Boon Ee Juan Report of Visit to Petronas Research Sdn Bhd For Geochemistry Subject, QAB2013 Prepared by, Name: BOON EE JUAN Student ID: 12542 Program: Petroleum Geoscience This report is intended to review the use of materials, apparatus, and analysis machines to do analyses on the source rock sample. To carry out the analyses until the final conclusion is made, they involve the preparations of rock samples, the methodologies to conduct the lab, and the interpretation of analyses results. In this report, every lab works will be discussed part by part, from preparation of sample to the expected result and interpretation. Soxhlet Extraction The objective of this lab is to extract the bitumen from the source rock. Material: Source rock sample, copper granule, Ageothropic solvent (93% Dichloromethane, 7% Methanol), and anti-bumping granules Apparatus: Soxhlet extractor, grinder, 180 micron size sieve, cellulose thimble, and rotary evaporator Methodology: 1. The source rock sample is crushed into powder form using grinder. 2. The powder is sieved using 180 micron size sieve. 3. This powder is placed inside the cellulose thimble and loaded into the main chamber of the Soxhlet extractor. 4. Soxhlet extractor comprises of 3 main parts: the flask; the Soxhlet main chamber with distillation arm, cellulose thimble and siphon; the condenser. 5. The flask is filled with Ageothropic solvent with volume 3 to 4 times the volume of the Soxhlet chamber, copper granule, and anti-bumping granules.
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Boon Ee Juan
Report of Visit to Petronas Research Sdn Bhd
For Geochemistry Subject, QAB2013
Prepared by,
Name: BOON EE JUAN
Student ID: 12542
Program: Petroleum Geoscience
This report is intended to review the use of materials, apparatus, and analysis machines to do analyses
on the source rock sample. To carry out the analyses until the final conclusion is made, they involve the
preparations of rock samples, the methodologies to conduct the lab, and the interpretation of analyses
results. In this report, every lab works will be discussed part by part, from preparation of sample to the
expected result and interpretation.
Soxhlet Extraction
The objective of this lab is to extract the bitumen from the source rock.
Material: Source rock sample, copper granule, Ageothropic solvent (93%
Dichloromethane, 7% Methanol), and anti-bumping granules
as mobile phase to transport the vaporized component compounds through the capillary
column.
4. The wall of the capillary column is coated with different stationary phase.
5. When the vaporized component compounds or gas stream flow through the capillary column,
they will interact with the stationary phase on the wall of the column. Different component
compounds interact differently with different stationary phase based on the strength of
absorption and in this process, they are separated. Thus, various component compounds will
elute at a different time and this is known as the retention time that can be qualitatively used
to recognise the component compounds.
6. The exit of the gas stream is monitored by a detector where the retention time and the
quantity of the component compounds can be determined. The most commonly used detector
is the flame ionization detector (FID) and the thermal conductivity detector (TCD).
7. GC can provide a result call gas chromatogram. The Y-axis shows the intensity whereas the X-
axis shows the retention time of the component compounds. Each peaks show different
component compounds eluting at different time with different intensity.
8. The processes are repeated again for extracted liquid aromatic compound.
Methodology of Mass Spectrometer (MS):
1. Straight after the ejection of component compounds from GC, they are re-injected into the vacuum chamber of MS where they are impacted with electron beam.
2. The electron beam ionized the component compounds and breaking them into ionized molecule fragments with mass to charge ratio m/z. This m/z is the characteristic of the molecule fragments. If the charge is fixed, then the m/z could be represented by the mass.
3. The quadrupole mass spectrometer is the detector of the m/z. It functions using 2 pairs of electrically charged poles that will drive and focus the ionized molecular fragments into the detector.
4. Since the charge of the ionized molecule fragments are fixed, the mass of them would affect the different in their acceleration and momentum when driven by the quadrapoles’ electric field. Thus, their mass spectra could be obtained.
5. MS can provide a result call mass spectra. The Y-axis shows the intensity whereas the X-axis shows the m/z ratio. Each peaks show different molecular fragments with different mass. A series of spectrum would be obtained for each separated component compounds in the aromatic and aliphatic after the GC.
Vitrinite Reflectance
The objective of this lab is to use the Vitrinite Reflectance (Vro) to measure the thermal maturity of source rock. The source rock can be an organic rich shale or coal. The present of macerals in the organic rich source rock such as Liptinite, Vitrinite and Inertinite can all be used to measure the thermal maturity of source rock by measuring their reflectance under the photometer microscope but Vitrinite is normally been used. This is because Vitrinite is not strongly prone to oil and gas formation. It is common as a residue in source rocks which spans from a wide range of depth and temperature. It is always present and not drastically reduces because of its oil and gas generation. Thus, it can be found within the whole range of maturity of source rock and using its different reflectance in different maturity to indicate the maturity. Like Liptinite which is oil prone, will generate oil in oil window and then drastically reduce in quantity after it is approaching to the end of oil window. Thus, the maturity of the source rock after that cannot be determined because the liptinite is very less or nearly disappear after the maturity of generating oil. In this case, Vitrinite presence is quite constant. Inertinite is seldom been used because it is present in post-maturity source rock which we are not interested. The review of Vitrinite evolution and changing of reflectance As the source rock is being buried deeper and deeper, the temperature is higher and higher and the time where the kerogen splits into its four distinctive types is called Carbonization Jump. At here, the organic compounds undergo reordering and become aligned parallel to the bedding. The Vitrinite has become dense Vitrinite. The source rock is continuing being buried deeper and temperature increases. The chemical composition of the Vitrinite will correspondingly alter, increasing the reflectivity of Vitrinite. Therefore, the percentage reflection of a beam of normal incident white light from the surface of a polished Vitrinite is a function of the maturity of the maceral and source rock.Thus, at different depth and temperature, the Vitrinite reflectance is different and from the Vitrinite
Figure 5: Mass spectra
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reflectance, the maturity is measured. The vitrinite reflectance value, Vro for oil window is 0.5; Vro for gas window is 1.2. Comparison Kerogen types are determined by the Von Krevelin graph or hydrogen index (HI) against oxygen index (OI) graph which both the indexes can be measured using Rock Eval. Without using Rock Eval, we can also predict the kerogen types by looking at the macerals in the source rock. The presence of liptinite which is oil prone is corresponding to the kerogen type I and II; Vitrinite which is oil and gas prone is corresponding to the kerogen type III; Inertinite which is non-hydrocarbon producing is corresponding to the kerogen type IV. Material: Source rock, resin, and hardener
Apparatus: Grinder, sieve, polish machine, and photometer microscope
Methodology:
1. The source rock is crushed into fine powder using grinder and then sieved. 2. The powdered source rock will then be mounted into a cylinder shape by using resin and
hardener. 3. This resin block is grounded and polished to a high standard. Poor polishing will lead to spurious
reflection measurements. 4. The photometer microscope is calibrated using sapphire or garnet. 5. The polished resin block is then inspected under the photometer microscope to measure the
Vitrinite reflectance. Normally 30 to 100 vitrinite measurements are taken. 6. The vitrinite reflectance value, Vro can be used to find the depth of oil and gas windows,
igneous intrusion, unconformity and structural deformation such as fault. All these can be found using the Log Vro against depth graph.
LECO – Multiphase Carbon Determinator The objective of this lab is to find the Total Organic Carbon (TOC) of the source rock. Material: Grain size source rock Apparatus: Weight balance and quartz boat Methodology:
1. The source rock is crushed into small grain size. 2. 0.5gram of the crushed source rock is weighed using weight balance and then transferred onto
the quartz boat. 3. At first the machine is being run without a sample to burn out moisture and possible carbon-
bearing phase presents.
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4. A calibration for carbon dioxide, CO2 and moisture, H2O is done with corresponding standards using mixture of calcite and gypsum.
5. Then, the loaded quartz boat is inserted into the combustion tube. 6. The furnace control system can control the temperature to be stepped and subjected to
ramping. Since various sources of carbon oxidize, decompose or turn into volatiles in different temperature, the temperature profile is completely programmable into 10 different phases. Just set the starting temperature, end temperature, ramping rate and the amount of time to hold at the ending temperature for each of the phases selected.
7. For analysing TOC, the source rock is normally heated from 350oC to 950oC. (This machine can heat up to 2000oC.)
8. The source rock is combusted using oxygen. Its organic compound and hydrocarbons content are cracked and oxidized to release carbon dioxide, CO2 and moisture, H2O. The CO2 and H2O are then measures using Infrared absorption cells detector. The presence of organic carbon may be verified by finding coincident peaks in H2O and CO2.
9. After that, the source rock is ignited in an inert N2 atmosphere with the afterburner and oxidation catalysts at 120oC. In here, only moisture and carbonate will be detected but not the organic carbon.
10. The result is printed out showing the TOC, moisture and carbonate value. 11. When the analysis is completed, the source rock is removed from the combustion tube.
Rock-Eval Pyrolyzer
The objective of this lab is to identify the potential source rock by using the S1, S2 and S3 peak of the Rock Eval analysis. The Rock-Eval Pyrolyzer is actually running a test to determine the bitumen or hydrocarbon that is readily present in the source rock (S1); cracking the kerogen in the source rock to produce hydrocarbon (S2); carbon dioxide, CO2 in (S3) is used to calculate the amount of oxygen readily present in the source rock. The hydrocarbon index (HI), oxygen index (OI) and production index (PI) can be calculated using S1, S2, S3 and TOC. These indexes will then be used to identify the kerogen type in the source rock. Material: Grain size source rock Apparatus: Weight balance Methodology:
1. The source rock is crushed into small grain size.
2. 60mg of the crushed source rock is weighed using weight balance.
3. The crushed source rock is inserted into the Rock-Eval Pyrolyzer.
4. The crushed source rock is heated in the inert atmosphere with helium.
5. The pyrolysis oven heated and kept isothermally at 300°C for 3 minutes.
6. The free hydrocarbons are volatilized, detected by flame ionization detector (FID) and
measured as the S1 peak.
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7. The temperature is then increased from 300° to 600°C at the rate of 25°C/min. This is the phase
of volatilization of the very heavy hydrocarbons compounds (>C40) as well as the cracking of
nonvolatile organic matter. The hydrocarbons released from this thermal cracking are
measured as the S2 peak by flame ionization detector (FID). The temperature at which S2
reaches its maximum depends on the nature and maturity of the kerogen and is called Tmax.
8. The CO2 escaped from the kerogen cracking is trapped in the 300°-390°C range. This trap is
heated and the CO2 is released and detected by thermal conductivity detector (TCD) as S3 peak
during the cooling of the pyrolysis oven.
9. The S1, S2 and S3 result is printed out.
10. If S1 is lower and S2 is higher peak, this indicate the rock sample is not yet thermally mature
enough to produce hydrocarbon but has the potential to be a source rock.
11. The hydrocarbon index (HI),
1. Oxygen index (OI),
2. Production index (PI),
3. Kerogen types are determined by the Von Krevelin graph or hydrogen index (HI) against oxygen