A description of the different reservoir rock samples for lab analysis.

2. RESERVOIR Rock Core
Samples
Yani Carolina Araujo

3. • Introduction: The reservoir
• Types of rock samples
• Drilling cuts
• Wall
• Core
• Coring process
• Core preservation
• Core preparation for laboratory
analysis
• Why we need rock samples?
CONTENT
“Any fool can know. The point is to understand.”
Albert Einstein

4. THE RESERVOIR
A petroleum reservoir, or oil and gas reservoir, is a subsurface container
of hydrocarbons confined in porous or fractured rock formations.
Reservoir
Rock
Impermeable
Rock
“Cap Rock”
Sedimentary Rock:
Sandstone
Carbonates

5. http://bc.outcrop.org/GEOL_B10/lecture13.html
Overburden Pressure (Confining or Lithostatic)
is the pressure or stress imposed on a layer of
rock by the weight of overlying material.
This pressure exerts pressure on both the grains
and pore fluids.
Formation pressure is the pressure of the fluid within the pore spaces of the rock.
THE RESERVOIR
Hydrostatic Pressure is the total fluid pressure created
by the weight of a column of fluid, acting on any given
point in a well.

6. Well Logs
WELL LOGS

7. Coring
Intervals
DEFINING THE CORING AREA

8. TYPES OF CORE SAMPLES
Drilling
Cuttings
SidewallSamples
SamplesforReservoirStudies
Broken bits of solid material
removed from a drilled borehole
Percussion:
 A gun assembly shooting hollow bullets
across mud into the formation
 Bullets designed for hard or soft rock
 Must be shot from bottom up to avoid
cutting cables holding bullets already
shot
Rotary:
 The rotary sidewall tool uses a small robotic core
bit to bore a core sideways into the formation.
 The core is then loose and withdrawn into the
main coring tool where the plug is retrieved and
stored. Then the tool is moved to another spot in
the hole, and the robotic bit is again extended
and used to take another core.

9. TYPES OF CORE SAMPLES
Samples for Reservoir
Studies
Core
Samples
 Obtained by drilling with special drills
into the reservoir with a
hollow steel tube called a core drill.
 The hole made for the core sample is
called the "core hole".
 A variety of core samplers exist to
sample different media under different
conditions.
 In the coring process, the sample is
pushed more or less intact into the
tube. Removed from the tube in the
laboratory, it is inspected and analyzed
by different techniques and equipment
depending on the type of data desired.
 A cylindrical section of rock from a specific
well depth
 Core preserves it’s geological structure and
physicochemical characteristics

10. CORING PROCESS

11. CORE PRESERVATION
Wax Preservation Other Methods:
Foam
Dry Ice
Steel Tube

12. CORE PREPARATION
Source: J. B. Martell Andrade, Desarrollo de la Evaluación
Petrofísica en México y su Futuro a través de la UNAM

13. WHY ROCK SAMPLES?
Rock cores are the only representative element of the reservoir rock that are physically
available for examination and modeling for basic flow processes