Ravva - Cairn’s first development success story has been the bedrock of innovation, and the foundation of our success story in the country and the region. Ravva, which in Sanskrit and Telegu means “diamond” showcases the journey of growth that Cairn has been able to achieve in its business. Incidentally, Ravva is the only field in India to get such a unique name indicating the belief of the nation in it. http://www.cairnindia.com/

1.
RAVVA
Celebrating 16 Years of Technical Excellence
Innovating Development | OBC Time Lapse Survey

2. Ravva | Innovating Development
Ravva OBC Time Lapse Survey
The Ravva JV has introduced many state-of-the-art technologies in the development phases to recover
more oil from the reservoir. One such initiative is to acquire time lapse data for by-passed oil identification
within the producing reservoirs.
To predict production induced time lapse
effects in seismic, two or more 3-D seismic
surveys are required at different periods over
the same area.
These differences can be calibrated to
changes in the reservoir properties,
saturation, pressure, and fluid properties.
As the reservoir is exploited, fluids in the
reservoir pore undergo changes in pressure,
composition and temperature. Production
causes lowering of fluid pressure, and
increasing the effective overburden pressure
of the reservoirs.
In some cases, the reservoir pressure is
maintained by the injection of water or gas.
This results in changes in fluid saturation in the reservoir over a period of time.
These changes alter the seismic velocity and the density of the reservoir and can be measured. When
these changes are large enough due to production, seismic acquired in two different times show different
attributes.
Ravva reservoirs respond acoustically to the production related changes in the reservoir. In general, in 4D
acquisition programmes, five percent change in the acoustic impedance changes is considered to be
within detectable limit. The estimated acoustic changes for the Ravva reservoir is between 2% and 10%.
The proposed 4D survey will be carried out during the fair weather window from January to April in 2010.
The survey will be carried out to cover all the producing blocks, satellite pools and other marginal
discoveries present in the permit area. The benefits of the survey will help to fine tune the infill well
locations and additional infill opportunities.