关键词: 油气储量, 圈闭, 油气成藏, 容积法, 储量计算, 主控因素

Abstract: There are three types of limits or boundaries involved in the estimation of oil and gas reserves with volumetric analysis, including trap boundaries, reservoir limits and reserve limits. The reserve limits in different classes could be determined with proper certainties, only when the definitions of those three boundaries are correctly determined, and the existed data are reasonably estimated as evidences related to the first two boundaries. The elements as parts of reservoir-forming mechanism are also the factors in considering volume assignments as different reserve categories. Among them, the reservoir type is the primary condition. For the structural reservoirs, the reliability of reserves is subject to the extent of attestation to structure maps and fluid contacts. For the sedimentary lithological deposits, the positions of pinch outlines delineate the maximum outlines of reservoirs. For diagenetic lithological hydrocarbon traps, the cutoffs of porosity or permeability and the fluid contacts control the reservoir sizes. For unconformable screened lithostratigraphic reservoirs, the unconformity dominates the distribution of oil and gas. Whatever the principal factor is, within the maximal outlines in lateral and the lowest depth in vertical, the drainage area of well is the key factor to assign the measured reserve volume.

Key words: oil and gas reserves, trap, hydrocarbon reservoir, volumetric analysis, reserves estimation, main control factors