Asa | Seafloor-following streamer |
US8442770B2 (en) | 2007-11-16 | 2013-05-14 | Statoil Asa | Forming a geological model |
US8797549B2 (en) | 2008-02-28 | 2014-08-05 | Statoil Petroleum As | Interferometric methods and apparatus for seismic exploration |
RU2516591C2 (en) * | 2008-11-07 | 2014-05-20 | Ион Геофизикал Корпорейшн | Method and system for controlling seismic cables |
GB2492013A (en) * | 2010-03-30 | 2012-12-19 | Pgs Geophysical As | Noise suppression by adaptive speed regulation of towed marine geophysical streamer |
AU2011234729B2 (en) * | 2010-03-30 | 2014-05-29 | Pgs Geophysical As | Noise suppression by adaptive speed regulation of towed marine geophysical streamer |
US8472281B2 (en) | 2010-03-30 | 2013-06-25 | Pgs Geophysical As | Noise suppression by adaptive speed regulation of towed marine geophysical streamer |
US9663192B2 (en) | 2010-03-30 | 2017-05-30 | Pgs Geophysical As | Noise suppression by adaptive speed regulations of towed marine geophysical streamer |
WO2011120832A3 (en) * | 2010-03-30 | 2012-06-28 | Pgs Geophysical As | Noise suppression by adaptive speed regulation of towed marine geophysical streamer |
US9121231B2 (en) | 2010-05-28 | 2015-09-01 | Statoil Petroleum As | Subsea hydrocarbon production system |
US8757270B2 (en) | 2010-05-28 | 2014-06-24 | Statoil Petroleum As | Subsea hydrocarbon production system |
US9851464B2 (en) | 2010-07-02 | 2017-12-26 | Pgs Geophysical As | Methods for gathering marine geophysical data |
GB2499397A (en) * | 2012-02-14 | 2013-08-21 | Statoil Petroleum As | Positioning towed underwater survey apparatus |
US9423519B2 (en) | 2013-03-14 | 2016-08-23 | Pgs Geophysical As | Automated lateral control of seismic streamers |
US10054705B2 (en) | 2013-03-14 | 2018-08-21 | Pgs Geophysical As | Automated lateral control of seismic streamers |
US11119236B2 (en) | 2013-03-14 | 2021-09-14 | Pgs Geophysical As | Automated lateral control of seismic streamers |
Also Published As
Publication number | Publication date |
---|---|
GB2331971B (en) | 1999-11-17 |
GB9726974D0 (en) | 1998-02-18 |
GB2331971A9 (en) |
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Legal Events
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COOA | Change in applicant's name or ownership of the application | ||
PE20 | Patent expired after termination of 20 years |
Expiry date: 20171218 |