Search and Discovery Article
By Cat Campbell,Mark H. Tobey
Rock-Eval hydrogen index (HI) is often used to compare relative maturities of a source horizon across a basin. Usually, there are
several
measurements from the source horizon at a single well, and the mean
hydrogen index is calculated, or the S2 is plotted against TOC. The slope
of the best fit line through that data is used as the representative HI for that well (sometimes referred to as the ‘slope HI
’ methodology). There
is a potential flaw in both these
methodologies; however, that renders the calculated HI as misleading if the source horizon being examined is
not relatively uniform in source quality, vertically in the stratigraphic column. From a geologic perspective, it would be unusual for the source
rock quality not to vary vertically in the stratigraphic column. Organic matter input, preservation, dilution, and sediment accumulation rate
typically vary in many depositional environments over the millions of years required to create a thick source rock
package. Nevertheless, there
are source rocks which do display remarkable source-quality uniformity from top to bottom of the stratigraphic package. We have examined
source rocks from several basins where the source quality is relatively uniform over the stratigraphic column, and source rocks where the
source quality varies greatly over the stratigraphic column. Methodologies to assess hydrogen index at specific wells for the
se two scenarios
differ. Most geoscientists may not be familiar with why a single technique is not suitable for both these scenarios, or how to correctly use
hydrogen index as a relative maturation proxy in the case where source rock quality is not uniform. We will demonstrate how to determine if
your source rock quality is uniform or varied relative to HI over the stratigraphic column, and how to assign a hydrogen index to the different
source facies when that source rock quality is not uniform. Further we will illustrate how to estimate the original hydrogen
index of the
different source facies and assign each a transformation ratio. The transformation ratio is a better proxy for relative maturity, since different
source facies may have different present-day hydrogen indices, but their present-day transformation ratio should be quite similar.
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American Association of Petroleum Geologists (AAPG)
Added on 17 February, 2017
Explorer Article
The AAPG Annual Convention and Exhibition will feature a variety of field trips that will bookend the meeting, spanning from March 26 to April 8.
American Association of Petroleum Geologists (AAPG)
Added on 01 February, 2017
Europe Blog
By Fionn Devine
Sign up for your place at this two-day Geosciences Technology Workshop (GTW) hosted by AAPG Europe at Vilnius University in the heart of the Lithuanian capital. This workshop will focus on Hydrocarbon Exploration in Lithuania and the Baltic Region and will include 12 technical themes which have been designed to help launch perspectives for increased exploration in this region.
American Association of Petroleum Geologists (AAPG)
Added on 16 September, 2016
Europe Blog
By Alice Beaden
The call for abstracts deadline is quickly approaching! Submit yours by 18 September 2016 to take part in the first Geosciences Technology Workshop (GTW) ever held in Lithuania. The workshop will cover everything from European basin modelling to carbonate sedimentology and offshore developments in the Baltic Sea.
American Association of Petroleum Geologists (AAPG)
Added on 23 August, 2016
Africa Blog
By Carol McGowen
Enhance your skills with this AAPG short course on Sequence Stratigraphy designed for geoscientists, geophysicists, biostratigraphers & engineers needing a fundamental understanding of the principles and applications of sequence stratigraphy.
American Association of Petroleum Geologists (AAPG)
Added on 07 July, 2016
Learn! Blog
By Stephanie Brown
Come for the GTW 'Making Money with Mature Fields', and stay for a short course; either 'The Petroleum Geochemistry Toolkit for Petroleum Exploration and Development' or 'Carbonate Depositional Systems'. All three will explore new and innovative technologies and ideas to lend increased business opportunities now and into the future.
American Association of Petroleum Geologists (AAPG)
Added on 23 June, 2016
Explorer Director’s Corner
By David Curtiss
Have you made plans to attend ACE this year? AAPG’s 2016 Annual Convention and Exhibition (ACE) is a dedicated opportunity for our members and other professionals to get together.
American Association of Petroleum Geologists (AAPG)
Added on 01 March, 2016
Middle East Blog
This is your last chance to register for the Source Rocks of the Middle East GTW, taking place in Abu Dhabi, UAE on 25-26 January. Do not miss out this exciting workshop!
American Association of Petroleum Geologists (AAPG)
Added on 11 January, 2016
Latin America Blog
By Emily Llinás
Looking for hassle free, cost-effective ways to keep your employees and your company competitive during the industry downturn? AAPG can provide you with customized in-house courses offered at reasonable rates.
American Association of Petroleum Geologists (AAPG)
Added on 05 January, 2016