NORTHERN GREEN RIVER BASIN

Aeromagnetic Survey and Geophysical Analysis

INTRODUCTION

EDCON-PRJ  has acquired an aeromagnetic survey over the northern Green River Basin, covering 76 townships in Sublette and Sweetwater Counties, Wyoming.

The data can be used to map lineaments, edges of structural bodies, and faulting/fracturing which are believed to be associated with basement structure and are thought to be important contributors to hydrocarbon trapping in this northern portion of the Green River Basin. Structural highs control some of the most significant fields discovered to date, and Paleozoic sections appear to be related to deep, reactivated basement structure. In addition, there are indications that secondary porosity macrofracture trends have propagated a significant distance up into sections overlying basement faults. Therefore, zones of intersecting basement fault trends will be more prospective for increased porosity and permeability.

The survey area is immediately southwest of the Wind River Mountains and in the greater Pinedale Field area. The area trends northwest to southeast with the northern boundary including portions of Township 37N-Range 112W through T37N-R110W. The area widens to the southeast and include portions of T26N-R110W through T26N-R105W in the south. The Wind River Mountains border the survey in the east, and the outcrops provide a reference for basement correlation. The LaBarge - Big Piney Complex on the northern part of the Moxa Arch borders the survey to the west.

ACQUISITION AND PROCESSING

The acquisition specifications are as follows:

• Flight Lines: 0.625 mile flown northeast/southwest (perpendicular to strike)
• Tie Lines: 2.25 miles flown northwest/southeast (just off strike)
• Flight elevation: 500 ft above ground; draped over mountainous areas
• Total line miles: 5,571 (approximately)

The processing and data analysis deliverables include the following:

• Total Magnetic Intensity Map (IGRF-removed) (Contoured/mylar and full color/paper)
• Flight Path Map (Black Line/mylar)
• Reduced-to-Pole Map (Contoured/mylar and full color/paper)
• Shaded-Relief Displays of the Horizontal Gradient (RTP) (Two sun angles) (Paper)
• Anomalies and Boundary Picks overlay (Clear Film)
• Vertical-Derivative of RTP (Contoured/mylar & full color/paper)
• Lineament Analysis overlay (Clear Film)
• Digital tape of gridded and profile data (Format specified by participant)