Ameren Illinois has announced the Centralia Natural Gas Storage Fields near the intersection of Calumet and Perrine Street on the city’s south side will undergo major rebuilding next year. The result is expected to be a smaller footprint and a more economical operation. Ameren has already completed similar reshaping at its natural gas storage fields in Tilden and Freeburg.
The Director of Storage Fields for Ameren Illinois Tim Eggers says the horizontal drilling process will allow 16 wells to be permanently plugged at the Centralia fields. They will be replaced with three new wells that will be located on one pad. The footprint of gathering pipeline will be reduced to 400 feet from 2.1 miles.
Eggers says they will be eliminating wells that do not have well pads or roads for access, reducing future crop damage and taking the wells out of farm fields and away from farming equipment. Most importantly, he says, the investment will allow the Centralia Natural Gas Storage Field to provide the region with reliable, price-hedged gas supply for generations to come.
Unlike oil reservoirs that are often 10,000 feet deep, Ameren’s Illinois storage fields are shallow, 875 feet in Centralia. This posed a significant technical hurdle. Without the weight of a long string of heavy drill pipe to provide force to make the curve to drill horizontally, engineers had to rely heavily on motor-driven force to guide the drill bit.
While the geology of the fields remains unchanged, horizontal wells offer grater contact with the reservoir, enabling higher withdrawal and injection rates.
Retired pipelines are purged, foamed, and plugged, remaining safely in place. This eliminates the need for annual pigging, corrosion monitoring, and other maintenance across 26 miles of small-diameter pipe.
Eggers says the shift also dramatically reduces third party damage risk: “No more wells in backyards or crop fields, and fewer changes of farm equipment strikes or children playing near exposed wellheads. Maintenance is also streamlined, crop damage minimized, and landowner compensation is no longer a recurring concern. The bottom-line impact is a projected savings of $400,000 annually in operations and maintenance.”
According to Ameren, underground natural gas storage units provide about 50-percent of the company’s natural gas to customers and on especially cold days keeps gas flowing without the company having to pay extremely high rates on the open market.
