Fitting Square Data Into Round Databases Data Management in the Papua New Guinea Foldbelt

Transcription

1 Fitting Square Data Into Round Databases Data Management in the Papua New Guinea Foldbelt S Kreibich Geotechnical Data Analyst Oil Search Ltd PPDM 2011 Perth Data Management Symposium 1

2 Oil Search Limited Tunisia Iraq Yemen Papua New Guinea Juha Hides Mananda Global Fold & Thrust Belts PNG Foldbelt Iagifu Hedinia Gobe Was incorporated in Papua New Guinea (PNG) in 1929 Is PNG's largest oil and gas producer and operates all of PNG's currently producing oil and gas fields Has exploration activities in PNG, Yemen, Iraq and Tunisia Port Moresby SRTM (Synthetic Radar Topography Model) 2

3 Remote & Rugged Environment Looking SW to Hides Hegigio Gorge Highlands Highway Strickland Gorge Hides Gas Plant Gobe/SE Gobe Facility 3

4 PNG Oil Fields Mountainous Terrain Mt Sisa 2270m Hides 2700m Mananda 2000m Moran 1760m Mt Kerewa 2930m Mt Bosavi 2500m Hedinia Iagifu 1380m Iagifu Ridge Camp 1390 Moro 830m Lake Kutubu 800m SE Hedinia 1120m * All heights Approximate Mt Kosciuszsko =2,228m DEM (Digital Elevation Model) 4

5 A Centralised Dataset Well Data Clean Up Duplicate and un-qc d data across multiple Geoframe Projects 3 Year Project Exploration Department implemented Landmark s Openworks R5000 (OW) Out of the Box database Same database for both interpretation tools & qc d data R5000 Openworks Master & Interpretation Projects Migration & QC performed in-house Data from Geoframe using Openspirit Able to migrate only the QC d Geoframe data Beneficial to the Well Clean up Project 5

6 Data Migration & QC Produced Well Data Set with QC d: Well Header Deviation Surveys Well Logs Benefits: Understand our data better Act of migrating as valuable as the database migrated to Data Management Archaeology QC d Data Identified by the Corporate Interpreter: AAA 6

7 Defining Corporate Stratigraphy Geoscientists collaborated to produce standardised stratigraphy Subset of PNG Stratigraphic Column linking Major Play Divisions across Applications Exploration wells correlated in OW AAA set of picks 7

8 Square Data? We may all encounter data from time to time which doesn t quite fit into our database. Square Data at Oil Search includes: Multiple well names Seismic Datums & Height Datums Formations that are repeated, over turned, faulted As Data Managers it is just as important to understand the data that doesn t fit into the database, as much as the data that does 8

9 The Square Example A fictional scenario of an Exploration Well in the Highlands called: Square 1 and how Square Data is accounted for in Openworks 9

10 Square Seismic Acquisition Juha Hides Hedinia - Iagifu Gobe FoldBelt 2D Seismic Helicopter Transportation Explosives Lowered Though Sky Hole Bridging Planting Geophones Percussion - Rock Hammer Drill 10

11 DEPTH TIME What Are Seismic Datums? Depth Domain REAL WORLD vs. SEISMIC WORLD Time = Distance Velocity Time Domain Datum Static = (SRD-Elevation) RepVel 0m MSL Elevation ZERO COMMON REFERENCE POINT RepVel Datum Static 0 ms SRD Changes to the SRD = Seismic Reference Datum And /Or RepVel = Replacement Velocity Will Result in Picked Horizon Time Being Different!!!! It is essential to keep a record of both Eg: SRD = 2800, RepVel = 3500 is often written as 2800m@3500m/s 11

12 Effects of Datums on Seismic If the Seismic Reference Datum & the Replacement Velocities Are Different Seismic Does Not Tie PN PN ch01 PN os11 PN PN PN m/s 4000m/s 3500m/s 2000m@3000m/s 12

13 Why Not Re-Datum Seismic It is not possible for all the seismic to exist on the same Datum Historical data processed with different datums would require reprocessing Changing replacement velocity can affect subsurface processing Juha Hides Komo Iagifu Ridge Moro Gobe Highlands Seismic Datasets which Cannot Currently be Tied in Time Domain 13

14 Seismic Datums In Openworks We record the SRD and RepVel in the Remarks section of the Seismic Data Manager SRD & RepVel combination is the most important piece of information to record with our seismic dataset 14

15 Tying Depth World to Seismic World We Tie Wells to Seismic Not Seismic to Wells By Adjusting Checkshots Different checkshot for different datums Checkshot Naming Convention = INTERPRETER_DATUM_WELLNAME 15

16 Wells Have Height Datums Too! Multiple Height datums in use Difference between them can be up to 21 metres Juha Datum Hides Datum Kutubu Datum (AKA Chevron Construction Datum) Chevron Datum (AKA CPD) Gobe Datum Incorrect Height Datum will give Incorrect Elevation LAT Kumul Kumul34 Local Height Datums in PNG Oil Fields * R Stanaway, Quickclose, Review and Validation of Geodetic Datums used in the PNG Oilfields - Report

17 Why Are Elevations Important? Can alter the Oil / Water Contact If one well in the field is using the wrong elevation This affects Reserves Calculations Value of the Company 17

18 Elevations in the Database All wells in Openworks are referenced to MSL Some areas of company still use Local Height Datum Remarks section notes MSL & Local Height Datum 18

19 Too Technical??? As Data Managers we need to know what information needs to be recorded in the database Even if we don t understand it Communicate with people who do Back to Square 1 19

20 Square 1 Selecting the Location Square 1 proposed Target Box on Topography Proposed Coordinates Proposed Elevation Proposed Trajectory Proposed Well Name Square 1 Target Box Scouting Trip 2 possible Well Pad Locations Coordinates & Elevations using handheld GPS from a helicopter 2 Proposed Coordinates 2 Proposed Elevation 2 Proposed Trajectory 1 Proposed Well Name 20

21 Square 1 Defining the Location Location Selected Well Pad Constructed 2 Proposed Cellars Square A Square B 2 Proposed Coordinates 2 Proposed Elevation 2 Proposed Trajectory 2 Well Names Cellars Constructed Survey Report by Licensed Surveyor Cellar Selected & Rig Mobilised Well called Square 1 again Final Coordinates Final Elevation Proposed Trajectory 1 Well Name Before Square 1 is Spudded : Coordinates = 6 Trajectory = 6 Elevations = 6 Names = 3 21

22 Square 1 Drilling Begins 800m - Rig is Skidded Well Re-Spudded New Coordinates New Surveyors Report New Name Square 1A New Final Coordinates New Final Elevation New Trajectory New Well Name Square 1A is sidetracked 3 times Square 1A ST1 Square 1A ST2 Square 1A ST3 3 BH Coordinates 3 Trajectory 3 Well Names The Square 1,1A & Sidetracks have produced: Coordinates = 7 Trajectory = 10 Elevations = 7 Names = 7 Which may explain why pre-migration & QC there were 1902 boreholes in the database and now there are only

23 So What Did We Find in Square 1AST3? A Simplified Example of what had happened: Compression Compression & Folding Compression Folding & Faulting Vertical & Overturned Beds 23

24 Square 1AST3 Square 1AST3 Stratigraphic Order Fault 1 Inverted Fault 2 Repeat Inverted Fault 3 Inverted & Repeat Inverted Multiple occurrences = observations Type of observation = Remarks 24

25 Square 1A Becomes the Square Field DISCOVERY! The Development Group want to use the Openworks dataset New Development Specific Square Data Other areas of the Company want to use Exploration's QC d dataset Document Managers, Engineers, Cartographers. 25

26 Epilogue Fast forward to 2026, 15 Years after Square 1 was spudded and the field has produced at record levels: The P&A d Square 1A ST3 is re-entered to function as a water injector and is now called SWT 1ST3 All interpretation packages in use, talk directly to a centralised database Company wide centralised repository for Well & Seismic information Interpretation tools re-datum checkshots on the fly Local Height Datums are stored in the database However, despite all these advances, there are still Foldbelts with Datums & unusual Geological Features and we still need to deal with Square Data 26

27 Questions? The Contributions to this presentation by staff at Oil Search Ltd, in particular; John Noonan, Jeremy Iwanec, Geoff Mansfield, Simon Skirrow, Peter Hamilton & Tony Young, are gratefully acknowledged 27