Saudi Aramco Completes First Giga-Cell Reservoir Simulation Run

An industry record was achieved Nov. 1 when the EXPEC Advanced Research Center (EXPEC ARC) completed its first giga-cell (billion cell) reservoir simulation run.

The achievement was made using GigaPOWERS, the advanced next-generation parallel reservoir simulator. It further solidifies Saudi Aramco's undisputed industry leadership in the area of parallel reservoir simulation. Khalid A. Al-Falih, accompanied by Exploration and Producing senior management, congratulated EXPEC ARC during a luncheon and received a plaque commemorating the event.

"I am very proud of this feat," said Al-Falih, executive vice president of Operations. "Achievements such as this buttress our effective strategy to manage our reservoirs and symbolize our commitment to the stewardship and sustainability of our precious hydrocarbon resources. It is also a manifestation of our expanding technology leadership in the industry."

Reservoir simulation is a core technology used for most of the decisions undertaken in the upstream oil industry to predict plateau levels of fields, calculate the number of wells to be drilled, select well locations, estimate facility requirements, calculate reserves depletions, and design reservoir management strategies for recovering more oil and gas. Knowing the importance of the technology, Saudi Aramco developed and deployed its first parallel reservoir simulator (POWERS I) in 2000. The simulator is used in managing all the company's oil and gas reservoirs. POWERS I is a mega-cell simulator, meaning it uses millions of cell grid blocks. When it was developed, it provided a 10-fold increase in capacity and speed over other simulators in the industry.

However, the widespread use of 3D seismic data and sophisticated modeling algorithms has resulted in detailed geologic models that describe the reservoir properties in high resolution. Most of that detail is lost when the models are used for reservoir simulation, since current simulators are incapable of handling a large number of cells. These high-resolution models are first "upscaled" before simulation -- in effect destroying the resolution by smearing and averaging the data to reduce the number of cells.

Simulators need to be able to simulate giant fields in high resolution by using the geologic models directly with no upscaling. In order to achieve that goal, those reservoir simulators must be capable of handling many more cells, and need to move from the mega-cell models (tens to hundreds of millions of cells) to giga-cell models.

Recently, EXPEC ARC embarked on developing the second generation of POWERS, called POWERS II, and set an eventual goal of breaking the billion-cell record over the next five to 10 years. However, that feat has already been achieved. The new simulator -- in prototype -- has been tested successfully on two giant reservoirs: Safaniya and Ghawar, both with giga-cell models.

Results showed that improved accuracy obtained by a billion-cell simulation yields a high-resolution picture of the reservoirs, showing additional oil zones not detectable by the mega-cell models. Because POWERS II broke the giga-cell simulation record, it has now been renamed GigaPOWERS.

"It was a long-held dream of the industry to be able to simulate reservoir performance at seismic scale, and at Saudi Aramco, we have got it," said Ali Dogru, chief technologist of Computational Modeling Technology at EXPEC ARC. "We developed a highly complex and mathematically intensive and sophisticated computational engine that captures the complex physics of fluid flow in the reservoir; that’s how this dream became a reality," he added.