Franciszek Hasiuk

Subseafloor sedimentary life in the South Pacific Gyre

The low-productivity South Pacific Gyre (SPG) is Earths largest oceanic province. Its sediment accumulates extraordinarily slowly (0.1–1 m per million years). This sediment contains a living community that is characterized by very low biomass and very low metabolic activity. At every depth in cored SPG sediment, mean cell abundances are 3 to 4 orders of magnitude lower than at the same depths in all previously explored subseafloor communities. The net rate of respiration by the subseafloor sedimentary community at each SPG site is 1 to 3 orders of magnitude lower than the rates at previously explored sites. Because of the low respiration rates and the thinness of the sediment, interstitial waters are oxic throughout the sediment column in most of this region. Consequently, the sedimentary community of the SPG is predominantly aerobic, unlike previously explored subseafloor communities. Generation of H2 by radiolysis of water is a significant electron-donor source for this community. The per-cell respiration rates of this community are about 2 orders of magnitude higher (in oxidation/reduction equivalents) than in previously explored anaerobic subseafloor communities. Respiration rates and cell concentrations in subseafloor sediment throughout almost half of the world ocean may approach those in SPG sediment.

Eocene climate record of a high southern latitude continental shelf: Seymour Island, Antarctica

A high-resolution record of Eocene paleotemperature variation is preserved within the high southern latitude, marine shelf succession of the La Meseta Formation on Seymour Island, off the NE side of the Antarctic Peninsula. 87 Sr/ 86 Sr ratios of bivalve shell carbonate indicate that the La Meseta Formation spans virtually the entire Eocene, and suggest the presence of an early middle Eocene unconformity. Paleoclimatic and paleoceanographic inferences are based on the stable oxygen and carbon isotope values of two genera of bivalves collected with a high degree of stratigraphic resolution within the formation, and with multiple replicate samples from each horizon. δ 18 O data indicate roughly 10 °C of cooling from the early Eocene climatic optimum (~15 °C) through the end of the Eocene (minimum ~5 °C), much of which took place in two comparatively short intervals at ca. 52 and ca. 41 Ma. Many features of the isotope curves generated from this Eocene shelf section are apparent in δ 18 O and δ 13 C data from the Southern and global oceans, including warm intervals that likely correspond to the early and middle Eocene climatic optima (EECO and MECO). A rapid middle Eocene shift to much more positive values is the most signifi cant in the section and refl ects a drop to universally cooler temperatures in the late middle and late Eocene that might also be associated with a short-lived glacial advance. However, even using a somewhat depleted value for δ 18 O of seawater in the Antarctic peninsular region, average Seymour Island shelf-water paleotemperatures did not reach freezing before the end of the Eocene. δ 13 C data similarly refl ect the documented middle Eocene surface ocean enrichment followed by more negative values, but depletion is much more pronounced on Seymour Island and persists for the remainder of the Eocene, suggesting a combination of upwelling, metabolic effects, and/or atypical carbon cycling on the shelf in this region. Isotope data capture information about changes in the paleoenvironment that also had consequences for the biota, as published paleontological records document marked change in the nature of terrestrial and marine biota at this time. The fact that middle Eocene cooling and biotic turnover in the Peninsular region correspond well in time to the proposed initial opening of Drake Passage suggests that the formation of gateways, in addition to changes in pCO 2 , had signifi cant consequences for the Earth’s climate system during the Paleogene.

Resurrection of a reservoir sandstone from tomographic data using three-dimensional printing

Three-dimensional (3-D) printing provides an opportunity to build lab-testable models of reservoir rocks from tomographic data. This study combines tomography and 3-D printing to reproduce a sample of the Fontainebleau sandstone at different magnifications to test how this workflow can help characterization of transport properties at multiple scales. For this sandstone, literature analysis has given a porosity of 11%, permeability of 455 md, mean pore throat radius of 15 μm, and a mean grain size of 250 μm. Digital rock analysis of tomographic data from the same sample yielded a porosity of 13%, a permeability of 251 md, and a mean pore throat radius of 15.2 μm. The 3-D printer available for this study was not able to reproduce the sample’s pore system at its original scale. Instead, models were 3-D printed at 5-fold, 10-fold, and 15-fold magnifications. Mercury porosimetry performed on these 3-D models revealed differences in porosity (28%–37%) compared to the literature (11%) and to digital calculations (12.7%). Mercury may have intruded the smallest matrix pores of the printing powder and led to a greater than 50% increase in measured porosity. However, the 3-D printed models’ pore throat size distribution (15 μm) and permeability (350–443 md) match both literature data and digital rock analysis. The powder-based 3-D printing method was only able to replicate parts of the pore system (permeability and pore throats) but not the pore bodies. Other 3-D printing methods, such as resin-based stereolithography and photopolymerization, may have the potential to reproduce reservoir rock porosity more accurately.

Three-dimensional Printing for Geoscience: Fundamental Research, Education, and Applications for the Petroleum Industry

Three-dimensional (3-D) printing provides a fast, cost-effective way to produce and replicate complicated designs with minimal flaws and little material waste. Early use of 3-D printing for engineering applications in the petroleum industry has stimulated further adoption by geoscience researchers and educators. Recent progress in geoscience is signified by capabilities that translate digital rock models into 3-D printed rock proxies. With a variety of material and geometric scaling options, 3-D printing of near-identical rock proxies provides a method to conduct repeatable laboratory experiments without destroying natural rock samples. Rock proxy experiments can potentially validate numerical simulations and complement existing laboratory measurements on changes of rock properties over geologic time scales. A review of published research from academic, government, and industry contributions indicates a growing community of rock proxy experimentalists. Three-dimensional printing techniques are being applied to fundamental research in the areas of multiphase fluid flow and reactive transport, geomechanics, physical properties, geomorphology, and paleontology. Further opportunities for geoscience research are discussed. Applications in education include teaching models of terrains, fossils, and crystals. The integration of digital data sets with 3-D printed geomorphologies supports communication for both societal and technical objectives. Broad benefits that could be realized from centralized 3-D printing facilities are also discussed.

TouchTerrain: A simple web-tool for creating 3D-printable topographic models

Abstract An open-source web-application, TouchTerrain, was developed to simplify the production of 3D-printable terrain models. Direct Digital Manufacturing (DDM) using 3D Printers can change how geoscientists, students, and stakeholders interact with 3D data, with the potential to improve geoscience communication and environmental literacy. No other manufacturing technology can convert digital data into tangible objects quickly at relatively low cost; however, the expertise necessary to produce a 3D-printed terrain model can be a substantial burden: knowledge of geographical information systems, computer aided design (CAD) software, and 3D printers may all be required. Furthermore, printing models larger than the build volume of a 3D printer can pose further technical hurdles. The TouchTerrain web-application simplifies DDM for elevation data by generating digital 3D models customized for a specific 3D printers capabilities. The only required user input is the selection of a region-of-interest using the provided web-application with a Google Maps-style interface. Publically available digital elevation data is processed via the Google Earth Engine API. To allow the manufacture of 3D terrain models larger than a 3D printers build volume the selected area can be split into multiple tiles without third-party software. This application significantly reduces the time and effort required for a non-expert like an educator to obtain 3D terrain models for use in class. The web application is deployed at http://touchterrain.geol.iastate.edu , while source code and installation instructions for a server and a stand-alone version are available at Github: https://github.com/ChHarding/TouchTerrain_for_CAGEO .

Comparison of Flow and Transport Experiments on 3D Printed Micromodels with Direct Numerical Simulations

Understanding pore-scale flow and transport processes is important for understanding flow and transport within rocks on a larger scale. Flow experiments on small-scale micromodels can be used to experimentally investigate pore-scale flow. Current manufacturing methods of micromodels are costly and time consuming. 3D printing is an alternative method for the production of micromodels. We have been able to visualise small-scale, single-phase flow and transport processes within a 3D printed micromodel using a custom-built visualisation cell. Results have been compared with the same experiments run on a micromodel with the same geometry made from polymethyl methacrylate (PMMA, also known as Perspex). Numerical simulations of the experiments indicate that differences in experimental results between the 3D printed micromodel and the Perspex micromodel may be due to variability in print geometry and surface properties between the samples. 3D printing technology looks promising as a micromodel manufacturing method; however, further work is needed to improve the accuracy and quality of 3D printed models in terms of geometry and surface roughness.

Validating 3D-printed porous proxies by tomography and porosimetry

Purpose The purpose of this study is to evaluate how accurately a 3D printer could manufacture basic porous models. Geoscience research is evolving toward numerical prediction of porous rock properties, but laboratory tests are still considered a standard practice. 3D printing digital designs of porous models (proxies) is a way to bridge the gap between these two realms of inquiry. Design/methodology/approach Digital designs of simple porous models have been 3D-printed on an inkjet-style (polyjet) 3D printer. Porosity and pore-throat size distribution of proxies have been measured with helium porosimetry, mercury porosimetry and computed tomography (CT) image analysis. Laboratory results on proxies have been compared with properties calculated on digital designs and CT images. Findings Bulk volume of proxies was by 0.6-6.7 per cent lower than digital designs. 3D-printed porosity increased from 0.2 to 1.9 per cent compared to digital designs (0-1.3 per cent). 3D-printed pore throats were thinner than designed by 10-31 per cent. Research limitations/implications Incomplete removal of support material from pores yielded inaccurate property measurements. The external envelope of proxies has been 3D-printed at higher accuracy than pores. Practical implications Characterization of these simple models improves understanding of how more complex rock models can be 3D-printed accurately and how both destructive (mercury porosimetry) and non-destructive (CT and helium porosimetry) methods can be used to characterize porous models. Originality/value Validation of 3D-printed porous models using a suite of destructive and non-destructive methods is novel.

Sequence Stratigraphy of the Mishrif Formation, West Qurna 1 Field, Iraq

The Mishrif formation in southern Iraq is a world class reservoir with over 100 GBO in place. The West Qurna 1 field (WQ1) is part of large N-trending anticlinal structure located near the eastern margin of the Arabian Plate, in the foreland of the Zagros fold and thrust front. An integrated reservoir study of the Mishrif is underway in the West Qurna contract area as part of a Technical Services Agreement with the South Oil Company of Iraq. The Mishrif has been under primary depletion since 1999, with intermittent disruptions due to wars. A key component of the field re-development plan is to implement a waterflood to increase reservoir pressure and improve recovery. Planning the waterfood requires an understanding of the permeability structure within the reservoir, including flow unit geometry and connectivity. A sequence-stratigraphic study of the Mishrif is underway to provide a foundation for reservoir characterization and modeling. The data currently available include data from 375 wells (200 acre well spacing), 17 cored wells, and limited 2D seismic. PLTs and recent MDTs provide data on zonal pressures and contributions to flow, and information on scaling differences between core plug, whole core and well-test derived permeabilities. The Mishrif is ~250m thick in the WQ1 area and was deposited on a low-angle carbonate ramp. The Mishrif is interpreted to be comprised of four (4) third-order depositional sequences (1-4, oldest to youngest), that span from the Lower Cenomanian to the Early to Middle Turonian (est. 5-7 Ma duration). The sequences are stacked into a second-order sequence that records an overall shoaling-upward pattern. Sequences 3 and 4 are each capped by major exposure surfaces that form tight “caprock” intervals. The sequence boundary at the top of the Mishrif (Sequence 4) corresponds to a plate wide unconformity (the 92 Ma SB of Sharland et al., 2002). Reservoir quality variations within the Mishrif are closely tied to original depositional textures that vary predictably within the sequence framework. Grainstones, often with coarse Rudist debris, form high porosity, high permeability flow zones that will dominate flow within the reservoir. Grainstone distribution is predicable within the sequence-stratigraphic framework. Much of the reservoir is microporous with high porosity, but low permeability. The high permeability contrast within the Mishrif presents a significant challenge to waterflood management. Reservoir modeling is underway to determine the optimum development plan for the Mishrif, including waterflood. The development plan will need to be tailored to account for the observed geologic variability, using the sequence-stratigraphic framework as a guide.