Reservoir Rock Laboratory Course (1st Ed.)

1. About This Course

2. Course Learning Outcome

3. Presentation and assessmentA. Class Projects (CLS PRJ)

4. Laboratory related issues

5. Review of Syllabus

6. Resources

7. Training Outline (beta)

8. Communication

1. Petrophysics

2. Coring and Plugging

Petrophysics definition

Petrophysics (from the Greek petra, "rock" and physis, "nature") is the study of physical and chemical rock properties and their

interactions with fluids.

A major application of petrophysics is in studying reservoirs for the hydrocarbon industry. Petrophysicists are employed

to help reservoir engineers and geoscientists understand the rock properties of the reservoir, particularly how pores in the subsurface are interconnected,

controlling the accumulation and migration of hydrocarbons.

Some of the key properties studied in petrophysics are lithology, porosity, water saturation, permeability and density.

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 5

key aspect of petrophysics

A key aspect of petrophysics is measuring and evaluating these rock properties by acquiring well log measurements - in which a string of

measurement tools are inserted in the borehole,

core measurements - in which rock samples are retrieved from subsurface, and

seismic measurements.

These studies are then combined with geological and geophysical studies and reservoir engineering to give a complete picture of the reservoir.

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 6

Categories of measured properties

While most petrophysicists work in the hydrocarbon industry, some also work in the mining and water resource industries.

The properties measured or computed fall into three broad categories: conventional (or reservoir) petrophysical properties,

Reservoir models are built upon their measured and derived properties to estimate the amount of hydrocarbon present in the reservoir, the rate at which that hydrocarbon can be produced to the Earth’s surface.

rock mechanical properties, and

ore quality

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 7

conventional (or reservoir) petrophysical properties,Lithology: rock's physical characteristics:

grain size, composition and texture and etc.By using log measurements,

such as natural gamma, neutron, density and resistivity

Porosity: from neutrons or by gamma rays, also sonic and NMR logging.

Water saturation: from an instrument that measures the resistivity of the rock

Permeability: From Formation testing, and empirical relationships with

other measurements such as porosity, NMR and sonic logging.

“Net Pay”

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 8

Rock mechanical properties

Some petrophysicists use acoustic and density measurements of rocks to compute their mechanical properties and strength. They measure the compressional (P) wave velocity of

sound through the rock and the shear (S) wave velocity and use these with the density of the rock to compute the rocks' compressive strengthThese measurements are useful to design programs to drill

wells that produce oil and gas.

also used to design dams, roads, foundations for buildings,

They can also be used to help interpret seismic signals from the Earth, either man-made seismic signals or those from earthquakes.

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 9

Methods of analysis

Coring and core analysis is a direct measurement of petrophysical properties. In the petroleum industry rock samples are retrieved

from subsurface and measured by core labs of oil company or some commercial core measurement service companies. This process is time consuming and expensive, thus cannot be

applied to all the wells drilled in a field.

Well Logging is used as a relatively inexpensive method to obtain petrophysical properties downhole. Measurement tools are conveyed downhole using either

wireline or LWD method.

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 10

major sources of petrophysical propertiesKnowledge of petrophysical and hydrodynamic

properties of reservoir rocks are of fundamental importance to the petroleum engineer. These data are obtained from two major sources:

core analysis and well logging. In this course we present some details about the analysis of

cores and review the nature and quality of the information that can be deduced from cores.

Cores are obtained during the drilling of a well by replacing the drill bit with a diamond core bit and a core barrel. The core barrel is basically a hollow pipe receiving the

continuous rock cylinder, and the rock is inside the core barrel when brought to surface.

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 12

Coring

Continuous mechanical coring is a costly procedure due to:The drill string must be pulled out of the hole to replace the

normal bit by core bit and core barrel.The coring operation itself is slow.The recovery of rocks drilled is not complete.A single core is usually not more than 9 m long, so extra trips

out of hole are required.

Coring should therefore be detailed programmed, especially in production wells.

In an exploration well the coring cannot always be accurately planned due to lack of knowledge about the rock.

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 13

sidewall coring

Now and then there is a need for sample in an already drilled interval, and then sidewall coring can be applied. In sidewall coring a wireline-conveyed core gun is used,

where a hollow cylindrical “bullet” is fired in to the wall of the hole.

These plugs are small and usually not very valuable for reservoir engineers.

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 14

The fluid content of the core

During drilling, the core becomes contaminated with drilling mud filtrate and the reduction of pressure and temperature while bringing the core to surface results in gas dissolution and further expansion of fluids.

The fluid content of the core observed on the surface cannot be used as a quantitative measure of saturation of oil, gas and water in the reservoir. However, if water based mud is used the presence of oil

in the core indicates that the rock information is oil bearing.

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 15

routine core analysis

When the core arrives in the laboratory plugs are usually drilled 20-30 cm apart throughout the

reservoir interval .

All these plugs are analyzed with respect to porosity, permeability, saturation and lithology. This analysis is usually called routine core analysis.

The results from routine core analysis are used in interpretation and evaluation of the reservoir.

Summer 14 H. AlamiNia Reservoir Rock Laboratory Course (1st Ed.) 16

1. “Petrophysics.” Wikipedia, the free encyclopedia 13 July 2014. Wikipedia. Web. 22 July 2014.

2. (KSU) M. Kinawy. “Reservoir engineering laboratory manual" Petroleum and Natural Gas Engineering Department, King Saud University, Riyadh (2009).

1. Without Distillation methods

2. Soxhlet Extraction method

3. Dean-Stark Distillation-Extraction

4. Conclusions and Recommendations