Research Article| December 01, 1990 Ancient subaerial exposure and freshwater leaching in sandstones D. Emery; Emery 1BP Exploration Company, Ltd., Britannic House, Moor Lane, London EC2Y 9BU, England Search for other works by this author on: GSW Google Scholar K. J. Myers; Myers R. Young Author Article Information Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print 0091-7613 Geology (1990) 18 (12): 1178–1181....

Introduction. Textural and Mineralogical Analysis. Fluid Inclusions Stable Isotopes. Radiogenic Porosity Permeability Prediction. Migration. Correlation. Petroleum Recovery. References

When a reservoir fills with petroleum, the process commonly takes about 10 Ma. Cementation of sandstone can occur in similarly short time. There is much direct evidence that these two processes at same In petroleum-bearing reservoirs it common to find inclusions petroleum trapped diagenetic minerals. The effect on porosity and permeability caused by interaction dramatic. Fields relatively early charge, earlier than cementation, be saved from ravages quality destruction. which were acting...

We present a model that explains the patterns of sandstone burial diagenesis in certain oil reservoirs, which petroleum migration and cementation were synchronous. The coincidence these two processes controls chemistry distribution major cement phases across field, turn reservoir quality, causing rapid decline porosity permeability with depth. Such poroperm deterioration is observed many North Sea oilfields; we highlight Magnus Sandstone Member Oilfield, northern as type example such...

The carbon and oxygen isotopic compositions of the Lincolnshire Limestone (Bajocian) East Midlands are shown to be determined largely by two end-member components: marine precipitates later sparry burial cements. origin major quantities such cement is controversial, extreme possibilities ranging from calcite precipitation meteoric groundwaters highly saline brines, with contrasting flow regimes. This study demonstrates how formation-wide sampling mapping stable cements Limestone, combined a...

Previous linear bifurcation analyses have evidenced that an axially stretched soft cylindrical tube may develop infinite-wavelength (localised) instability when one or both of its lateral surfaces are under sufficient surface tension. Phase transition interpretations also highlighted the admits a final evolved "two-phase" state. How localised initiates and evolves into state is still matter contention, this focus current study. Through weakly non-linear analysis conducted for general...

ABSTRACT Strontium isotopic composition ( 87 Sr/ 86 Sr) of two petrographically, chemically and isotopically (δ 18 O δ 13 C) distinct phases burial calcites from the Lincolnshire Limestone are indistinguishable (0.70820± 26). The mean Sr ratio these is considerably more radiogenic than ratios Bajocian marine waters (∼0.70725). Neither nor meteoric buffered by host carbonate in could have precipitated spars. Radiogenic strontium may been contributed K‐feldspar dissolution and/or clay...

Summary Two phases of burial calcite from the Lincolnshire Limestone (Bajocian) central have been analysed for their trace element (Fe, Mn, Mg, Sr) and strontium isotopic compositions. The earliest, non-ferroan, brightly luminescent phase has following mean concentrations: Fe- 919 ppm; Mn- 116 ppm: 3 1778 Sr- 327 ppm. later, ferroan, dully compositions: 3580 225 Mg- 1400 318 composition two is indistinguishable, with a 87 Sr/ 86 Sr ratio 0.70820. This value considerably more radiogenic than...

Abstract We provide an extension to previous analysis of the localised beading instability soft slender tubes under surface tension and axial stretching. The primary questions pondered here are as follows: what loading conditions, if any, can bifurcation into circumferential buckling modes occur, do such solutions dominate localisation periodic modes? Three distinct boundary conditions considered: in case 1 tube’s curved surfaces traction-free tension, whilst cases 2 3 inner outer...

Localized pattern formations and "two-phase" deformations are studied theoretically in soft compressible cylinders subject to surface tension axial loading through several force-controlled scenarios. By drawing upon known results for separate yet mathematically similar elastic localization problems, a concise family of analytical bifurcation conditions localized bulging or necking derived terms general strain energy function. The effect material compressibility strain-stiffening behaviour on...