Sidewall and Drill Cuttings Analysis

Sidewall core analysis

Petrophysical property determination of sidewall samples requires adapted laboratory techniques and procedures. PanTerra has skilled personnel available to obtain the maximum information from these small samples that are often invaded by drilling mud and can be damaged by sample acquisition.

Sidewall sample quality and test suitability
Rotary sidewall samples are drilled from the borehole. Standard tests such as Dean Stark saturation, porosimetry and permeability can be well performed. Some special core analysis tests can also be performed if a high quality sample of sufficient volume has been acquired, .
Percusion sidewall samples taken from hard rocks often shatter (fracture) when the bullet impacts on the borehole wall. This can lead to over-estimation of the measured porosity and permeability. Soft or unconsolidated rocks tend to compact on impact of the sidewall bullet, leading to under-estimation of porosity and permeability.

Available Tests:
- Dean Stark for Oil and Water Saturations.
- Porosity and Permeability for basic rock properties.
- Acid solubility determination.
- Laser Particle Size Analysis for textural information and grain size sorting data.
- Petrographic evaluation using Thin section, SEM and XRD.
- Mud invasion; Sidewall core samples can be evaluated for mud invasion prior to analysis. SEM, XRD and thin section will aid in the interpretation of the petrophysical properties and alteration by possible mud invasion and coring induced damage.
- Detailed sedimentological description.

Basic rock property results are supplied with short lead-times, enabling the client to make founded well completion decisions based on porosity, permeability, oil and water saturations.

Drill Cutting analysis

When no core or sidewall samples are available, it may still be possible to extract valuable information from drill cuttings. A microscope geologist will prepare and select drill cuttings, using a binoculair.

Mineralogical Analysis
For petrography usually a small amount of rock is sufficient for XRD/SEM/Particle size or thin section description.

Porosity and permeability
- High pressure mercury injection can be used on small core chips or drill cuttings to determine porosity, capillary pressure, pore throat size distribtion and theoretical permeability.
- Darcylog (IFP) can be used as a non-destructive method to determine porosity and permeability (SPE 77563). Permeabilities are often accurate within an order of a magnitude .