scholarly journals Structural Interpretation of Seismic Data of Mishrif Formation in East Abu-Amoud Field, South-eastern Iraq

2021 ◽  
pp. 3612-3619
Author(s):  
Mohammed H. Al-Aaraji ◽  
Hussein H. Karim
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Well Logs ◽  
Seismic Section ◽  
Reflected Waves ◽  
South Eastern ◽  
Vertical Variations ◽  
Structural Image ◽  
Seismic Sections ◽  
Sonic Logs

      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 Abu-amoud field. The Mishrif Formation is rich in petroleum in this area, with an area covering about 820 km2. The seismic interpretation of this study was carried out utilizing the software of Petrel-2017. 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 interpretations process for identifying the upper and lower boundaries of Mishrif Formation. As well, mapping of two-way time and depth structural maps was carried out, to aid in understanding the lateral and vertical variations and to show the formation of the structural surfaces. The study found that Mishrif thickness increases toward the east, which means that it increases from the Abu-Amoud field in Nasiriyah towards the East Abu-Amoud field in Missan province.       The aim of the study is to draw a high-resolution structural image of the East Abu Amoud field in southeast Iraq and to show the types of the existing faults and structures in the study area.

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.

Outcrops and well logs as a practicum for calibrating the accuracy of traveltime tomograms

2015 ◽  
Vol 3 (3) ◽  
pp. SY27-SY40 ◽  
Author(s):  
Sherif M. Hanafy ◽  
Ann Mattson ◽  
Ronald L. Bruhn ◽  
Shengdong Liu ◽  
Gerard T. Schuster
Keyword(s):  
High Resolution ◽  
Fault Zone ◽  
Great Basin ◽  
Seismic Tomography ◽  
Seismic Data ◽  
Hanging Wall ◽  
Normal Fault ◽  
Well Logs ◽  
Drill Core ◽  
Sufficient Detail

We have developed two case studies demonstrating the use of high-resolution seismic tomography and reflection imaging in the field of paleoseismology. The first study, of the Washington fault in southern Utah, USA, evaluated the subsurface deposits in the hanging wall of the normal fault. The second study, of the Mercur fault in the eastern Great Basin of Utah, USA, helped to establish borehole locations for sampling subsurface colluvial deposits buried deeper than those previously trenched along the fault zone. We evaluated the seismic data interpretations by comparison with data obtained by trenching and logging deposits across the Washington fault, and by drill-core sampling and video logging of boreholes penetrating imaged deposits along the Mercur fault. The seismic tomograms provided critical information on colluvial wedges and faults but lacked sufficient detail to resolve individual paleoearthquakes.

scholarly journals Transition zones analysis using empirical capillary pressure model from well logs and 3D seismic data on ‘Stephs’ field, onshore, Niger Delta, Nigeria

2019 ◽  
Vol 10 (3) ◽  
pp. 1227-1242
Author(s):  
O. Abiola ◽  
F. O. Obasuyi
Keyword(s):  
Capillary Pressure ◽  
Seismic Data ◽  
Niger Delta ◽  
Time Structure ◽  
Well Logs ◽  
3D Seismic ◽  
Seismic Section ◽  
Transition Zones ◽  
Mobile Water ◽  
3D Seismic Data

AbstractCapillary pressure is an important characteristic that indicates the zones of interaction between two-phase fluids or fluid and rock occurring in the subsurface. The analysis of transition zones (TZs) using Goda (Sam) et al.’s empirical capillary pressure from well logs and 3D seismic data in ‘Stephs’ field, Niger Delta, was carried out to remove the effect of mobile water above the oil–water contact in reservoirs in the absence of core data/information. Two reservoirs (RES B and C) were utilized for this study with net thicknesses (NTG) ranging from 194.14 to 209.08 m. Petrophysical parameters computed from well logs indicate that the reservoirs’ effective porosity ranges from 10 to 30% and the permeability ranges from 100 to > 1000 mD, which are important characteristics of good hydrocarbon bearing zone. Checkshot data were used to tie the well to the seismic section. Faults and horizons were mapped on the seismic section. Time structure maps were generated, and a velocity model was used to convert the time structure maps to its depth equivalent. A total of six faults were mapped, three of which are major growth faults (F1, F4 and F5) and cut across the study area. Reservoir properties were modelled using SIS and SGS. The capillary pressure log, curves and models generated were useful in identifying the impact of mobile water in the reservoir as they show the trend of saturating and interacting fluids. The volume of oil estimated from reservoirs B and C without taking TZ into consideration was 273 × 106 and 406 × 106 mmbbls, respectively, and was found to be higher than the volume of oil estimated from the two reservoirs while taking TZ into consideration which was 242 × 106 and 256 × 106 mmbbls, respectively. The results have indicated the presence of mobile water, which have further established that conventionally recoverable hydrocarbon (RHC) is usually overestimated; hence, TZ analysis has to be performed for enhancing RHC for cost-effective extraction and profit maximization.

scholarly journals Application of high resolution seismic to search for local gas anomalies in the South Kirinskoye oil and gas condensate field

2020 ◽  
Vol 4 (4) ◽  
pp. 384-392
Author(s):  
V.K. Leksin ◽  
Keyword(s):  
High Resolution ◽  
Oil And Gas ◽  
Drilling Fluid ◽  
Gas Production ◽  
Gas Condensate ◽  
Single Type ◽  
Geological Hazards ◽  
The South ◽  
Seismic Section ◽  
Seismic Sections

Searches for local gas anomalies in water areas are necessary to improve the safety of the construction of offshore oil and gas production facilities. The article presents the results of studies of geological hazards at the South Kirinskoye oil and gas condensate field using high resolution seismic from 2010 to 2017. New high-quality seismic sections, reduced to a single type and level, were built, which to make a correlation of reflecting horizons and map geological hazards at intersecting research sites of different years. Based on the results of the interpretation of seismic sections, local anomalies were found in the upper part of the section, indicating the presence of gas. By the structural features of the bedding in the channel on seismic sections, a turbidite flow was detected at a depth of 900 m from the seabed with a width of 1000 m and a length of more than two and a half kilometers. Correlations between the amplitude on the seismic section and the value of methane content (C1) in the drilling fluid on the log were revealed. The result of the work is the first compiled consolidated map of all geological hazards within the South Kirinskoye oil and gas condensate field, discovered as a result of the interpretation of seismic sections.

Locating faults in underground coal mines using high‐resolution seismic reflection techniques

Geophysics ◽  
1989 ◽  
Vol 54 (12) ◽  
pp. 1521-1527 ◽  
Author(s):  
Lawrence M. Gochioco ◽  
Steven A. Cotten
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Seismic Reflection ◽  
Coal Mines ◽  
Seismic Source ◽  
Seismic Survey ◽  
Underground Coal Mines ◽  
Vertical Displacements ◽  
Seismic Sections ◽  
Mine Development

A high‐resolution seismic reflection technique was used to locate faults in coal seams that were not visible on the surface and could only be observed in underground coal mines. An 8‐gauge buffalo gun, built by the research and development department of Consolidation Coal Company, was used as the seismic source. The coal seam at a depth of 700 ft produces a reflection with a predominant frequency of about 125 Hz. The high‐resolution seismic data permitted faults with vertical displacements of the same magnitude as the seam thickness to be detected at depths of several hundred feet beneath the surface. Several faults were detected and interpreted from the seismic sections, and the magnitudes of their displacement were estimated by matching the recorded seismic data to synthetic seismic data. Subsequent underground mine development in the study area confirmed two interpreted faults and their estimated displacements. Mining engineers were able to use the information provided by the seismic survey to plan an entry system through the fault zone so that less rock needed to be mined, resulting in a safer and more productive mine.

Modeling studies of interference reflections in thin‐layered media bounded by coal seams

Geophysics ◽  
1992 ◽  
Vol 57 (9) ◽  
pp. 1209-1216 ◽  
Author(s):  
Lawrence M. Gochioco
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Oil And Gas ◽  
Close Correlation ◽  
Destructive Interference ◽  
Modeling Studies ◽  
Velocity Information ◽  
Interpretation Process ◽  
Ricker Wavelet ◽  
Sonic Logs

High‐resolution seismic data collected over a major U.S. coal basin indicated potential complex problems associated with interference reflections. These problems differed from those normally encountered in the exploration of oil and gas because of differences in the geologic boundary conditions. Modeling studies were conducted to investigate the effects of overlapping primary reflections and the composite reflection that result from stacking individual wavelets. A modified empirical formula of Lindseth’s linear relationship between acoustic impedance and velocity is used to extrapolate velocity information from density logs to provide appropriate geophysical properties for modeling. The synthetic seismograms generated from density and synthetic sonic logs correlated well with the processed seismic data. A 150-Hz Ricker wavelet is used to convolve with the computer models, and the models showed that certain anomalous composite reflections result from the superposition of overlapping primary reflections. Depending on the traveltime delay of latter primary reflections, constructive or destructive interference could significantly alter the signature of the initial reflection associated with the bed of interest, which may lead to misinterpretations if not properly identified. The stratigraphic modeling technique further enhances the interpretation process and shows a close correlation with the seismic data, suggesting that more precise analytical methods need to be used to interpret, sometimes complex, high‐resolution seismic data.

Decoupling of seismic reflectors and stratigraphic timelines: A modeling study of Tertiary strata from Svalbard

Geophysics ◽  
2007 ◽  
Vol 72 (5) ◽  
pp. SM273-SM280 ◽  
Author(s):  
Ståle Johansen ◽  
Espen Granberg ◽  
Donatella Mellere ◽  
Børge Arntsen ◽  
Torben Olsen
Keyword(s):  
Seismic Data ◽  
Low Frequency ◽  
Ground Control ◽  
Seismic Section ◽  
Sequence Stratigraphic ◽  
Fundamental Assumption ◽  
Geologic Model ◽  
Seismic Sections ◽  
High Level ◽  
Seismic Reflectors

In sequence stratigraphic interpretations, the key premise is that stratal surfaces effectively represent geologic timelines. When applied to seismic sections, the fundamental assumption is that primary reflections generally mimic stratigraphic timelines. The main objective of this study was to test how well key reflectors in a seismic section couple to timelines. To achieve the high level of ground control needed for such testing, we combined photogrammetry and traditional sedimentologic fieldwork to optimize the geologic model. We relied further on petrophysical analysis to derive a numerical model suitable for the simulation of seismic data. In spite of laterally discontinuous vertical-impedance contrasts (VICs), false seismic continuity was created, and we observed frequent decoupling of seismic reflectors and stratigraphic timelines. These observations demonstrate how the low-frequency seismic method fails to image normal complexity in a stratigraphic unit. A seismic correlation test showed that the interpreters made numerous mistakes and that such mistakes are very difficult to avoid. The failure of a fundamental assumption, as illustrated here, creates serious problems for the sequence stratigraphic concept when applied to detailed correlation analysis on seismic sections.

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.

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