Seismic Sequence Stratigraphy in Mapping Complex Reservoir Reef Build-up Geometries (Offshore Abu Dhabi field).

Author(s):  
Samir Bellah ◽  
Abdulla Abdul Qader Al Shateri ◽  
Michael George Kumpas
2009 ◽  
Vol 252 ◽  
pp. 459-468 ◽  
Author(s):  
Laju Michael ◽  
D. Gopala Rao ◽  
K. S. Krishna ◽  
K. H. Vora

2021 ◽  
Vol 11 (11) ◽  
pp. 5156
Author(s):  
Abd Al-Salam Al-Masgari ◽  
Mohamed Elsaadany ◽  
Numair A. Siddiqui ◽  
Abdul Halim Abdul Latiff ◽  
Azli Abu Bakar ◽  
...  

This study identified the Pleistocene depositional succession of the group (A) (marine, estuarine, and fluvial depositional systems) of the Melor and Inas fields in the central Malay Basin from the seafloor to approximately −507 ms (522 m). During the last few years, hydrocarbon exploration in Malay Basin has moved to focus on stratigraphic traps, specifically those that existed with channel sands. These traps motivate carrying out this research to image and locate these kinds of traps. It can be difficult to determine if closely spaced-out channels and channel belts exist within several seismic sequences in map-view with proper seismic sequence geomorphic elements and stratigraphic surfaces seismic cross lines, or probably reinforce the auto-cyclic aggregational stacking of the avulsing rivers precisely. This analysis overcomes this challenge by combining well-log with three-dimensional (3D) seismic data to resolve the deposition stratigraphic discontinuities’ considerable resolution. Three-dimensional (3D) seismic volume and high-resolution two-dimensional (2D) seismic sections with several wells were utilized. A high-resolution seismic sequence stratigraphy framework of three main seismic sequences (3rd order), four Parasequences sets (4th order), and seven Parasequences (5th order) have been established. The time slice images at consecutive two-way times display single meandering channels ranging in width from 170 to 900 m. Moreover, other geomorphological elements have been perfectly imaged, elements such as interfluves, incised valleys, chute cutoff, point bars, and extinction surfaces, providing proof of rapid growth and transformation of deposits. The high-resolution 2D sections with Cosine of Phase seismic attributes have facilitated identifying the reflection terminations against the stratigraphic amplitude. Several continuous and discontinuous channels, fluvial point bars, and marine sediments through the sequence stratigraphic framework have been addressed. The whole series reveals that almost all fluvial systems lay in the valleys at each depositional sequence’s bottom bars. The degradational stacking patterns are characterized by the fluvial channels with no evidence of fluvial aggradation. Moreover, the aggradation stage is restricted to marine sedimentation incursions. The 3D description of these deposits permits distinguishing seismic facies of the abandoned mud channel and the sand point bar deposits. The continuous meandering channel, which is filled by muddy deposits, may function as horizontal muddy barriers or baffles that might isolate the reservoir body into separate storage containers. The 3rd, 4th, and 5th orders of the seismic sequences were established for the studied succession. The essential geomorphological elements have been imaged utilizing several seismic attributes.


2021 ◽  
Vol 40 (3) ◽  
pp. 186-192
Author(s):  
Thomas Krayenbuehl ◽  
Nadeem Balushi ◽  
Stephane Gesbert

The principles and benefits of seismic sequence stratigraphy have withstood the test of time, but the application of seismic sequence stratigraphy is still carried out mostly manually. Several tool kits have been developed to semiautomatically extract dense stacks of horizons from seismic data, but they stop short of exploiting the full potential of seismo-stratigraphic models. We introduce novel geometric seismic attributes that associate relative geologic age models with seismic geomorphological models. We propose that a relative sea level curve can be derived from the models. The approach is demonstrated on a case study from the Lower Cretaceous Kahmah Group in the northwestern part of Oman where it helps in sweet-spotting and derisking elusive stratigraphic traps.


2021 ◽  
Author(s):  
Subrata Chakraborty ◽  
Monica Maria Mihai ◽  
Nacera Maache ◽  
Gabriela Salomia ◽  
Abdulla Al Blooshi ◽  
...  

Abstract In Abu Dhabi, the Mishrif Formation is developed in the eastern and western parts conformably above the Shilaif Formation and forms several commercial discoveries. The present study was carried out to understand the development of the Mishrif Formation over a large area in western onshore Abu Dhabi and to identify possible Mishrif sweet spots as future drilling locations. To achieve this objective, seismic mapping of various reflectors below, above, and within the Mishrif Formation was attempted. From drilled wells all the available wireline data and cores were studied. Detailed seismic sequence stratigraphic analysis was carried out to understand the evolution of the Mishrif Formation and places where the good porosity-permeability development and oil accumulation might have happened. The seismic characters of the Mishrif Formation in dry and successful wells were studied and were calibrated with well data. The Mishrif Formation was deposited during Late Cretaceous Cenomanian time. In the study area it has a gross thickness ranging from 532 to 1,269 ft as derived from the drilled wells; the thickness rapidly decreases eastward toward the shelf edge and approaching the Shilaif basin. The Mishrif was divided into three third-order sequences based on core observations from seven wells and log signatures from 25 wells. The bottom-most sequence Mishrif 1.0 was identified is the thickest unit but was also found dry. The next identified sequence Mishrif 2.0 was also dry. The next and the uppermost sequence identified as Mishrif 3.0 shows a thickness from 123 to 328 ft. All the tested oil-bearing intervals lie within this sequence. This sequence was further subdivided into three fourth-order sequences based on log and core signatures; namely, Mishrif 3.1, 3.2, and 3.3. In six selected seismic lines of 181 Line Km (LKM) cutting across the depositional axis, seismic sequence stratigraphic analysis was carried out. In those sections all the visible seismic reflectors were picked using a stratigraphic interpretation software. Reflector groups were made to identify lowstand systems tract, transgressive systems tract, maximum flooding surface, and highstand systems tract by tying with the observations of log and core at the wells and by seismic signature. Wheeler diagrams were generated in all these six sections to understand the lateral disposition of these events and locales of their development. Based on stratigraphic analysis, a zone with likely grainy porous facies development was identified in Mishrif 3.0. Paleotopography at the top of Mishrif was reconstructed to help delineate areas where sea-level fall generated leaching-related sweet spots. Analysis of measured permeability data identified the presence of local permeability baffles affecting the reservoir quality and hydrocarbon accumulation. This study helped to identify several drilling locations based on a generic understanding of the Mishrif Formation. Such stratigraphic techniques can be successfully applied in similar carbonate reservoirs to identify the prospect areas.


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