[en] The model of chiral superfield related with low-energy limit of superstring theory and characterized by kahlerian K(Φ, Φ-bar) and chiral W(Φ) potentials is considered. The approach to solving the general problem of the loop quantum correction at arbitrary K(Φ, Φ-bar), W(Φ) is developed. The aspects of supergraph computational technique for perturbative contribution to superfield effective action are investigated. The explicit expressions for one- and two-loop corrections to kahlerian effective potential are obtained. The leading two-loop correction to chiral potential is found. It is shown that its computing does not require introduction of counterterms at all, independently of the forms of K(Φ, Φ-bar) and W(Φ)