Hydrocarbon accumulation in network and its application in the continental rift basin

Abstract

The concept of hydrocarbon accumulation in network was presented on basis of the overall analysis of the formation and evolution characteristics of the continental faulted basin and of the systemic research on the major controlling factors on the hydrocarbon accumulation. The hydrocarbon accumulation in network can be defined as hydrocarbon accumulation in a three-dimensional network system which is constituted by the hydrocarbon migration passages under multiple dynamics, following the hydrocarbon generation from source rocks. The research shows that the hydrocarbon accumulation in network is composed of four elements, i.e., hydrocarbon source (source rock kitchen), hydrocarbon accumulation terminal (trap), network pathway connecting source and terminal (transporting system), and network potential driving hydrocarbon migration in the network pathway (migration dynamics). Compared with other networks, hydrocarbon accumulation in network has three basic characteristics: the irreversible geological process of material and information flow in the network; the loss of material and information in the flow process in the network; the multiple dynamics in the flow process. Interaction of all the elements in the geological process can be called hydrocarbon accumulation in network. There are three basic models for hydrocarbon accumulation in network, that is, hydrocarbon accumulation in the network source area, hydrocarbon accumulation in the network pathway, and hydrocarbon accumulation in the network terminal. The key in the application of the hydrocarbon accumulation models in network in practice is to confirm the major accumulation stage and the function range of the four elements controlling the hydrocarbon firstly, to predict the profitable accumulation region by superposition of the favorable areas confirmed by four elements consequently, and to evaluate the oil-bearing property of the trap as well as confirm drilling targets. This paper takes the Dongying Depression in the Bohai Bay Basin as an application example.