Abstract
Hydrocarbon reservoirs can be divided into 3 groups and 8 sub-groups. The 8 sub-groups include hydrocarbon reservoirs caused by: (i) high pressure potential fields; (ii) low pressure potential fields; (iii) release of dissolved gas from oil and water; (iv) buoyancy; (v) capillary pressure; (vi) deep-basin gas accumulations; (vii) coal-bed methane accumulations formed by molecular adsorption; and (viii) hydrate formation. The 8 sub-groups can be more broadly combined into 3 groups: (1) hydrocarbon reservoirs resulted from episodic fluid pressure, which include sub-groups (i) and (ii); (2) hydrocarbon reservoirs caused by steady and continuous hydrocarbon potential difference, including sub-groups (iii)-(v); (3) hydrocarbon reservoirs formed under unconventional conditions, which are represented by sub-groups (vi)-(viii). Hydrocarbon reservoirs with the same dynamic origin can be further subdivided into groups according to their geological settings. With different dynamic origins, various hydrocarbon reservoirs have different distribution patterns and major controlling factors. In order to enhance oil and gas field exploration and increase exploration probabilities of success, it is both important and necessary to study the dynamic mechanisms and associated genetic models for hydrocarbon migration and accumulation.