Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 1
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Quad Neutron Measurement –Seligi Experience
EQ Petroleum Developments, Sdn. Bhd
Presenter: W A Manan
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 2
• Introduction
• Concept of the technology
• Effect of reservoir fluids on the measurement
• Quad Neutron Log output
• Interpretation
• Log examples
• Application of the technology
• Limitations
Agenda:
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 3
Low salinity formation water, deep borehole fluid invasion in high water cut wells,oil smeared into gas zones and cross flow between reservoirs pose problems influid contacts monitoring in Seligi Field using conventional pulsed neutron loggingtools.
Introduction.
Structural Cross-Section – Tinggi to Seligi Central & South Culminations
A A’
L-10
GH
B
E
TINGGI
A
DCF
A’
A
Location Map
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 4
Thru pipe thermal neutron and gamma activation measurement and compensation are used, to overcame limitations in conventional pulse neutron technology in measuring reservoir properties (PHIT, Sw, Fluid Type). Porosity are estimated using different 4 different approaches and the differences between them are used, using overlay technique to identify fluid type and oil saturation, Oil/Water differentiation is less sensitive to formation water salinity.
Concept of the technology:Quad Neutron Logging
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 5
Effect of Oil Api and Salinity on NN & NG.
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 6
i. Porosity:
Calculate porosity using 4 different approaches
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Quad Neutron Log Output.
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 7
Quad Neutron Log output :
ii. Relative Bulk Density (CE)
Calculated from NN and NG interaction of long and short spacing - and used to correct QL
for saturation calculation and gas flagging
iii. Quad Clay – is based on Gr emitted by Aluminium as result of Neutron activation in the measured
volume. Is used to calculate VSH, Effective porosity
iv. Saturation – Calculated from overlay between QTP and QL
Quad Neutron Log Output.
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 8
Fluid Types identification
Utilize overlay technique and different sensitivities of computed porosity to identify fluid types.
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 9
Validation of Roke (Perforating): Se-D21, K20
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 10
Validation of Roke (Consistency)
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 11
Important: Integration with other information is important in cased hole log interpretation to avoid error in the interpretation
Well integrity – Cross flow behind casing, additional information to reservoir management.
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 12
Important: To provide all the relevant well information: correct completion
diagram and reservoir fluid properties to avoid error in the
interpretation.
reservoir information
Processing input parameters
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 13
The Results
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Applications of the technology
Quad Neutron Logging – Seligi Experience;Division – EQ Petroleum Development MalaysiaW A Manan ©Petroliam Nasional Berhad (PETRONAS) 2014 14
• Annulus between the tool and tubing/casing must be liquid field.
• Depth of investigation is between 2 to 3 ft. In deep borehole fluid invasion.
i.e., high water cut wells, readings will be affected by invading borehole fluid.
• Erratic readings in poor quality rocks, occasionally indicate oil in shale.
• Good for Qualitative interpretation, OWC and GWC. Probably large error in So
estimation.
• Affected by borehole quality: poor cement quality, large washout complicate borehole correction calculation.
• Fluid properties (water salinity and oil API) affect the interpretation. Logging objectives and reservoir fluid information need to be provided during planning
stage.
Limitations
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