Exhibit 21.1

Subsidiaries of Riata Energy, Inc.

Lariat Services, Inc., a Texas Corporation

ROC Gas Company, a Texas Corporation

Alsate Management and Investment Company, a Texas Corporation

Riata Drilling Company, Inc., a Texas Corporation

Integra Energy, LLC, a Texas Limited Liability Company

Sagebrush Pipeline, LLC, a Colorado Limited Liability Company

PetroSource Energy Company, L.P., a Texas Limited Partnership

PSE Management, LLC, a Texas Limited Liability Company

PSCO2, L.P., a Texas Limited Partnership

PetroSource Production Company, L.P., a Texas Limited Partnership

PetroSource Energy Management, LLC, a Texas Limited Liability Company

TransPecos Logging, LLC, a Texas Limited Liability Company

Riata Piceance, LLC, a Colorado Limited Liability Company

Chaparral Supply, LLC, a Texas Limited Liability Company

Midcontintent Resources, LLC, a Texas Limited Liability Company

Lariat Compression Company, a Texas Corporation

Symbol Energy, Inc., a Texas Corporation

Sierra Madera CO2 Pipeline, Ltd., a Texas Limited Patnership

Sierra Madera Management, LLC, a Texas Limited Liability Company

Stockton Plaza, LP, a Texas Limited Partnership

Stockton Plaza Management, LLC, a Texas Limited Liability Company