The successive loss of two benzyl radicals from the [M +Na](+) ions of the isomeric dihydroxybenzene dibenzyl ethers (2-4) and of the isomeric trihydroxybenzene tribenzyl ethers (5-7) under ESI/CID conditions has been studied by deuterium labelling, MS experiments and DFT calculations. The fragmentation of the [M + Na](+) ions of 2 and 4 consists exclusively of the consecutive losses of two C7H7* (benzyl) radicals. This process is largely suppressed in the corresponding [M + Na](+) ions of the meta isomer 3 and also in those of the 1,3,5-analog, phloroglucinol tribenzyl ether (6), suggesting the facile formation of sodiated ortho- and para-quinone ions, [C6H4O2 + Na](+), in the cases of 2 and 4, respectively. This finding is corroborated by a detailed investigation of the sodiated tribenzyl ethers of pyrogallol, [5 + Na](+), and 1,2,4-trihydroxybenzene, [7 + Na](+), and their isotopologs bearing differently labelled benzyl residues. Again, the successive loss of two C7H7* radicals is the only fragmentation channel for ions [7 + Na](+) and strongly predominates for ions [5 + Na](+), with the primary and secondary losses being highly regiospecific: ions [5 + Na](+) lose the first benzyl residue almost exclusively from the central position (0-2) and only then a lateral C7H7* radical (from 0-1 or 0-3). Surprisingly, the very minor primary loss of a lateral benzyl group is followed by that of the other lateral one, suggesting a two-step isomerization process initiated by a 1,4-H* shift. Ions [7 + Na](+) lose the first benzyl radical almost exclusively from 0-1, in very minor amounts from 0-2 but not at all from 0-4. The secondary loss of C7H7* subsequent to the major primary loss occurs from both 0-2 and 0-4 in similar amounts, reflecting the relative stabilities of the sodiated benzyloxy-substituted ortho- and para-benzoquinones. This and several other details of the energy profiles associated with the twofold benzyl loss from ions [5 + Na](+) and [7 + Na](+) were calculated by use of the DFT methodology and were found to agree very well with the regioselectivities observed. Finally, the pyrogallol-based ions [5 + Na](+) were found to eliminate benzaldehyde in minor but significant relative amounts, which takes place with high regioselectivity from 0-1 or 0-3. (C) 2014 Elsevier B.V. All rights reserved.

Abstract Three laboratory methods were developed to measure matrix gas permeability (Km) of Devonian shale cores and drill cuttings at native water saturations. The first method uses pulse pressure testing of core plugs with helium. The second, new method uses pulse pressure testing of core chips or drill cuttings with helium. These methods gave comparable results on 23 companion shale samples from two wells, with Km = 0.2 to 19 × 10−8 md. The third, new method uses degassibility of core plugs with helium and methane, and yielded Km higher by a factor of 3 to 10. Most of the core plugs tested showed multiple microfractures that remain open at reservoir stress, and these dominate conventional flow tests. These microfractures are parallel to bedding, are coring induced, and are not present in the reservoir. Knowledge of Km is important in computer simulation modeling of long term Devonian shale gas production, and has been a key to understanding the nature of the natural fracture network present in the reservoir.

Summary A novel design for a downhole flowmeter that can locate and quantify gas-entry points in a well is presented. The instrument has a gas-tracer injector at its lower end and a tracer detector at its upper end. We determine gas flow in the well by injecting tracer gas at a precisely measured rate into the natural gas flow and measuring the concentration with the detector. The result is a wireline log that locates and quantifies natural gas sources from the decrease in measured flow as the wireline instrument passes each source. The new design has been tested against calibrated gas flows in the laboratory and in Devonian shale gas wells in the field. The new flowmeter is compared with spinner, temperature, sonic, and television logs. The instrument provides an expanded flow range compared with spinner logs and furnishes quantitative mass-flow information compared with incomplete and qualitative indications provided by temperature and sonic logs.

ABSTRACT Sorption properties of individual constituents of Devonian shale were compared with similar properties of a wide variety of shales of different lithologies. Major components examined included illite, quartz, chlorite, kerogen, and oil. Kerogen was isolated from a core sample retrieved from a producing gas well, while the oil used was taken from a gas well in West Virginia that is producing from the shale interval. Helium and methane isotherms were collected up to 1000 psia for analysis of the adsorptive properties of these substances. It is shown that about 50% of the gas in the rock is associated with and stored in the open porosity of the rock. The remaining 50% is more intimately associated with some of the mineral or organic constituents of the shale. Some of the gas is dissolved in the oil which serves as an efficient storage material. In addition, the solid kerogen can also store gas by adsorption, as can other minerals, such as illite. All materials examined contributed to the total sorption isotherm, with smaller amounts being associated with storage in quartz and chlorite. This total isotherm is, however, less than the composite isotherm obtained by summing the separate isotherms of its constituents. This implies a possible blocking phenomenon that reduces the storage efficiency of the minerals.