WesternGeco
`
`Seeing Below the Surface
`It is widely agreed throughout the exploration and production (E&P) industry
`that seismic technology has contributed most to increasing the success of hydrocarbon
`exploration programs during the past hoo decades.
`
`In the 1970s, the drilling success rate was about 10%,
`
`but this figure had risen to 32% by the 1990s. This
`increase is primarily due to the accuracy and clarity
`that 3-D provides. Shell was one of the first operators to
`realize the value of 3-D seismic technology and has since
`pioneered a variety of new applications in the pursuit of
`continuous improvement in quality and efficiency.
`WesternGeco has worked with Shell to provide the
`technology for many innovative techniques, including
`the acquisition during the 1980s of 3-D data over huge
`areas offshore The :'\etherlands using a highly efficient
`"Quad-Quad" geometry. This technique involved two
`vessels, each equipped with two seismic sources and
`multiple streamers. WesternGeco continues to supply
`much of the seismic infonnation required for Shell's
`interpretation, exploration and development projects.
`Recent WesternGeco 3-D marine seismic acquisition
`projects for Shell include an assignment for the Geco Emerald
`for Shell Ylalaysia offshore Sabah; a 3-D survey by the
`Gero Eagle offshore Sarawa.k, also in Malaysia; and an east
`coast Canada 3-D survey by the Western Monarch.
`On land, WesternGeco has been continuously
`acquiring 3-D seismic surveys for Petroleum Development
`Oman (PDO) for several years. Last year, VVestemGeco
`conducted eight land-based 3-D seismic assignments
`with Shell in Canada and is involved with a Shell project
`onshore :\ew Zealand.
`The WesternGeco Seismic Reservoir Services (SRS)
`group provided a number of services on Shell projects,
`including reservoir characterization using EarthGM*,
`WesternGeco' s geostatistical modeling software, for
`studies with PDO and a 3-D acoustic inversion study
`for Shell Venezuela.
`"Our partnership with WestemGeco in managing
`seismic data processing has facilitated us delivering a
`quality product that meets the demand of our oil and gas
`business," said Don Spillman, manager of seismic
`
`23 Shell E&P Technology ·:· MAY 2002
`
`The Western
`Monarch
`perfonns 3-D
`sun>eys off·
`tlze east coast
`of Canada.
`
`technology fo r Shell Exploration and
`Development Co.
`As 3-D seismic technology has become
`widespread, quality also has improved,
`partly because of finer spatial san1pling
`and more accurate acquisition systems,
`but largely as a result of better processing
`technologies. Seismic acquisition records data sampled
`in the time domain, typically at 2-millisecond or
`4-milli.second intervals between 6 seconds and 12 seconds.
`Most data processing also is performed in the time
`domain, as are the data volumes ultimately delivered
`for structural and stratigraphic interpretation,
`combined with downhole geophysical and geological
`information. Time domain imaging is based on a
`variety of assumptions that break down and lead to
`positioning errors and uncertainties in the presence of
`complex structures, such as those found in and around
`salt bodies, to which many of the world's most
`prospective hydrocarbon reservoirs are related.
`
`PGS v WESTERNGECO (IPR2014-00688)
`WESTERNGECO Exhibit 2100, pg. 1
`
`

`

`WesternGeco has led the seismic services industry in
`delivering migration in the depth domain; placing
`reflections in their correct location to optimally focus the
`3-D seismic image. New depth migration processes,
`applied earlier in the overall processu1g sequence, not
`only produce images in which the drill bit can be directly
`located, but also provide much clearer images in
`very structurally complex environments. WestemGeco
`has delivered depth migrated 3-D volumes covering
`nearly 39,000 sq miles (100,000 sq km) over complex
`areas, such as the Southern North Sea and Gulf of
`Mexico. Recent depth
`imaging projects for Shell
`include the Mars and Ursa areas of the Mississippi
`Canyon where a 46-block final volume report was
`completed in 37 days and the Princess project, completed
`in 3 weeks. Several other Shell projects that include depth
`imagu1g are ongoing throughout various locations in the
`Gulf of Mexico.
`!v!ost land seismic systems and all towed streamer
`marine systems record only pressure (P} waves. In most
`circumstances, these provide excellent images; however,
`in some geological situations, P-wave imaging is
`inadequate - gas-filled sediments absorb and distort P(cid:173)
`wave energy, masking reflections from underlying strata.
`To achieve accurate in1aging in such situations requires
`the recording of multicomponent data, which provides
`shear (S) wave data in addition to P-waves. Shear waves
`are unaffected by pore fill, so can linage beneath gas
`clouds. The combination of P- and S-wave data also can
`often resolve w1eertainties about lithology and provide
`an indication of pore fluids, distinguishing anwng oil,
`water and gas. Shear waves do not travel through liquids,
`so marine surveys are recorded using an ocean bottom
`cable (OBC) containing hydrophones and groups of three
`orthogonally mounted geophones, providing four
`component (4C) data. vVesternGeco has provided Shell
`with the acquisition and processing and analysis on a
`number of recent OBC projects including the U.K. North
`Sea Brent survey, and K: Slllveys in the South Timbalier
`and Main Pass/High Island areas of the Gulf of Mexico.
`Recovery rates of known oil-in-place are commonly
`only one-third and seldom more than one-half. Factors
`contributing to this inefficient recovery include non-optimwn
`positioning of producing and injector wells and premature
`water break-through due to inaccurate knowledge of reservoir
`pore fill and flow.
`Four-dimensional time-lapse seismic can map fluid
`movement and the gas-oil contact/ oil-water contact;
`track pore fluid saturation changes; identify flow units,
`flow barriers, by-passed oil and in-fill drilling opportwliti.es;
`and monitor the performance of enhanced recovery
`
`WesternGeco
`Schlumberger House
`Gat.~ick Airport, Wast Stma~
`RH2 7EU
`EnQiand
`(Tel): 44 1293 556655
`Web site: www.wes!Bmgeco.com
`
`progran1s. TI1e 4-D method
`involves the accurate measme(cid:173)
`ment of changes in the seisnlic
`response of a reservoir due to
`the extraction and movement
`of hydrocarbons during time.
`These changes are usually
`extremely subtle and can
`easily be masked by various
`types of noise inherent to
`conventional seisnlic methods.
`To address this problem,
`V\'esternGeco has developed a
`new system that takes seisnlic
`imaging to a new level of quality and accuracy.
`This engineering project -
`the largest in the company's
`history - was launched in the mid-1990s to provide a
`revolutionary new technology for land and marine
`environments. The result, simply called o•·, has been
`applied to onshore and offshore surface seismic. The
`offshore implementation is called Q-Marine*.
`Q-Marine addresses the critical perturbations in the
`marine acquisition system that introduces noise into the
`seismic data. These perturbations come from wave and
`swell noise, positional errors, and variations ul the
`seismic source and in the recording equipment. Q-Marine
`can record the signals from up to 80,000 individual
`hydrophones, requiring data rates in excess of 20 MB
`per second, made possible by advances in electronics
`and fiber-optic networks. Each hydrophone is of a new
`tubular design, individually calibrated to produce high(cid:173)
`fidelity responses and preserve the received signal
`amplitude. The system supports more than 4,000
`hydrophones per streamer and up to 20 streamers.
`TI1is very high cha.Jmel single-sensor capability not
`only ensures the seismic wavefield is adequately
`sampled, but also properly records the noise, which is
`attenuated using adaptive software techniques that are
`much more effective than the analog methods of
`conventional systems.
`Single-sensor seismic technology has long been a goal
`because of its promise to record a wavefield that could be
`unambiguously reconstructed at any place and any tin1e.
`Shell's Leo Onkiehong and others first envisioned it in
`the late 1980s. As cited early on by Onkiehong, while "a
`recording system roith a separate clumnel for ench geophone is
`still the comprehensive solution ... it will require another step in
`hardware development nnd dntn processing price reduction."
`With Q, this is now a reality. ·'
`
`' !Vinrk ofWcstcmGNo
`
`PGS v WESTERNGECO (IPR2014-00688)
`WESTERNGECO Exhibit 2100, pg. 2
`
`