A new procedure has been devekJped to predict the abrupt in-situ compaction and the associated surface subsidence above high-porosity carbonate fields that show pore collapse. The approach is based on an extensive laboratory compaction study in which the effects of carbonate type, porosity, core preparation, pore saturant, horizontal/vertical stress ratio, and loading rate on pore-collapse behavior were investigated.For a number of carbonate types, a trendline was established that describes the relationship between the porosity after collapse and the vertical effective stress. This trendline concept, in combination with existing subsidence models, enables reservoir compaction and surface subsidence to be predicted on the basis of wireline porosity logs. Static and dynamic elastic constants were found to be uncorrelated during pore collapse.The position of the trendline depends strongly on carbonate type, pore saturant, loading rate, and stress ratio. Therefore, procedures are given to derive the correct in-situ trendline from laboratory compaction experiments.

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Time-resolved methods are used to study scattering and trapping processes in a one-dimensional triplet exciton system. Electron spin echo experiments indicate that intraband scattering in the lowest triplet exciton band t, in 1,2,4,5-tetrachlorobenzene is independent of chemical purity and certain forms of structural damage. Optical measurements between 0.35 K and 1.25 K demonstrate the importance of an 8 cm -1 trap at low temperature, and show further that trapping rates are independent of band state k for deep X-traps. The results suggest that the X-traps are not directly incorporated into the band structure of the host.