REFRACT: Integrated Fractured Reservoir Modeling

Successful fracture modeling requires the integration of two components: fracture indicators available at the wells and fracture drivers, such as seismic attributes, lithology, porosity, and structural data. Most of the fracture drivers are easily derived from seismic data; thus, the inclusion of seismic attributes in fracture modeling provides a robust and efficient methodology to predict the distribution of fractures over the entire reservoir.

Prism Seismic makes this methodology easily accessible to the earth science professionals with its REFRACT software. REFRACT allows you to predict fractures away from the wellbore, utilizing and incorporating the valuable information available from a multitude of pre-stack and post-stack seismic attributes.

Unlike the DFN approach, REFRACT uses the patented Continuous Fracture Modeling (CFM) approach. The DFN methodology cannot predict fractures away from the wells, and uses the upscaling of randomly distributed discrete fracture planes to generate a “noisy” permeability tensor. Instead, the CFM approach in REFRACT uses a geocellular grid, where seismic and geologic properties are used, along with fracture indicators at the wells, to estimate the distribution of fractures and their effect on permeability and fluid flow. Fracture models derived with REFRACT have been consistently able to reproduce, without history matching, at least 80% of the well performances for any recovery mechanism, including water and gas injection. If a DFN is required, REFRACT can use the continuous fracture models to generate a constrained DFN model.

Unlike all the other fracture modeling approaches, the CFM technology available in REFRACT is proven with the drill bit on numerous fields around the world. The case studies showing the drill bit results as compared to the REFRACT forecast are available in various publications.

ReFract effortlessly adds a critical piece in the well-established reservoir modeling workflow.

REFRACT solves the fracture modeling problem by reading data from other geomodeling software such as Crystal and Petrel, and writes its output directly to simulators, such as Sensor, VIP, CMG and Eclipse, or back to the original geomodeling software. All the valuable information produced in the geophysical and geologic software can be used in REFRACT to derive extremely accurate fracture models.

REFRACT Methodology in a Nutshell:

REFRACT uses all available geological and geophysical reservoir properties that could in any way be related to fracturing. These attributes are correlated with a fracture indicator chosen at the wells using highly robust artificial intelligence tools. Prior to finding this possible relationship between a large number of potential geologic drivers and fracture intensity, the ranking and the analysis of the drivers is used to better understand what controls the fracturing.

Four types of data can be used in REFRACT to derive integrated fractured models:

	High resolution seismic attributes that could contain information about fracturing or any geologic driver related to fracturing. These seismic attributes could be derived from processes that use either pre-stack or post-stack seismic data.
	Geologic attributes that could contain information about lithology, grain size and mineral composition, lithofacies, porosity, or pore pressure. Preferably these geologic attributes are derived by using geostatistics and constrained to seismic.
	Geomechanical attributes derived from complex or simple geomechanical modeling tools that give information on current and/or paleostresses.
	Structural information providing information on faults, structural surfaces, and thicknesses. Structural slopes, curvatures, distance to faults and pseudo strains are readily available in REFRACT as drivers.

This flexibility in the use of the different types of data available for a given fractured reservoir improves the accuracy in defining the fracture origins. Hence, the REFRACT user will not depend solely on curvature or a simplistic set of seismic attributes to correlate to the fracture distribution.

REFRACT uses a stochastic approach to generate many realizations of fracture models that can be used to estimate uncertainties at undrilled locations.

REFRACT is a truly cross-platform software available on Windows, Unix, and Linux. Its user-friendly workflow simplifies learning and use of the package. Different display windows allow rapid examination of both input data as well as the resulting fracture models.

REFRACT Features:

	Unique tool for integration of high resolution seismic inversion and spectral imaging attributes, as well as geologic and dynamic data, into a fractured reservoir model.
	Intuitive, work-flow oriented, user-friendly interface facilitates the use of REFRACT
	Use of static and/or dynamic data to define a Fracture Indicator. Does not necessarily need image logs to derive a fracture model.
	Flexibility in the use of the different type of data available for the given fractured reservoir at all stages of reservoir development (from exploration to secondary recovery)
	Geomechanical analysis (curvature, strain analysis)
	Ranking of the geologic drivers to assess their importance for fracturing
	2D and 3D fracture intensity distribution over the entire reservoir
	Anisotropy volumes that help identify fracture directions and types of fractures
	Discrete Fracture Network (DFN) constrained by an integrated continuous fracture model
	Connectivity analysis using Pipe models.
	Dynamic validation of the models
	Well extraction to predict the fracture intensity distribution of new wells
	Provides an accurate way to compute and export matrix block size, shape factor and other input for dual-porosity models
	Links to other geological modeling and reservoir simulation packages

For an evaluation of the software and pricing, please contact Prism Seismic at contact@prismseismic.com.