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Green S.,Ikon Science | Swarbrick R.E.,Ikon Science Ltd | O'Connor S.A.,Ikon Science Ltd
Proceedings of the Annual Offshore Technology Conference | Year: 2014

Hydrodynamically active reservoirs have been recognized in various parts of the world. The majority of these are termed "conventional", following the nomenclature presented in Swarbrick (2009), whereby fluid flow is driven by hydraulic head. More recently "unconventional" hydrodynamic reservoirs have been recognized where fluid flow is driven by lateral drainage, typically found in laterally extensive reservoirs. The lateral drainage of pressure in reservoir sand units leads to a pressure gradient from higher pressured non-reservoir sediments (shales) above and below into the reservoir, leading to a focus of fluids, including hydrocarbons, within the reservoir. Within a laterally extensive reservoir fill and spill up-dip is likely to dominate the trapping of hydrocarbons, which is typically assisted by hydrodynamic flow as the aquifer will drain up-dip. Hence, secondary migration along extensive sand units is a highly effective carrier system, with little/no potential for vertical migration of hydrocarbons since there are higher pressures above and below. Hydrocarbon column heights can extend above the limits imposed by capillary entry pressures on account of the higher water pressures in the sealing rocks relative to the aquifer pressures in the sands. Such reservoirs are present in the Miocene of the Gulf of Mexico and there are multiple sources of evidence for active "unconventional" hydrodynamics which are summarized within this paper. Furthermore, new data is presented that indicates the deeper Lower Tertiary Wilcox play is hydrodynamically active by combining direct pressure data interpretation with the geological depositional model. Copyright 2014, Offshore Technology Conference.

Bale S.,University of Cardiff | Bale S.,Ikon Science Ltd. | Alves T.M.,University of Cardiff | Moore G.F.,University of Hawaii at Manoa
Geochemistry, Geophysics, Geosystems | Year: 2014

A 3D seismic volume from the Nankai Trough accretionary wedge (SE Japan) is used to evaluate the subsurface distribution of gas hydrates as a function of structural and stratigraphic complexity, variable heat flow patterns and the presence of subsurface fluid conduits. Eleven equations were modified for depth, pressure, and temperature, modeled in 3D, and compared with the distribution of Bottom-Simulating Reflections (BSRs) offshore Nankai. The results show that the equations produce overlapping - and thus potentially consistent - predictions for the distribution of BSRs, leading us to propose the concept of a "BSR Stability Envelope" as a method to quantify the subsurface distribution of gas hydrates on continental margins. In addition, we show that the ratio (R) between shallow and deep BSRs of seven subenvelopes, which are defined by BSR stability equations, indicates local gas hydrate equilibrium conditions. Values of R < 1 relate to cooler regions, whereas when R > 1 the majority of BSRs are located in warmer structural traps. The method in this paper can be used to recognize any divergence between observed and theoretical depths of occurrence of BSRs on 3D or 4D (time lapse) seismic volumes. In the Nankai Trough, our results point out for equilibrium conditions in BSRs located away from the Megasplay Fault Zone and major thrust faults. This latter observation demonstrates the applicability of the method to: (a) the recognition of subsurface fluid conduits and (b) the prediction of maximum and minimum depths of occurrence of gas hydrates on continental margins, under distinct thermal and hydrologic conditions. Key Points BSRs occur within stability envelopes BSRs distribution depends on heat flow Porosity, pressure, and salinity have little influence stability boundaries ©2013. The Authors. Geochemistry, Geophysics, Geosystems published by Wiley Periodicals, Inc. on behalf of American Geophysical Union.

Bailey T.,Ikon Science Ltd | Dutton D.,Nexen Inc.
74th European Association of Geoscientists and Engineers Conference and Exhibition 2012 Incorporating SPE EUROPEC 2012: Responsibly Securing Natural Resources | Year: 2012

The shales of the Kimmeridge Clay formation cover an extensive area of the North Sea and act as both seal and source rock for many reservoirs. Much of the Kimmeridge Clay of the Moray Firth area can be seen to lie off the Greenberg-Castagna (1992) Vp-Vs trend for shales. Here we document the Kimmeridge Clay trend for the Moray Firth area using a database of some forty wells, creating a suggested empirical trend for the Kimmeridge Clay shales in this area. Also, some ideas will be put forward to suggest the causes for the change in shale trend.

Waters K.D.,Ikon Science Ltd
74th European Association of Geoscientists and Engineers Conference and Exhibition 2012 Incorporating SPE EUROPEC 2012: Responsibly Securing Natural Resources | Year: 2012

Oil and gas has been found in clastic reservoirs of Eocene, Palaeocene, Cretaceous and Jurassic age and in fractured basement of Devonian/Carboniferous age in the West of Shetland area. The majority of discoveries have been in Palaeocene age reservoirs. Successful prospects tend to be in combination structural/stratigraphic plays which rely on pinch-out or facies changes up dip to the east as seen at Laggan. Most of the wells targeting Tertiary prospects were drilled on amplitude or AVO anomalies. Roughly three quarters of these wells failed to find hydrocarbons. A rock physics analysis of 35 wells in the WOS was performed on a well by well and subsequently regional basis. The analysis identifies the possibility for additional mechanisms which may help to explain the amplitudes encountered during seismic interpretation in terms of not only rock and fluid properties, but of these properties within the context of complex burial and uplift histories and changing pressure regimes. The study utilises geological reports, digital well logs, pressure data, core data, biostratigraphy, AFTA analysis and temperature data along with rock physics techniques to enhance our understanding of the WOS petroleum system.

Somoza A.V.,Ikon Science Ltd | Waters K.,Ikon Science Ltd | Kemper M.,Ikon Science Ltd
3rd EAGE Workshop on Rock Physics: From Rocks to Basin - Applying Rock Physics in Prospect Evaluation and Reservoir Characterization | Year: 2015

Seismic inversion is routinely used in the delineation of drillable leads and prospects. However, the algorithms and techniques that are most widely used today suffer from a number of shortcomings. In this paper we demonstrate how we can use per-facies compaction trends, derived from a regional rock physics study in Central North Sea, to perform joint inversion of seismic data from the Brenda and Forties fields. No wells from the Brenda or Forties field were used in deriving the per-facies compaction trends. The joint inversion results provide reliable estimates of seismic facies and corresponding absolute rock properties without the requirement for direct well calibration and model building.

Kemper M.,Ikon Science Ltd. | Gunning J.,CSIRO
First Break | Year: 2014

In this paper we will first review the industry-standard simultaneous inversion method (which derives continuous impedances) and subsequently identify some pitfalls. We will then introduce our new Joint Impedance and Facies Inversion technology (which we call Ji-Fi for short in this paper), which overcomes these pitfalls by recasting the seismic inverse problem as mixed discrete/continuous. Having so captured the correct physics, we apply this first on a wedge model, followed by a case study, before drawing some conclusions. Note that in this paper, it is assumed that the seismic to be inverted is an ensemble of true amplitude partial angle stacks with corresponding wavelets derived from well ties. © 2014 EAGE.

Sams M.,Ikon Science Ltd
76th European Association of Geoscientists and Engineers Conference and Exhibition 2014: Experience the Energy - Incorporating SPE EUROPEC 2014 | Year: 2014

In the context of seismic reservoir characterisation the availability of high quality and consistent petrophysical analysis is essential. Achieving consistency is often compromised by poor data quality, lack of sufficient data and ambiguities in the data. Rock physics modelling can help to improve the consistency by ensuring that the petrophysical interpretations are also constrained by the elastic logs. There are three ways that rock physics can be used. First as a simple quality control, second to provide quantitative feedback to the petrophysics and third in a joint interpretation. The choice of method depending on the confidence achieved in the rock physics model.

Payne S.,Ikon Science Ltd. | Wild P.,Ikon Science Ltd. | Lubbe R.,Ikon Science Ltd.
2nd EAGE Workshop on Rock Physics 2014 - Rock Physics: Integration and Beyond | Year: 2014

An integrated workflow is presented to model the seismic response of a fractured carbonate reservoir. Carbonate rocks are known to have a more complicated, heterogeneous pore structure than sandstone rocks. The workflow uses P-wave and porosity log data to calibrate a multi-porosity model using the extended Xu-White model (Xu and Payne, 2009). The model is then up-scaled to investigate the low frequency seismic response through the inclusion of aligned meso-scale fracture sets. Analysis is shown for log data measured in a fractured limestone reservoir. The rock physics model was used to predict the P-wave and P-to-S wave reflectivity from the top of the limestone reservoir. The results demonstrate that rock physics is able to play an important role in modelling and characterizing the seismic response of carbonate reservoirs.

Waters K.D.,Ikon Science Ltd. | Kemper M.A.C.,Ikon Science Ltd.
Interpretation | Year: 2014

Full-stack seismic interpretation continues to be the primary means of subsurface interpretation. However, the underlying impact of amplitude variation with offset (AVO) is effectively ignored or overlooked during the full-stack interpretation process. Recent advances in well-logging and rock physics techniques highlight the fact that AVO is a useful tool not only for detection of fluid anomalies, but also for the detection and characterization of lithology. We evaluated an overview of some of the key steps in the rock physics assessment of well logs and seismic data, and highlight the potential to move toward a new convention of interpretation on so-called lithology stacks. Lithology stacks may come in a variety of forms but should form the focus of interpretation efforts in the early part of the exploration and appraisal cycle. Several case studies were used to highlight that subtle fluid effects can only be extracted from the seismic data after careful assessment of the lithology response. These case studies cover a wide geography and variable geology and demonstrate that the techniques we tested are transferable and applicable across many different oil and gas provinces. The use of lithology stacks has many benefits. It allows interpretation on a single stack rather than many different offset or angle stacks. A lithology stack provides a robust, objective framework for lithostratigraphic interpretation and can be calibrated to offset wells when available. They are conceptually simple, repeatable, and transferable, allowing close cooperation across the different subsurface disciplines. © 2014 Society of Exploration Geophysicists and American Association of Petroleum Geologists. All rights reserved.

Ikon Science Ltd | Date: 2016-04-05

Computer software for use in upstream oil and gas industry for the identification of hydrocarbon locations in the subsurface; Computer software for interpretation and analysis of oilfield, geological and seismic survey data; Computer software for geophysical modelling; data-processing equipment; surveying machines and instruments; parts and fittings for data-processing equipment and surveying machines and instruments. Scientific and technological services, namely, scientific research, scientific testing, scientific consulting services, quantitative analyses, forecasting, optimisation in the field of subsurface, geological, well and seismic data for use in connection with hydrocarbon exploration, development, production and drilling; research and design services in the field of modelling, simulation, optimisation, and prediction of subsurface, geological and seismic data for use in connection with exploration, production, development and drilling operations; industrial analysis and research services in the field of modelling, simulation, optimisation, and prediction of subsurface, geological and seismic data for use in connection with exploration, production, development and drilling operations; design and development of computer software; mathematical manipulation, processing and analysis of data in the field of modelling, stochastic simulation, optimisation, and probabilistic prediction of subsurface, geological and seismic data for use in connection with exploration, production, development and drilling operations; production of mathematical models for use in analysis of subsurface, geological, well and seismic data for use in connection with hydrocarbon exploration, development, production and drilling; evaluation, analysis and interpretation of available measured and inferred geological, geophysical, petrophysical and engineering data and knowledge in the exploration, production, development and drilling of hydrocarbons in the subsurface; producing predictions in the field of hydrocarbon recovery based on combining expert knowledge and measured data; geophysical exploration, geological modelling, engineering forecasting, reserves estimation, well planning, production optimisation for the oil, gas and mining industries; petrophysical exploration for the oil, gas and mining industries; interpretation and analysis of oilfield, seismic and geological survey data.

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