This document describes a post well analysis project by TGS-NOPEC Geophysical Company ASA to analyze 84 exploration wells drilled in the Norwegian part of the Barents Sea. The project involves extracting data on the reservoirs, traps, seals, hydrocarbons and charges from each well and storing it in a GIS-based database. This database will allow users to query and visualize parameters influencing hydrocarbon discoveries to improve understanding of the petroleum systems and reduce future drilling risks.

1. © 2015 TGS-NOPEC Geophysical Company ASA. All rights reserved.
See the energy at TGS.com
Post Well Analysis (PWA)
BARENTS SEA
Exploration successes occur when all the following prerequisites are
fulfilled:
ƒƒ Presence of effective RESERVOIR
ƒƒ Presence of effective SEAL (top, fault and lateral seals)
ƒƒ Presence of TRAP prior to hydrocarbon charge (structural and/or
stratigraphic)
ƒƒ Hydrocarbon CHARGE (generation/migration)
By analyzing the reasons for success and failure we can learn more
about the hydrocarbon system in which the well was drilled, and
improve the chances of success in the future. TGS has reviewed the
most representative exploration wells (84) drilled to test independent
prospects in the Norwegian part of the Barents Sea. All prospective
levels in each well were investigated irrespective of the primary target
of the well.
Well Data
The following data sources provide input to the analysis:
ƒƒ Norwegian Petroleum Directorate (NPD) website
ƒƒ Original composite logs, well reports, etc.
ƒƒ TGS’ Barents Sea Facies Map Browser (including litho-/
chronostratigraphy)
ƒƒ TGS’ petrophysical database (CPI)
ƒƒ Geochemical and well pressure data
Seismic Data
For the evaluation of geometric properties of traps and for maturation
modelling of drainage areas, a regular regional grid of 2D data has
been utilized. This seismic grid consists mainly of the NBR long offset
data (approx. 80,000 km). Furthermore, public data (2D and 3D) was
used where appropriate.

2. © 2015 TGS-NOPEC Geophysical Company ASA. All rights reserved.
See the energy at TGS.com
Deliverables
The Barents Sea Post Well Analysis (BS PWA) is a new GIS-based
exploration aid. It is designed to analyze and explore the full range
of factors influencing the presence/quality of trap, reservoir, seal and
hydrocarbon charge (including retention) for all prospective levels in all
tested structures.
The project addresses 84 released exploration wells by extracting
parameter subsets from all prospective intervals.
Data recorded includes:
1. General well information
2. Reservoirs
ƒƒ Lithological, stratigraphic and facies features
ƒƒ Petrophysical parameters (N/G, av. poroperms)
3. Traps
ƒƒ Type, closure, faults and effectiveness
ƒƒ Timing of emplacement, modification, exhumation, DHI
4. Seals
ƒƒ Top seal; lithological, stratigraphic and facies features
ƒƒ Bottom seal, critical seal, waste and thief zones
5. Hydrocarbons
ƒƒ Type and features of HC columns and/or shows
ƒƒ Retention
6. Charges
ƒƒ Lithological, stratigraphic and facies features
ƒƒ Quality of source in well including average TOC and HI, max
maturity, max and present day temperature, age of expulsion
ƒƒ Quality of source in the kitchen
ƒƒ Migration
The PWA also includes general information on the SINTEF boreholes
and unreleased well data in the Barents Sea for a comprehensive well
database.
Data Viewer
The database is delivered as an ESRI ArcGIS Geodatabase, in Access®
or binary format, containing all spatial data and spatial analysis using
data types supported by ArcGIS software.
TGS is also seeking to develop a Facies Map Browser (FMB) PWA plug-in,
so the PWA can be viewed and queried within the FMB regional geological
interpretation tool without the need for a separate ArcGIS license.
Query Tool
The PWA will include a query toolbar to enable graphical representation
of regional and localized query results. There are multiple queries and
these will include:
ƒƒ Reservoir presence, effectiveness and fluids
ƒƒ Trap type, effectiveness and retention failure
ƒƒ Top seal and critical seal
ƒƒ Charge rating (up to 5 charges per reservoir)
ƒƒ Main failure mechanism
Images
The database also includes images of the following:
ƒƒ A pie chart scheme that summarizes the results of each well (PDF)
ƒƒ Lithostratigraphy and wireline data for each well (JPG)
ƒƒ One image minimum of a representative seismic line for each
well (PDF)
ƒƒ One grid map minimum for a representative horizon for each
well (PDF)
Benefits
ƒƒ Complete well parameter interpretation in a single location
saves time
ƒƒ Access to collated learning from well failures and successes
facilitates new analytical approaches (within the GIS-environment)
and reduces future risk of drilling dry holes
ƒƒ Graphical display of queries for reservoir, seal, trap and charge
improves understanding of petroleum systems
For more information, contact TGS at:
UK
Tel: +44 208 339 4200
Email: gps-sales@tgs.com
Access is a registered trademark of Microsoft Corporation in the United States and/or other countries