Zkhus, I.D.; Bakhtin, V.V.
An examination is made of problems associated with the properties of clays as an mantles over petroleum and gas beds with abnormally high stratal pressures (AHSP), with changes in the clays that are characteristic of AHSP zones, with catagenetic transformations of clay minerals, and with their superimposed catagenesis under the influence of fluids in the interstitial coronas. The study of the lithogenetic transformations of clay was shown to be of practical use for forecasting AHSP zones and estimating stratal pressures as well as for the operative development of an optimal system for drilling deep wells. The gradient distribution of AHSP for the layer of clay mantles was demonstrated for the first time as was the coincidence of the maximum values of those gradients with the hydrodynamic threshold. The over-all effect of dispersing rock in the AHSP zones was shown to have a universal significance and importance to forecasting beds with AHSP and the safe drilling of boreholes by means of the timely identification of AHSP zones. Calculations were made for the first time on the effect that the thickness of mantles has on fracture time of the fluids. 150 references, 27 figures, 21 tables.