Peter Hennings

University of Texas at Austin | UT · Bureau of Economic Geology

Rates of seismicity in the Delaware Basin of Texas and New Mexico increased from 10 earthquakes per year of local magnitude (ML) 3.0 and above in 2017 to more than 185 in 2022, coincident with increasing oil and gas production and wastewater re‐injection into strata shallow or deeper than producing intervals. Events of large magnitude—up to ML 5.4...

The Delaware Basin in west Texas and southeast New Mexico is now the largest global oil producing basin, averaging ~400,000 m3 (~2,500,000 barrels) per day in 2022. The shale-dominated strata targeted for production can co-produce 4-5 times more water than oil, necessitating disposal by injection of ~1,400,000 m3 (~8,700,000 barrels) of water per d...

The seismicity rate in the Fort-Worth Basin, north-central Texas, increased significantly from 2008. Previous studies attributed the seismic events to pore pressure increase caused by wastewater injection into the Ellenburger Formation. However, hydrocarbon production from the overlying Barnett Shale was not included in those previous studies. This...

A little more than a decade ago, the southern midcontinent of the U.S. began experiencing an increasing number of earthquakes, including several large events in Arkansas and then Oklahoma. As that increase in seismicity spread to multiple states, attention focused on how disposal of large volumes of brine from oil production could trigger earthquak...

The Fort Worth Basin of north-central Texas is a prolific petroleum basin that is increasingly seismically active, with over 125 earthquakes of magnitude Mw ≥2.5 since 2006, impacting the Dallas–Fort Worth metropolitan area and surrounding communities. These earthquakes have been attributed to increased pore fluid pressure from wastewater injection...

There is a well-known occurrence of felt seismicity and smaller seismic events in areas where hydraulic fracturing (HF) operations occur. The Eagle Ford shale play of south-central Texas experienced an increase in the rate of felt seismicity from 2014 to 2019, temporally coincident with petroleum development in the region. By mid-2019, the rate of...

Earthquakes linked to oil and gas development and saltwater disposal have increased in recent decades. This increase has led to a regulatory response in the form of traffic light systems for hydraulic fracturing and regional disposal curtailments for saltwater disposal wells. While the implementation of hydraulic fracturing traffic lights can be re...

The Delaware Basin of Texas and New Mexico is experiencing elevated levels of seismicity. There have been more than 130 earthquakes with moment magnitudes of at least 3.0 recorded between 2017 and 2021, with earthquakes occurring in spatiotemporally isolated and diffuse clusters. Many of these events have been linked to oilfield operations such as...

Study region: A flat, large, semi-arid plateau in the southwest United States (west Texas and southeast New Mexico) underlain by a deep Paleozoic sedimentary basin, the tectonic Delaware Basin, host of intensive hydrocarbon production. Study focus: Impacts of injection of large volumes of water produced from oil and gas wells and injected through...

Deepwater siliciclastic deposits of the Delaware Mountain Group (DMG) in the Delaware Basin (DB) are the primary interval for disposal of hydraulic fracturing flowback and produced water from unconventional oil production. Understanding the storage capacity of the DMG is critical in mitigating potential risks such as induced seismicity, water encro...

Plain Language Summary Increases in subsurface fluid pressure following years of deep disposal of oilfield wastewater are widely accepted to have caused earthquakes from 2008 through 2020 in the Fort Worth Basin (FWB) of north‐central Texas, underlying the population centers of the Dallas‐Fort Worth metropolitan area, were caused by increases in su...

The Delaware basin of west Texas and southeast New Mexico has experienced elevated earthquake rates linked spatiotemporally to unconventional petroleum operations. Limited knowledge of subsurface faults, the in situ geomechanical state, and the exact way in which petroleum operations have affected pore pressure (Pp) and stress state at depth makes...

The Permian Basin of Texas and New Mexico is an important petroleum province with a complex tectonic history. This region has been shaped by several divergent and convergent deformation events since the Proterozoic. Each subsequent event was influenced by the accumulated tectonic fabric through fault reactivation and strain transfer. These events h...

Since 2009 the Delaware Basin of Texas and New Mexico has experienced increased seismicity related to oilfield operations. Available near present-day principal stress orientations, relative magnitudes, and vertical stress estimates are integrated to characterize 20 stress domains in the Delaware Basin. Data density, variability, and quality inform...

Plain Language Summary Over the past decade, breakthroughs in horizontal drilling and hydraulic fracturing have made the Permian Basin one of the most productive oil fields in the world. Using spaceborne interferometric synthetic aperture radar (InSAR), we mapped how the Permian Basin's land surface has deformed from oil and gas production activiti...

A series of earthquakes was recorded along a mapped fault system near Azle, Texas, in 2013. To identify the mechanism of seismicity, geologic, production/injection, and seismicity data are gathered to build a detailed simulation model with coupled fluid flow and geomechanics to model fluid injection/production and the potential onset of seismicity....

From 2006 through mid-2018 there have been 125 Mw = 2.5 recorded earthquakes within the Fort Worth Basin and the Dallas-Fort Worth metropolitan area. There is general scientific consensus that this increase in seismicity has been induced by increases in pore fluid pressure from waste water injection and from cross-fault pore pressure imbalance due...

In recent years, numerous small earthquakes have occurred near the town of Pecos in West Texas; however, when this activity began and whether it was caused by increased petroleum industry activity has been uncertain because prior to 2017 there were few permanent seismograph stations in the region. We identify and locate earthquakes using data recor...

Subsurface disposal of salt water coproduced with oil and gas has become a critical issue in the United States because of linkages with induced seismicity, as seen in Oklahoma and northcentral Texas. Here, we assess the spatiotemporal and stratigraphic variations of salt-water disposal (SWD) volumes in the Permian Basin. The results of this analysi...

The response of basement faults to oil and gas production and wastewater injection is influenced by local hydromechanical properties within the basement and at the basement-sediment interface. Lithologic, structural, and metamorphic fabric, uplift, weathering and alteration history, and the nature of the overlying strata may all play a role in the...

Disposal of hydraulic fracturing flowback and produced water into Ordovician and Cambrian formations of the Fort Worth Basin (FWB), coupled with an increase in observed seismicity in the Dallas-Fort Worth area, necessitates an understanding of the geologic character of these disposal targets. More than two billion barrels (Bbbls) of wastewater have...

The rate of seismicity in the hydrocarbon‐producing Fort Worth Basin of north‐central Texas, which underlies the Dallas–Fort Worth metropolitan area, increased markedly from 2008 through 2015, coinciding spatiotemporally with injection of 2 billion barrels of wastewater into deep aquifers. Although the rate of seismicity has declined with injection...

The response of basement faults to oil and gas production and wastewater injection is influenced by local hydromechanical properties within the basement and at the basement-sediment interface. Lithologic, structural, and metamorphic fabric, uplift, weathering and alteration history, and the nature of the overlying strata may all play a role in the...

A series of earthquakes was recorded along a mapped fault system near Azle, Texas in 2013. To identify the mechanism of seismicity, coupled fluid flow and geomechanical simulation is carried out to model fluid injection/production and the potential onset of seismicity. Sensitivity studies for a broad range of reservoir and geomechanical parameters...

The Jurassic to Cretaceous sedimentary rocks of the Surat Basin in southeast Queensland host a significant volume of coal seam gas resources. Consequently, knowledge of the in situ stress is important for coal permeability enhancement and wellbore stability. Using wireline log data and direct stress measurements, we have calculated stress orientati...

Anticlines of Pennsylvanian Tensleep Sandstone are the most prolific oil-producing reservoirs in the Laramide Rockies. While the Tensleep's eolian and mixed carbonate lithologies are typically of excellent reservoir quality, the patterns of local production performance are complex being attributed to diagenetic variations and degree of natural frac...

Production from self-sourced reservoirs relies on natural and induced fracturing for permeability and conductance of hydrocarbons to the producing wellbores, thus natural or induced fracturing is often a key to success in unconventional reservoir plays. On the other hand, fractures may compromise seals and large or well-connected fractures or fault...

We analyze fracture-density variations in subsurface fault-damage zones in two distinct geologic environments, adjacent to faults in the granitic SSC reservoir and adjacent to faults in arkosic sandstones near the San Andreas fault in central California. These damage zones are similar in terms of width, peak fracture or fault (FF) density, and the...

Suban field in southern Sumatra, Indonesia, is a fractured carbonate/crystalline wet-gas reservoir in a tectonically active island-arc setting. Reservoir-scale right-oblique reverse faults and folds that have trapped the hydrocarbons have been related previously to deformation in the back-arc setting of Sumatra associated with oblique subduction of...

The cause of hydraulic fracture induced microseismicity involves a range of dynamic hydromechanical processes, from which there are two main concepts. The first is that the geomechanical activation criterion has been met for each microseismic event. Assessing Coulomb failure is a practical technique to determine if pre-existing faults, fractures, o...

The contribution investigates the relationship between in situ stress regimes, natural fracture systems and the propagation of induced hydraulic fractures in APLNG's (Australia Pacific Liquid Natural Gas) acreage within the Jurassic to Cretaceous Surat Basin in southeast Queensland. On a regional scale the data suggest that large basement fault sys...

Secondary fractures and faults associated with reservoir-scale faults affect both permeability and permeability anisotropy and hence play an important role in controlling the production behavior of a faulted reservoir. It is well known from geologic studies that there is a concentration of secondary fractures and faults in damage zones adjacent to...

The aim of part 2 is to understand the development of complex hydraulic fractures (HFs) that are commonly observed in the field and in experiments but are not explained by most models. Our approach uses finite element simulations and a numerical rheology developed in part 1 to model damage fracturing, the fracturing process by damage propagation in...

It is becoming widely recognized that a relationship exists between stress, stress heterogeneity, and the permeability of subsurface fractures and faults. We present an analysis of the South Sumatra Suban gas field, developed mainly in fractured carbonate and crystalline basement, where active deformation has partitioned the reservoir into distinct...

We report a study on sub-surface fault damage zones adjacent to faults in a gas field in Southeast Asia and near the San Andreas Fault in central California. The importance of characterizing damage zones arises from the important role that damage zones and natural fractures play in governing fluid flow through low permeability reservoirs. While the...

We simulated rock mechanics tests to model the effect of cementation on the Mohr Coulomb failure parameters of reservoir rock. Experiments show that lithologic variations affect both elastic and inelastic constitutive behavior. To understand controls on inelastic parameters we combined finite element (FE) modeling, a powerful technique that can sol...

In this study, we present a method to incorporate the effects of fault damage zones (DZs) in a reservoir-simulation model. Permeability anisotropy associated with fault DZs depends on many factors, including the geometry of the faults in the reservoir and the associated dimension and density of fractures in the DZs. To model permeability anisotropy...

Peter Hennings received his B.S. and M.S. degrees in geology from Texas A&M University and his Ph.D. in geology from the University of Texas. He has held various technical and supervisory positions in Mobil Research Company, Phillips Petroleum Company, and ConocoPhillips. His research and application focus in these positions includes structure and...

The geometric characteristics of natural fractures significantly impact the hydraulic behavior of fractured reservoirs. Prediction of fracture geometry is therefore important for reservoir development decisions and production forecasting. Although many geometric, kinematic, mechanical, geomechanical, petrophysical, sedimentary, and geophysical attr...

Fracture prediction in subsurface reservoirs is critical for exploration through exploitation of hydrocarbons. Methods of predicting fractures commonly neglect to include the stratigraphic architecture as part of the prediction or characterization process. This omission is a critical mistake. We have documented a complex heterogeneous fracture deve...

Understanding the development of fracture networks within layered sedimentary sequences requires consideration of realistic rheology and progressive failure processes. Rock mechanics experiments have shown that rock failure under tension and compression loading is characterized by 1) elasticity (linear or nonlinear), followed by 2) strain hardening...

Secondary fractures and faults associated with reservoir scale faults affect both permeability and permeability anisotropy and hence may play an important role in controlling production from a faulted reservoir. It is well known from geologic studies that there is a concentration of secondary fractures and faults in a damage zone adjacent to larger...

Fractures, which are common structural heterogeneities in geological folds and domes, impact the charge, seal, and trapping potential of hydrocarbon reservoirs. Because of their effects on reservoir quality, the numerical prediction of fractures has recently been the focus of petroleum geoscientists. A horizon's curvature is commonly used to infer...

A comparison between a spectral and a factorial kriging analysis is presented for the calculation of scale -dependent normal surface curvatures. Knowledge of scale -dependent curvatures of geological surfaces plays an important role in quantitative structural geology. Often, curvature analyses of geological surfaces, such as horizon tops, are perfo...

Combining a detailed outcrop characterization of fracture and fault occurrence with attributes from a three-dimensional model of an anticlinally folded clastic reservoir body, we determine which characteristics of the structural form and evolution are most closely related to the development of important reservoir-scale structures. Our example reser...

The quantification of fracture spacing and length are crucial for determination of effective block sizes to be used in reservoir simulation. Outcrop and modeling studies have shown that average values of these parameters do not adequately describe a fracture pattern, however. Observational work suggests that the cumulative number of fractures large...

We have observed numerous examples of complex 3D deformation associated with oblique ramps near abrupt thrust terminations. The structures are restricted to hanging-walls of thrust sheets and are associated with zones of rapid loss in stratigraphic separation and/or large displacement gradients along strike. These structures produce a complex but c...

A restorable structural transect has been constructed across the southern end of the Chihuahua Fold Belt segment of the Cordilleran foreland fold and thrust belt of northeastern Chihuahua, Mexico, and west Texas. The 160-km transect begins near Ojinaga and ends near Aldama, Chihuahua. It has been found that the Mesozoic Chihuahua Trough was inverte...

Typescript (photocopy). Part of illustrative matter on 2 folded leaves in pocket. Thesis (M.S.)--Texas A & M University, 1986. Vita. Includes bibliographical references (leaves 104-107). "Major subject: Geology."

The extrapolation of cover rock geometry to delineate crystalline basement configuration can yield a unique three dimensional solution if logically positioned, balanced cross-sections are constructed. Dry Fork Ridge is a Precambrian basement cored uplift on the northeastern margin of the Bighorn Mountains. An asymmetric, overturned anticline-syncli...