121.- recent developments in acquisition and dp technology to image through complex overburdens

7/31/2019 121.- Recent Developments in Acquisition and DP Technology to Image Through Complex Overburdens

1/3

Authors:

Nick Moldoveanu,

Tim Bunting,

Jeremy Browett,

Title:

Recent Developments in Marine Acquisition and DP Technology to Improve

Imaging Through Complex Overburdens

Principle Category: Geophysics

Secondary category: Seismic data processing

Description (max 60 words):

Driven by the desire to image pre-salt targets in the GOM, the industry has made

significant improvements in acquisition and DP Technology to improve imaging through

complex over-burdens. This paper will review some of these recent improvements

which may have applicability on the Mexico side of the GOM.

Application (max 60 words):

Recent improvements in marine acquisition technology include modifications of the

surface geometry to ensure more consistent target illumination and multi-measurement

techniques(Over/Under, Dual Component) to increase bandwidth by mitigating for the

surface ghost effect. These acquisition techniques in conjunction with two way wave

equation application for imaging and model building have shown significant uplift in the

US side of the GOM.

Results (max 150 words):

Over the last ten years the industry has moved to new geometries which mitigate for thelimited azimuth collection of a towed streamer spread. Recent extensions to these

solutions include acquiring full azimuth long offset datasets to optimize the illumination

of very complex targets below highly complex overburdens.

Figure 1 details the results of a modeling study aimed at understanding the value of

long offset full azimuth data in optimizing the imaging of the ultra deep pre-salt plays in


2/3

the GOM. In this case the SEG seam model was used to synthetically acquire and

image several full azimuth datasets with various offset limitations. The study

demonstrates that for the ultra complex sub-salt targets both full azimuth and long offset

acquisition is required.

WAZ Geometry with 8km Offsets Dual Coil Geometry with 14km offsets

Figure 1 Finite difference modeling and RTM migration of a standard GOM WAZ geometry(left)

and a dual coil geometry(right). Note the improvements in imaging of the sediments below the

complex salt and the improved illumination of the sub-salt structure.

In addition to improvements in acquisition design the industry has moved to true two

way wave equation approaches for both imaging and velocity model building and is also

using true azimuth 3D multiple prediction techniques. Figure 2 details a comparison of

the same profile using state of the art technologies in 2005 and 2010. The acquisition

and DP technology advancements, over this short period of time, provide significantuplift in imaging the deep sub-salt plays.


3/3

2005 Technologies NAZ/SRME/WEM 2010 Technologies WAZ/GSMP/FWI/RTM

Figure 2 Comparison of images using 2005 state of the art technology(left) and 2010 state of

the art technology(right). Even over this limited time period the improvements in acquisition and

DP technology provide significant uplift.

Observations and Conclusions (max 150 words):

The combination of advances in acquisition geometries and advanced imaging solutions

has shown real value in improving the image of the sub-salt GOM plays. The geological

corollaries to the GOM on the Mexican side of the border suggest that these techniques

should be evaluated.

121.- recent developments in acquisition and dp technology to image through complex overburdens

Documents