ABSTRACT: Integrated 3-D Field Study on Workstation Results in New Reserves in an Old Field -- High Island 140 Field, Offshore Texas

SCHWARTZ, BERNIE N.

High Island 140 Field was discovered in 1958 by the Standard Oil Company of Texas Federal Block 140-L No.1 well. The field has been producing since 1967, and to date has produced in excess of 210 Bcf. and 1167 Mstb. The primary producing horizons are Lower Miocene Rob L (M-20 Sand) and Rob M (M-40 Sand) in age. Pennzoil acquired a 3-D seismic survey over the field in 1993.

High Island 140 Field is a large domal feature associated with a major northwest-southeast down-to-the south fault system. This fault system divides the field into upthrown and downthrown reservoirs and is responsible for some growth between the M-20 and M-40 producing intervals. The M-20 through M-40 interval comprises interbedded thick prodelta mudstones and sandy progradational sequences deposited near the margin of a large delta complex. A series of smaller down-to-the-southeast faults further subdivides the field into a number of separate fault blocks.

Interpretation of the 3-D data volume showed that the fault pattern was more complex than previously mapped using subsurface data and the available 2-D seismic data. The 3-D data significantly reduced risk by providing the ability to accurately map smaller fault blocks and targets. To date, two successful wells have been drilled based on the 3-D interpretation giving new life to this declining field. On the basis of geological subsurface data and 2-D seismic, it is doubtful that these results would have been obtained.

AAPG Search and Discovery Article #90941©1997 GCAGS 47th Annual Meeting, New Orleans, Louisiana