Fracture Facies: Static Fracture Distribution Model Based on Sedimentary Facies

Abstract

Abstract

Fluid flow modeling of highly heterogeneous reservoirs, both, siliciclastic (SR) and naturally fractured (NFR), requires stratigraphic and facies architecture characterization, fracture systems identification, and zonation of petrophysical parameters.

Fracture systems in reservoir modeling are usually represented as lines or planes, giving inaccurate values of petrophysical parameters, disconnecting the dynamic conceptual model from its geological controls. An alternative to characterize fracture systems, taking in account their 3D attributes, is to explore the correlation between sedimentary facies distribution and the probability distribution of fracture systems, giving rise to the fracture facies characterization.

In this work we show the static characterization of a SR analogue using outcrop data to investigate the stratigraphic architecture control over fluid flow using the probability distributions of fractures systems for each sedimentary facies association proposed. Fracture facies technique provide an independent scalar statistical framework to characterize the spatial heterogeneity of a sedimentary deposits, allowing to identify, and to quantify, rock volumes with parameters statistically similar without oversimplifying SR and NFRs heterogeneities.

Sedimentological and structural descriptions were performed on outcrops and drilling cores recovered from siliciclastic intervals of the Chicontepec Fm., sedimentary facies were logged and grouped to form facies associations, which were then complemented with their respective intensity distributions of fracture systems.

The intensity distribution of fractures was obtained with curves of cumulative fracture intensity (CFI), which allowed to determine the type of correlation (positive or negative) between the distribution of fractures and the facies which contain them. The CFI curves allow to essay models for the distribution of fractures as a function of different sedimentary facies associations.

We conclude that CFI curves are useful to identify areas with different fracture intensity values (mechanical layers), which adds to characterize the geological/petrophysical model of highly heterogeneous reservoirs.

AAPG Datapages/Search and Discovery Article #90260 © 2016 AAPG/SEG International Conference & Exhibition, Cancun, Mexico, September 6-9, 2016