About Z-Pinnate® Technology

Even with recent advancements improving vertical and horizontal drilling methodologies, the industry still experiences marginal or uneconomic results in the more challenging coalbed methane (CBM) reservoirs. As a result of patented drilling technologies introduced by CDX Gas, producing CBM is more efficient and effective, and can be utilized even in the most environmentally sensitive areas. The Z-Pinnate® Horizontal Drilling and Completion System, combines a vertical and intersecting horizontal wellbore system (referred to as a dual-well configuration), underbalanced drilling techniques, a multi-lateral drainage network and other technologies that permit access of up to 1,800+ acres of coalbed from a single well site. By contrast, traditional “drill and frac” recovery methods typically require one well for every 20-80 acres of coal. The technology has a broad range of application, but has been applied most successfully in low-medium permeability formations, restricted surface access areas or when rapid degasification is desired.

Cross-Section Example of the Dual-Well Configuration

Utilizing substantially fewer surface penetrations, application of the Z-Pinnate technology results in
a positive environmental effect through minimal surface disturbance while still accelerating hydrocarbon recovery.

The CDX Footprint – One Well Site Can Access up to 1,800 Acres

While each component of the system overcomes particular disadvantages of other vertical and horizontal methodologies, the Z-Pinnate System as a whole has produced extraordinary and repeatable successes. Among the more significant advantages of the Z-Pinnate System are helps avoid damage to formation permeability during the drilling process, minimizes the de-watering periods, increases reserve recovery, minimal surface area requirements and efficient degasification in coal mine applications.

Underbalanced Drilling

Because CBM reservoirs are inherently low pressure formations, it is critical to ensure the pressures exerted during the drilling process do not cause damage to the formation negatively impacting permeability. Particularly, the fluids used to operate the drill bit and transport cuttings to the surface exert a hydrostatic pressure on the formation. If this hydrostatic pressure exceeds the pressure in the formation, drilling fluids and cuttings can be pushed into the small cracks and natural fractures of the formation. These small cracks and fractures are pathways critical to the production of CBM. If the pathways are plugged by the drilling fluid and cuttings, the methane remains trapped in the coal unable to migrate to the wellbore. The dual-well configuration accommodates under-balanced drilling methods so to avoid creating a downhole pressure greater than that of the formation, thereby eliminating or otherwise minimizing formation damage negatively impacting permeability.

Enhanced De-Watering Process

The dual-well configuration also provides a means to enhance the de-watering process. In all CBM wells, the methane remains trapped in the reservoir until the overall reservoir pressure has been reduced. Pressure reduction is accomplished by removal of water entrained in the formation. Unfortunately, the most optimal methods for dewatering do not work well in horizontal well bores or around the curved portion of a radiused bore. Thus, the dewatering process is often inefficient in a horizontal well thereby hampering the recovery of CBM. Unlike other horizontal wells, the dual-well configuration permits use of optimal dewatering methods. In addition, an enlarged cavity formed at the intersection of the vertical and horizontal wells in the dual-well configuration of the Z-Pinnate System provides an efficient downhole water separator, allowing water to be easily pumped off of the formation. The water being pumped off reduces the downhole pressure and allows the gas to migrate to the wellbore.

Increased Exposure to the Coalbed

The multi-lateral drainage network increases exposure to the coalbed for more uniform drainage and greater initial production rates.  This accelerated and increased ultimate hydrocarbon recovery represents significant economic benefits.