February Luncheon - Molly Turko, Devon Energy, Turko Tectonics

The Impact of the Wichita Uplift on the Anadarko Basin

How Understanding Structural Complexity Helps Mitigate Operational Risk

Dr. Molly Turko

ABSTRACT

In order to mitigate the risk associated with structural complexity in a basin, it is vital to

understand the mechanical stratigraphy alongside the origin and kinematics of structures (and

reactivated structures). In this talk we will look at the evolution of the basin, discuss the driving

mechanism for strike-slip deformation, and review associated fault kinematics that can aid in

predicting sub-seismic structures.

The Anadarko Basin originated in the Precambrian during the breakup of Rodinia when one arm

of a failed rift tore through southern Oklahoma as a large igneous province was emplaced.

During the Pennsylvanian Orogeny, intra-plate tectonics inverted the failed rift creating the

Wichita Uplift and associated Anadarko foreland basin as seen today.

Deformation styles between the southern and northern parts of the Anadarko Basin differ, yet

both record the tectonic evolution of the basin. In the southern Anadarko Basin, deformation is

dominated by thin-skin fold-thrust structures along detachments that can be linked back to

thick-skin deformation along the Wichita Uplift. Several of these structures were cut by late-

stage strike-slip faults recording a rotation in the regional stress field from NE-directed in the

Early to Mid-Pennsylvanian to ENE-directed during the Late Pennsylvanian.

The central and northern regions of the Anadarko Basin tend to be dominated by high-angle

strike-slip faults with limited horizontal and vertical offset. The timing of these faults is

synchronous with the Wichita Uplift and form at an optimal orientation for strike-slip

deformation under a NE-directed stress field. Additional structures in the basin include fracture

corridors and reactivated basement faults. While these structures tend to be more subtle in

seismic data, including the strike-slip faults, they still have the ability to wreak havoc on

operations in the basin. Operators commonly deal with mud losses, well connectivity, and

reservoir compartmentalization in areas that appear to be structurally quiet. By understanding

the origin and kinematics of these structures, operators can mitigate and prepare for the

associated risks.

BIO

Molly Turko has nearly 15 years of experience in the oil and gas industry and is a subject matter

expert in structural geology. She received both a B.Sc. (2009) and a M.Sc. (2011) in geology from the

University of Tulsa followed by a Ph.D. (2019) from the University of Oklahoma. Her work

experience includes several small operators, Chesapeake Energy, and she is currently full-time with

Devon Energy. She has taught courses for R.M.A.G., AAPG, Applied Stratigraphix, and for the Ore

Geology Conference. Molly is the President of AAPG’s Petroleum Structure and Geomechanics

Division, treasurer of the AAPG Midcontinent Section, serves on the board of the OKC Geological

Society, and is an associate editor for several leading geoscience journals.