Rock Typing

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Rock Typing is a technique used to predict thespatial distribution of petrophysical parameterssuch as porosity, permeability and saturation, on afield-wide level.

We have divided our Rock Typing Workflow intothree main components:

  Flow Unit Characterization

  Dynamic Validation and Prediction

  Field Development Application

Within each particular area, a number of specificdeliverables will be provided.

Flow Unit Characterization

There are several steps to encompass thecomprehensive review of rock characteristics thatare critical to fluid flow:

  Data QC focuses on gathering all available dataand information within a geomechanical unitthat is relevant to gain a full understanding ofrock static and dynamic behavior differentiation;

  Hydraulic Rock Types (HRT) quantify thephysical flow and storage properties of therocks from core analysis relative to native fluids,as controlled by grain size/pore throatdimensions, geometry and the distribution ofcurrent pore and pore throat structures, using amodified Lorenz plot;

  Depositional Rock Types (DRT) are derivedfrom core descriptions (and/or boreholeimages) of genetic units, according tosimilarities in rock composition, texture,sedimentary structure, fracture distribution, andstratigraphic sequences as influenced by thedepositional environment.

  Petrographic Rock Types (PRT) are describedbased upon criteria of pore-scale microscopicimaging (i.e. SEM) of pore structure, rocktexture, clay mineralogy, and diagenesis.

Modified Lorenz Plot to Delineate Hydraulic Rock Types

Hydraulic Rock Types Differentiation on Core Samples

Correlate Depositional Rock Types to Flow Behaviors

Identify Petrographic Characteristics related to DynamicFlow Behavior

 

 

Bringing Visions to the Surface  

Dynamic Validation and Prediction

Identified Rock Type characteristics are validatedagainst (or to predict) dynamic flow behaviors, e.g.rate transient analysis (RTA), pressure transientanalysis (PTA) and production logs. In this phase,the focus of the evaluation process is placed uponthe consistency of Rock Types and dynamicphenomena. Not only do we always find greatcorrelation between identified rock types withdynamic behavior, but also the value of RockTyping drastically increases as a simple yet usefultool for realistic applications to diagnose or optimizea field development plan.

The highest quality rock (Rock Type #4) is consistentwith observed high productivity index.

Predict rock types using BHI and OH logs with andwithout core data. The prediction successfully explainsa production log behavior (see below) that wasotherwise unclear to the operator. 

Predicted rock types explained clearly the productiondiscrepancy in two clean sandy turbidite intervals.

Field Development Application

The ultimate objective in Rock Typing is to guideoptimized drilling, completion and stimulationoperations, to reach a successful technical andeconomic development of the fields of interests. Toachieve the desired goals, Rock Typing can haveseveral applications, to name a few:

  Production Mechanism Diagnosis

  Sweet Spot Identification

  Facilitating Static Modeling

  Evaluating Leverett J Function for CapillaryPressure and Relative Permeability Modeling

The aggregation of high quality rock is determined from primary porosity (DRT) and the diagenetic process andtectonic events (PRT) that are consistent with flowbehavior and HRT. This defines sweet spot allocations.

The established relationships between depositionalenvironment, rock composition and mechanicalboundaries are very important for controlling staticmodel propagation, in addition to maintainingdynamic validity ultimately leading to a realistic andrepresentative optimized field development plan.

Fronterra Geosciences is a global

independent provider of industry

leading, integrated geoscience

solutions, from single well analysis to

complete reservoir studies.

Some tasks described herein may be

 performed by one or more associates.