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Wednesday 21 February 2018  17:00 - 19:00

PGK Lecture and AGM: Peter Mesdag - CGG GeoSoftware - A new approach to quantitative azimuthal inversion for stress and fracture detection. Working with effective elastic parameters in anisotropic media.

Organiser: PGK
Lecturer: Peter Mesdag CGG Geosoftware

Programme 21st February 2018:
17:00 - 18:00: Social hour
18:00 - 18:30: Lecture
18:30 - 19:00: AGM
19:00 onwards buffet reception at Hathor

A new approach to quantitative azimuthal inversion for stress and fracture detection.
Working with effective elastic parameters in anisotropic media.

Peter Mesdag - CGG GeoSoftware, The Hague, Netherlands

Exploration and development of unconventional reservoirs, where fractures and in-situ stress play a key role, calls for improved characterization workflows. The effects of anisotropy on the estimated reservoir parameters can no longer be ignored. In this work, we present a method for quantitative estimation of anisotropic parameters related to stress and fracture detection that makes use of standard isotropic modeling and inversion techniques in anisotropic media. Based on reflectivity equations for TI media, we build a set of transforms that map the elastic parameters used in prestack inversion into effective anisotropic elastic parameters. When used in isotropic forward modeling and inversion, these effective parameters accurately mimic the anisotropic reflectivity behavior of the seismic data, thus closing the loop between well log data and seismic inversion results in the anisotropic case.
Here we show that using these effective elastic parameters in isotropic modeling we produce exactly the same synthetics as when using more complex anisotropic modeling.
When estimates of the Thomsen parameters are known at well control, isotropic well measurements can be transformed into effective elastic parameters. This allows for more accurate well tying and wavelet estimation, and also for quantitative post-inversion analysis.
Results from azimuthally sectored inversions are analyzed through Fourier techniques to produce measures of anisotropy magnitude and orientation. Assuming an underlying model these quantitative measures can be transformed into measures of fracture density, rock weakness or stress.
After a brief introduction the power of this proposed method will be illustrated by means of a feasibility study. Here the importance of an Azimuthal Low Frequency Model (ALFM) will become evident.

Biography

Dr Ir P.R. Mesdag received a B.Sc (1980), M.Sc (1980) and Ph.D (1985) in Physics from the Delft University of Technology in the Netherlands. He started working for Jason Geosystems in 1986 and has over 32 years experience in the development and application of advanced, quantitative data analysis techniques including inversion, geostatistics, wavelet estimation, modelling and reservoir characterization. In his 32 year career with Jason he has undertaken a wide range of on-site and off-site client projects with oil and gas companies throughout the world, utilizing the full range of technologies available in the Jason Geoscience Workbench. Currently he is technical product manager for Deterministic Reservoir Characterization at CGG.

Location

KIVI
Prinsessegracht 23
2514 AP
The Hague
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Wednesday 17 January 2018  17:00 - 19:00

PGK Monthly Lecture: Unfaulting, unfolding and unconformities in the Schoonebeek Oil Field, the Netherlands

Lecturer: Kees W. Rutten

Program Wednesday 17th January, 2018 : 17:00-18:00 Social hour; 18:00-19:00 Lecture

Unfaulting, unfolding and unconformities in the Schoonebeek Oil Field, the Netherlands

Kees W. Rutten Slokkert Consultancy; slokkert@xs4all.nl

Abstract
We have applied the Landmark ezValidator software on the 2005 NAM high-resolution seismic survey of the Schoonebeek oil field to clarify the stratigraphic relationships of the Early Cretaceous Bentheim Sandstone Member reservoir unit to its underlying and overlying successions. ezValidator (www.slokkert.nl) provides a view of the seismic after restoration, i.e. unbroken by faults, and unfolded on one or more horizons. Unconformities can be shown as gaps representing missing section.

The original seismic survey was post-processed using a Structural Oriented Filter for noise reduction (Fig. 1). Three major unconformities are shown in the restored section (Fig. 2). The unconformity gaps are determined by the unfolding of seven horizons, using a top and a base horizon for each unconformity. This display can be interpreted like a Wheeler diagram.

The deepest, Late Jurassic unconformity (Weiteveen-C; Atlantic break-up) shows little missing section in the center and major erosion on the sides. The center part apparently subsided prior to the unconformity, protecting the sediments locally. In addition, there might be several other unconformities just above and below the mapped Weiteveen-C level.

The base-Bentheim unconformity shows substantial erosion of the underlying Coevorden Formation towards the NE side and limited erosion on the SW flank. The Coevorden Formation was protected by subsidence on the SW flank prior to unconformity time. On the NE side, above the unconformity, sediment formed a wedge onlapping onto the unconformity.

Two complementary displays provide more detail of the base-Bentheim unconformity. The first display (Fig. 3) highlights the paleostructure by unfolding the unconformity itself, assuming that the unconformity peneplenated the underlying succession. This shows the paleostructure of the subsided SW flank of the Coevorden Formation. The second display (Fig. 4) highlights the interaction of the stratigraphy by unfolding on a horizon above and a horizon below, while the unconformity itself is shown as a gap determined by the unfolding space requirements. This shows the onlapping wedge on the NE side really well. By mapping thickness variations and seismic reflection terminations in these structural and stratigraphic displays the relative timing and onlap/offlap/erosion relationships of the sediments above and below the unconformity can be defined.

The Paleocene unconformity (Fig. 1) shows the Late Cretaceous uplift and Early Tertiary erosion in the center. Towards both flanks the earlier sediments were protected. The bowl-shaped unconformity gap is the opposite of the butterfly-shaped gap of the Weiteveen-C unconformity.

Location

KIVI
Prinsessegracht 23
2514 AP
Den Haag
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lecture · dinner · drinks

Wednesday 20 December 2017  17:00

PGK Christmas Lecture and Buffet Dinner

Organiser: PGK

Join us for the Christmas Lecture "Prehistoric humankind adapted to changing sea-levels, so why can't we?" by Salomon Kroonenberg followed by the Christmas buffet dinner and party at Luden.

Program: 20th December 2017

17:00 - 18:00: Social hour (at KIVI)
18:00 - 19:00: Christmas lecture Salomon Kroonenberg
19:00 - 23:00: Christmas Buffet Dinner (at Luden).

KIVI, Prinsessegracht 23, 2514 AP Den Haag
Luden, Plein 6-7, 2511 CR Den Haag

Please note that this is a paid event. If you wish to attend the buffet dinner at Luden the cost, including dinner and drinks is EUR15. For registration follow this link.

Prehistoric humankind adapted to changing sea-levels, so why can't we?
Salomon Kroonenberg

About 120,000 years ago, the surface of the sea was six metres above where it is now. When Neanderthal people on the Channel island of Jersey discovered that the source of flint for their stone implements became flooded, they turned to quartz, and when sea level dropped again they returned to flint, because it was better raw material.

The staple food of South African Homo sapiens during the Eemian highstand was black mussels, a species that lives clinging to the rocks in the surf. When sea level dropped and the rocks fell dry, they changed to white mussels, a species that lives in the beach sand under the waterline. If our ancestors over 100,000 years ago could adapt their staple food and mineral resources to changing sea levels, why wouldn't we be able to do so?

During the coldest part of the last Ice Age, 20,000 years ago, people lived on the dry bottom of the North Sea. When sea level started to rise in the Late Pleistocene and Holocene, they adapted by steadfastly moving their dwellings landwards - probably except those living on Doggerland, which might have drowned indeed.

Over the last six thousand years, sea level has been relatively stable, and global tide gauges do not show any acceleration in sea level rise since the end of the 19th century up to the present day: global sea-level rises at ~20 cm per century. Alpine, Alaskan and Arctic glaciers are still longer than they were in Roman and Mediaeval times, showing that their present retreat is still within the range of natural processes. There is nothing "unprecedented" in sea-level rise so far. Considering how inventive our ancestors were at adapting to sea-level changes with the paltry means at their disposal, we should not worry about our ability to do so in the future.

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lecture · drinks · meeting

Wednesday 6 December 2017  18:30

PGK/AAPG YP Allard Martinius (Statoil)

Click here to go to the YP Pages for full instructions for registering and to read the abstract.

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Wednesday 22 November 2017  17:00 - 19:00

PGK Satellite Event - Amsterdam: How well do we predict depth? Guido Hoetz, EBN; and From Seismic to Rocks Stephane Gesbert, Shell

Program: 17:00 - 18:00: drinks at Symphonies Bar (Ground floor Symphony offices)
18:00 - 19:00: Lectures by Guido Hoetz and Stephane Gesbert
19:00 - onwards: drinks nearby

How well do we predict depth?
Observations from systematic depth conversion reviews and the impact on the drilling portfolio.

Presented by Guido Hoetz, EBN.

Abstract
Systematic well reviews are essential for improving on future drilling performance. The accuracy of depth prognosis results has being analyzed in detail by EBN using an extensive dataset; 253 recently drilled petroleum wells in the Netherlands. The outcome reflects uncertainties in seismic interpretation and -more importantly- velocity models. The data indicates that the predicted depth at reservoir level shows an uncertainty of 1.2% (1 sigma). Also a clear bias towards predicting too shallow is evident from the dataset. A possible explanation based on the mechanism of selection bias is being presented.

From Seismic to Rocks - seismic interpretation advances in the last 10 years
Presented by Stephane Gesbert, Exploration Technologies Shell Global Solutions International B.V.

Abstract
In the past 10 years, the E&P industry has developed novel Seismic Interpretation technologies to get "more geology out of seismic data." At Shell, the development effort was originally driven by the need to robustly identify and de-risk stratigraphic traps in seismic data, but turned out to have broader appeal and impact. A central articulation of this capability is (1) the rapid interpretation of an arbitrary number of wall-to-wall seismic horizon. In turn, this dense stack of horizons enables (2) seismic attribute mapping at all stratigraphic levels. Finally, the classic offering of seismic attributes has been augmented with (3) novel attributes to characterize and visualize seismic stratigraphy to an unprecedented level of detail.
In this presentation, we will review these key elements of modern 3D Seismic Interpretation, illustrate them with recent case studies, discuss current challenges and the road ahead.

Location

Vermilion Amsterdam
Symphony Offices, Gustav Mahlerplein 11-13
1082 MT
Amsterdam
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Wednesday 15 November 2017  17:00 - 19:00

PGK Lecture: Gerhard Diephuis – There is more in and about salt than meets an oilman’s eye

Abstract

Magnesium rich minerals are being exploited by NedMag in the North of The Netherlands, around the town of Veendam. These salts have been discovered during appraisal and development of giant Slochteren gasfield. A considerable research effort has been made to elucidate parameters that determine deposition of such high-soluble evaporites. About two years ago, seismic inversion has been applied on the 3D dataset, owned and imaged by NAM. The interpretation and some rock physics modelling led to much improved insight into the possible occurrences and internal geometry of Bischofite-rich sequences. Uncertainties will be discussed prior to conclusions.

NAM is acknowledged for the seismic datasets, NedMag for its cheerful support and RWTH
(Aachen) for its effective and pleasant cooperation.

Location

KIVI
Prinsessegracht 23
2514 AP
Den Haag
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Wednesday 18 October 2017  17:00 - 19:00

PGK Lecture: Edward van Riessen – How to make oil price forecasts?

In 2014 several people in the hydrocarbon business told me the oil price would never again drop below 100$/bbl. Some of them now have to live with unprofitable projects because of this belief. The reasons why I did not agree with them at the time generally still apply. They will form the core of this lecture.

Oil price forecasts are used by oil and fuel traders, airlines and other energy related industries, but the E&P Industry is special, since it requires long term forecasts for project economic evaluations. Let us first review the past, to understand the reasons for oil price fluctuations. From the oil price record we can learn that the price is cyclic, with 5-10 year cycles. Changes are driven by world economic up- or downturns, political events (e.g. the start of the OPEC in 1973) and wars. Especially wars that affected the Middle East and temporary supply restrictions dictated by OPEC caused sudden large price increases. Emotional behavior of traders tends to amplify the change. There have not been shortages of global oil reserves, but the fear of running out of oil has driven the price up at several occasions (e.g. Club of Rome, "Limits to Growth" 1972: peak oil scenario). With the present consumption of 90M bbl. / day, the global reserves will last some 60 years. New plays, enhanced recoveries and efforts to conserve energy will increase the time reserves will last. Apart from the mentioned triggers for change, supply and demand have dictated the price over time. There is a balancing system: when the price drops, E&P companies will limit investments in order to maintain a profit. Global rig count is a good measure for E&P activities: it dropped in 2015 from 3500 to 1500. As production of oilfields declines with time, the global production capacity will hence decline as well at a rate of 2-3%/year, without additional drilling and development activity. This is currently happening. After a few years of excess production, supply and demand are now about in balance, but production capacity is likely to decline further. As soon as the excess stocks, currently estimated at 1 B bbl., have been depleted, the price will go up again.

Having analyzed what is likely to happen in the short term, we need to have a look at the longer term future: the next 10-30 years. Extrapolating past growth, global demand for oil is likely to increase with almost 1% per year. However, will other factors influence the demand such that we will see a peak demand scenario? Some of these factors are: 1. The declining share of oil used for power generation. 2. The increasing application of renewables for power generation. 3. The change from fuel engines to electric engines for cars. 4. The efforts to reduce CO2 emissions. 5. The stabilizing political situation in Iran, Iraq and Libya, allows an increase of oil production from these countries, and hence global supply. An attempt will be made to illustrate how one can analyze and use this information to make long term oil price scenarios.

Location

KIVI
Prinsessegracht 23
2514 AP
Den Haag
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Wednesday 4 October 2017  18:30 - Wednesday 4 October 2017  

PGK/AAPG YP Wiekert Visser From specialist to generalist

The Young Professionals section of the PGK-AAPG is pleased to announce our next event for petroleum geology students and young professionals: Wiekert Visser (Independent geoscientist, former professor at GUtech Oman and former Shell) will be sharing his experiences in his talk titled "From specialist to generalist", in combination with examples of beautiful geology from Oman.

Please see the YP pages for the abstract:

We invite you to join us for the lecture at the Shell offices in The Hague, followed by drinks (first few are on us!) in the Sherlock Holmes pub, a short walk from the lecture venue.

Note that this event is free, but to access the venue, you need to pre-register by confirming your attendance here or via an email to YP@PGKNET.NL. You will also need to bring your ID.

Location

Shell HQ
Carel van Bylandtlaan 30
The Hague
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