MACC Analysis: Reservoir Characterisation Using Drill Cuttings

There is an ever-present and ongoing need to better define, characterise and quiantify exploration opportunities and producing reservoirs. That's why, for more than 15 years, our techonlogy partner, HOT Engineering has been succesfully 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.

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.