The influence of hydrocarbons on the physical properties of the Black Sea sediments under high pressure and temperature conditions

In this work, we have a specific task, namely: what effect do petroleum products have on the physical properties of sediments when they replace the moisture contained in them, and is it possible to register the accumulation (localization) of petroleum products on the bottom of certain areas of the Black Sea using geophysical methods. In other words, it is necessary to evaluate changes in the elastic, magnetic, and electrical parameters of bottom sediments in connection with filling them (or replacing them with seawater) with organic gas-liquid media. For the first time, the results of complex laboratory studies of the influence of hydrocarbons on the propagation velocities of longitudinal waves, magnetic susceptibility, specific electrical resistance and relative electrical permeability in bottom sediments are presented. Possible signs of hydrocarbons in geophysical fields are outlined. As a result, two opposite effects of the influence of hydrocarbons on elastic-density properties in the upper and deeper horizons of sediments under normal temperature conditions were established. The effect of different stages of diagenesis (in conditions of conditionally high temperatures, heating more than 100 degrees & Scy;) in the presence of saturation of the sample with petroleum product leads to an increase in the propagation speed of elastic waves in muds. This effect can take place in natural conditions during the formation of localization - at depths corresponding to these temperatures. It is possible to outline the localization of petroleum products by sediment -hardening zones, areas with higher V P and rho, and, therefore, an intense reflection of the seismoacoustic signal, which can be search signs for the search for petroleum product localization sin layers of unconsolidated sediments. The results of the research show that an increase in temperature even in samples not saturated with carbohydrates leads to a small change in magnetic susceptibility. Saturation of sediments with carbohydrates leads to an increase in the intensity of this process. It was established that under the influence of hydrocarbons, the specific electrical resistance of marine sediment samples increases by several orders of magnitude, and the relative dielectric constant decreases by several units.