Integrating potential field data with seismic, geochemistry and structural geology. Prepared for: Finding Petroleum

Size: px

Start display at page:

Download "Integrating potential field data with seismic, geochemistry and structural geology. Prepared for: Finding Petroleum"

Milo Dixon
5 years ago
Views:

1 Integrating potential field data with seismic, geochemistry and structural geology Prepared for: Finding Petroleum

2 Contents Historical issues Non-integration Present day, integration Seismic planning Mapping structural geology Magnetic data Geochemical integration Hyperspectral imaging Conclusions

3 Overview Seismic s little brother Airborne surveying has had significant success in frontier exploration. Integration of all datasets key.

4 Historically Gravity response d1 d1 d2 d1 d2 d2 d4 d5 d3 d3 d3 Correct model? Gravity data seen as a regional tool Generally limited experience within oil companies Non-uniqueness therefore uncertainty?

5 Why so Underused? We acquired grav and mag but haven t done much with it. I don t understand how it s useful to my exploration? Sounds great, but we re on an exploration timeline no time to figure out how it really works!

6 Time for a better Understanding We need to effectively become part of the exploration team to deliver results alongside and integrated with the exploration program. Geophysical models rather than geological Data that is not explained is misunderstood and useless

7 Not integrated Geophysical 2D model Depth estimate calculations

exploration areas such as Africa The data is not the problem 1 2 3 FTG

8 Present day Modern acquisition techniques allow very high resolution datasets Cover large areas quickly and cheaply Ideal for frontier exploration areas such as Africa The data is not the problem FTG data courtesy of Bell Geospace Magnetic image courtesy of SRK Consulting km

calc50kmhp Used correctly mgals 4.00 0.00 Calculated gravity response -4.

9 calc50kmhp Used correctly mgals Calculated gravity response calc50kmhp Depth (km) Geological 2D model Gravity data Depth to basement surface

10 Integration with seismic data Gravity and magnetics often a pre-cursor to seismic acquisition. Particularly in Africa, with large frontier areas. Logistical and security issues of establishing a large seismic crew in country. Arguably assisting in the seismic planning from a cost/logistics point of view is as important as any subsequent detailed geological results Typical airborne gravity and magnetic survey could have the cost equivalent of 70km of 2D land seismic.

11 Seismic planning Typical 2D seismic survey planning without gravity and magnetics as a tool The same seismic line km s located more efficiently based on prior airborne surveying

12 FINAL_Tz (m) FINAL_Tz_10kmres FINAL_Tz_25kmres (m) Seismic integration and structural geology

13 Mapping structural geology Surface geology Gravity data with surface faulting overlaid Gravity derived fault mapping

14 Mapping structural geology Description Major thrust Symbol Major offset Anticline Syncline Minor thrust Minor offset

15 Geochemical data Surface geochemical can indicate a working system, but little indication of size and extent Potential fields can indicate large basinal areas, but no direct indication of a hydrocarbon producing system Gravity and Magnetics Seismic Geochemical Integrated model In frontier areas the establishment of a working system is key for companies to assist with exploration funding, farm-ins, CPR s etc.

16 ' ' ' ' ' ' ' ' ' ' 49 15' ' Gravity derived depth structure and surface seeps ' ' ' ' ' ' ' (m WGS 84

17 Hyperspectral imaging Hyperspectral imaging has been used routinely in environmental and mineral studies. Used to map different materials at the surface of the Earth based on their spectral characteristics.

18 Hyperspectral imaging Studies have been completed on its use in onshore oil seep detection (Ellis). By combining gravity, magnetics, hyperspectral in a single aircraft a multidisciplinary survey can be flown. Other airborne oil sniffer technologies in development. Image courtesy of Northrop Grumman

19 Conclusions Data nowadays is very high resolution. Integration with other datasets is key. Producing geological models and deliverables are critical to the exploration process. Not just gravity: magnetics, hyperspectral, geochemical all add extra information.

20 The End

Airborne gravity gradiometer surveying of petroleum systems under Lake Tanganyika, Tanzania

Airborne gravity gradiometer surveying of petroleum systems under Lake Tanganyika, Tanzania D. Roberts Beach Energy P. Roy Chowdhury CGG S. J. Lowe CGG A. N. Christensen CGG Outline Introduction Geology