Geology topics

Trenton T. Cladouhos

Publications and source records attributed to Trenton T. Cladouhos.

3 recordsLinked to original sources

USGS2021

Stochastic inversion of gravity, magnetic, tracer, lithology, and fault data for geologically realistic structural models: Patua Geothermal Field case study

Financial risk due to geological uncertainty is a major barrier for geothermal development. Production from a geothermal well depends on the unknown location of subsurface geological structures, such as faults that contain hydrothermal fluids. Traditionally, geoscientists collect many different datasets, interpret the datasets manually, and create a single model estimating faults' locations. This method, however, does not provide information about the uncertainty regarding the location of faults and often does not fully respect all observed datasets. Previous researchers investigated the use of stochastic inversion schemes for addressing geological uncertainty, but often at the expense of geologic realism. In this paper, we present algorithms and open-source code to stochastically invert five typical datasets for creating geologically realistic structural models. Using a case study with real data from the Patua Geothermal Field, we show that these inversion algorithms are successful in finding an ensemble of structural models that are geologically realistic and match the observed data sufficiently. Geoscientists can use this ensemble of models to optimize reservoir management decisions given structural uncertainty.

Nevada↗

USGS2018

Controls on deep direct-use thermal energy storage (DDU-TES) in the Portland Basin, Oregon, USA

Aquifer Thermal Energy Storage is being evaluated as a complementary technology to Deep Direct-Use for the Portland Basin, Oregon, USA. Aquifers can be used to efficiently distribute and store heat for seasonal use. The use of injection-extraction well pairs precludes the need to store or dispose of large volumes of pumped groundwater or to obtain a consumptive groundwater right. Injection temperatures vary seasonally, and well pairs can operate in continuous (single direction of flow) or cyclic (seasonal reversal of flow) modes. The target injection aquifers are the lowest Columbia River Basalt Group interflow zones, which are thermally and hydraulically separated from the overlying aquifer system, minimizing heat loss. A new aquifer thermal energy storage design tool allows assessment of thermal storage and recovery using: (1) system design parameters (e.g., well spacing and pumping rate), (2) thermal and hydraulic property values, and (3) regional groundwater flow rates. In continuous mode, extracted water temperature trends towards the flow-weighted average temperature of injected water over time, with the injected signal significantly lagged and damped. By controlling well spacing and temperature of delivered water (possibly using supplemental heating) continuous mode provides steady reliable warm water to end-users year-round. In cyclic mode, there is an advectively and conductively heated zone near the hot well and a cooled zone near the cool well, with temperatures substantially above and below the flow-weighted average injection temperature, respectively. In cyclic mode, during extraction, water temperatures start high or low, depending on the well, and temperatures trend towards the average injection temperature over the season. For the Columbia River Basalt Group in the Portland Basin, the quantity and quality of heat delivered depends most strongly on operational schedule, well spacing, mode of operation, and heterogeneity of the injection horizon.

Oregon↗

USGS2008

Field and Laboratory Data From an Earthquake History Study of Scarps in the Hanging Wall of the Tacoma Fault, Mason and Pierce Counties, Washington

As part of the effort to assess seismic hazard in the Puget Sound region, we map fault scarps on Airborne Laser Swath Mapping (ALSM, an application of LiDAR) imagery (with 2.5-m elevation contours on 1:4,000-scale maps) and show field and laboratory data from backhoe trenches across the scarps that are being used to develop a latest Pleistocene and Holocene history of large earthquakes on the Tacoma fault. We supplement previous Tacoma fault paleoseismic studies with data from five trenches on the hanging wall of the fault. In a new trench across the Catfish Lake scarp, broad folding of more tightly folded glacial sediment does not predate 4.3 ka because detrital charcoal of this age was found in stream-channel sand in the trench beneath the crest of the scarp. A post-4.3-ka age for scarp folding is consistent with previously identified uplift across the fault during AD 770-1160. In the trench across the younger of the two Stansberry Lake scarps, six maximum 14C ages on detrital charcoal in pre-faulting B and C soil horizons and three minimum ages on a tree root in post-faulting colluvium, limit a single oblique-slip (right-lateral) surface faulting event to AD 410-990. Stratigraphy and sedimentary structures in the trench across the older scarp at the same site show eroded glacial sediments, probably cut by a meltwater channel, with no evidence of post-glacial deformation. At the northeast end of the Sunset Beach scarps, charcoal ages in two trenches across graben-forming scarps give a close maximum age of 1.3 ka for graben formation. The ages that best limit the time of faulting and folding in each of the trenches are consistent with the time of the large regional earthquake in southern Puget Sound about AD 900-930.

Scientific Investigations Map↗