Rock Physics Model for Fluid Substitution in Carbonates
Principal investigator: Dr. Sandra Vega (The Petroleum Institute, PI)
Participants: Dr. Soufiane Jouini, Mr. El Amin Mokhtar, Dr. Jyotshana Prajapat, Mr. Ahmed Abed Hasan (PI undergraduate), and Mr. Ammar El Husseiny (PI undergraduate).
Former participants: Ms. Mariam Al Bloushi (ADCO), Mr. Abdul Aziz Al Mazrooei (former PI undergraduate, now in ADCO),
Mr. Mohamed Eid Al Suwaidi (former PI undergraduate, now in ADCO).

Summary

 

The primary objective of this project is to develop an improved quantitative model that relates seismic response to changes in fluids and pressure in carbonate reservoirs. The principal outcome will be a quantitative rock physics model that better predicts 4D seismic response of carbonate reservoirs with production.
In this project, we aim to (1) evaluate different fluid substitution models that adjust better to the properties of UAE carbonates, (2) choose the best model(s) that predicts changes in seismic due to fluid changes, (3) develop a new model(s) for carbonates, (4) study the effect of pressure versus fluid changes in the seismic response in these carbonates, (5) include the best model(s) in the Rock Physics feasibility studies of carbonates.

  

 

Research Themes

In order to accomplish our objectives we are working in the following tasks:

  
 
Models comparison: Study of the applicability of fluid substitution models in carbonate rocks. Using Gassmann as a reference model, we have compared other models and the actual 4D seismic response… (click here for more details and  related papers).  
A study of velocity and permeability anisotropy using sedimentological approach: Some carbonate rocks show clear permeability anisotropy that can be detected with shear waves… It seems to be related to the internal structure of the rocks… (Click here for more details and related papers).  
4-D seismic uncertainty: 4D-seismic analysis and interpretation.  4D changes, lithology and production correlation… (Click here for more details and related papers)  
  Experiments to investigate the effect of diagenesis in carbonates minerals and their applicability in Gassmann equation: Physical and Chemical Digenesis Effects on Acoustic Properties of Forming Carbonate Minerals: Calcite and Dolomite. A series of experiments to study the basic process of diagenesis in carbonates minerals using sound waves... (Click here for more details and related papers)  
A study the effect of patchy saturation in UAE carbonates:Correlation between Rock Physical Properties, Sedimentological and Diagenetic Characteristics of Early Cretaceous Carbonate Rocks from the Middle East. A study to better understand the seismic response using sedimentological approach… (Click here for more details and related papers)  
An examination of Vp & Vs pressure dependence: Pressure does not seem to affect much seismic in carbonates due to fluid substitution. However, the velocity-pressure response is heterogeneous and sometimes it might become as important as the change in fluids… (Click here for more details and related papers)  
Vp and Vs as function of fluid saturation and seismic inversion : Vp/Vs ratio for these cretaceous carbonate rocks is around 1.82 which is between the expected values for dolomite (1.8) and limestone (1.9).