Mud Gas Analysis in Formation Evaluation

Weatherford Surface Logging Systems SPE talk: Mud gas analysis in formation evaluation Giovanni N. Pinna 1st of November 2012, Geneva - Switzerland

Mud gas analysis in formation evaluation

DEFINITIONS: MUD

GAS CONSISTS OF HYDROCARBON AND NON HYDROCARBON VOLATILE

MOLECULES THAT CAN BE EXTRACTED FROM THE DRILLING MUD.

THE

COMPOSITIONAL ANALYSIS OF GASES PRESENT IN DRILLING FLUIDS AT

SURFACE REFLECTS THE FLUID PHASE OF THE RESERVOIRS AND PROVIDES IMPORTANT INDICATIONS ABOUT THE PETROPHYSICAL CHARACTERISTICS OF THE DRILLED ROCKS.

© 2008 Weatherford. All rights reserved.

Mud gas analysis in formation evaluation WHY IS MUD GAS LOG AS IMPORTANT AS OTHER LOGS? Fluid ID

Complex reservoirs multi reservoirs.

Fractured and vuggy reservoirs.

High pressure zone/fluid ID

GOC, GWC, OWC

Green sands with low resistivity.

Low resistivity pay sands (conductive minerals or diagenetic clays with high CEC).

Casing points

Compartmentalisation

Immature sandstones rich in radioactive minerals.

Tuffaceous sandstones with complex composition.

Picking up coring points

Optimizing mini DST and DST

High CO2 content

Igneous reservoirs where hydrocarbon reserves are trapped in fractures.

Optimizing completion

Optimizing downhole sampling

Unknown water salinity, unknown m and n values.

Tight gas sandstones

Shale plays


Mud gas analysis in formation evaluation COST VS INFORMATION (VALUE)

10%

100%

85%

80% 60% 40%

10%

20%

90%

0%

5% Logging Drilling Geophysical Survey

Logging Coring/Cuttings

LOGGING REPRESENTS ON AVERAGE 10% OF THE WELL COST BUT IT PROVIDES APPROXIMATELY 90% OF THE WELLBORE INFORMATION.

Modified from Well Logging Data Acquisition and Application – O. & L. Serra. (issued by Serra Log 2004) © 2008 Weatherford. All rights reserved.

3

Mud gas analysis in formation evaluation Well Test

8 6

Mini DST

4

Wireline Logs

Coring

TIME DAYS

14 12 10

2

LWD including Formation Testing

Mudlog

1

2

3 SERVICE COST MUS$

4

DW RESERVOIR EVALUATION: TIME VS SERVICE COST PER WELL © 2008 Weatherford. All rights reserved.

Courtesy of ENI Indonesia

5

6

Mud gas analysis in formation evaluation MAIN LIMITATIONS FOR RELIABLE INTERPRETATION OF THE MUD GAS:

DRILLING MUD ACTS AS BARRIER BETWEEN FORMATION AND SURFACE.

HYDROCARBON GASES ARE PARTIALLY DISSOLVED INTO THE MUD, ESPECIALLY WHEN USING SYNTHETIC OIL BASE MUD.

THE DEGASSING EFFICIENCY IS A FUNCTION OF SEVERAL VARIABLES (EXTRACTOR EFFICIENCY, MUD TYPE, TEMPERATURE, ETC.) AND IT IS DIFFERENT FOR DIFFERENT COMPONENTS (C1 TO C8 AND AROMATICS).

LOW MUD TEMPERATURE DUE TO EFFICIENCY.

MUD LEVEL FLUCTUATION IN THE POSSUM BELLY AFFECTS THE QUALITY OF THE GAS DATA.

CIRCULATION THROUGH A RISER STRONGLY REDUCES THE DEGASSING

IN THE LAST 10 YEARS DEVELOPMENTS IN MUD GAS EXTRACTORS, IMPROVEMENTS IN ANALYTICAL DETECTORS, INTERPRETATIVE METHODOLOGIES AND QUALITY CONTROL PROCEDURES STRONGLY INCREASED THE ACCURACY AND RELIABILITY OF MUD GAS FINGERPRINTING.

Courtesy of Carlo Carugo (ENI) © 2008 Weatherford. All rights reserved.

Mud gas analysis in formation evaluation 1969 SPE: FORMATION EVALUATION BY ANALYSIS OF HYDROCARBON RATIOS. PIXLER, B.O., BAROID DIV. NATIONAL LEAD CO.

1984 SPE: RESERVOIR CHARACTERIZATION SHOWS.

BY

ANALYSIS

OF

LIGHT HYDROCARBON

HAWORTH, J.H., SELLENS, M.P., GURVIS, R.L., EXPLORATION LOGGING INC.

1999 SPLWA: GAS WHILE DRILLING (GWD); A REAL TIME GEOLOGIC AND RESERVOIR INTERPRETATION TOOL. G.BEDA, R.QUAGLIAROLI ENI AGIP DIV., MILANO, ITALY; G.SEGALINI, B.BARRAUD, A.MITCHELL ELF EP, PAU, FRANCE.



80’

CF

FID

TG

90’

00’

10’

20’

QGM CVT-TCD-MEMBRANE TG and CHROMATOGRAM

CT>1 min C1-C5


CT≈30 sec C1-C5

CT ≈30 sec C1-C5 CT≈60 sec C1-C8 Aromatics CO2, N2

CT ≈30 sec C1-C5 CT≈60 sec C1-C8 CT ≈120 sec C1-C10 Cycloalkanes Aromatics CO2, N2


Courtesy of ENI

GAS DATA ACCURACY DEPENDS ON SEVERAL FACTORS THAT NEED TO BE TAKEN IN CONSIDERATION FOR QUALITY CONTROL: DOWNHOLE INFLUENCES, FLOWLINE, GAS TRAP, GAS LINE, ANALYSER. © 2008 Weatherford. All rights reserved.

Mud gas analysis in formation evaluation GAS W HILE DRILLING METHODOLOGY (GWDTM)

THIS

METHODOLOGY IS BASED ON THE COMPUTATION AND ANALYSIS OF SEVERAL GAS RATIOS OBTAINED USING THE DIFFERENT GAS

(C1-C7) CONTINUOUSLY EXTRACTED FROM THE CIRCULATING MUD AND MONITORED AT THE RIG SITE THE MUD LOGGING COMPANY. THE METHODOLOGY HAS BEEN DEVELOPED IN THE FRAME OF A JOINT ENI-TOTAL R&D PROJECT. COMPONENTS

Courtesy of ENI © 2008 Weatherford. All rights reserved.

IN

REAL-TIME BY

Mud gas analysis in formation evaluation 80

70

membrane GC-Tracer

RFT 1

DST 1

agitator Gas Trap GC

DST 2

60

(mol%)

50

40

30

20

10

0 nC1

nC2

nC3

iC4

nC4

iC5

nC5

THE TRADITIONAL GAS TRAP WITH AGITATOR IS NOT CAPABLE TO RELEASE OF RELEASING HEAVY COMPONENTS FROM THE MUD. THE RESULT IS THAT AGITATOR SYSTEMS OVERESTIMATE THE LIGHT COMPONENTS AND UNDERESTIMATE THE HEAVIER COMPONENTS. © 2008 Weatherford. All rights reserved.

Mud gas analysis in formation evaluation THE MUD LOGGING INDUSTRY HAS DEVELOPED ADVANCED GAS DETECTORS IN ORDER TO IMPROVE THE EXTRACTION EFFICIENCY. THE OBJECTIVE HAS BEEN ACHIEVED IN TWO WAYS: ADOPTING A MUD HEATER OR ADOPTING THE SEMI-PERMEABLE MEMBRANE.

HIGH EXTRACTION EFFICIENCY

REAL-TIME FLUID PHASE CHARACTERIZATION

GAS RATIOS IN LINE WITH OFFSET WELLS ANALYSIS.


PVT ANALYSIS, ISOTOPIC ANALYSIS, GEOCHEMICAL


Concentration Plot 13

Color by Well 1 2 3 4 5 6 7 9 8

Compartment 3

Compartment 1 12

C2_norm

11 10

Compartment 2

9 8

Compartment 4 7 6

7

8

9

10

11

C3_norm Ratios 11 10

C1/C2

9 8 7 6 5 7

8

9

10 C1/C3

Courtesy of SHELL © 2008 Weatherford. All rights reserved.

11

12

13

Shape by Analysis GCTracer SSF GAS Data Single Stage Flash

Mud gas analysis in formation evaluation REAL-TIME ADVANCED GAS DETECTION FLUID COMPOSITION C1 %

C2 %

C3 %

iC4 %

nC4 %

iC5 %

nC5 %

C6 %

C7 %

C8 %

81.06

10.64

5.13

0.68

1.45

0.59

0.46

0.00

0.00

0.00

81.20

10.56

5.09

0.67

1.44

0.58

0.45

0.00

0.00

0.00

81.34

10.42

5.10

0.67

1.45

0.58

0.44

0.00

0.00

0.00

81.00

10.47

5.26

0.69

1.51

0.60

0.48

0.00

0.00

0.00

81.00

10.47

5.26

0.69

1.51

0.60

0.48

0.00

0.00

0.00

80.53

10.59

5.39

0.73

1.60

0.68

0.48

0.00

0.00

0.00

80.87

10.33

5.23

0.78

1.58

0.66

0.49

0.00

0.00

0.06

80.97

10.25

5.19

0.79

1.57

0.66

0.49

0.00

0.00

0.08

80.94

10.35

5.27

0.74

1.57

0.62

0.49

0.00

0.00

0.02

80.89

10.35

5.28

0.71

1.56

0.69

0.51

0.00

0.00

0.00

80.41

10.55

5.43

0.74

1.61

0.71

0.55

0.00

0.00

0.00

MDT GAS ANALYSIS C1 %

C2 %

C3 %

iC4 %

nC4 %

iC5 %

nC5 %

C6 %

C7 %

C8 %

81.76

10.95

4.04

0.68

1.18

0.44

0.43

0.22

0.16

0.13


Mud gas analysis in formation evaluation REAL-TIME FORMATION EVALUATION γ ray Res. N&D C1/C2 THC C1% G/L FS


HC ARO/ALK

Mud gas analysis in formation evaluation FLUID PHASE ID

High pressure zone

Condensate


Wet Gas

15

Mud gas analysis in formation evaluation COMPARTMENTALISATION

GAS CONDENSATE OIL


Mud gas analysis in formation evaluation 1) IDENTIFY THE SIGNIFICANT GAS EVENTS 2) FLUID PHASE CHARACTERIZATION 3) SWEET SPOTS γ ray

Res. N&D


C1% HC THC ARO/ALK

G/L LHR




ACKNOWLEDGMENTS Carlo Carugo (ENI) Graziano Capone (ENI Indonesia) Luca Magini (Total Angola) Hani Elshahawi (SHELL)


19

Mud gas analysis in formation evaluation REFERENCES A.Mitchell, B.Barraud, G.Segalini, Elf Exploration Production, CSTJF; G.Beda, R.Quagliaroli, EM Agip Div. GAS WHILE DRILLING (GWD); A REAL TIME GEOLOGIC AND RESERVOIR INTERPRETATION TOOL. SPWLA 40 Annual Logging Symposium, 1999 P. Blanc, Total; J. Brevière, Geoservices; F. Laran, Total; H. Chauvin, Geoservices; C. Boehm, Total; N. Frechin, Geoservices; M. Capot, Total; A. Benayoun, Geoservices. Reducing Uncertainties In Formation Evaluation Through Innovative Mud Logging Techniques. SPE Annual Technical Conference and Exhibition, 5-8 October 2003, Denver, Colorado. Daniel McKinney, Matthew Flannery, and Hani Elshahawi, Shell International E&P Inc.; Artur Stankiewicz and Ed Clarke, Shell International E&P B.V.; and Jerome Breviere and Sachin Sharma, Geoservices. Advanced Mud Gas Logging in Combination with Wireline Formation Testing and Geochemical Fingerprinting for an Improved Understanding of Reservoir Architecture. SPE Annual Technical Conference and Exhibition, 11-14 November 2007, Anaheim, California, U.S.A.. Giovanni N. Pinna, Douglas J. Law International Logging Inc. ADVANCES IN MUD GAS INTERPRETATION WHILST DRILLING. 49th Annual Logging Symposium, May 25 - 28, 2008 , Edinburgh, Scotland. Ton Loermans, Saudi Aramco; Farouk Kimour, Geoservices; Charles Bradford and Yacine Meridji, Saudi Aramco; Karim Bondabou, Pawel Kasprzykowski, Reda Karoum, and Mathieu Naigeon, Geoservices; and Alberto Marsala, Saudi Aramco. Results From Pilot Tests Prove the Potential of Advanced Mud Logging. SPE/DGS Saudi Arabia Section Technical Symposium and Exhibition, 15-18 May 2011, Al-Khobar, Saudi Arabia. D. Tonner, Weatherford Surface Logging Systems - J. Chopty, M. Jaipersad, Weatherford - K. Al-Maslout, G. Pinna, D. Forber, W. Davies, Weatherford Surface Logging Systems. THE BENEFITS AND APPLICATION OF SEMI-PERMEABLE MEMBRANE GAS DETECTION DURING MANAGED PRESSURE DRILLING. Offshore Mediterranean Conference and Exhibition, March 23 - 25, 2011 , Ravenna, Italy. C. Carugo (Eni), S. Joshi (Shlumberger), L. Magini* (Eni Ghana) & G.N. Pinna (Weatherford). A Multidisciplinary Application for an Exploration Well in the Tano Basin, Ghana. SPE Europec/EAGE Annual Conference, 4-7 June 2012, Copenhagen, Denmark. Talal Al-Adwani, Sunil Singh, Badruzzaman Khan, and Jalal Dashti, Kuwait Oil Company; and Gionata Ferroni, Alberto Martocchia, and Javad Estarabadi, GEOLOG International. Real Time Advanced Surface Flow Analysis for Detection of Open Fractures. SPE Europec/EAGE Annual Conference, 4-7 June 2012, Copenhagen, Denmark. © 2008 Weatherford. All rights reserved.

20

Mud Gas Analysis in Formation Evaluation

Recommend Documents