油气成藏与分布的递变序列

在分析成藏过程的基础上,指出了不同类型油气藏分布的序列性。油气生成的多源性和不同聚集条件下成藏聚集的多变性构成了油气在平、剖面上发育和分布的序列性,它由生供烃序列、运移序列、封存序列以及成藏序列等构成,多因素变化导致不同盆地中的油气藏分布构成多种变化序列。若将不同盆地中的典型油气藏片段进行时空组接,则上述所有油气藏类型都将在理想的盆地中出现,构成理论上完整的油气成藏机理序列。对具体的盆地而言,由于不同类型油气藏的存在几率及发育的规模和程度各有差异,通常形成以几种机理类型为主的油气藏组合序列。单就一定条件下的天然气成藏分析而言,煤层气或页岩气、根缘气、致密砂岩气、水溶气、常规圈闭气以及甲烷水合物等可构成完整的油气成藏机理递变序列。

MECHANIC SPECTRUM FOR THE MIGRATION AND ACCUMULATION OF HYDROCARBONS

The diversifications of generation, migration and accumulation of oil and gas constitute a continuous and perplexed mechanic sequence, in which the oil and gas reservoirs are formed and distributed successively in vertical sections and horizontal planes. As a sequence chain, the biochemistry gas, prematurely hydrocarbon, normally thermogenic oil and gas, post mature gas, re mature gas, abio generated gas, and even the oxidative degraded oil compose the substance foundation of sequential chain of oil and gas. Affected mainly by the environmental pressures and temperatures, the sorption of source rocks and capillarity of cap rocks or tight sand reservoirs structure the existing and sealing sequence of oil and gas, which was always complicated by hydrodynamic forces, abnormal pressures, and numerator diffusion. Since the gradual changes of reservoir media and hydrocarbon properties restrict the essential types of migration, sealing, and accumulation, the dominant couples of dynamic powers for oil and gas to migrate or accumulate will change successively. For respectively the adsorbed gas, source contacting gas, normally trapped oil and gas, water dissolved gas and hydrate, and even the oil sands, the dominant couples of dynamic powers are correspondingly the sorption vs. diffusion, the generating expansibility of hydrocarbons vs. the sum of hydrostatic pressures and capillary pressures, the buoyancies vs. the capillary pressures, the dissolution vs. separation, and even the gravities vs. the earth agents. Finally, the distinctive conditions and powers result in varied sequences of oil and gas in different basins.Aimed at gas spectrums, the coal bed gas or gas shale, source contacting gas or basin centered gas, tight sand gas, dissolved gas, normally trapped gas and even hydrate constitute the whole sequence of gas accumulations.