We investigated chemical radial gradient changes in a massive galaxy disk owing to its interaction (encountering) with a low-mass satellite with lowered heavy elements abundance. To consider this problem, a special computer program for dynamical simulation of galaxies mergers through the N-body method was developed. This N-body algorithm realization also includes the processes of viscosity particle collisions. The disk galaxy and its dwarf satellite are described at the initial moment as balanced configurations of the Plummer-Kuzmin and Plummer particle distributions, respectively. We also included the conception of heavy elements abundance in particles (Z) in N-body dynamical model. In such form particles (bodies) describe the whole gravitationaly combined regions of gas and stars mixture. As the first approximation, we do not consider the star formation processes and the heavy elements enrichment of individual modelled particles which is related to them. We also neglect possible mass exchanges (and chemical elements exchanges) between particles. We determine the radial gradient of heavy elements abundance in galactic disk after the collision over the set of dynamical particles mexture from both disk (bulge) particles and dwarf satellite particles. As a result of our simulations we derived that in comparison with dynamical evolution process of isolated disk galaxy, in the case of its encounter with a dwarf galaxy (for the same value of dissipative parameter) the radial gradient of heavy elements abundance in galaxy disk feels stronger changes (decreases more considerably). Much the same chemical radial gradient decreasing for isolated disk galaxy model can be obtained by increasing the dissipative parameter value in one and a half times. Also, in the process of dwarf and disk galaxies encounter in our model we observe a distinct lowering of chemical heavy elements abundance in the disk at the place of dwarf galaxy position. With our modelled parameters this lowering diffuses during about 6 billions of years after the encounter. We compared our results with observational data for the NGC 2903 disk galaxy. In this galaxy the compact area with lowered heavy elements abundance is clearly defined. Thus, it may be concluded that the dwarf galaxy absorbtion at this object has happened less than 6 billion years ago.