Salt Strata Research Articles

Closure of a Nuclear Waste Repository Deeply Imbedded in a Stratified Salt Bed

The Waste Isolation Pilot Plant (WIPP) is a repository vault, mined deep into a salt strata. It eventually closes in on itself, encapsulating its contents. At room temperature salt may be regarded as a linear, isotropic, viscoelastic material. In this study, using triaxial compression test results on salt, we determine the relaxation functions and set up the boundary value problem for the encapsulation mechanism of a salt vault. Closure of the repository as a function of time is determined using a three-dimensional finite element model. The Tresca failure criterion is used to predict the stability of the repository. Finally, the study is validated by comparing our results to in-situ measured data.

Displacement of salt by the Laurentide Ice Sheet

In central New York, deformation of salt of the Salina Formation by the Laurentide Ice Sheet is shown by a thinning of the salt stratum in and near the outcrop zone where it was overridden by the ice sheet and by a thickening down-dip near the glacial limit. Less definitive suggestions of deformation by glacial overriding of the Salina outcrop zone in northeastern Ohio are seen in salt-cored anticlines in the vicinity of the glacial limit. In the lower peninsula of Michigan, isopachs of salt curve around Saginaw Bay, which suggests that the salt was displaced southwestward, away from the bay, by pressure of the Saginaw lobe of the ice sheet. All but one of the major Paleozoic salt deposits of North America lie in a zone that girdles two-thirds of the Canadian Shield from where glacial erosion removed all but occasional outliers of Phanerozoic strata.

Mediterranean sub-bottom giant Messinian salt as a precipitite

We question the widely held view that the sub-Mediterranean giant salt is anevaporite deposited in a dessicated deep basin (Hsu model). Instead we suggest it to be aprecipitite (new word, as the termevaporite tends to beg the question) precipitated within a deep water saturated brine (Schmalz model). We question the validity of supposed dessication indicators (mud cracks, stromatolites, etc.). One is reminded of the 1950’s when submarine canyons and deep sea sand were falsely interpreted to mean ocean basins had dried up. Remarkable hypothesis require extraordinary proof! Precipitation better accounts for the usual draping (rather than ponding) of the salt strata, their apparent deposition on young oceanic crust, general lack of erosional redepositional unconformities and interposed beds with deep water fauna. The repeated (ca. 12 times) absolute blocking at the Gibraltar portal by tectonism of a flow equivalent to several Amazons defies the geomorphic principle that river cutting overpowers tectonic uplift. In isolated large arid basins, (e.g. Caspian Sea, Aral Sea, Dead Sea, Great Salt Lake) complete dessication, which requires zero precipitation and zero inflow, is an asymptotic end point never achievable in reality. Ground water hydrologic regimes and a paleo-Nile which flowed in from tropical rain forest are additional problems. Recent deposition (1983–85) of 4 cm of halite in the Dead Sea provides an actualistic example of precipitation. Undirectional inflow through a coral reef barrier dam at the Gibraltar portal is offered as possibly causing brine saturation in the Mediterranean 5 Ma.

Drill Stem Corrosion in West Texas

Abstract Each of the 700 or more drilling rigs operating in West Texas has an investment of $30,000 to $70,000 in drill stem and one one drilling company there estimates drill stem costs on each rig to be $137 a day. A large part of the cost is attributed to rapid depreciation of drill stem from corrosion and corrosion fatigue, heavy corrosion from underlying salt strata being the principal culprit. Deeper wells drilled recently have faced an increasing corrosion problem as a result of reduction in salt content of well fluids. The very costly results of corrosion fatigue failures of drill collar joints is cited, including the numerous operational difficulties resulting from mitigation measures. Hughes Tool Company first placed cast zine rings in boxes before the pin was screwed in, thus forcing the ring into place and intimately engaging the unengaged threads at the bottom of the box. These proved unsatisfactory, so magnesium strip was pressed in place in the, drill collarbox. Tests of the rings are descr...