Estimating the Ultimate Recoverable Reserves of the Paris Basin, France
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Oil & Gas Science and Technology – Rev. IFP, Vol. 57 (2002), No. 6, pp. 621-629 Copyright © 2002, Éditions Technip Estimating the Ultimate Recoverable Reserves of the Paris Basin, France J. Wendebourg1 and C. Lamiraux2 1 Institut français du pétrole, 1 et 4, avenue de Bois-Préau, 92852 Rueil-Malmaison Cedex - France 2 Direction générale de l’énergie et des matière premières (DGEMP), 41, boulevard Vincent Auriol, 75703 Paris Cedex 13 - France e-mail: [email protected] Résumé — Estimation des réserves ultimes récupérables du Bassin parisien, France — Le Bassin parisien est un bassin mature en exploration pétrolière. Pas moins de 800 puits exploratoires ont été forés pendant les 40 dernières années et 52 champs de pétrole ont été découverts : 33,4 Mt de pétrole ont été produits jusqu’en 2000. Le potentiel du Bassin parisien est estimé à l’aide de méthodes statistiques. La taille moyenne d’un champ est de 100 000 t avec une probabilité de 5 % de trouver un champ de plus de 2,5 Mt. Les réserves ultimes récupérables étaient de 15 Mt en 1986, 29 Mt en 1991 et 46 Mt en 1996. Aujourd’hui, il y a une probabilité de 5 % de trouver un champ de plus de 4 Mt dans les grès du Dogger ou du Keuper. Le taux de succès augmente de 1/66 dans la formation du Néocomien, le réservoir le moins profond, à 1/8 dans le Keuper, le réservoir le plus profond et le plus récemment foré. L’analyse présentée s’appuie sur des données de production et ne prend pas en compte une production supplémentaire éventuelle grâce à des méthodes de récupération assistée ou grâce à des découvertes basées sur de nouveaux concepts d’exploration, susceptibles d’augmenter les réserves de façon significative, bien au-delà des chiffres présentés comme cela est démontré par l’analyse de la courbe crémière. Abstract — Estimating the Ultimate Recoverable Reserves of the Paris Basin, France — The Paris Basin is a mature basin from an exploration point of view. More than 800 exploration wells have been drilled over the last 40 years and 52 fields have been discovered from which 33.4 Mt of petroleum have been produced by the end 2000. Based on past production data, the future exploration and production potential of the Paris Basin is estimated using classical statistical methods. The mean size of a field in the Paris Basin is about 100 000 t with a 5% chance of a field whose size is greater than 2.5 Mt. The ultimate recoverable reserves based on the creaming curve analysis were about 15 Mt in 1986, 29 Mt in 1991 and 46 Mt in 1996. At present, there is a 5% chance of finding a field in the Dogger and Keuper formations that is bigger than 4 Mt. The drilling success ratio increases from 1/66 for the shallowest, the Cretaceous Neocomian formation to 1/8 in the deepest and latest to be drilled Triassic Keuper formation. The data analysis presented in the paper is based on known production data which do not take into account additional production gained by enhanced recovery methods or additional reserves added by discoveries based on new plays, that however may significantly increase reserves beyond the numbers presented here as the creaming curve analysis has shown. 622 Oil & Gas Science and Technology – Rev. IFP, Vol. 57 (2002), No. 6 INTRODUCTION future exploration potential, particularly in a mature basin such as the Paris Basin. The Paris Basin is one of the major petroleum production The Paris Basin is an intracratonic basin located in basins of continental Europe and the premier petroleum Northern France, with an extension of about 500 km east- province of France (Weaver et al., 1988). More than 800 west and 300 km north-south, approximately coinciding with exploration wells have been drilled over the last 40 years and the drainage basin of the Seine river (Fig. 1). It is a saucer- 52 fields have been discovered from which 33.4 Mt of shaped basin with a maximum thickness of sediments of petroleum have been produced by the end 2000. The Paris more than 3 km. The basin is slightly asymetric due to Basin is a good example of a mature petroleum basin where Tertiary erosion and uplift in its Eastern part (Fig. 2). The exploration is polyphase following technological progress stratigraphic column in the basin center includes some 150 m and favorable economics and where production is presently of Tertiary, about 1000 m of Cretaceous, some 1500 m of Jurassic and some 500 m of Permo-Triassic sediments in decline. In this paper, we will examine, based on past (Fig. 3). The fault pattern of the basin is governed by the Pre- production data, the future exploration and production mesozoic basement with NW-SE striking fault zones of potential of this mature basin using classical statistical Hercynian heritage. The principal oil-bearing formations are methods (Harbaugh et al., 1995). This approach does not try the Middle Jurassic (Bathonian) Dogger carbonates, the to develop new exploration plays based on new geophysical Upper Triassic Keuper sandstones, but also the Lower or geochemical data, or identify enhanced production Cretaceous Neocomian sandstones and the Upper Triassic possibilities of existing producing fields. It is based on the Rhaetian sandstones (Lamiraux and Mascle, 1998). The assumption that a sedimentary basin is a closed petroleum principal source rocks for the oils in the Paris Basin are the system and that past production data can be used to infer Lower Jurassic Toarcian black shales (schistes carton). They 0° Permian basin of Autun 0 100 km Tertiary Cretaceous Jurassic Triassic Basement Figure 1 Location map (from Perrodon and Zabek, 1991). J Wendebourg and C Lamiraux / Estimating the Ultimate Recoverable Reserves of the Paris Basin, France 623 W E TriassicLiassic Dogger Eocene Oligocene Upper CretaceousLower CretaceousUpper Jurassic KeuperMuschelkalkBunterPermian PARIS Basement 1 km ? 100 km 0 Carboniferous basin Figure 2 Cross section (from Perrodon and Zabek, 1991). 70 STAGES TECTO. LITHO. Source- Oil and gas 0 rocks fields 60 CENO. 50 65 Ma Up 40 Cret. Low. 30 Malm. 20 Jura. Dogger 10 MESO. Lias Number of exploration wells Rhaetian 0 Keuper 1952 1954 1955 1958 1960 1962 1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 Trias Musch. Years Bunt. 225 Ma Perm. Figure 4 PALEO. Stephan. Total number of exploration wells drilled yearly in the Paris Carbo. Basin. Westphal. Figure 3 pause in the 1970s. In the 1980s, exploration experienced a revival with new discoveries in Triassic Keuper sediments, Chronostratigraphic log (from Lamiraux and Mascle, 1998). the most spectacular of which was the discovery of the Chaunoy field in 1982 which by the end 2000 has produced are presently in the oil window in the center of the basin almost 9.5 Mt of petroleum. Figures 7 and 8 show the (Gaulier and Burrus, 1994). Oil migration occurred vertically location and extension of all fields in the central part of the into the overlying Middle Jurassic carbonates and into the basin having produced from the Dogger and Keuper underlying Triassic sandstones, and then laterally within the reservoirs. Cumulative petroleum production as a function reservoir formations. of year of discovery reflects this evolution (Fig. 6). Petroleum exploration in the Paris Basin started in the Discoveries in the 1960s are fields that had produced more 1950s (Fig. 4) with a present-day maximum density of wells than 1 Mt of petroleum in 2000. After a low in the 1970s, in the central part just east of Paris (Fig. 5). First discoveries petroleum production picks up in the 1980s. In the 1990s, were made in the Cretaceous Neocomian sandstones and several discoveries of small to intermediate size have been in the Jurassic Dogger carbonates (Fig. 6). The first made. The production curve of the entire basin is dominated exploration peak was reached in the 1960s followed by a by the two biggest fields, Villeperdue and Chaunoy, both 624 Oil & Gas Science and Technology – Rev. IFP, Vol. 57 (2002), No. 6 600 650 700 750 150 150 MTL 1 RCQ 1 COM 1 NT 1 DPR 1 Montmorency JY 1 VIN 1 VS 1 Château-Thierry MTX 1D BEB 1 LVX 1 SMS 1 VRY 1 CAN 1 EI 1 AVE 1 MTR 1D VRY 2 Meaux MAP 1 VSO 1 Argenteuil CMT 1 MT 1 LUC 1 CPG 1 IDG 2D BUS 1 MTT 1 LMN 1D TRI 1 CS 44- CS 42 RZB 1D 33-32-35- 29-30-40 MV 101 VLL 1D MIL 1 CS 34 GLT 1 VLY 3 CSBE 2 CS 31 45 ME 1 CSBE 4 CSBE 3 CS 37 LFS 1D CS 26 VLY 1 IDG 1 ME 2 CS 41- HFE 6D BVE 1 28 49-43-46- HFE 5D VPS 101 CSBE 1 39-21-24 QV 7 18 FAB 3 FAB 13 CSBE 5 CS 19- HFE 1GD IDG 3D 16 9 50-36-38- FAB 11D 27-15-4 HFE 2 LSY 1 FAB 7 VLY 2 CS 5 SN 101 FAB 14D QV 1 CS 23-17- 2 PL 1 FAB 9D FAB 16 14-10-11- CS 4 FAB 10D FAB 1 FAB 15D FABE 1 13-8-12- CS 22 MEZ 1B PRN 1D 20-25-6 FAB 2 CS 7 Le Petit Morin HFE 7D CS 3 FAB 12D HM 1 VPU 171 FAB 6D FAB 8D CPV 1 VPU 143 FAB 4 MT 101 VPU 177H BYE 1 NSD 1 BTS 1 VPU 124 VPU 29D VPU 50 VPU 13 25D VPU 149 VPU 123 MV 1 22D 172H LEP 1 MT 2 145H FAB 5 PARIS CRY 1 MT 103 173H 141H SNC 1 VPU 1 37 83 169H 180H VGR 1 125 170H VPU 98 LCH 1D VPU 9 10 26D 179H SDN 102 VPU 74 BYL 2 175H 176H 81GD 38D 11 PMR 1 SDN 107 BLY 1 MT 102 12 84BD VPU 156 La Marne MAL 1 45D 82 VPU 47D 39D 41D 46D VPU 174H 43D 20 CFX 1 CGY 1 VPU 31 7 15 RB 101 35D 8 14 66BD 18 VPU 77 BYL 3 BRU 1 VPU 27D 17 SDN 105 SDN 1 VPU 21 36D VPU 86 VPU 3D 6 23 VPU 118 VPU P 1 VXP 1 VPU 4D 32D 24D 19 40 VPU 79 SDN 110D VPU 2D 28 SDN 104 Le Grand Morin 30D 48 133 VPU 87 BYL 1 CBG 1D VPU 178d CSM 1D VPU 5D SDN 103 VPU 33 34 44 42 VPU 72 SDN 101 MBN 1 LMS 1D VPU 57 LVV 1 SLZ 1 VPU 54 VPU 96 VPU 69 VPU 93 CPN 1 SDN 106 MR 101 VPU 16 VPU 62 LHB 101 MLN 2 MLN 7D JSL 1D LCY 1 Brie-Comte