Fluid-Pulse Technology Boosts Oil Recovery
Brett Davidson, SPE, Wavefront Technology Solutions
A unique fluid-pulse technology has generated impressive increases in ultimate oil recovery in applications in North and South America and the Middle East. Developed in Alberta, Canada, the fluid-pulse technology has proved its ability to recover oil previously left behind in fields thought to be depleted or uneconomical—potentially billions of barrels globally.
In addition to driving the phenomenal growth of the Alberta oil sands, Canada’s oil industry has developed a depth and breadth of experience in some of the world’s harshest conditions. Those harsh conditions often create opportunities for new technologies to show their capabilities to a largely cautious industry.
A recent report by the United States Energy Information Administration notes that the US imported about 45% of the 18.8 million B/D of crude oil and petroleum products it consumed in 2011. Although dependence on foreign petroleum has declined since peaking in 2005, the quest is still on for ways to increase domestic production and reduce reliance on imports. Fluid-pulse technology is one way to revive oil fields by recovering more barrels, flattening decline curves, and reducing production costs.
Pulsating Injection Stream
While waterflooding techniques have been used for secondary oil recovery since the 1920s, fluid-pulse injection optimization brings much higher efficiency to these methods. With most US production growth over the next 2 years predicted to come from tight rock plays in North Dakota and Texas, the fluid-pulse technology is uniquely suited to this type of tight formation, as well as being effective under many other challenging conditions.
A downhole tool works with conventional surface equipment and is installed into injection wells to transform the normally steady rate of injection to a pulsating injection stream with typically 10 or more pulses per minute (Fig. 1). Similar to the idea of kinking a garden hose, precise amounts of energy are repeatedly built up and released by the tool. The pulses add acceleration and momentum to the injected fluid, forcing it into the reservoirs’ nooks and crannies and more impermeable rock at speeds of up to 100 m/s. This enables the injection fluid to enter pore spaces that have remained untouched. The result is a much better sweep of the oil toward the surrounding producing wells.
A small independent operator in Alberta implemented the technology with six tools in the relatively tight Viking formation in December 2010. This is a mature waterflood in sandstone with average porosity of approximately 9% and permeability ranging from 0 to 50 md. In this light oil project, production increased from the offset producers by 69 BOPD, or 52% above the base decline trend.
The technology was also installed in a dolomite formation in Crane County, Texas, in March 2010, where the reservoir has approximately 15% porosity and permeability of 0 to 50 md. Production has increased by about 30% compared with the pre-existing trend, and the underlying base decline has decreased from 3.8% to about 1.5% per month.
An independent exploration and production company in Michigan used the fluid-pulse technology with existing well infrastructure in a carbonate pinnacle reef field to broaden CO2 distribution in a reservoir flood. The enhanced oil recovery (EOR) project began in September 2008 and lasted approximately 17 months. It included three production wells and one injection well.
Significant production benefits resulted, with a project rate of return exceeding 100%. The average oil cut increased to 97% compared with the previous 82%. The operator realized a 144% increase in oil production and an 83% reduction in the decline rate (Fig. 2).
Research Inspired by Seismic Activity
Inspiration for the fluid-pulse technology came from research into the mechanisms that contribute to increased oil production rates following earthquakes. The three researchers (the author of this article, professor Tim Spanos of the University of Alberta, and professor Maurice Dusseault of the University of Waterloo) found that generating a precisely controlled fluid pressure pulse allows the injected fluid to move outside the preferential flow path. The pressure pulses move fluid into and out of a larger number of pore networks, thereby obtaining a more uniform injection front and enabling increased oil production and recovery.
The fluid-pulse technology optimizes the performance of existing methods, such as chemical EOR technologies, liquid CO2 injection, water injection, and surfactant/polymer flooding. When effectively implemented, it is the most efficient way to disperse liquids through oil-bearing geological material.
Enhanced Ultimate Oil Recovery
The fluid-pulse technology has been used by large and small oil producers to improve sweep efficiency and thereby increase ultimate oil recovery, prolonging the lives of fields that may have been largely depleted or abandoned.
One of the key features of the fluid-pulse technology is the way in which it increases the efficiency of existing infrastructure with minimal additions. In lieu of drilling more wells, the technology can increase the operator’s recovery factor within the framework of the existing production system. In some cases, it is possible to achieve equivalent or better oil production with fewer wells.
The fluid-pulse technology is being used by producers around the world, including in Canada, the US, Brazil, Colombia, Argentina, and the Middle East. It has proved to be an efficient and straightforward method of increasing oil recovery factors and maximizing the life expectancy of oil resources.