石油实验地质
石油實驗地質
석유실험지질
EXPERIMENTAL PETROLEUM GEOLOGY
2015年
1期
53-56,63
,共5页
油气地质特征%成藏模式%油气分布%盐下%桑托斯盆地
油氣地質特徵%成藏模式%油氣分佈%鹽下%桑託斯盆地
유기지질특정%성장모식%유기분포%염하%상탁사분지
petroleum geologic characteristics%hydrocarbon accumulation pattern%hydrocarbon distribution%pre-salt%Santos Basin
巴西桑托斯盆地经历了裂谷期、过渡期和被动大陆边缘期3个构造演化阶段，发育了盐下、盐岩和盐上3套层序。盐下下裂谷期烃源岩是盆地内的主力烃源岩，具有良好的生烃能力；盐下储层主要为上裂谷—坳陷期生物灰岩、上裂谷期介壳灰岩；盐岩层在深水区厚度大，呈连续分布，封盖能力强；基底断垒带有利于形成各类构造圈闭，有利的地质条件为盆地盐下巨型油气藏的形成提供了良好基础。盆地北部深水区的基底断垒带是盐下油气聚集的有利场所，这一区域盐下烃源岩演化程度适中，巨厚连续分布的盐岩层提供了良好的保存条件；基底断垒形成的古浅水区有利于碳酸盐岩储层的发育，断垒、翘倾断块、披覆背斜圈闭十分丰富，周边地堑区生成大量的油气就近运移到地垒区聚集成藏。其他地区盐下层序存在各种风险，成藏条件略差。
巴西桑託斯盆地經歷瞭裂穀期、過渡期和被動大陸邊緣期3箇構造縯化階段，髮育瞭鹽下、鹽巖和鹽上3套層序。鹽下下裂穀期烴源巖是盆地內的主力烴源巖，具有良好的生烴能力；鹽下儲層主要為上裂穀—坳陷期生物灰巖、上裂穀期介殼灰巖；鹽巖層在深水區厚度大，呈連續分佈，封蓋能力彊；基底斷壘帶有利于形成各類構造圈閉，有利的地質條件為盆地鹽下巨型油氣藏的形成提供瞭良好基礎。盆地北部深水區的基底斷壘帶是鹽下油氣聚集的有利場所，這一區域鹽下烴源巖縯化程度適中，巨厚連續分佈的鹽巖層提供瞭良好的保存條件；基底斷壘形成的古淺水區有利于碳痠鹽巖儲層的髮育，斷壘、翹傾斷塊、披覆揹斜圈閉十分豐富，週邊地塹區生成大量的油氣就近運移到地壘區聚集成藏。其他地區鹽下層序存在各種風險，成藏條件略差。
파서상탁사분지경력료렬곡기、과도기화피동대륙변연기3개구조연화계단，발육료염하、염암화염상3투층서。염하하렬곡기경원암시분지내적주력경원암，구유량호적생경능력；염하저층주요위상렬곡—요함기생물회암、상렬곡기개각회암；염암층재심수구후도대，정련속분포，봉개능력강；기저단루대유리우형성각류구조권폐，유리적지질조건위분지염하거형유기장적형성제공료량호기출。분지북부심수구적기저단루대시염하유기취집적유리장소，저일구역염하경원암연화정도괄중，거후련속분포적염암층제공료량호적보존조건；기저단루형성적고천수구유리우탄산염암저층적발육，단루、교경단괴、피복배사권폐십분봉부，주변지참구생성대량적유기취근운이도지루구취집성장。기타지구염하층서존재각충풍험，성장조건략차。
The Santos Basin in Brazil has experienced three tectonic evolution stages ( rifting, transitional and passive continental) with three sequences deposited ( pre?salt, salt and post?salt) . Source rocks in the pre?salt formations in the lower rift were the most effective source rocks in the basin. Microbial limestones in the upper rift and depression, and coquina limestones in upper rift served as the main reservoirs for the pre?salt source rocks. The salt formations had strong capping capacity thanks to great thickness and continuous distribution in the deep water area. The basement horst belt helped the formation of various structural traps. All these advantageous geo?logic conditions provided a good basis for the generation of giant oil and gas pools in the pre?salt formations in the basin. The basement horst belt in the deep water area in the north of the basin was a favorable location for the pre?salt hydrocarbon accumulation, where the source rocks were moderately mature, and the thick, continuously distributed salt formations provided a good preservation environment. In the shallow water area formed by a base?ment horst, carbonate reservoirs were well?developed, and traps such as horsts, tilted fault blocks and drape an?ticlines were very common. Hydrocarbons generated in the surrounding grabens migrated to and accumulated in the horsts. The other pre?salt formations had poor accumulation conditions.
