GEOLOGICAL AND GEOPHYSICAL ASSESMENT OF SHALE GAS RESOURCES IN PERTAMINA WORKING AREA

Transcription

1 GEOLOGICAL AND GEOPHYSICAL ASSESMENT OF SHALE GAS RESOURCES IN WORKING AREA BANGKITKAN ENERGI NEGERI Dian Larasati PT Pertamina (Persero) Chiang Mai, 23rd September 2015

2 OUTLINE INTRODUCTION WORKFLOW OF THE SHALE GAS STUDY CASE STUDY: BARITO BASIN

3 INTRODUCTION 2012 : G&G Study and Evaluation of Shale Gas Potential in Sumatra-Java by NEGT UTC-PT Pertamina (Persero) 2013 : G&G Study and Evaluation of Shale Gas Potential in Kalimantan and Eastern Indonesia by NEGT UTC-PT Pertamina (Persero)

4 WORKFLOW OF SHALE GAS STUDY PREPARATION STAGE (DATA GATHERING, LITERATURE) GEOLOGY GEOPHYSICS ROCK SAMPLES (OUTCROP, CORE) WELL LOGS well to seismic tie SEISMIC MINERAL COMPOSITION & FABRIC LITHOFACIES POROSITY & PERMEABILITY VERTICAL INTEREST ZONE, PAY THICKNESS DEPOSITIONAL HISTORY SEISMIC HORIZON & STRUCTURAL INTERPRETATION MAPPING KEY STRATIGRAPHIC SURFACE PORE-TYPE AND NETWORK GEOCHEMICAL ANALYSIS INTEGRATING DATA SET FOR STRATIGRAHIC PROPERTIES MODELLING AND MAPPING GEOMECHANICAL ANALYSIS BASIN MODELLING MAPPING PROPERTIES SHALE GAS SYSTEM, GIP CALCULATION

5 CASE STUDY: BARITO BASIN

6 MAP OF STUDY AREA TANJUNG-2 TANJUNG wells 459 2D seismic lines 1 cube of 3D seismic

7 GEOLOGY OF BARITO BASIN Extensional movement in the late Cretaceous-early Miocene (Syn- and post-rifting phases) Compression movement in the Plio-Pleistocene created reverse fault and fold structures (Kusuma and Darin, 1986)

8 FIELD & LABORATORY ANALYSES

9 GEOLOGICAL MAP

10 TANJUNG FORMATION The lowermost three stages comprise the Lower Tanjung Formation, and primarily represent localized non-marine rift infilling sediments The uppermost Stage 4 (also termed the Upper Tanjung Formation) represents regional marine deposition

11 PETROGRAPHY ANALYSIS Sample Rock Name : KCM-3 : Organic-rich Claystone Silt grains Organic-rich laminae Silt grains Organic-rich laminae Clay mineral Clay mineral Organic materials Organic materials 500 µm 500 µm PPL XPL Fine to medium silt-sized siliciclastic grains (white in XPL - lower picture) and dark brown organic materials are disseminated in clay matrix. Clay materials have locally been recrystallized into fibrous clay minerals. Concentration of elongated organic materials forms thin laminae in the sample.

12 SEM ANALYSES Upper Tanjung Formation The rocks show occurence of lamination, cementation by pyrite (pore spaces), secondary dissolution, and microfracture. Lower Tanjung Formation The rocks shows occurence of lamination, secondary dissolution, and microfracture.

13 GEOCHEMISTRY ANALYSES * = unreliable reading

14 GEOCHEMISTRY ANALYSES

15 POROSITY & PERMEABILITY ANALYSES No. Sample Name Dry mass (kg) Length (cm) Diameter (cm) Porosity (%) Permeability (md) 1 KCM-3 (1) KCM-3 (2) KCM-3 (3) BBPK-1 (1) BBPK-1 (2) ABC-1 (1) ABC-1 (2) BMT Porosity test Permeability test

16 XRD ANALYSES (Jarvier et al., 2007) Average BI: 0.48

17 WELL ANALYSES SEISMIC INTERPRETATION

18 GEOCHEMISTRY ANALYSIS (BAGOK-1 WELL) SHALE GAS POTENTIAL BAGOK-1 GEOCHEMISTRY SUMMARY PARAMETERS Upper Tanjung Lower Tanjung MIN TOC (% Wt) MAX AVERAGE MIN HI (Mg/gc MAX AVERAGE MIN Tmax MAX AVERAGE TOC FAIR FAIR SUMMARY HI GAS GAS Ro OIL WINDOW EARLY MATURE Tmax MATURE MATURE

19 THERMAL MATURITY GENERATION (BAGOK-1) 0.3(%Ro) 0.4 (%Ro) Early Mature 0.5 (%Ro)

20 BRITTLENESS INDEX ANALYSIS CLAY MINERALS (%) CARBONATE MINERALS (%) OTHER MINERALS (%) TOTAL (%) NO NAME OF WELL DEPTH (METER) SMECTITE ILLITE KAOLINITE CHLORITE CALCITE DOLOMITE SIDERITE QUARTZ FELDSPAR PLAGIOCLASE PYRITE GYPSUM CLAY CARBONATE TOC (%) ROCK NAME FORMATION BI 1 Jelmusibak SHALE TANJUNG Jelmusibak SHALE TANJUNG Jelmusibak SHALE TANJUNG Jelmusibak SHALE TANJUNG Jelmusibak SHALE TANJUNG Jelmusibak SHALE TANJUNG Jelmusibak SHALE TANJUNG 0.47 BI from well

21 PETROPHYSICAL ANALYSIS CLAY VOLUME ESTIMATION Linear Equation SW ESTIMATION Simandeux Method was used for zone with sand clay domination Commonly used when Vsh > 0.2 and Rsh < 8 ohmm GR Min GR Max

22 PETROPHYSICAL ANALYSIS Lumping Nama Formasi Parameter Min Mean Max Net Pay 60.2ft 280ft 340.8ft TOC 4.6% 5.4% 6.2% Lower Tanjung Densitas SW Porosity Cut off Porosity <10% Sw <60% Vsh 30%<Vsh<70% Thickness 1 meter TOC 1%

23 STRATIGRAPHIC CORRELATION W E S N SHALE GAS BEARING (FORMASI TANJUNG)

24 SEISMIC INTERPRETATION SNE NNW Index Map

25 SWEET SPOT AREA Oil Windows Wet Gas Windows

26 RESOURCE CALCULATION (Ambrose et al., 2010) (Jarvie, 2004) Upper Tanjung Fm PARAMETER UNIT MIN MEAN MAX AREA ACREE THICKNESS FT VOLUME AREA ACREE FT 28,566, ,427, ,994, POROSITY % 4.60% 6.20% 8.30% SW % 40.00% 45.00% 50.00% SG % 10.00% 40.00% 40.00% 1/bg 1/FVF DENSITY gr/cm FACTOR OF FREE GAS frac FACTOR OF GIP frac 1, , , TOTAL GIP UNIT MIN MEAN MAX GAS CONTENT-FREE GAS SCF/TON GAS CONTENT-ADSORBED GAS SCF/TON Total GIP of Upper Tanjung Fm 19.9 TCF Total GIP of Lower Tanjung Fm 36.8 TCF TOTAL GAS CONTENT SCF/TON GIP-FREE GAS TCF GIP-ADSORBED GAS TCF TOTAL GIP TCF

27