Total innovates with 4d technology
In summer 2014, Total carried out a large scale 4D seismic acquisition survey on Al-Khalij field in partnership with Qatar Petroleum (QP). This was the first time that such a survey was carried out in Qatar, marking the evolution of seismic monitoring aid in field development.
The fact that the 4D acquisition needed to mimic the survey conducted in 1999 was a real challenge in the context of a mature field: new platforms which were not present earlier, ongoing production and drilling operations in the field, and environmental protection as a priority.
This operation is part of the actions undertaken to enhance oil recovery of such a maturing field, with due regards to health, safety and environment.
Commitment to a challenging field
Total operates Al-Khalij field, a complex and challenging offshore carbonate oilfield discovered in 1991 on Block 6, located around 120km north-east of Doha. It comprises of eight platforms and 58 wells, 48 of which are oil producing. Production from this oilfield started in 1997. Today, close to 25,000 barrels of oil per day are sent via two subsea pipelines to a treatment facility located on Halul Island.
In November 2015, Total reached the milestone of 200 Million barrels of oil produced from the field.
Innovation for recovery
The main purpose of the survey was to understand production mechanisms at stake in Al-Khalij field. This will help in enhancing oil recovery and having a better reservoir management. This survey will also help to understand water movement in the reservoir, to identify bypassed oil pool, to highlight flow barriers and drains….
The full 4D seismic process was employed over a period of one year, passing through acquisition, processing, and interpretation of repeated seismic survey.
Five marine vessels were used for this survey, which punctually sailed to deploy and recover seismic cables, perform maintenance of equipments, and to perform the seismic acquisition.
The data acquired will enable to better capture changes that have taken place in the field since 1999, when the initial baseline survey was conducted.
No compromise on Safety and Environment
With safety as Total’s top priority, the survey was completed without any incidents or accidents
An Environmental Impact Assessment (EIA) was conducted and mitigation measures were ensured. A Marine Mammal Observer was deployed onboard the vessel to protect mammals and marine turtles. Soft Start Shooting method was also carried out: starting the noisy pulls slowly and with low energy to softly warn animals and allow them the time to leave the acquisition area. The acquisition itself, with high energy pulse, starts only after being sure that mammals have left the survey area.
The success of the survey was a milestone project for Total, thanks to trust laid by Qatar Petroleum (QP) in operating the field. This has built on Total’s well-established partnership with QP, and is a proof of our commitment to operational excellence.