Paper ID : Conceptual Exploration Abu Khashab Oil Discovery IPR/OVL Block XXIV, Syria

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1 Paper ID : Conceptual Exploration Abu Khashab Oil Discovery IPR/OVL Block XXIV, Syria Emin Yanilmaz, Aziz T. Mansour, James Peters, Z. S. Sagwal IPRMEL/OVL eminyanilmaz@iprmel.com, Abstract The IPR/OVL Block XXIV is located in the northeastern part of Syria, approximately 550 km northeast of Damascus (Fig.1). The subject geological terrain has undergone several phases of deposition, erosion and inversion from Cambrian to Late Miocene (Messinian) times. After the Devonian plate-wide unconformity, Early Permian glacial hiatus and late Jurassic-Neocomian regional uplift the main inversion of the area was caused by the rejuvenation of Palmyride rift faults during the Late Cretaceous. Thermal subsidence of Paleogene was followed by inversion of Palmyride Fold Belt and transpression of Euphrates Basin. Miocene carbonate and clastic depositional regime together with widespread volcanism was followed again by the inversion of the area at the end of Messinian. The Abu Khashab closure was formed during this Messinian inversion. Since 1975 the Block XXIV area has been explored extensively by major international oil companies and Syrian Petroleum Company (SPC). Thousands of line kilometers of 2D seismic were shot and close to 20 exploratory wells were drilled. Even after the SPC s Derro Oil Field Block XXIV N E U P H R A T E S R I V E R Abu Khashab Oil Field Hanadie Al Dahl Halima N.Dibssan Kalaa Wadi Obied Rashid Derro Zemlah Dbissan Al Kharrata RSI 0 10 Km Bishri Dafayen Al Mazraa Figure 1. Location map of Block XXIV, Syria Mahash El Isba Atallah Jafra KHABOUR discovery in the and Transition Zone formations of Early Miocene, successor companies targeted the formations of Early Cretaceous and older age in their exploration programs. IPR Mediterranean Exploration Ltd (IPRMEL) and ONGC Videsh Limited (OVL) exploration team s approach to the area was simple but entirely methodic. A multi-disciplinary approach based on 1

2 paleogeography, depositional models, diligent seismic interpretation and local petroleum geology is applied in order to come up with a workable exploration concept. The prolific Silurian source rocks in the Sinjar Basin, which is located to the northeast of Abu Khashab Oil Field, generated high gravity oil and gas. During the Pliocene tectonics, this basin was inverted once more and tilted towards the northeast. After the Pliocene these hydrocarbons have migrated vertically through the faults up to the Transition Zone () of Early Miocene, which is regionally sealed by the evaporites of Middle Miocene. Porous-permeable limestones of the Chilou and formations and permeable dolomite beds of the and Dibbane formation carried these hydrocarbons laterally towards the structurally higher southwestern areas. According to this concept, every structure at the Chilou, Dibbane, and Transition Zone levels on the migration path from the Sinjar Basin to the Abu Khashab Field must have been filled down to their spill points (Fig.2). Seismic interpretation of 360 km of reprocessed 2D data has resulted in the mapping of the main fourway closure of Abu Khashab with some satellite closures. The Abu Khashab-1 discovery well penetrated the formation at 949 m with strong oil and gas shows. Subsequent extended open hole drill stem test proved substantial oil flow of 34º API oil with 4% H2S. INTRODUCTION Block XXIV was granted to IPRMEL-OVL in 2004 for three phases totaling seven years of exploration by the Syrian Petroleum Company (SPC) and the Ministry of Petroleum & Mineral Resources. The block area was explored before by major oil companies and relinquished for not being prospective. IPRMEL exploration team has conducted a methodological and systematic study in order to outline the hydrocarbon (HC) plays, by studying the paleogeography, regional tectonics and seismic interpretation. Although this study covers the whole stratigraphic column over the entire Block XXIV, this paper focuses only on the Miocene play in the northeastern corner of the block (Panhandle Area). SPC s Derro Field, which was discovered in 1977, is producing from Miocene age and Transition Zone () formations. The field is a large gentle four-way closure. The apex of the field is around 225 m above the sea level. The oil water contact is 280 m subsea. However the spill point of this gentle closure is at 300 m subsea. The reservoir section is sealed by the evaporites of the Lower Fars formation. The production is maximum 200 bbls/d/well by pumping. The 35º API gravity oil has 4 % H2S. The source of oil is Silurian age. The nearby well to the Derro Field, Misrame-1, is located to the southeast of the field and has penetrated the formation at 155 m subsea, which is 70 m higher than the Derro Field but the is not HC bearing. Also Kasra-101 & Kasra North-1 wells are structurally higher than the Derro Field at level but also not HC bearing. THE CONCEPT The approach to the area was simple but entirely methodic. This multi-disciplinary approach was found on paleogeography, depositional model, extremely diligent seismic interpretation and local petroleum geology. The prolific Silurian source rocks in the Sinjar Basin generated high gravity oil and gas. After the Pliocene, the subject basin was inverted, resulting in the generated hydrocarbons to migrate vertically through the faults up to the Chilou formation of Oligocene age and the formation of Early Miocene age, which are sealed by the evaporites of the Dibbane and of Miocene age successively. The regional seal is Middle Miocene age Lower Fars formation. 2

3 Abu Khashab Oil Discovery HC Migration Derro Field Figure 2. Location of Sinjar Basin relative to Block XXIV Porous-permeable limestones of the Chilou and and porous-permeable dolomite beds of the Dibbane and carried these hydrocarbons laterally towards the southwest, which is structurally higher. According to this concept, every structure on the migration path from Sinjar Basin to the Derro Field must have been filled down to their spill points. However, the amount of migrated hydrocarbons was not sufficient enough to fill the Chilou and Dibbane in the Abu Khashab area and the in the Derro Field down to their spill points Fig. 3). For this reason, there is no HC in the Chilou and Dibbane of Derro Field because these reservoirs were not filled down to their spill points in newly discovered Abu Khashab Oil field. For the same reason, even though they are drilled on structure and higher than Derro Field wells, formation is not HC bearing in the wells Misrame-1, Kasra-101 and Kasra North Sea De pth L evel (m ) Kasra North-1 1 Der r o-2 A bu Khashab- Derro-2 A bu Khashab- Al Houlou- B Al Houlou-1 Abu Kha shab-1 & 2 Al Houlou-B Al Houlou Je ribe D ib bane L ow er Fa rs O.W.C T Z Jerib e D ib ba ne T Z Lower Fars L ow er Fars -500 C hilo u sea lev el JERIBE -700 C hilo u DIBBA NEH CHILOU Jaddala O.W.C O.W.C -900 Jadd ala Jadda la D ibb ane C hilo u Jad dala 20 0 m Legend Index Map km Oil Prod ucing Zon e Oil Shows Gas Sh ows HC Migration from Sinjar to Derro Field Figure 3. Pre-dril x-section explaining the play concept of Abu Khashab discovery 3

4 Based on this concept, 360 line km of 2D seismic (Fig.4) has been reprocessed successfully. All existing mis-tie problems were corrected (Figs. 5a & 5b) and the Abu Khashab-1 well was drilled successfully and has proved the viability of this concept (Fig.6). Oil migrated from Sinjar Basin Derro Oil Field Abu Khashab Oil Discovery New Acquisition seismic data Reprocessed seismic data New Reprocessed data (2009) New data from Petrocanada Figure 4. 2D seismic coverage over the Panhandle area NW AK-1 AK-2 SE Dibbane Chilou Figure 5a. 2D seismic line MA14, trending in NW-SE direction 4

5 SW AK-1 AK-2 NE Dibbane Chilou Figure 5b. 2D seismic line MA16. Gentle structure is also seen at the surface 5

6 Abu Khashab Oil Discovery AK-2 AK-1 Figure 6. Formation Depth structure map and location of discovery wells THE RESULTS Open hole extended drill stem test has resulted in the production of average 1000 barrels of light oil with no water. Consecutive reservoir study revealed that the well is capable of producing 3000 barrels/day. The gravity of oil is 34 API with 4% H2S. The second well Abu Khashab-2 in the area at an offset of 650 meters is drilled down into Chilou formation. Chilou and Dibbane formations produced 1500 barrels/day and 1350 barrels/day successively during production tests. Discovery of commercial oil in Chilou and Dibbane formations in addition to the appraisal has further confirmed the concept and methodology used by IPRMEL/OVL in this project. 6

7 ACKNOWLEDGEMENTS The Authors wish to thank the Managements of IPR and OVL for their permission to publish this paper. Our thanks are extended to IPRMEL Exploration Department staff for their valuable contributions to the study. * Speaker IPRMEL: IPR Mediterranean Exploration Ltd. (IPRMEL) - Syria OVL: ONGC Videsh Limited - India 7