Print this pageUlrich (Yegua) Field, Harris County, Texas
Ann Ayers Martin, William K. Peebles
The Ulrich (Yegua) field complex in Harris and Chambers Counties, Texas, produces gas and condensate from Eocene sediments of the Yegua Formation in a geologic trend commonly known as the Downdip Yegua trend. The field produces from several discrete sand units, each representing a different deltaic depositional pattern. Channels, sheet floodplain deposits, and various bar types are present in the depositional sequence. Distinctive local paleontological markers persist throughout the complex and are related to inner and middle neritic ecological zones.
The integration of several technical disciplines was necessary to first discover and then develop the field. Salt modeling of gravity data was particularly useful in interpreting seismic data.
The Ulrich (Yegua) field is notable in several aspects. The Yegua 
1-D
reservoir has produced at a rate in excess of 45 million ft3 of
gas/day from a single well. The Yegua 2A zone is commercially productive from a
well with electric log resistivity of 0.8 ohmmeters. Other unique features of
this field include trapping faults of unusually low angles and growth faults
with highly variable throws.
AAPG Search and Discovery Article #91022©1989 AAPG Annual Convention, April 23-26, 1989, San Antonio, Texas.