PETROLEUM MIGRATION AND CHARGE MODELLING, MURZUK BASIN, LIBYA

Transcription

1 TROLUM MIGRATIO A HARG MOLLIG,

2 ii TABL OF OTT 1.0 ITROUTIO/BAKGROU OBJTIV RT AY TROLUM HYROGOLOGY Formation Fluids Formation Water Oil Water Flow Oil Migration Tilted Oil/Water ontacts HOLO TROLUM HYROGOLOGY (10,000 y B) Formation Fluids Water Flow Oil Migration RTAOU TROLUM HYROGOLOGY (c. 65 million years B) Formation Fluids Water Flow Oil Migration ARBOIFROU TROLUM HYROGOLOGY (c. 284 million years B) Formation Fluids Water Flow Oil Migration Issue of cale of Analysis OLUIO ROMMATIO Regional Local Analysis RFR...18

3 iii FIGUR Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Figure 10. Figure 11. Figure 12. Figure 13. Figure 14. Figure 15. Figure 16. Figure 17. Figure 18. Figure 19. Figure 20. Figure 21. Figure 22. Figure 23. Figure 24. Figure 25. Geology and License Map - Murzuk Basin tratigraphic Table - Murzuk Basin Well B1-174 Basin Modelling Ground urface Topography and Bedrock Geology Map chematic Geological ross-ection Through the Murzuk Basin, outhwest Libya tructure Map - amb. Ordovician Reservoir alinity vs. epth Graph - Murzuk Basin Water ensity at Reservoir onditions - Murzuk Basin AI vs. epth Graph - Murzuk Basin alculating Oil ensity at Reservoir onditions (Logic and Methodology) Oil ensity at Reservoir onditions - Murzuk Basin lephant Oil Field RFT ressure rofile - Murzuk Basin resent ay Head Map - amb. Ordovician Reservoir ynamic Oil Migration Map - amb. Ordovician Reservoir Tilt Amplification Factor Table - Murzuk Basin Tilt Amplification Factor ensitivity Graph - am-ord Reservoir - Murzuk Basin resent ay Tilts Map - amb. Ordovician Reservoir Holocene Head Map - amb. Ordovician Reservoir ynamic Oil Migration Map - amb. Ordovician Reservoir ynamic Oil Migration Map - nd-retaceous Reservoir ynamic Oil Migration Map - amb. Ordovician Reservoir tructure with Head - amb. Ordovician Reservoir lephant Oil Field ross-ection - Murzuk Basin tructure Map - nd-retaceous Reservoir tructure Map - amb. Ordovician Reservoir AI Appendix A. Hydrodynamics Theory and Methodology

4 iv LOUR nclosure 1. Ground urface Topography and Bedrock Geology Map nclosure 2. Murzuk Basin chematic Geological ross-ections through the Murzuk Basin, outhwest Libya nclosure 3. tructure Map - amb. Ordovician Reservoir nclosure 4. resent ay Head Map - amb. Ordovician Reservoir nclosure 5. ynamic Oil Migration Map - amb. Ordovician Reservoir nclosure 6. resent ay Tilts Map - amb. Ordovician Reservoir nclosure 7. Holocene Head Map - amb. Ordovician Reservoir nclosure 8. ynamic Oil Migration Map - amb. Ordovician Reservoir nclosure 9. ynamic Oil Migration Map - nd-retaceous Reservoir nclosure 10. ynamic Oil Migration Map - amb. Ordovician Reservoir nclosure 11. tructure with Head - amb. Ordovician Reservoir nclosure 12. tructure Map - nd-retaceous Reservoir nclosure 13. tructure Map - amb. Ordovician Reservoir

5 age 1 of ITROUTIO/BAKGROU The study area for this project is the Murzuk Basin of southwest Libya, orth Africa. The Murzuk is one of several incratonic sag basins present in north Africa. The Murzuk Basin is bordered by the Al Hamadah Basin in northern Libya and the Illizi Basin in Algeria to the west. The Murzuk Basin is bounded on three sides by prominent structural highs: the Tihemboka High to the west, the Gargaf (also called Al uarqaf or Jabal Fazzan) Arch to the north and the Tibesti Uplift to the east (Figure 1). These structures together define the uplifted margins of the basin and each exhibits a wide aleozoic outcrop belt at high topographic elevation. The southern edge of the study area is the border with iger. The southern 250 km of the Murzuk Basin lies in iger and was not analysed in this project. The Murzuk Basin is an elliptical saucer-shaped intracratonic sag basin with a long diameter (northsouth) approximately 880 km in length. The basin is 785 km wide at the centre narrowing towards its southern rim in iger. The basin fill is predominantly aleozoic and Mesozoic and the sediments are almost exclusively sandstones and shales, with rare limestones and no evaporites (Figure 2). The total sedimentary thickness is 3,500 m in the basin centre. The basin has been impacted by four major orogenic events: the aledonian (pre-evonian), the Hercynian (pre-triassic), the Austrian (mid-retaceous) and the Alpine (ocene-oligocene). Major faults occur, which displace lower aleozoic strata in excess of 600 ft. Most large faults appear to be concentrated in the central and western parts of the basin. Figure 2 shows a composite stratigraphic column for the Murzuk Basin. The main petroleum reservoir is the upper Ordovician Memouniat Formation sandstone. Over parts of the basin, the upper Ordovician is absent and in many wells lacking Ordovician oil, the geology has not been differentiated beyond the designation ambrian-ordovician. Hence, the rock unit we are mapping is more properly called the ambrian-ordovician. The primary source rock in the basin is the ilurian Tanezzuft Formation and source rock facies of varying quality in the Tanezzuft Formation throughout the basin has been mapped. Where both formations are present, the Tanezzuft directly overlies the Memouniat. Mapping indicates that the entire ilurian section is absent over the northeastern quadrant of the basin. Basin modelling indicates that in the deeper parts of the basin, the organic shales of the Tanezzuft Formation have been oil generative since the late evonian. As shown on the burial history curve for the B1-174 well (Figure 3), the Tanezzuft

6 age 2 of 2 entered the mid-mature oil window (0.7% Ro) in late ennsylvanian time and started to generate late mature oil (1.0% Ro) during the late retaceous to aleocene. etroleum migration patterns since the late ennsylvanian have changed in response to evolving basin structure and patterns of water flow. ince the basin was uplifted above sea level following the Hercynian Orogeny, meteoric water recharge at the exposed basin margins has complicated the pattern of oil migration and introduced the risk of flushing. ue to the complexity of the charge and flushing history of the basin, it was decided that further exploration in the basin may benefit greatly from petroleum migration modelling as a means of reducing risk.

7 Geology & Licence Map, Murzuk Basin GHAAM BAI ILLIZI BAI ALGRIA T-RV -O MU KY UATRARY OG O ALAO B-1 O TRTIARY TO RT VOLAI UR RTAOU LOWR RTAOU TRIAI-JURAI ARBOIFROU ILURIA AMBRO-OROVIIA VOIA MOZOI & ALAOG UIFFRTIAT RAMBRIA GA FIL OIL FIL H I G H O T I H M B O K A -O A T H A A R H O O A1-1 L K1-1 A1-145 L1-1 G1-1 B1-1 M F B K1-115 M16 M1 M2 A KM A I O B1-151 M13 -O M3 M4 M14 G A R G A F A R H -O A2 B A1-68 G1 A B F1 A H J3 F2 J2 J1 B1 1 L1 -O LIBYA -O M5 M7 M9 O1-101 A1-73 F3 F1 A1 G F2 1 B1 1 J1 1 A F1 I1 2 J2 1 K1 1 H1 L1 M1 G G1-58 A1-58 B F1-58 H1-58 Kour 1 Kouna-1 O Ati Anticline Kourneida-1 MU IGR MU M8 A1-34 Field Area A1-64 M10 M11 -O K -O A1-77 -O B1-77 -O T I B T I H I G H Murzuk HA T-RV T-RV ast T-RV Field Area Map showing Geological ross-ections through the Ati Anticline. Rakhit etroleum onsulting Ltd. JOB MBM AT 05/25/2001 FIL Figure01.cdr BY B RW HJ HK B Geology & License Map Murzuk Basin FIGUR 1

8 nvironment Age (million y B) ontinental ontinental Marine Rakhit etroleum onsulting Ltd. JOB MBM AT 05/29/2001 FIL Figure02.cdr BY B RW HJ HK B tratigraphic Table Murzuk Basin FIGUR 2

9 Well B1-174 Basin Modelling Rakhit etroleum onsulting Ltd. JOB MBM AT 05/25/2001 FIL Figure03.cdr BY B RW HJ HK B Well B1-nc174 Basin Modelling FIGUR 3