A New Bathymetric Map for the Israeli EEZ: Preliminary Results

Transcription

1 A New Bathymetric Map for the Israeli EEZ: Preliminary Results Hall J.K., Lippman S., Tibor G., Gardosh M., Sade A.R., Sade H., Golan A., Amit G., Gur-Arie L., Nissim I.

2 תקציר מפה בתימטרית רגיונלית של מזרח ים התיכון פורסמה בעבר בשנת מפה זו נערכה מכל מדידות העומק שהיו זמינות באותה העת. בשנים האחרונות נאספה כמות גדולה של נתוני עומק חדשים במים הכלכלים של מדינת ישראל במסגרת פרוייקט המיפוי הבתימטרי הלאומי, פעילות מסחרית ומחקרית. לאור המשך הפעילות הענפה בים התיכון על ידי חברות הנפט והגז, המשימות הרגולטוריות העומדות בפני משרדי הממשלה השונים וכן העניין הרב הקיים באקדמיה ובציבור נוצר צורך בהכנה של מפה בתימטרית מעודכנת. בעבודה זו אנו מציגים מפת עומק חדשה ומפורטת של אזור המים הכלכלים של מדינת ישראל בים התיכון אשר הוכנה מכל הנתונים הזמינים היום, הכוללים נתוני סונאר חד ורב אלומה חדשים שנאספו על-ידי המכון לחקר ימים ואגמים לישראל, סקרים סיסמיים דו-מימדיים ותלת-מימדיים שנאספו במסגרת חיפושי הידרוקרבונים, קידוחי נפט וגז וכן מדידות עומק ישנות. באזורים הרדודים (בין מטר) המיפוי מתבסס בעיקר על סונאר רב אלומה. בחלק העמוק יותר של המים הכלכלים (עמוק יותר מ מטר) המיפוי מבוסס בעיקר על פענוח נתונים סיסמיים. בעתיד תעודכן המפה הנוכחית בעזרת נתונים מסקרי סונאר רב-אלומה חדשים שיערכו בים העמוק בעזרת ספינת המחקר החדשה "בת גלים" שתחל בפעילות בסוף שנת 2015.

3 Introduction State of Israel A regional bathymetric map of the Eastern Mediterranean area was previously published in This map was compiled from all the depth measurements available at the time. In recent years large amount of new bathymetric data was collected offshore Israel within the framework of Israel National Bathymetric Survey, research and hydrocarbon exploration activities. The continuing interest in the Israeli Exclusive Economic Zone (EEZ) by oil and gas companies, governmental agencies, academia and the general public requires an update of the map published in In this report we present a new high resolution bathymetric map of the EEZ area. The map was prepared by collaboration between the Israel Oceanographic and Limnological Research (IOLR), Geological Survey of Israel (GSI), Petroleum Unit in the Ministry of National Infrastructures, Energy and Water Resources and the Survey of Israel. A. Multibeam bathymetry acquired by IOLR between B. 3D Seismic Surveys GSI-MGD seismic survey of Ras al Bayada during "Operation Litani" in Southern Israel Emed Merge Lebanese coastal and fishing charts Sara Myra Northwestern Area Arie Pelagic BG Gal C Neta Royee Ruth C Medimap Group Mediterranean multibeam sonar compilation available to contributing members as a 500m grid. C. 2D Seismic Surveys Eastern Area Horizon 1983 Isramco 1988 Isramco 1991 GSI-IOLR-SOI Israel NBS EM1002 multibeam sonar survey Petro Med Spectrum 2001 TGS 2000 Oceana coastal pipeline survey done for the Ministry of National Infrastructures in TGS 2008 D. Legacy data sets GSI-MGD reconnaissance seismic surveys Northern Area French Ifremer's 'Shalimar' EM302 survey by R/V Suroit in 2004 for the Lebanese government. E. The land data is from NASA METI ASTER 30m GDEM global topographic dataset. F. Well Data: Aphrodite 02, Leviathan 01-04, Tamar 02-06, Tanin 01, Karish 01, Myra 01 Dolphin 01, Sara 01, Shimshon 01 Table 1: Data sets used to create the new bathymetry map

4 Workflow The data sets used for the compilation of the new map is shown in Table 1. In the shallow area (10 to 1600 m below MSL) mapping is primarily based on new multibeam data (Table 1, A). In the deeper part of the EEZ mapping is based on the Water-Bottom (WB) horizon identified in 2D and 3D seismic surveys (Table 1, B,C) and well control (Table 1, F). The 3D seismic sets consist of eight adjacent and overlapping seismic cubes that provide good coverage of the deep offshore (Fig. 1). Gaps in areas with no multibeam or 3D seismic coverage were mapped with data from 2D seismic profiles (Fig. 2). The depth to the WB in the seismic data is correlated to the 'peak' of the first seismic reflection across the 3D cube or 2D profile. When the seismic data was available only in two-way travel time it was converted to depth using the velocity of sound in the water column (1520 m/s). Figure 1: Map showing the location and spatial resolution of Multibeam and 3D seismic data used in this study.

5 Figure 2: Map showing the areas of gaps in 3D and multibeam data coverage that were filled by the interpretation of 2D seismic profiles. Working Steps 1. Manual picking of WB seismic reflector on 3D data (Fig. 3) 2. Auto-picking of entire 3D cube (Fig. 3) 3. Surface creation (spatial resolution as seismic data) 4. Depth conversion (where needed) 5. Surface adjustment to WB from well control (Fig. 4) 6. Merge 3D surfaces (Fig. 5) 7. Manual picking of WB seismic reflector on 2D lines 8. Create surface of 2D picking 9. Depth Conversion of surface 10. Merge 3D & 2D water bottom surfaces 11. Merge seismic water bottom surface with legacy & land data (Fig. 6,7,8)

6 (a) (b) Figure 3: Example of manual (a) and automatic picking (b) of the water-bottom reflection on 3D seismic data. Myra 01 WB Before Well Tie WB After Well Tie Average well tie correction in all surveys ~4m Figure 4: Correction of the water-bottom reflection, interpreted in a 3D seismic survey by correlation to the depth of the water-bottom in the Myra-1 well.

7 Ruth C (TWT converted to TVD) WB Sara Myra (TVD) Figure 5: Merging of the interpreted, water-bottom seismic reflection in two seismic surveys, Sara-Myra (yellow) and Ruth C (red). MB (100X100m resolution grid) WB Sara Myra Grid (TVD) Average mis tie ~3-5m Figure 6: Merging of the water-bottom seismic reflection (yellow) and depth data from multibeam survey (red).

8 State of Israel Figure 7: A contour map of the depth to the WB, shown on the background of a high resolution image of the seafloor. Depth values are in meters below mean sea level. Coordinates are in UTM Projection (WGS-84 Datum Zone 360N). The white polygon outlines the area of the Israeli EEZ.

9 State of Israel g e b f d a c Figure 8: A high-resolution image showing the complex nature of the seafloor in the Eastern Mediterranean Sea. White letters mark areas with distinct geomorphologic features (See more details in the text). Coordinates are in UTM Projection (WGS-84 Datum Zone 360N). The white polygon outlines the area of the Israeli EEZ.

10 Results A high resolution image of the Eastern Mediterranean seafloor is presented in Figures 7 and 8. The white polygon displayed in these maps is the outline of the Israeli EEZ as defined by the Survey of Israel. Figure 7 shows a bathymetry map with contour intervals ranging from meters, and Figure 8 highlights various features on the sea-floor. Digital files of the images in Figures 7 and 8 are found in Appendices A and B. The bathymetric grid (ASCII format Zmap) is found in Appendix C As shown in Figure 8, the area near the shoreline comprises a wide and flat submarine, continental shelf (a). Towards the north the shelf narrows, it drops sharply to the deep basin and it is heavily incised by deep submarine canyons (b). In the central area and near the edge of the shelf, the conspicuous, box-shaped Palmahim Slide is observed (c). The surface of the deep-marine basin is highly rugose and displays variety of morphologic features that were not recognized in the older bathymetric map of A series of meandering submarine channels, km long and up to several hundred meters wide extend from the south, southeast and southwest towards the northern part of the EEZ (d). Several sets of narrow ridges (e) and sharp lineaments (f) are found throughout the deep basin. These are probably associated with the activity of shallow folds and faults. The resolution of the image in Figure 7, 8 is affected by data coverage. Areas covered with multibeam and 3D seismic data show many details, whereas areas with poor coverage are relatively smooth and lack details (g in Figure 7). Plans for future activity include acquisition of multibeam data throughout the deep basin. This survey will be conducted with the R/V Bat Galim, a new research vessel recently purchased by the IOLR that will be equipped with two Kongsberg multibeam systems, the EM2040 for shallow water (up to WD of 500m) and the EM302 (up to WD of 6,000 m). The R/V Bat Galim will become operational in late 2015.

11 Acknowledgments Part of the 3D seismic data used in this study is courtesy of companies that operate in the East Mediterranean area. We would like to thank the following companies: AGR Petroleum Services Holdings SA, ARI Investment Partners VII Ltd., ATP Oil & Gas Corporation, Avner Oil and Gas, Coleridge Gas & Oil Exploration Israel Ltd. Partnership, Daden Investments Ltd., Delek Drilling Ltd. Partnership, Dor Gas Exploration Ltd. Partnership, Edison International SPA, Emanuelle Energy Ltd., Emanuelle Energy Oil & Gas Ltd. Partnership, Energean E&P Holding Ltd., Frendum Investments Ltd., GeoGlobal Resources (India) Inc., IDB Development Corporation Ltd., INOC Dead Sea Ltd. Partnership, I.P.C. Oil and Gas (Israel) Ltd. Partnership, Israel Oil Comp., Israel Opportunity - Energy Resources Ltd. Partnership, Isramco Negev 2 Ltd. Partnership, Lapidoth-Heletz Ltd. Partnership, Modiin Energy Ltd. Partnership, Nammax Oil & Gas Ltd., Naphta Exploration Ltd. Partnership, Noble Energy Mediterranean Ltd., Ratio Oil Exploration Ltd. Partnership, The Israel Land Development Company Ltd. Disclaimer: The maps and surfaces published in this report are provided "as-is" and are not legal surveys or legal descriptions. We disclaim any representations and warranties as to the accuracy of the maps and surface. These maps and surface are not intended for navigational, commercial, legal or political purposes. Appendices A Depth contour map of the EEZ area in TIFF format. B High-resolution bathymetric map of the EEZ area in TIFF format. C Bathymetric grid of the EEZ area (250X250 meter) in ASCII format.