TECTONIC ASPECTS OF OIL AND GAS ACCUMULATION ON CONTINENTAL MARGINS

Abstract

The tectonic regime has a very great effect on the lithologic composition of deposits, on the sedimentation rate, and on the conditions of accumulation and preservation of petroleum and gaseous hydrocarbons in continent-ocean transition zones in regions with both passive and active continental margins. The lithologic composition of the sedimentary cover of basins is determined by their structural-tectonic position on one continental margin or another, as well as on the general trend of evolution in that part of the transition zone. The same criteria can be used to determine the combination of genetic types of deposits and their accumulation rate. Whether all these deposits will become petroliferous depends chiefly on the rate and the duration of sedimentation, as well as on the extent to which organic matter participates in this process. The oil- and gas-generating potential of organic matter will be realized if the first two conditions are fulfilled. Any rocks, including fine-grained diatomite and fractural clay, will become oil and gas reservoirs if they have a high enough storage capacity.