Petrophysical Analysis Of Reservoir Rock Of Kadanwari Gas [Autosaved]
1. Petrophysical Analysis Of
Reservoir Rock Of Kadanwari
block
By
Muhammad Ali
MS Geophysics
Project Supervisor: Prof. Dr. Mubarik Ali
Project Co-Supervisor: Mr. Abid Hussain
2. OUTLINE
1. INTRODUCTION OF THE STUDY AREA
2. OBJECTIVE
3. GEOLOGY, TECTONICS AND STRATIGRAPHY
4. DATABASE
5. METHODOLOGY
6. RESULTS
7. CONCLUSIONS
8. RECOMMENDATIONS
9. ACKNOWLEDGEMENT
3. Location Map of Study Area
The assigned study area is geographically located at 27º 01′ 00′′ to 27º 10′ 00′′ N Latitude and
69º 05′ 00′′ to 69 º 22′ 00′′ E Longitude. District Khairpur, Sindh Province of Pakistan.
4. EXPLORATION HISTORY OF THE
STUDY AREA
• The Kadanwari gas field discover in 1989 and brought on stream in
1995.
• The operator started the field operation in may 1987 with acquisition
of 2D seismic.
• The field was discover by the K-1 well which was drilled in September
1989.
• The reservoir section at Kadanwari belong to the lower Goru sand
while the sealing is provided the upper Goru shaley sequence.
5. OBJECTIVE
• Lithology identification.
• Calculate of shale volume.
• Determining the porosity of reservoirs.
• Determining the water saturation and hydrocarbon.
• Net pay thicknеss.
• Borehole geometry.
• Isochore map
• Iso-porosity map
• Iso-shale map
• Iso-water saturation map
• Net Pay map
12. Shale Volume
• Gamma ray log used to calculate of shale volume
• And also used to differentiate b/w shale and Non Shale
• Gamma ray log scale range we used 0-250 API
14. Effective Porosity
• Effective porosity is calculated by sonic log.
• Use when density log is not presented, or when dеnsity log is affected by bad hole.
• Effective porosity = total porosity – non effective porosity (shale porosity)
• Sonic porosity equation.
• PHIS = (DT - DTma) ÷ (DTfld - DTma)
• Shale porosity equation.
• PHISSH = (DTshl - DTma) ÷ (DTfld - DTma)
• After calculated porosity from both equation than we computed effective porosity from;
• PHIE_S = (PHIS - Vshl * PHISSH)
• Where
• PHIS = Sonic Porosity
• PHISSH = Shale Porosity
• PHIE_S = Effective Porosity
DTshl = interval transit time of shale
DTma = interval transit time of matrix
DT = interval transit time of formation
15.
16. WATER SATURATION
• Water saturation is the amount of water in relation to the pore space only.
• Indonesian equation:
• Where
• Sw = water saturation of formation
• Rt = True resistivity (log reading)
• Vsh = volume of shale
• Rsh = resistivity of shale (log reading)
Rw = resistvity of formation water (computed from
pickett plot)
Фe = effectivity prosity (computed from sonic log)
m = cementation factor (pickett plot)
a = Archie constant (0.68 for sandstone)
n = Saturation exponent
17. SATURATION HYDROCARBON
• Saturation Hydrocarbon
In general HC saturation is denoted by Shc. Hydrocarbon Saturation is computed by
using formula which is given below
Sg = 1-Swl (Schlumberger, 1974).
Swl = Water Saturation
• Bulk Volume of Water
Bvw = Swi *effective porosity
Where
Swi = water saturation is uninvaded zone
18. Permeability From Log
Permeability should only be calculate from log when the formation is at
irreducible water saturation . This condition can be determination using
the Bulk volume water relationship.
BVW = Sw*effective porosity
When the Bulk volume water value are constant the interval is at
irreducible saturation.
K = (79 * PHIE^3/SwIrr)^2 (For gas)
K = (250 * PHIE^3/SwIrr)^2 (For oil)
19. Net Pay
Net pay is the portion of a resеrvoir from which hydrocrbons can be produced at
economic proportions, given a particular production method (Lisa Dean 2007).
NET PAY = PHIE_S > PhiCutoff and SwI< SwCutoff and Vshl < VshCutoff
Cutoff value
Cut off value are which I applied in own zone of interest:
• Sw < 0. 5
• Vshl < 0.35
• Phie > 0.04
(Overall VSh in Lower Goru 35%)
22. Rw Calculate From Pickett Plot
No. Well name Rw m a for s.st
1 Kadanwari well-01 0.30 1.80 0.68
2 Kadanwari well-03 0.33 1.82 0.68
3 Kadanwari well-10 0.22 1.76 0.68
4 Kadanwari well-11 0.27 1.80 0.68
23. Identifying the depth of mud cake and caving zone
Lithology identification using Gamma ray log
Detect the water bearing zone Detect the hydrocarbon bearing zone
Select the zone of interest and estimate the logging parameter for interpretation
Estimate of shale
volume
Assessment the porosity
From den/neutron and
sonic log
Determination of water
from Indonesian
method
Bulk volume water
Decision making for
next exploration
work
Log Interpretation Methodology
29. Interpretation of Kadanwari Well-03
KAD WELL_03 TYPE TOP BASE THICKNESS PHIE PHIshl Vshl K Sw Sg BVW BVG HCPV
ZONE_1
GROSS 2885 2888 2.4m
11.13% 33.58% 16.22% 393.86 38.27% 61.73% 6.88% 6.88% 0.4911
PAY 2886 2888 2m
ZONE_2
GROSS 3346 3354 8.1m
7.32% 33.58% 12.92% 113.58 40.22% 59.78% 4.95% 4.95% 0.7823
PAY 3352 3354 2m
The BVW (Product of porosity and water saturation) has been estimated from Indonesia - model’s water
saturation of gas sands which ranges from 0.04 to 0.07 respectively. Detailed results of BVW are shown in
table. These values are indicating that the grain size of this reservoir sand is medium to fine and very fine,
respectively.
34. Lateral Variation of Petrophysical
Characteristics
• Shale Content Distribution Map
• Porosity Distribution Map
• Water Saturation Distribution map
• Hydrocarbon Saturation Distribution Map
• Net Pay Map
40. Conclusion
• After importing Las files on petrophysical software quality control were done on all wells,
Data for density log and neutron log is not reliable as many zones affected from borehole
irregularities (washout/breakout). The data quality is not too good so we have calculated
porosity from sonic log.
• The derived formation resistivity factors (a, m) and Sw exponent (n) from graphical method
of Pickett plot and formation water salinity had proved the reliability of the reflected
petrophysical results. The computed porosity by Sonic-Raymer model was proved as more
reliable model for the calculation of porosity for heterogeneous shaly sand reservoir where
bad hole condition present. The Density-Neutron porosity model, was alternated in there not
bad hole section present.
• The Indonesia model was used effectively to calculate water saturation for heterogeneous
shaly sand reservoirs. This technique was used effectively and widely in petrophysical
studies for the shaly sand reservoir in the Kadanwari Gas fields. B/c it gave more accurate
water saturation values in the shalier zones.
• The petrophysical analysis of kadanwari gas field revealed that the field is a prolific gas
zone. Many zones (well-01, well-03, wel-10 and well-11) were delineated and the
petrophysical parameters of these reservoirs were carefully analysed. The analysis revealed
that the reservoirs are good quality reservoir sands with average porosities ranging from 0.11
– 0.44, average water saturation ranging from 0.18 – 0.45 and hydrocarbon saturation
averaging between 0.59 – 0.86. The net/gross of the reservoir is between 0.21 – 0.47. By
contouring thickness trend is seems that the depositional strike at the time of deposition of
Lower Goru is in S-N direction in General.
41. Suggestions for Further Work
• Due to limited data and the bad quality of available data the scope of study was restricted to
basic petro physical study of reservoir, so it is highly recommended to provide more data for
the detailed analysis.
• It also recommended to drilling more wells into / for the central part of the southwestern and
south-eastern part of the study area, In the vicinity of South Kadanwari-01 well, for more
hydrocarbon production from Lower Goru, for more favourable economic conditions. It also
suggested to avoiding drilling into/for the areas of high concentrations of water saturation
north-eastern and north-western part of the area. Because the shale content increase in lower
goru formation increase at north-eastern and noth-western side.
42. Acknowledgement
I would like to express my deepest gratitude to:
• Professor Dr. Mubarik Ali (Research Supervisor , HOD E & ES )
• Mr. Abid Hussain ( Research Co-Supervisor , Senior Geologist at Ppl)
