The geological sample preparation laboratories of the Libyan Petroleum Institute (LPI) have good experience in achieving different service activities that include:
The geological sample preparation laboratories of the Libyan Petroleum Institute (LPI) have good experience in handling cores of various sizes and lengths. Core samples are usually shipped directly from the drilling rig to our laboratory facility, normally in 1m (3 feet) lengths. Recently most of the cored samples are preserved in aluminum barrels. The geological sample preparation laboratories are equipped with experienced staff and heavy duty cutting machines to remove the external metallic barrels.
After the extraction of the inner barrels, the cored rocks are washed to remove any sticking dirties such as drilling muds. Next to that the cores are labeled with two parallel lines following the core marking procedures found in an old Exxon/Esso Well site manual.
Gamma ray logging is a method of using natural gamma radiation to characterize the rock or sediment core samples recovered from drilled wells from different fields in oil- and gas-well drilling. All rocks contains natural radioactivity (natural Gamma-rays). The most common sources of natural Gamma-rays are Potassium, Thorium, and Uranium. The Spectral core gamma instrument which is used in the LPI to determine the quantity of various isotopes in the core is Core Spectral Gamma-Ray Unit Model SGR-2003, made by Corex-UK. A conveyor carries the core through a lead tunnel to reduce the background radiation level, past a scintillation detector, which produces an output when gamma rays are incident upon it.
A "slabbed" core is simply a core that is sawn down the middle by a powerful rock saw. Cutting the fresh, flat, surface allows the geologists and petroleum engineers to see things in the core much more clearly. They are usually looking for indicators that will tell them what environment the rock was formed in, such a beach, a sand bar, or a river system. They will also note grain sizes, small fossils, and burrows caused by worms or other marine life. They will look very closely for the presence of oil in the rock or any hint of gas bubbles. Core slabbing is one of the services that can be done in the geologic laboratories of the Libyan Petroleum Institute.
Photography serves are available at the geologic laboratories of the Libyan Petroleum Institute as a permanent record of core sections and is most useful for presentations and detailed geological studies. Core can be photographed in a large variety of formats and under either white or ultraviolet (UV) light. UV photography highlights the oil in core sections and is therefore a useful tool in reservoir evaluation. Typically, slabbed core sections are photographed under white light as well as under ultra violet light to capture the oil (if present) fluorescence. Digitized images of the core can be stored on photo CDs as a substitute for a hard copy of the core photography or negatives, which will deteriorate over time. These images have the added advantage of being able to be transferred electronically and enlarged to zoom in on minute details.
A thin section is a hair-thin slice of rock, mounted on a microscope slide. Making high quality thin section is one of the services the geologic laboratories of the Libyan Petroleum Institute can provide. The geological sample preparation laboratories are equipped with experienced staff and with state-of-the-art equipments for cutting a slice from samples (hand samples, cuttings or loose sediments) with a diamond saw, an iron lap wheel and vacuum ovens.
Sample processing is a basic, but critical step. For reliable results, high standards must be maintained at the processing stage. LPI goal is to provide the highest quality custom sample processing. The available services include:
Within geology accurate grain size analyses are required for petrophysical studies which relate sandy texture to porosity and permeability. The distribution of sediment for water wells also requires a detailed knowledge of the sediment of aquifers. Grain size analysis data can be used as an interpretive tool to determine the depositional environment of ancient sediments. We can determine size distributions by the classical way to determine the size distribution of particles (sieve analysis). At the geologic laboratories of the Libyan Petroleum Institute this can be done with a large variety of sieves. The results of these analyses are applicable for:
Samples are taken at either selected locations or fixed intervals. They are subsequently used for a wide variety of analyses performed to determine physical, chemical and geological parameters important for the assessment of potential oil and gas fields. Plugs of standard length and diameter are taken either “horizontal” (perpendicular to the core axis and parallel to the inclination) or “vertical” (parallel to the core axis). These plugs are obtained by drilling cylinders from the core using lubricants such as water, brine or oil and trimming the ends of the cylinders. Standard plugs are used for the determination of oil and water saturation, porosity, permeability and grain density measurements (at ambient pressure or at higher pressures to mimic sub-surface conditions) and for a variety of Special Core Analysis tests.
Whole core scanning and logging
The Chemostratigraphy equipment is one of the latest equipments installed in the on campus of the Libyan Petroleum Institute.