Published November 2011

Evaluation and regularities analysis of rocks physical-mechanical properties changing by the well drilling technological data

G.M. Efendiyev

E.M. Naghiyev

This article analyzes the rocks physical-mechanical properties change by the depth according to drilling data taking into account the influence of abnormally high reservoir pressure (AHRP). The difference in the geological properties of most oil fields is also determined with the depth characteristics. The presence of correlation between porous pressure and porosity of clay rocks provides an opportunity to forecast AHRP zones and make their quantitative assessment on the basis of direct and indirect measuring of clay porosity changing from the depth. The key procedure is to set a tendency of rocks porosity index decreasing with the depth in normal conditions, find out and quantitatively evaluate the declination from this tendency in AHRP zones. The porosity and rock hardness from the depth functions have been identified. Under the influence of above located rocks pressures the porosity of clay by the depth have to decrease in normal conditions, but in the hardness indexes in these conditions in general is observed increase by the depth. The reviewed profile is characterized by the AHRP zones presence in which significantly are observed porosity increase and hardness decrease. Thus, while this function developing at the beginning were used the indexes characterizing normal zones and then were applied corrections in AHRP influence.