Print this pageAbstract: Gas Storage Rehden (Northwest Germany) - Geological Aspects of Horizontal Drilling and Completion
UBBENJANS, HERMANN, and HELMUT ZIMMERHOF
The Underground Gas Storage Facility (UGS) of Rehden is part of the WINGAS-owned pipeline system MIDAL/STEGAL. The company WINGAS, a joint venture between GAZPROM and WINTERSHALL AG, is the owner of this UGS, which was established in a depleted gas field located 70 km south of Bremen. The storage horizon is the Hauptdolomit (Ca2) of the Upper Permian Zechstein Formation. The structure is a horst block which is extremely faulted. Good porosity, high permeability and natural fractures are found throughout the reservoir.
The UGS was developed to accommodate approximately 2 billion m3 of working gas. A maximum capacity of approximately 4 billion m3 is possible and is expected to be reached in the next 3 years.
From 1992 - 1995 thirteen horizontal wells were drilled with a TVD of approximately 2000 meters. The average horizontal length within the Hauptdolomit formation was 300 - 400 meters. MWD directional tools were used to provide control on the drilled profile at all times and to avoid excessive dog-leg severity. FMI logs for fracture detection were recorded in all Rehden UGS wells. The wells were drilled as close as possible to perpendicular to the main fracture orientation.
The wells were equipped with a preperforated 7"-liner including 3 ECPs, allowing selective acid treatments to be performed. The tubing diameter was chosen to minimize flow restriction with 7" in the lower part and 7 5/8" in the upper part. The wells were stimulated and showed a flow capacity of up to 100,000 m3 (Vn) gas/well/hour.
AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria