Looking for ways to reduce water use impacts
In our Haynesville Shale play of northwestern Louisiana, we have a goal to use alternate water sources wherever we can, and we're looking for ways to reduce the amount of water we use.

Many local residents rely on the Carrizo-Wilcox aquifer as a source of fresh water in the Haynesville area. In response to concerns that oil and gas activity may be contributing to depletion of the aquifer, state officials encouraged operators to use alternate water sources as much as possible. With a focus on this environmental impact, we have made a commitment to minimize water used from this aquifer.

Approximately 85 to 90 percent of the water we use for Haynesville completions activities comes from surface sources such as rivers, creeks, bayous and ponds. Unlike the Carrizo-Wilcox groundwater, surface water is more readily available in this area.

We are looking at opportunities to recycle water and this option will become more viable as the play is further developed. Until then, research continues and other creative options are being explored, such as using treated produced water for our completion operations. This process will decrease the amount of fresh water needed to fracture stimulate wells and will ultimately reduce the need to haul water long distances. This is a win for the environment and for residents impacted by truck traffic.

Similar projects are being considered across our operations in this region in an organized effort to minimize our use of fresh water - one of our most precious resources.

Drilling technology reduces emissions

To minimize our environmental footprint, in 2008 we tested a new underbalanced drilling technology using natural gas, instead of nitrogen, to reduce or eliminate flaring in our operations in the Jean Marie Basin.

• greenhouse gas reduced: CO₂ equivalent avoided 18,500 tonnes cumulatively to June 2009
• natural gas conserved: 122 MMscf of natural gas from 11 wells in 2008

In order to avoid significant formation damage, underbalanced drilling, which is historically performed with nitrogen, is required when drilling in sensitive formations such as the Jean Marie formation in our Greater Sierra resource play in northeast British Columbia.

Although the technology has been used elsewhere in the world, this is the first large-scale, long-term implementation.

• develop a system to safely and reliably recover up to 80 percent of the natural gas produced during a typical underbalanced drilling project
• ensure drilling performance is not compromised
• keep costs comparable to existing technology
• minimize the risks to the pipeline and process equipment downstream from the well site

• drilling with a flammable gas
• dealing with trace amounts of H₂S from the pipeline
• managing oxygen in the gas returns to pipeline in detail to the parts per million level

Typically, 150 to 200 wells are drilled by the industry in this area annually with typical flared volumes of approximately 600,000 m³ per well, resulting in a total annual flared volume of 90,000,000 to 120,000,000 m³. This flared volume accounts for roughly 35 percent of the annual flared volumes from the British Columbia upstream oil and gas sector.