1. Routine Core Analysis
&
Special Core Analysis
PRESENTED BY:
SHUJAUDDIN
DEPARTMENT OF PETROLEUM & NATURAL GAS
MUET SZAB CAMPUS KHAIRPUR MIR’S
2. Core analysis:
Core Analysis Can be divided into two categories:
Routine (Conventional) Core Analysis.
Special Core Analysis.
3. Routine core analysis:
The core is usually slabbed, cut lengthwise to make the structure visible. Provides information on
lithology, fluid saturation, porosity, permeability and grain density.
Routine core analysis involves the measurement of the most fundamental rock properties which are
given below:
1). Porosity (storage capacity for reservoir fluids).
2).permeability (reservoir flow capacity).
3).saturation (fluid type and content).
Above properties provide critical information in deciding whether a wellbore will be economic or
not.
4. Routine core analysis attempts to give only the very basic properties. Taken in context routine
data can provide a useful guide to well and reservoir performance, provided its limitations are
appreciated.
Routine core analysis data is cheap, and often form the great majority of the dataset
representing reservoir core data.
5. 1). Porosity:
A number of techniques are employed for the measurement of porosity in consolidated rocks.
Boyle's-law helium-expansion is a standard method for measuring either pore volume or grain
volume.
Although significant progress has been made in both CT and MRI to measure the porosity of
saturated cores, these instruments are not widely available.
Few commercial laboratories have CT capabilities and none offer MRI services. Both CT and MRI
instruments are expensive and require highly skilled operators.
6. 2). Permeability:
Routine single-phase permeability measurements are fundamental to understanding fluid flow
in porous media. Darcy's law is used to explain the relationships among the variables involved in
the flow of fluids through rocks.
Permeability can be estimated indirectly using wireline logging and pressure transient methods,
or directly with core-based techniques.
Indirect methods often prove to be unreliable.
7. 3). Fluid saturation:
Saturation is the measure of the fluid volume present in the pore volume of a porous medium.
Karl Fischer technique can be used in many cases to more accurately define water saturation.
CT and MRI are also used in fluid saturation.
8. SPECIAL CORE ANALYSIS:
• Special core analysis is a laboratory procedure for conducting flow experiments on core.
• Special core analysis separates from "routine or conventional core analysis" by adding more
experiments.
• Special Core Analysis attempts to extend the data provided by routine. SCAL data is used to
support log and well test data in gaining overall reservoir performance.
SCAL measurements are more expensive, and are commonly only done on a small selected
group of samples.
We find properties like capillary pressure, relative permeability and wettability.
9. Capillary pressure:
capillary pressure is the pressure between two immiscible fluids in a thin tube, resulting from
the interactions of forces between the fluids and solid walls of the tube.
These include the, porous-plate, mercury-injection, and water-vapor de-sorption methods.
Automated mercury-injection instruments can now attain pressures in excess of 60,000 psi for
obtaining capillary-pressure data in the low-saturation region.
10. Relative permeability & wettability:
• It is the ratio of the effective permeability to the absolute permeability.
These data are used for prediction of reservoir performance and determination of ultimate fluid
recoveries.
Wettability: It is defined as the tendency of one fluid to spread on or adhere to a solid surface in
the presence of other immiscible fluids.
Wettability is a major factor controlling the location, flow, and distribution of fluids in rocks.
11. How we retrieved core sample:
Two techniques commonly used at present.
The first is the "whole core", It is cut with a "core barrel", a hollow pipe tipped with a ring-
shaped diamond chip-studded bit that can cut a plug and bring it to the surface.
The other, cheaper, technique for obtaining samples of the formation is "Sidewall Coring".
12. Handling of core sample:
Once the core is retrieve to surface then it is important that it should remain as unchanged as
possible.
The core should be prevented from drying out, coming into contact with oxygen or being
mechanically damaged.
Core barrel is filled with resin to prevent the core from moving and to minimize the exposed
surface area.
Freezing the core in freezer containers. Core sample is wrapped in a plastic film, aluminum foil
and then dipped in molten wax.
