--> Abstract: Modern 3D Interpretation of a Mature, Structurally-Complex Oil Field, Los Angeles Basin, California, by J. R. Scheevel, M. McCaskey, and J. Byl; #90092 (2009)

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Modern 3D Interpretation of a Mature, Structurally-Complex Oil Field, Los Angeles Basin, California

Jay R. Scheevel1, Michael McCaskey2, and Jason Byl3
1Scheevel Geo Technologies LLC., Grand Junction, CO
2Matrix Oil Corporation, Santa Barbara, CA
3Bankers Petroleum, Los Angeles, CA

The Whittier field is one of many aging Los Angeles Basin fields. The reservoir section consists of deep-water turbidites both channelized and amalgamated fans. The field was developed over 100 years starting with cable-tool, then rotary vertical drilling (no logs), then with rotary directionally drilling (logged using modern wireline tools). The wireline data combined with limited data from older wells provides the control set for our complete 3D model study.

The structural geometry is very difficult to interpret from logs alone because of vertical and overturned beds. Log signatures vary wildly with the wide range of penetration angles relative to bedding. Lateral variations in stratigraphy further complicate interpretation. Because of these difficulties, historical development has been based on a strategy of offsetting successful wells along strike.

Our study integrates log data, surface mapping, surface and subsurface dip data and hydrocarbon indicators into a 3D volume interpretation environment. Well correlation using bedding-parallel foreshortened views enables accurate true stratigraphic thickness correlations. Translation of surfaces conforming to dip control and perpendicular to layering (pseudo-concentric construction using a neural-network dip prediction algorithm) aids construction of the faulted, near vertical and overturned footwall structures. Horizons modeled in 3D were used to construct layered stratigraphic grids. Geostatistical and probabilistic modeling of rock-type consistent with paleodepositional trends were performed on these stratigraphic grids.

The resulting integrated 3D model reveals that the trapping of hydrocarbons in both the hanging wall and the footwall, is controlled by both stratigraphy and fault truncation. New drilling has been successful by targeting specific elements of the structure and stratigraphy.

AAPG Search and Discovery Article #90092©2009 AAPG Rocky Mountain Section, July 9-11, 2008, Denver, Colorado