Geochemical Evaluation of Extracts of Source Rocks

Introduction to the General Methodology

MSc Sergio Perez-Rodriguez October, 2015

To introduce the general methodology to make geochemical evaluation of source rocks.

To address the importance of such evaluations as vital data to figure the potential of source rocks to host unconventional resources

Objectives

General Methodology

Workflow

Rock extract

Diagnosis of chemical properties

Composition

Saturated

Aromatic

NSO

Biomarkers Isotopes NSO Compounds

As a result of the geochemical evaluation of source rocks, it is found the answers of the questions

What is the original sedimentary environment (marine? lacustrine?) What is the total content of organic carbon (TOC)? What are the likely changes of the kerogen to become hydrocarbon?

Of what kind ? What is the degree of thermal maturity of the samples evaluated? What are the estimates of adsorbed gas and free gas that are

present for different degrees of thermal maturity of the samples evaluated?

Discussion of the General Methodology

Several answers provided by the geochemical evaluation of source rocks are vital for the diagnosis of unconventional resources, because they provide information about important standards these rock are required to achieve to be regarded as worthily hosts of reserves of oil and gas:

Is their TOC greater than 1.5% (Murillo Muñeton, 2013)?

It is an oil prone, a gas prone or an oil & gas prone source rock?

For a given degree of thermal maturity, how much hydrocarbon is left in the source rock? In such grounds, what is the status and expectations provided by the samples evaluated?

Discussion Importance for the Assessment of

Unconventional Resources

Geochemical evaluations provide vital information of the quality of source rocks as host of unconventional hydrocarbons

The information is essential to support the quantitative analysis of

the likely types and amounts of unconventional reserves feasible to develop in the area under scrutiny.

The aforementioned statement is further explained taking into account that the recovery factor depends on the kind of unconventional resource to be exploited. For shale gas ranges between 15 to 35%, while for shale oil are lower, in the range of 3 to 7% (EIA, 2015)

Conclusions

EIA, 2015. Technically Recoverable Shale Oil and Shale Gas Resources: Mexico. U.S. Department of Energy, 34 p.

Murillo Muñeton G., 2013. Aspectos Geológicos. Taller de Hidrocarburos en Lutitas. Gas Shale. IMP, 32 p.

References