Johannes Schoenherr

Supervisors:

Janos L. Urai,

Peter A. Kukla,

Ralf Littke

Petroleum Development Oman

The Evolution of Halite and solid Bitumen in the Petroleum System of the South Oman Salt Basin

100 km

The geology of Oman

The Petroleum System of the SOSB

after Qobi, 2001

100 km

after Qobi, 2001

Surface-piercing Salt Domes of interior Oman

100 kmafter Qobi, 2001

100 km

Surface piercing Salt Domes - Qarn Sahmah

3 km

N

Dome size: 2.8 x 2.5 kmHeight: 100 m

Salt Dome Qarn Sahmah

View from a flank of Salt Dome Qarn Kibrit

Salt Dome Qarn Alam

I---- 4 cm ----I

Rocks of the surface-piercing Salt Domes

seal

reservoir

source rock

1000

2000

3000

4000

5000

0 20000 40000 60000 80000 100000 120000

Formation Pressure (kPa)

hydrostaticRFT

1 AND 3 in salt

RFT

Formation pressures of SOSB

In-situ stress and pore pressures

Stratigraphy & Geometry of Ara Group

GoCAD 3D model

Stringers

A1c –yellow

A2c – red

A3c – blue

View from west, Top Salt colour-coded by depth, with

boreholes. Note absence of stringers under Haima basinafter Droste, 2001

Key aspects of project

1. Evolution of Halite

A) Study of halite-plugged carbonate stringers

• Plugging mechanism• Diagenesis

B) Study “Ara Salt”• Microstructures• Rheology

2. Evolution of solid Bitumen

• Plugging mechanism

Methods:• Microstructural investigation• RockEval• biomarker analysis• GC analysis• Maturity analysis (BR-% measurement)

Problem statement

• Some wells have failed to produce at

significant rates (Al-Abry, 2004)

• Detailed core analysis of one stringer

revealed extensively plugging with salt and

solid bitumen (Al-Siyabi, 2005)

Outlook & aims

Problem statement

• Some wells have failed to produce at significant rates (Al-Abry,

2004)

• Detailed core analysis of one stringer revealed extensively

plugging with salt and solid bitumen (Al-Siyabi, 2005)

Aims

• Understand the plugging mechanisms

• Understand the spatial distribution of Halite and solid

Bitumen inside the stringers (Al-Siyabi, 2005)

Give a contribution to predict reservoir quality of stringers

2 cm

Case study of the sealing capacity of Halite

1 cmthin section

Under what conditions salt can leak?

Summary of PhD contents

1. Study of Salt DomesAim: Comparison of facies and HC-potential with SOSB-rocks

2. Study the diagenetic evolution of carbonate stringersAim: Contribute to give a better prediction for reservoir quality

3. Case study of the sealing capacity of Halite