Seismic Driven Geomechanical Modeling of Uplifted and Subsided Wells in Mumbai Offshore and Its Engineering Implications

Seismic data provide evidence about hydrocarbon deposition, geological and geophysical subsurface information, including geomechanical aspects. Deriving and understanding geomechanical properties is crucial for reservoir management as it can avoid drilling and production-related problems that cause environmental impacts associated with land subsidence and uplift. The Poison's ratio (PR), Young Modulus (YM), and elastic moduli for a reservoir block were estimated using 3D seismic pre-stack data and well data. 3D Mechanical Earth Models (MEM) were also developed using the well logs, seismic horizons, and drilling data. Seismic data-derived geomechanical properties were compared with the mechanical earth models for the first time for this field. Well-tie analysis was used for inversion of 3D seismic data to extract detailed waveform and amplitude information. The brittleness index of the subsurface layers was estimated, which is a critical rock property that provides information about rock hardness and fragility phenomenon. The brittleness index has a diverse range from 5-35%, with significant contrast at shallow zones. PR and YM models generated from 3D MEM and seismic data have average values of 0.2 -0.6 and 5 - 28 GPa with significant contrast from shales and carbonates. The study recommends that the drilling through these problematic zones should be avoided to avoid wellbore problems that cause challenges in maintaining wellbore integrity and reservoir management in the North-Heera field, Mumbai Offshore Basin.

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DEMETER HIGH RESOLUTION 3D SEISMIC SURVEY—REVITALISED DEVELOPMENT AND EXPLORATION ON THE NORTH WEST SHELF, AUSTRALIA

The APPEA Journal ◽

10.1071/aj05007 ◽

2006 ◽

Vol 46 (1) ◽

pp. 101 ◽

Cited By ~ 1

Author(s):

K.J. Bennett ◽

M.R. Bussell

Keyword(s):

High Resolution ◽

Seismic Data ◽

New Technologies ◽

Seismic Survey ◽

Future Application ◽

3D Seismic ◽

Gas Field ◽

North West ◽

The North ◽

Exploration And Development

The newly acquired 3,590 km2 Demeter 3D high resolution seismic survey covers most of the North West Shelf Venture (NWSV) area; a prolific hydrocarbon province with ultimate recoverable reserves of greater than 30 Tcf gas and 1.5 billion bbls of oil and natural gas liquids. The exploration and development of this area has evolved in parallel with the advent of new technologies, maturing into the present phase of revitalised development and exploration based on the Demeter 3D.The NWSV is entering a period of growing gas market demand and infrastructure expansion, combined with a more diverse and mature supply portfolio of offshore fields. A sequence of satellite fields will require optimised development over the next 5–10 years, with a large number of wells to be drilled.The NWSV area is acknowledged to be a complex seismic environment that, until recently, was imaged by a patchwork of eight vintage (1981–98) 3D seismic surveys, each acquired with different parameters. With most of the clearly defined structural highs drilled, exploration success in recent years has been modest. This is due primarily to severe seismic multiple contamination masking the more subtle and deeper exploration prospects. The poor quality and low resolution of vintage seismic data has also impeded reservoir characterisation and sub-surface modelling. These sub-surface uncertainties, together with the large planned expenditure associated with forthcoming development, justified the need for the Demeter leading edge 3D seismic acquisition and processing techniques to underpin field development planning and reserves evaluations.The objective of the Demeter 3D survey was to re-image the NWSV area with a single acquisition and processing sequence to reduce multiple contamination and improve imaging of intra-reservoir architecture. Single source (133 nominal fold), shallow solid streamer acquisition combined with five stages of demultiple and detailed velocity analysis are considered key components of Demeter.The final Demeter volumes were delivered early 2005 and already some benefits of the higher resolution data have been realised, exemplified in the following:Successful drilling of development wells on the Wanaea, Lambert and Hermes oil fields and identification of further opportunities on Wanaea-Cossack and Lambert- Hermes;Dramatic improvements in seismic data quality observed at the giant Perseus gas field helping define seven development well locations;Considerably improved definition of fluvial channel architecture in the south of the Goodwyn gas field allowing for improved well placement and understanding of reservoir distribution;Identification of new exploration prospects and reevaluation of the existing prospect portfolio. Although the Demeter data set has given significant bandwidth needed for this revitalised phase of exploration and development, there remain areas that still suffer from poor seismic imaging, providing challenges for the future application of new technologies.

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Unconventional Reservoir characterization and Sensitive Attributes Determination: A Case Study of Eastern Sembar Formation, Lower Indus Basin, Pakistan

Geophysics ◽

10.1190/geo2018-0761.1 ◽

2020 ◽

pp. 1-67

Author(s):

Muhammad Abid ◽

Liping Niu ◽

Jiqiang Ma ◽

Jianhua Geng

Keyword(s):

Organic Matter ◽

Seismic Data ◽

Wave Impedance ◽

P Wave ◽

Indus Basin ◽

Brittleness Index ◽

Poor Correlation ◽

Unconventional Reservoir ◽

Geomechanical Properties ◽

Lower Indus Basin

The Sembar Shale formation in Lower Indus Basin Pakistan is thought to contain significant potential of unconventional resources; however, no detailed study has yet been carried out to quantify its potential. In conventional oil and gas exploration, reservoir rocks have been the main focus therefore, limited number of wells target the Sembar Formation. To explore its regional view, the seismic characterization of these shale is required. Generally, a poor correlation is generally observed between P-wave impedance and the reservoir and geomechanical properties of rocks, making it challenging to characterize them using seismic data. We present a workflow for characterizing the seismic derived unconventional prospect of the Sembar Shale using prestack seismic data along with well logs. The logging results of the two wells show that organic matter richness of well A is in high to very high values while, well B is in low to very low values. Considering the mineral composition and brittleness index evaluation the Sembar Shale in well A is brittle to less brittle in nature. The organic content, porosity, and brittleness index results in well A makes the Lower Cretaceous Sembar Formation favorable to be considered as a potential organic shale reservoir. Four sensitive attributes, derived through integration of the rock petrophysical, geochemical and geomechanical parameters, are correlated with P-wave impedance. The correlation of each sensitive attribute has been applied to characterize the Sembar Shale potential. These attributes are first-order indicators to depict organic matter, porosity and geomechanical properties. This attribute approach is further validated through rock physics modeling. The workflow presented in this study can be employed to assess unconventional reservoir potential of the Sembar Formation in other parts of the basin.

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Quaternary evolution of the northern North Sea

10.5194/egusphere-egu2020-10118 ◽

2020 ◽

Author(s):

Christine Batchelor ◽

Dag Ottesen ◽

Benjamin Bellwald ◽

Sverre Planke ◽

Helge Løseth ◽

...

Keyword(s):

North Sea ◽

Seismic Data ◽

3D Seismic ◽

Quaternary Sediments ◽

The North ◽

The North Sea ◽

Data Coverage ◽

Northern North Sea ◽

2D And 3D ◽

3D Seismic Data

The North Sea has arguably the most extensive geophysical data coverage of any glacier-influenced sedimentary regime on Earth, enabling detailed investigation of the thick (up to 1 km) sequence of Quaternary sediments that is preserved within the North Sea Basin. At the start of the Quaternary, the bathymetry of the northern North Sea was dominated by a deep depression that provided accommodation for sediment input from the Norwegian mainland and the East Shetland Platform. Here we use an extensive database of 2D and 3D seismic data to investigate the geological development of the northern North Sea through the Quaternary.Three main sedimentary processes were dominant within the northern North Sea during the early Quaternary: 1) the delivery and associated basinward transfer of glacier-derived sediments from an ice mass centred over mainland Norway; 2) the delivery of fluvio-deltaic sediments from the East Shetland Platform; and 3) contourite deposition and the reworking of sediments by contour currents. The infilling of the North Sea Basin during the early Quaternary increased the width and reduced the water depth of the continental shelf, facilitating the initiation of the Norwegian Channel Ice Stream.

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Extensive, Gas-charged Quaternary Sand Accumulations of the Northern North Sea and North Sea Fan

10.5194/egusphere-egu2020-18701 ◽

2020 ◽

Author(s):

Benjamin Bellwald ◽

Sverre Planke ◽

Sunil Vadakkepuliyambatta ◽

Stefan Buenz ◽

Christine Batchelor ◽

...

Keyword(s):

North Sea ◽

Seismic Data ◽

Data Sets ◽

3D Seismic ◽

Fine Grained ◽

The North ◽

Northern North Sea ◽

Well Data ◽

Sea Fan ◽

3D Seismic Data

Sediments deposited by marine-based ice sheets are dominantly fine-grained glacial muds, which are commonly known for their sealing properties for migrating fluids. However, the Peon and Aviat hydrocarbon discoveries in the North Sea show that coarse-grained glacial sands can occur over large areas in formerly glaciated continental shelves. In this study, we use conventional and high-resolution 2D and 3D seismic data combined with well information to present new models for large-scale fluid accumulations within the shallow subsurface of the Norwegian Continental Shelf. The data include 48,000 km2 of high-quality 3D seismic data and 150 km2 of high-resolution P-Cable 3D seismic data, with a vertical resolution of 2 m and a horizontal resolution of 6 to 10 m in these data sets. We conducted horizon picking, gridding and attribute extractions as well as seismic geomorphological interpretation, and integrated the results obtained from the seismic interpretation with existing well data.The thicknesses of the Quaternary deposits vary from hundreds of meters of subglacial till in the Northern North Sea to several kilometers of glacigenic sediments in the North Sea Fan. Gas-charged, sandy accumulations are characterized by phase-reserved reflections with anomalously high amplitudes in the seismic data as well as density and velocity decreases in the well data. Extensive (>10 km2) Quaternary sand accumulations within this package include (i) glacial sands in an ice-marginal outwash fan, sealed by stiff glacial tills deposited by repeated glaciations (the Peon discovery in the Northern North Sea), (ii) sandy channel-levee systems sealed by fine-grained mud within sequences of glacigenic debris flows, formed during shelf-edge glaciations, (iii) fine-grained glacimarine sands of contouritic origin sealed by gas hydrates, and (iv) remobilized oozes above large evacuation craters and sealed by megaslides and glacial muds. The development of the Fennoscandian Ice Sheet resulted in a rich variety of depositional environments with frequently changing types and patterns of glacial sedimentation. Extensive new 3D seismic data sets are crucial to correctly interpret glacial processes and to analyze the grain sizes of the related deposits. Furthermore, these data sets allow the identification of localized extensive fluid accumulations within the Quaternary succession and distinguish stratigraphic levels favorable for fluid accumulations from layers acting as fluid barriers.

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Diapiric shale and coast-perpendicular, fault-related subbasins, south Texas Gulf Coast

Interpretation ◽

10.1190/int-2014-0016.1 ◽

2015 ◽

Vol 3 (2) ◽

pp. T43-T56 ◽

Cited By ~ 2

Author(s):

Osareni C. Ogiesoba ◽

Rodolfo Hernandez

Keyword(s):

Seismic Data ◽

Gulf Coast ◽

Structural Features ◽

South Texas ◽

3D Seismic ◽

Texas Gulf Coast ◽

Vertical Loading ◽

The North ◽

Visualization Tools ◽

3D Seismic Data

Coast-perpendicular shale ridges are rare structural features worldwide, and their origin remains a subject of debate. We studied some coast-perpendicular shale ridges and faults within a minibasin located onshore in Refugio County in the Texas Gulf Coast. We used 3D seismic data, visualization tools, and seismic attributes to examine the geometry of coast-perpendicular diapiric structures associated subbasins (SBs) and faults, and coast-parallel listric faults. Our results indicated that the minibasin is subdivided into four SBs by five diapiric shale ridges that intrude through the fault heaves of down-to-the-basin (synthetic) and coast-perpendicular faults. Three of the SBs are oriented perpendicular to the coast, whereas the fourth has a curvilinear form trending northeast–southwest–southeast. Of the five diapiric shale ridges, three are coast-perpendicular. The other two are curvilinear to the coast. All five diapiric shale ridges are associated with coast-perpendicular faults that bound the flanks of the ridges. On the basis of our mapping results, we deduced that the origin of the coast-perpendicular faults in the study area are related to the coalescing of en echelon synthetic faults, as well as the coalition of synthetic and antithetic fault planes. We inferred that the origin of the shale diapirs is related to vertical loading and, possibly, local southwest–northeast lateral compression of interbedded, overpressured, shale-prone intervals. The coast-perpendicular faults within the Frio formed as a result of reactivation of the Eocene-Vicksburg coast-perpendicular faults. Synthetic faults dominate the pattern within the SB in the north where shale ridges are broad, whereas antithetic faults dominate the pattern in the south where shale ridges are narrow.

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Estimation of stress and geomechanical properties using 3D seismic data

First Break ◽

10.3997/1365-2397.2011042 ◽

2012 ◽

Vol 30 (1821) ◽

Cited By ~ 42

Author(s):

D. Gray ◽

P. Anderson ◽

J. Logel ◽

F. Delbecq ◽

D. Schmidt ◽

...

Keyword(s):

Seismic Data ◽

3D Seismic ◽

Geomechanical Properties ◽

3D Seismic Data

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Structural and Stratigraphic Resolution of the Permian Minnelusa Formation with 3D Seismic Data at the North Rainbow Ranch Field, Powder River Basin, Wyoming: ABSTRACT

AAPG Bulletin ◽

10.1306/8d2b210f-171e-11d7-8645000102c1865d ◽

1995 ◽

Vol 79 ◽

Author(s):

Peter G. Smith

Keyword(s):

River Basin ◽

Seismic Data ◽

Powder River Basin ◽

3D Seismic ◽

The North ◽

3D Seismic Data

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SEISMIC DELINEATION OF STRUCTURE-CONTROLLED CARBONATE CEMENT AND POTENTIAL ECONOMIC IMPLICATIONS, ANGEL FIELD, NORTH WEST SHELF

The APPEA Journal ◽

10.1071/aj94017 ◽

1995 ◽

Vol 35 (1) ◽

pp. 280

Author(s):

S. Ryan-Grigor ◽

J.P. Schulz-Rojahn

Keyword(s):

Seismic Data ◽

High Amplitude ◽

Fault System ◽

3D Seismic ◽

Economic Implications ◽

Northern Margin ◽

North West ◽

The North ◽

Migration Pathways ◽

3D Seismic Data

Major carbonate-cemented zones occur in Late Jurassic Angel Formation sandstones of marine mass flow origin that contain large hydrocarbon reserves in the Angel Field, Dampier Sub-basin. Preliminary results suggest that poikilotopic dolomite cement is dominant. The carbonate-cemented zones are identifiable from wireline log response and 3D seismic data, and occur in discrete intervals with a cumulative thickness of approximately 165m at Angel-2. These intervals produce a zone of high amplitude reflections of about 100 ms two-way time. Field-wide seismic mapping indicates that these carbonate-cemented zones sharply abut the northern margin of a major east-west trending strike-slip fault system that traverses this field. The carbonate-cemented zones extend in a wedge-like shape towards the northeast and concentrate along the crest of the main structural trend.The results underscore the importance of 3D seismic data for a better estimation of reservoir risk and reserves in variably carbonate-cemented sandstones.The carbonate-cemented zones may represent a 'plume' related to migration of petroleum and/or carbon dioxide. Therefore delineation of major carbonate-cemented zones using seismic data may aid in the identification of petroleum migration pathways and pools in the North West Shelf. Alternatively, carbonate cements dissolved south of the major fault zone and possibly in downdip locations in which case dissolution pores may exist in these areas. Further research is required to evaluate these hypotheses.

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