Hydraulic Fracturing in the Haynesville Shale: What’s Different?

As domestic exploration and development efforts continue to shift toward the extraction of liquid hydrocarbons, a few plays are still producing natural gas at low commodity prices, which continues, under certain circumstances, to make fiscal sense. The Haynesville in East Texas and Louisiana is one such play. Though drilling and completion (D&C) costs can be significantly higher than in the typical North American unconventional plays and though decline rates can be abnormally high, the tremendous initial production rates can contribute to relatively short payout times.

The Need for State-of-the-Art Technology

Extraction of gaseous hydrocarbons from the Haynesville involves invoking state-of-the-art equipment and processes. Two root causes of this requirement are high treating pressures and high temperatures associated with typical Haynesville reservoirs. As in many Gulf Coast geosyncline formations, this shale is radically over-pressured, likely due in part to historical sediment loading and partly because of internal volumetric expansion associated with the maturing of individual microscopic pockets of hydrocarbons over geologic time. Static reservoir pressure gradients are typically from 0.87 to 0.91 psi/foot, and fracture gradients range from 0.95 to over 1.1 psi/foot.
As a result, typical surface treating pressures during fracture stimulation operations are between 10,000 and 15,000 psi. The typical temperature gradient is about 1.8 degrees F/100 feet, so static temperatures range between 265 and 320 degrees F. This temperature span can present difficulties with respect to degradation of downhole electronic measurement and control devices, and accelerate the vulcanization and eventual destruction of various synthetic, rubber-based mechanical sealing devices.
As with other North American unconventional plays, statistical evidence shows that the Haynesville is a resource play in which D&C processes can influence the rate of acceleration of reserve recovery as much as geological and geophysical issues can affect it. Unlike conventional reservoirs (where understanding of geological and geophysical parameters is wholly dominant), the particular methods chosen to fracture-stimulate the reservoir are critical to early production profiles