opening fundacion ypf 2014(2)

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Instructor: Dr. Carlos Torres-Verdín

Argentina, Octubre 2014

Evaluación de FormacionesConvencionales

y no Convencionales

INSTRUCTOR:

Carlos Torres-Verdín, Ph.D.Professor

Zarrow Centennial Professorship inPetroleum Engineering

Department of Petroleum and GeosystemsEngineering

The University of Texas at Austin

http://uts.cc.utexas.edu/~cefe/index2.html



Wells and Well-Logging Tools

Well Logging Tools



Well Logging Tools

Formation

Tester

6

Formation Evaluation: Key Products

• Fluid Storage (Reserves)

• Speed of Flow (Permeability)

• Uniformity of Flow (Capillary

Pressure and

Relative

Permeability)

• Production Decline with Time

• Recovery Factor

• Net‐to‐Gross



WHAT IS A WELL LOG?

8

Different Tools:

Different Physics,

Different

Volumes

of

Investigation



9

Rock Physics

• Laboratory Rock Physics

• In‐Situ Rock Physics

• Electrical conductivity, dielectric

properties, magnetic properties

• Elastic properties

• Nuclear properties

• Magnetic resonance properties

• Pressure and

fluid

flow

• Fluid properties, electrolyte diffusion

Physical contrast

enhancement

Effective‐medium

properties of porous

media

10

Heterogeneity and Upscaling

C o r e = 9 6 c m

P l u g = > 3 . 8 c m

G R =>

3 0 c m

N e u t r o n

=> 3 0 c m

S o n i c =>

1 5 ‐1 0 0 c m

I n d u c t i o n=> 3 0 ‐1 2 2 c m

R E S O L U T I O N A N D

D E P T H O F I N V

E S T I G A T I O N

N M R => 2 3 ‐ 7 6 c m

D e n s i t y=>

2 0

c m

8 cm

1.2‐3.8 cm

23 cm

23 cm

25 ‐ 228 cm

13 cm

60 cm



Interpreting a Well Log is in some ways

similar to solving a SUDOKU puzzle!!

BALANCE and CONSERVATION constraints are important!

Integrated Formation

Evaluation

COREDATA

PETROPHYSICSMEASUREMENT PHYSICS,

CHEMISTRY, and

FLUID PROPERTIES

GEOLOGY

COREDATA

PETROPHYSICSMEASUREMENT PHYSICS,

CHEMISTRY, and

FLUID PROPERTIES

GEOLOGY



Pore scaleCore plug scale

Stratum scale

Bedding scale Well logs

THE ROAD FROM THE MICRO-SCALE TO WELL LOGS …

SEM ( m)1 cm

THIN SECTIONS

CORES

6 in

6-12 in

Pore scaleCore plug scale

Stratum scaleBedding scale

Well logs

… THE ROAD FROM WELL LOGS TO THE MACRO-SCALE

CROSS-WELL (1-10 m) 6-12 in

SEISMIC DATA(10-50m)

VSP (5-15 m)



What does the trained eye see?

Resistivity Gamma

RayDensity

Porosity

Logging

Tool

The Reverse Process

Resistivity Gamma

RayDensity

Porosity



OUTCROP ANALOGUES CORE SCALE

PORE SCALE SEM SCALE



Reserves and Producibility



SOME TECHNICAL DETAILS

CONCERNING THE ORGANIZATION

OF THIS COURSE

1. Porosity, TOTAL and EFFECTIVE, e

2. Moveable Hydrocarbon Saturation, Seh

3. Thickness of Flow Units, Net Pay, Thickness (ft)

4. Areal Extent (Acreage), Area (acres)

5. Recovery Factor, R

6. Fluid Volumetric Expansion Factor at SurfaceConditions, Exp

Reserves = [ e] x [Seh] x [thickness] x [ Area] x [R] x [Exp]

Units = STB [Stock-Tank Barrels]/7,758 (Oil)

Estimation of in-Place Hydrocarbon Reserves

Key Parameters:



1. Effective Porosity

2. Irreducible Water Saturation

3. Capillary-Bound Water

4. Absolute Permeability

5. Permeability Anisotropy

6. Capillary Pressure

7. Relative Permeability

8. Wettabil ity

9. Pressure-Volume-Temperature (PVT) Fluid Properties

10.Wettability Alterations

Estimation of Reservoir Producibili ty

Key Parameters:

Remark: Most of these parameters are not available from well-logs; rock-

core measurements and fluid samples are commonly used to estimate them.

1. Quality Control of Well Logs and Rock-Core Data: ToolCalibration, Caliper, Differential Caliper, Cable Tension,Cable Speed, Temperature, Delta Density, Depth Control,Relative and Absolute Location Control, etc.

2. Assessment of Borehole Environmental Variables (Mud

Type, Mud Logs, Mud Properties, Paper-Filter Test, BitSize, Borehole Size, Temperature, etc.)

3. Environmental Corrections (and de-Corrections!),Relative Size of Environmental Corrections (Low- andHigh-Porosity Formations), and InterpretationCorrections.

4. Assessment of Mud-Filtrate Invasion and Identificationof Porous and Permeable Units

Basic Well-Log Interpretation Sequence

Sequential Steps (I):



5. Siliciclastic, Carbonate, Naturally Fractured, or MixedRock Sequence? Sedimentary Environment!

6. Assessment of Lithology and Lithology Proportions.

7. Simple Density Porosity Estimation Based on MudFiltrate.

8. Fluid Correction of Density Porosity based on NeutronPorosity; Correlation with Sonic Porosity.

9. Assessment of Archie’s Parameters: Rock-CoreMeasurements

10.Assessment of the Electr ical Resist ivi ty (SaltConcentration) of Connate Water (is it constant withdepth?)


Sequential Steps (II):

11.Assessment of In-Situ and Moveable HydrocarbonSaturation: Clean Sand Model, Shaly Sand Model(Simandoux, Dual-Water, Waxman-Smits, etc.),Carbonate Model.

12.Assessment of Effective Porosity and Effective

Hydrocarbon Saturation: Iteration between porosity andhydrocarbon saturation!

13.Calculation of In-Place Hydrocarbon Reserves.

14.Estimation of Irreducible Water Saturation and AbsolutePermeability.

15.Correlation with Rock-Core Measurements.

16.Uncertainty Analysis and Error Bounds.


Sequential Steps (III):

opening fundacion ypf 2014(2)

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