A Novel Approach To Fracture Characterization Utilizing Borehole Seismic Data

Summary The Najmah, Sargelu, and Marrat reservoirs are the main Jurassic reservoirs in Kuwait. These fractured-carbonate reservoirs that have moderate-to-low porosity were deposited in an inner- to midramp warm marine environment. The fracture systems play a significant role in production in these reservoirs, and it is essential to identify areas of high fracture density. It has been observed that fractures associated with certain faults have facilitated the flow in the Jurassic reservoirs. Identification of faults and associated fractures mainly has been on the basis of 3D-/2D-seismic data, image logs, cores, and thin sections. The Greater Burgan field consists of the Burgan, Magwa, and Ahmadi structures. The four main reservoir units in the Greater Burgan field are the Wara, Mauddud, Burgan Third, and Burgan Fourth sands. The deeper reservoirs--namely, the Lower Cretaceous Ratawi and Minagish limestone--and the Jurassic Marrat formation contain significant oil reserves but are of less importance. However, a recent successful exploratory well in the Arifjan prospect, which is located on the eastern flank of the Greater Burgan field, has opened up a large area that was previously considered to be nonproductive. It has been noticed that there is excellent correlation between the fractures observed in cores and image logs and those predicted from the converted component of the zero-offset vertical seismic profile (VSP). After registration of the z-component image with the converted image for various prominent reflectors, the discontinuities in the reflectors in the converted-component image revealed fracture swarms that could be traced away from the wellbore. This technique of processing the VSP data to identify fracture clusters could form a bridge between surface and borehole data and improve confidence in predicting fracture swarms away from the wellbore and also assist in planning of future surface seismic and 3D VSP surveys.

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Integrated magnetotelluric and seismic investigation of Cenozoic graben structure near Obrzycko, Poland

Acta Geophysica ◽

10.1007/s11600-020-00534-w ◽

2021 ◽

Author(s):

Adam Cygal ◽

Michał Stefaniuk ◽

Anna Kret

Keyword(s):

Seismic Data ◽

Geophysical Methods ◽

Geological Structure ◽

Data Sets ◽

Low Velocity ◽

Shallow Subsurface ◽

Geophysical Model ◽

Novel Approach ◽

Loose Deposits ◽

Static Corrections

AbstractThis article presents the results of an integrated interpretation of measurements made using Audio-Magnetotellurics and Seismic Reflection geophysical methods. The obtained results were used to build an integrated geophysical model of shallow subsurface cover consisting of Cenozoic deposits, which then formed the basis for a detailed lithological and tectonic interpretation of deeper Mesozoic sediments. Such shallow covers, consisting mainly of glacial Pleistocene deposits, are typical for central and northern Poland. This investigation concentrated on delineating the accurate geometry of Obrzycko Cenozoic graben structure filled with loose deposits, as it was of great importance to the acquisition, processing and interpretation of seismic data that was to reveal the tectonic structure of the Cretaceous and Jurassic sediments which underly the study area. Previously, some problems with estimation of seismic static corrections over similar grabens filled with more recent, low-velocity deposits were encountered. Therefore, a novel approach to estimating the exact thickness of such shallow cover consisting of low-velocity deposits was applied in the presented investigation. The study shows that some alternative geophysical data sets (such as magnetotellurics) can be used to significantly improve the imaging of geological structure in areas where seismic data are very distorted or too noisy to be used alone

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Synthetic seismograms from borehole seismic data and well logs, Beaufort-Mackenzie Basin

10.4095/296213 ◽

2015 ◽

Author(s):

K Hu ◽

T A Brent ◽

D R Issler ◽

Z Chen

Keyword(s):

Seismic Data ◽

Synthetic Seismograms ◽

Well Logs ◽

Mackenzie Basin ◽

Borehole Seismic

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Uniwell Borehole Seismic Data on Tube Wave Noise Abatement

60th EAGE Conference and Exhibition ◽

10.3997/2214-4609.201408264 ◽

1998 ◽

Author(s):

L. Walter ◽

P. Leary

Keyword(s):

Seismic Data ◽

Noise Abatement ◽

Tube Wave ◽

Borehole Seismic

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Fracture Characterization – A Fully Integrated Study, from Borehole Imagery, Cores and Seismic Data to Production Logs

4th North African/Mediterranean Petroleum and Geosciences Conference and Exhibition Tunis 2009 ◽

10.3997/2214-4609.20145785 ◽

2009 ◽

Author(s):

M. Panien ◽

E. Portier ◽

F. Marcy ◽

L. Ghilardini ◽

T. Dehaeck ◽

...

Keyword(s):

Seismic Data ◽

Fracture Characterization ◽

Fully Integrated ◽

Integrated Study

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Imaging below a complex overburden with borehole-seismic data

Geophysics ◽

10.1190/geo2019-0123.1 ◽

2020 ◽

Vol 85 (3) ◽

pp. S135-S150

Author(s):

Jakob B. U. Haldorsen ◽

Leif Jahren

Keyword(s):

Economic Evaluation ◽

Seismic Data ◽

Seismic Profile ◽

Profile Data ◽

Vertical Seismic Profile ◽

S Waves ◽

Critical Information ◽

Measured Polarization ◽

Borehole Seismic

We have determined how the measured polarization and traveltime for P- and S-waves can be used directly with vertical seismic profile data for estimating the salt exit points in a salt-proximity survey. As with interferometry, the processes described use only local velocities. For the data analyzed in this paper, our procedures have confirmed the location, inferred from surface-seismic data, of the flank of a steeply dipping salt body near the well. This has provided us more confidence in the estimated reservoir extent moving toward the salt face, which in turn has added critical information for the economic evaluation of a possible new well into the reservoir. We also have found that ray-based vector migration, based on the assumptions of locally plane wavefronts and locally plane formation interfaces, can be used to create 3D reflection images of steeply dipping sediments near the well, again using only local velocities. Our local reflection images have helped confirm the dips of the sediments between the well and the salt flank. Because all parameters used in these processes are local and can be extracted from the data themselves, the processes can be considered to be self-sufficient.

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PRACTICAL USE OF BOREHOLE SEISMIC IN EXPLORATION

The APPEA Journal ◽

10.1071/aj83034 ◽

1984 ◽

Vol 24 (1) ◽

pp. 429

Author(s):

F. Sandnes W. L. Nutt ◽

S. G. Henry

Keyword(s):

Seismic Data ◽

Seismic Profile ◽

Seismic Survey ◽

Vertical Seismic Profile ◽

Direct Signal ◽

Seismic Fault ◽

Time Calibration ◽

Vsp Data ◽

Borehole Seismic ◽

Processing Techniques

The improvement of acquisition and processing techniques has made it possible to study seismic wavetrains in boreholes.With careful acquisition procedures and quantitative data processing, one can extract useful information on the propagation of seismic events through the earth, on generation of multiples and on the different reflections coming from horizons that may not all be accessible by surface seismic.An extensive borehole seismic survey was conducted in a well in Conoco's contract area 'Block B' in the South China Sea. Shots at 96 levels were recorded, and the resulting Vertical Seismic Profile (VSP) was carefully processed and analyzed together with the Synthetic Seismogram (Geogram*) and the Synthetic Vertical Seismic Profile (Synthetic VSP).In addition to the general interpretation of the VSP data, i.e. time calibration of surface seismic, fault identification, VSP trace inversion and VSP Direct Signal Analysis, the practical inclusion of VSP data in the reprocessing of surface seismic data was studied. Conclusions that can be drawn are that deconvolution of surface seismic data using VSP data must be carefully approached and that VSP can be successfully used to examine phase relationships in seismic data.

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