MINERALOGY OF EOLIAN SAND DEPOSITS IN NORTH-CENTRAL NORTH DAKOTA EVALUATED FOR USE AS IN-BASIN SOURCED PROPPANT

The mineralogy of eolian sand deposits, occurring in low (<3m) and high-relief (>3m) dunes in north-central North Dakota, was characterized by X-ray diffraction (XRD) analysis from 22 dune locations in northeastern McHenry County. Bulk (unwashed and unsized) sand contains 70% quartz, 22% feldspar (as plagioclase and K-feldspar), and 3% clays (illite) on average and is devoid of carbonates. Washed and sized sand in the 40/70, 50/140, and 70/140 size classes contains 76% quartz, 22% felspars (as albite and microcline), and 1.1% clays (illite) on average, also with no carbonates. Additional sedimentological and materials testing, using accepted American Institute of Petroleum (API) methods for the evaluation of natural sand proppant, revealed that these eolian sands are consistently well sorted, medium to very-fine grained, with crush resistance ranging from 4,000 to 7,000 psi (4K to 7K). Acid solubility averaged 6.3% and turbidity 28% with loss on ignition (LOI) values averaging 0.6% suggesting a low presence of detrital lignite and deleterious mineralogy. Sand grain particle shape factors average 0.6 for roundness and 0.8 for sphericity. Sedimentological and mineralogic character are consistent in both low and high-relief dune settings. Quartz contents appear slightly higher along the western and southeastern deposit margins which are at the furthest extent of eolian transport distance. These dunes presumably formed as the eolian accumulate of glaciofluvial and glaciolacustrine sediments originally deposited within the former Glacial Lake Souris basin. Overall, these eolian sand deposits appear suitable for use as proppant in the hydraulic fracturing of oil and gas wells in the Williston Basin under current industry requirements.