Density‐based reflectivity in seismic exploration for coal in Alberta, Canada

Geophysics ◽  
1991 ◽  
Vol 56 (1) ◽  
pp. 139-141 ◽  
Author(s):  
D. C. Lawton ◽  
H. V. Lyatsky
Keyword(s):  
Seismic Data ◽  
Compressional Wave ◽  
Seismic Exploration ◽  
Coal Field ◽  
Compressional Wave Velocity ◽  
Coal Seams ◽  
Seismic Section ◽  
Reflection Seismic ◽  
Sonic Logs ◽  
Different Parts

At a coal field in central Alberta, Canada, the acoustic reflectivity of shallow coal seams was found to be dominated by the density contrast between coal and host bentonitic sediments. Sonic logs and a check‐shot survey showed that the compressional‐wave velocity is almost constant through the coal zone and the overlying sediments, and ranges in value between 2000 m/s and 2350 m/s over different parts of the coal field. The average coal density is [Formula: see text], whereas the density of the sediments is about [Formula: see text]. Results are illustrated using logs from a typical drillhole in the coal field. At this location, the time reflectivity sequence based on both the density and sonic logs is very similar to that obtained when the density log only is used, with a constant velocity assumed through the coal zone. At another drillhole location in the coal field, where reflection seismic data had been acquired, a synthetic seismogram generated from the density log closely matches the stacked seismic section.

Study on Vibroseis Data Preprocessing Method of Metal Mining Seismic Exploration

2013 ◽  
Vol 448-453 ◽  
pp. 3751-3756 ◽  
Author(s):  
Jun Qiu Wang ◽  
Jun Lin ◽  
Xiang Bo Gong ◽  
Ran Zeng
Keyword(s):  
Seismic Data ◽  
Data Preprocessing ◽  
Seismic Exploration ◽  
Metal Mining ◽  
Seismic Section ◽  
Denoising Method ◽  
Copper Nickel ◽  
Correlation Algorithm ◽  
Preprocessing Method

In order to improve the resolution of seismic exploration, this paper mainly studied the vibroseis data preprocessing method of metal mining seismic exploration. With the characteristics of vibroseis seismic data, we studied the correlation algorithm of detecting shot gather records, system analyzed the source and classification of noise in copper-nickel detection with Hydraulic sweep source in Jinchang, and chose the denoising method according to the characteristics of noise in the shot gather records. After preprocessing, the SNR of vibroseis seismic data is effectively improved, and then the resolution of seismic section is enhanced.

scholarly journals Reflection seismic studies over the end-glacial Burträsk fault, Skellefteå, Sweden

2010 ◽  
Vol 2 (2) ◽  
pp. 307-329 ◽  
Author(s):  
C. Juhlin ◽  
B. Lund
Keyword(s):  
Fracture Zone ◽  
Seismic Data ◽  
Mafic Rock ◽  
Seismic Profile ◽  
Large Displacements ◽  
Fault Geometry ◽  
Seismic Section ◽  
Glacial Ice ◽  
Crustal Rocks ◽  
Reflection Seismic

Abstract. Reflection seismic data were acquired along a ca. 22 km long profile over the end-glacial Burträsk Fault with a nominal receiver and source spacing of 20 m. A steeply dipping reflection can be correlated to the Burträsk Fault, indicating that the fault dips at about 55° to the southeast near the surface. The reflection from the fault is rather poorly imaged, probably due to a jump in the fault and the crookedness of the seismic profile in the vicinity of the fault. A more pronounced steeply dipping reflection is observed about 4 km southeast of the Burträsk Fault. Based on its correlation with a topographic low at the surface this reflection is interpreted to originate from a fracture zone. There are no signs of large displacements along this fault as the glacial ice receded, but it may be active today. Other reflections on the processed seismic section may originate from changes in lithological variations in the supra-crustal rocks or from intrusions of more mafic rock. Constraints on the fault geometry provided by the reflection seismic data will help determine what stresses were required to activate the fault when the major rupture along it occurred.

A new interpretation of geological structure of Tempoku Coal Field by crooked-line survey

1992 ◽  
Vol 23 (2) ◽  
pp. 241
Author(s):  
O. Nakano ◽  
M. Endo ◽  
E. Ishii ◽  
H. Watanabe
Keyword(s):  
Large Scale ◽  
Geological Structure ◽  
Seismic Survey ◽  
Coal Field ◽  
Coal Seams ◽  
Reflection Seismic ◽  
Line Method ◽  
Northern Island ◽  
New Interpretation ◽  
Seismic Lines

Tempoku Coal Field is located in the northern area of Japan's northern island, Hokkaido. Here the exploration target, the Soya Coal-Bearing Formation, is of Tertiary age overlying Cretaceous basement. The regional structure of the area is characterised by a series of synclines and anticlines trending north-northwest, with several reverse faults. A suite of surveys was carried out in 1991, in the Asajino area in the central part of the coal field. The study included drilling, vertical seismic profiling, and trenching, as well as a reflection seismic survey with the crooked-line method, which is the subject of this paper. The crooked-line method was adopted because of the mountainous terrain of the area. The seismic lines were laid out along existing tracks and valleys. The main geological structure of the area had long been considered to be a monotonous series of folds. However, the 1991 survey revealed a large-scale thrust-related structure in the main coal seams, which presented clear reflectors. Together with the data from other surveys, a reinterpretation of the structure of the Asajino area is proposed.

scholarly journals Reflection seismic studies over the end-glacial Burträsk fault, Skellefteå, Sweden

Solid Earth ◽  
2011 ◽  
Vol 2 (1) ◽  
pp. 9-16 ◽  
Author(s):  
C. Juhlin ◽  
B. Lund
Keyword(s):  
Seismic Data ◽  
Mafic Rock ◽  
Seismic Profile ◽  
Large Displacements ◽  
Fault Geometry ◽  
Seismic Section ◽  
Glacial Ice ◽  
Crustal Rocks ◽  
Reflection Seismic ◽  
Lateral Offset

Abstract. Reflection seismic data were acquired along a ca. 22 km long profile over the end-glacial Burträsk fault with a nominal receiver and source spacing of 20 m. A steeply dipping reflection can be correlated to the Burträsk fault, indicating that the fault dips at about 55° to the southeast near the surface. The reflection from the fault is rather poorly imaged, probably due to a lateral offset in the fault of about 1 km at this location and the crookedness of the seismic profile in the vicinity of the fault. A more pronounced steeply dipping reflection is observed about 4 km southeast of the Burträsk fault. Based on its correlation with a topographic low at the surface this reflection is interpreted to originate from a fracture zone. There are no signs of large displacements along this zone as the glacial ice receded, but earthquakes could be associated with it today. Other reflections on the processed seismic section may originate from changes in lithological variations in the supra-crustal rocks or from intrusions of more mafic rock. Constraints on the fault geometry provided by the reflection seismic data will help determine what stresses were required to activate the fault when the major rupture along it occurred ca. 9500 years ago.

scholarly journals Use of Attributes on 3D Seismic Data for Studying Mishrif Formation in East Abu-Amoud Field, South-Eastern Iraq

2021 ◽  
pp. 4802-4809
Author(s):  
Mohammed H. Al-Aaraji ◽  
Hussein H. Karim
Keyword(s):  
Seismic Data ◽  
Acoustic Impedance ◽  
Seismic Attributes ◽  
3D Seismic ◽  
Seismic Section ◽  
Reflected Waves ◽  
South Eastern ◽  
Seismic Sections ◽  
Sonic Logs ◽  
3D Seismic Data

      The seismic method depends on the nature of the reflected waves from the interfaces between layers, which in turn depends on the density and velocity of the layer, and this is called acoustic impedance. The seismic sections of the East Abu-Amoud field that is located in Missan Province, south-eastern Iraq, were studied and interpreted for updating the structural picture of the major Mishrif Formation for the reservoir in the field. The Mishrif Formation is rich in petroleum in this area, with an area covering about 820 km2. The horizon was calibrated and defined on the seismic section with well logs data (well tops, check shot, sonic logs, and density logs) in the interpretation process to identify the upper and lower boundaries of the Formation.  Seismic attributes were used to study the formation, including instantaneous phase attributes and relative acoustic impedance on time slice of 3D seismic data . Also, relative acoustic impedance was utilized to study the top of the Mishrif Formation. Based on these seismic attributes, karst features of the formation were identified. In addition, the nature of the lithology in the study area and the change in porosity were determined through the relative acoustic impedance The overlap of the top of the Mishrif Formation with the bottom of the Khasib Formation was determined because the Mishrif Formation is considered as an unconformity surface.

scholarly journals Time-Depth Curve Evaluation Method for Conversion Time to Depth at Penobscot Field, Nova-Scotia, Canada

2017 ◽  
Vol 17 (1) ◽  
pp. 25
Author(s):  
Fitri Rizqi Azizah ◽  
Puguh Hiskiawan ◽  
Sri Hartanto
Keyword(s):  
Time Domain ◽  
Seismic Data ◽  
Evaluation Method ◽  
Seismic Survey ◽  
Seismic Exploration ◽  
Reflection Seismic ◽  
Conversion Time ◽  
Well Data ◽  
The Time Domain ◽  
Depth Curve

Oil and natural gas as a fossil fuel that is essential for human civilization, and included in nonrenewable energy, making this energy source is not easy for updated availability. So that it is necessary for exploration and exploitation reliable implementation. Seismic exploration becomes the method most widely applied in the oil, in particular reflection seismic exploration. Data wells (depth domain) and seismic data (time domain) of reflection seismic survey provides information wellbore within the timescale. As for the good interpretation needed information about the state of the earth and is able to accurately describe the actual situation (scale depth). Conversion time domain into the depth domain into things that need to be done in generating qualified exploration map. Method of time-depth curve to be the method most preferred by the geophysical interpreter, in addition to a fairly short turnaround times, also do not require a large budget. Through data information check-shot consisting of the well data and seismic data, which is then exchanged plotted, forming a curve time-depth curve, has been able to produce a map domain depth fairly reliable based on the validation value obtained in the range of 54 - 176m difference compared to the time domain maps previously generated.Keywords: Energy nonrenewable, survei seismik, peta domain waktu, peta domain kedalaman, time-depth curve

scholarly journals Fault interpretation in seismic reflection data: an experiment analysing the impact of conceptual model anchoring and vertical exaggeration

Solid Earth ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 1651-1662 ◽  
Author(s):  
Juan Alcalde ◽  
Clare E. Bond ◽  
Gareth Johnson ◽  
Armelle Kloppenburg ◽  
Oriol Ferrer ◽  
...  
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Conceptual Models ◽  
Seismic Section ◽  
Seismic Reflection Data ◽  
Reflection Seismic ◽  
Reflection Data ◽  
Interpretation Process ◽  
Fault Interpretation ◽  
The Impact

Abstract. The use of conceptual models is essential in the interpretation of reflection seismic data. It allows interpreters to make geological sense of seismic data, which carries inherent uncertainty. However, conceptual models can create powerful anchors that prevent interpreters from reassessing and adapting their interpretations as part of the interpretation process, which can subsequently lead to flawed or erroneous outcomes. It is therefore critical to understand how conceptual models are generated and applied to reduce unwanted effects in interpretation results. Here we have tested how interpretation of vertically exaggerated seismic data influenced the creation and adoption of the conceptual models of 161 participants in a paper-based interpretation experiment. Participants were asked to interpret a series of faults and a horizon, offset by those faults, in a seismic section. The seismic section was randomly presented to the participants with different horizontal–vertical exaggeration (1:4 or 1:2). Statistical analysis of the results indicates that early anchoring to specific conceptual models had the most impact on interpretation outcome, with the degree of vertical exaggeration having a subdued influence. Three different conceptual models were adopted by participants, constrained by initial observations of the seismic data. Interpreted fault dip angles show no evidence of other constraints (e.g. from the application of accepted fault dip models). Our results provide evidence of biases in interpretation of uncertain geological and geophysical data, including the use of heuristics to form initial conceptual models and anchoring to these models, confirming the need for increased understanding and mitigation of these biases to improve interpretation outcomes.

VIBROSEIS DOWN THE HOLE

1983 ◽  
Vol 23 (1) ◽  
pp. 203
Author(s):  
J. T. Frazer
Keyword(s):  
Seismic Data ◽  
Seismic Source ◽  
Seismic Signal ◽  
Structure Mapping ◽  
Time Duration ◽  
Seismic Section ◽  
Reflection Seismic ◽  
The Past ◽  
Field Estimation ◽  
Seismic Reflections

A variety of problems associated with the Vibroseis® source have been encountered over the past few years which have presented difficulties in tieing surveys using different control systems and in depth mapping.Accurate depth structure mapping and field estimation from seismic data requires good correlation of seismic reflections with stratigraphic boundaries. The information required, a known seismic signal and vertical rock velocities can only be obtained from measurements down the hole.Seismic time to depth correlation can be obtained from an integrated sonic velocity curve tied to conventional well shoot data only if the source is the same as that used for the reflection seismic data or the relation between the well shoot and seismic source is known. It has been apparent for some time that the signal from the Vibroseis source has not been adequately defined from surface measurements.A number of parameters must be monitored to ensure that the signal transmitted during a Vibroseis sweep is properly calibrated. The synchronisation of phase, time duration of the sweep, sweep bandwidth, vibrator drive levels and the phase relation of the pilot sweep to the signal transmitted from the baseplate, contribute to determine the character of the signal seen on a seismic section.®Trademark of Conoco, Inc.

Compressional Wave Velocity and Compressibility of Aggregates of Particles of Different Materials

1967 ◽  
Vol 34 (4) ◽  
pp. 866-872 ◽  
Author(s):  
H. Brandt
Keyword(s):  
Elastic Properties ◽  
Wave Velocity ◽  
Material Properties ◽  
Oil Production ◽  
Compressional Wave ◽  
Spherical Particles ◽  
Seismic Exploration ◽  
Compressional Wave Velocity

The compressional wave velocity and compressibility of a fluid-saturated aggregate of randomly stacked spherical particles of four sizes are determined. The particles may have different elastic properties so that variations in compressional wave velocity and compressibility can be determined as a function of the material properties of the particles and of the bulk moduli of the saturating fluids. Applications of the theory to problems in seismic exploration and oil production are given.

Vp/Vs—A POTENTIAL HYDROCARBON INDICATOR

Geophysics ◽  
1976 ◽  
Vol 41 (5) ◽  
pp. 837-849 ◽  
Author(s):  
Robert H. Tatham ◽  
Paul L. Stoffa
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Mode Conversion ◽  
High Water ◽  
Compressional Wave ◽  
P Wave ◽  
Angle Of Incidence ◽  
Seismic Velocities ◽  
Compressional Wave Velocity ◽  
Reflection Seismic

Theoretically and experimentally, the shear‐wave velocity of a porous rock has been shown to be less sensitive to fluid saturants than the compressional wave velocity. Thus, observation of the ratio of the seismic velocities for waves which traverse a changing or laterally varying zone of undersaturation or gas saturation could produce an observable anomaly which is independent of the regional variation in compressional wave velocity. One source of shear‐wave data in reflection seismic prospecting is mode conversion of P waves to shear waves in marine areas of high water bottom P-wave velocity. A relatively simple interpretative technique, based on amplitude variation as a function of the angle of incidence, is a possible discriminant between shear and multiple compressional arrivals, and data for a real case are shown. A normal moveout velocity analysis, carefully coupled with this offset discriminant, leads to the construction of a shear‐wave reflection section which can then be correlated with the usual compressional wave section. One such a section has been constructed, the variation in the ratio of the seismic velocities can be mapped, and potentially anomalous subsurface regions observed.

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