MACC Analysis
Reservoir Characterisation Using Drill Cuttings

There is an ever-present and ongoing need to better define, characterise and quantify exploration opportunities and producing reservoirs.

That’s why, for more than 15 years, HOT has been successfully integrating all of our clients’ engineering, wireline, seismic and rock-based data – including cuttings – in clastic, carbonate and volcanoclastic reservoirs. As core is relatively rare and cuttings are ubiquitous, HOT uses a semi-quantitative, microscopic technique called MACC (Microscopic Analysis of Core and Cuttings), also known as Drill Cuttings Analysis, to describe rock and pore characteristics and classify the drilled section into permeability classes.

“Drill cuttings provide a continuous, independent
and relatively inexpensive data source.”

Sharon Tiainen
Senior Reservoir Geologist, HOT

Discover Your Bonanza of Data

The ideal data set includes enough representative conventional core data for us to directly derive our geological model. In conjunction, wireline, seismic, and engineering data are used to develop and constrain our petrophysical, geophysical, and dynamic reservoir models.

However, for many reasons geological data sets may be somewhat lacking. That’s when uncertainty can creep into static and ultimately into dynamic models. To help manage this uncertainty we can substitute in drill cuttings.

From stored and perhaps forgotten drill cuttings lies a potential bonanza of data. Using MACC (Microscopic Analysis of Core and Cuttings), a technique described as ‘a visual method of semi-quantitatively describing rock and pore characteristics from either core or cuttings using a stereo, reflected-light, binocular microscope’ key characteristics such as lithology, grain size, sorting, framework components and cement types can be determined. By carefully observing these and other rock properties a relatively rich and importantly continuous data set can be generated and used for the interpretation of porosity and permeability, the identification of correlative surfaces, the interpretation of depositional environments and to develop geological models.

Drill Cuttings_1

But do Drill Cuttings Provide Reliable Estimates for Permeability?

Our permeability estimates assign the sample to a permeability class or rock type that corresponds with an ambient value range and a geomean in millidarcies (Fig. 1).
Published data shows a strong correlation with production and test derived kh (Fig. 2).

Permeability classes_Production_DSTkh vs MACC

A comparison of microscopically determined estimates of permeability (MACC) to those derived from drill stem test (DST) and routine core analysis (RCA) data
has shown that MACC is a valid and alternative means of accurately estimating permeability (Fig. 3).

Hot Comparison of MACC Diagramm

MACC allows you to unlock your understanding away from core control as drill cuttings contain a wealth of critical information. You can verify your petrophysics, augment core-based porosity-permeability data sets and reduce uncertainty on your geological models. Additionally, the following characteristics can be determined:

Bioturbation and hard-ground

Hard-grounds (exposure surfaces), bioturbation and rare coarse grains interpreted as being deposited in a paralic setting

Carbonate porosity types

Inter and intra granular and vug porosity in dolomite

Low and high energy environments

Changes in grainsize, framework content and sorting differentiate depositional environments: e.g. floodplain and fluvial channel

High-quality reservoirs (>100mD ambient)

Clastic and carbonate with visible connected marco porosity

Natural fractures

Presence of open natural fractures indicated by growth of quartz crystals

Poor-quality reservoirs (<1mD ambient)

Clastic and carbonate with negligible visible porosity

FIGURE-bioturbation-and-hardground
FIGURE-carbonate-porosity-types
FIGURE-high-energy
FIGURE-low-energy
FIGURE-high-quality-clastic
FIGURE-high-quality-carbonate
FIGURE-natural-fractures-1
FIGURE-low-quality-clastic
FIGURE-low-quality-carbonate

MACC Applications

Geology and Geophysics

  • Sequence Stratigraphy
  • Facies Analysis
  • Natural fracture detection
  • Reservoir quality
  • Diagenetic interpretation
  • Geological model development

Engineering

  • K and kh determination
  • Can calibrate to in-situ with well tests
  • Identify by-passed pay
  • Fracture stimulation design
  • Perforation planning
  • Flow rate prediction

Petrophysics

  • Porosity and permeability estimation
  • Rock properties such as m
  • Log calibration
  • Pseudo core data
  • Gas or fluid detection

Drilling

  • Calling drill stem test
  • Determining core point
  • Case or abandon decision
  • Log substitute
  • Can be acquired real time

HOT Engineering GmbH   Tel: +43 3842 43 0 53-0   Fax +43 3842 43 0 53-1   hot@hoteng.com