Summary

The Fort Worth Basin (FWB) is a shallow north – south elongated foreland basin, encompassing roughly 15,000 sq. mi in north Texas. It formed during the late Paleozoic Ouachita orogeny (Walper, 1982) and displays a complex structural basement mainly due to the collision of the North and South American plates during the Paleozoic.

This work compares horizontal derivative of the tilt derivative maps (HD_TDR), seismic attributes including most positive curvature and image enhancing over most positive curvature-sliced along the Viola Lm. And Ellenburger Group horizons, and azimuth frequency diagrams (rose diagrams) for two different areas in order to compare the Maximum and Minimum Horizontal stress of lineaments related to collapse structures, and faults and fracture patterns at specific horizons with the discontinuities in the basement.

The main conclusion of this work is that intra-sedimentary features such as collapse structures, faults and fracture patterns for the Viola Lm. and Ellenburger Group horizons are mainly related to basement structures because they tend to align along these discontinuities.

Introduction

The Fort Worth Basin (FWB) is a shallow north – south elongated foreland basin, encompassing roughly 15,000 sq. mi in north Texas. It formed during the late Paleozoic Ouachita orogeny (Walper, 1982) due to collision of the North and South American plates during the Paleozoic. This collision continued during the early Pennsylvanian and caused overthrusting along the eastern margin of the basin, the formation of the Ouachita structural front, and the onset of the orogeny. The basin is delimited in the east by the Ouachita Thrust Front, to the north by the Red River Arch, to the north – northeast by the Muenster Arch, to the west by the Bend arch, Eastern shelf and Concho arch, and to the south by the Llano Uplift (Figure 1).

Although the FWB is considered to be a mature basin and has been extensively explored for hydrocarbons, very little has been published about its basement. Sullivan et al. (2006), hypothesizes that the basement influences collapse features and fracture patterns in shallower horizons and Aktepe et al. (2008), used pre-stack depth migration data to show that basement structures can be quite complex.

Figure 1 reveals the complexity of the basement in the area of study. The black dashed line shows the location of the most prominent structural element known as the Mineral Wells fault (MWF). This MWF is a major northeastsouthwest striking fault extending for more than 65 miles (100 km). It is a normal fault with a strike-slip component.

For this work, horizontal gradient magnitude (HMG) maps were generated from high resolution aeromagnetic (HRAM) data. HMG maps derived from HRAM data reflects abrupt lateral changes in magnetization in the area (Elebiju, 2008) and the tilt derivative (TD) maps help to enhance the continuity of such anomaly if it is close to a magnetic source. Thus, the horizontal derivative of the tilt derivative map (HD_TDR) enhances prominent edges of a magnetic source that could be related to faults and discontinuities in the basement.

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