论文部分内容阅读
厄瓜多尔 Oriente盆地是南美安第斯山前盆地中最大的产油盆地之一,截止到1986年年底,累积产油达1×10~9bbl以上,目前的日产量约3×10~5bbl。迄今已发现了至少20个油田,其中5个属巨型油田。目前的勘探处于一个新勘探阶段的早期并已取得了初步成功,在这一新勘探阶段 10家经营者计划于1985～1992年间钻40 口井。 Oriente盆地拥有古生代至现今的沉积充填,重要的商业性石油仅限于侏罗纪沉积旋回。石油产自Hollin组和Napo组的河流三角洲和海相砂岩。绝大多数产油构造是低幅度的南北向背斜,类型有两种,即与正断层下盘有关的背斜(类型1)和与逆断层上盘有关的背斜(类型2)。前中新世构造发育重要性的证据有:1 类构造中前白垩纪“基底”断层于早—中白垩世时期的复活和2类构造中“早安第斯期”(白垩纪末—渐新世)的挤压作用。在与“晚安第斯期”(中新世至上新世)挤压有关的构造中发现的油田数量不多,主要因为这些构造晚于油气生成和运移的主要阶段。由于潜在生油岩即白垩系 Napo组的海相泥岩和灰岩在现今 Oriente盆地范围内一般是不成熟的或处于边缘成熟状态,油源尚有问题。油样分析表明,它们系单一石油族。现有的证据以及构造和地球化学资料都支持早安第斯期是主要的油气生成和运移阶段的推测。石油的类型变化很大,包括 37°API、气油比(GOR)为 250～300的含蜡油至10°API的重油。不仅油田之间存在着明显的差异,而且同一口井的不同油藏中也有明显的变化。所观测到的变化趋势绝大部分可作如下解释:早期油气生成、运移和圈闭,随后的构造演化包括局部的生物降解、水洗和(或)水侵以及再运移。
The Oriente Basin in Ecuador is one of the largest oil basins in the Andean frontal basin of South America. As of the end of 1986, cumulative oil production reached 1 × 10 ~ 9bbl and the current daily output is about 3 × 10 ~ 5bbl. To date, at least 20 fields have been discovered, five of which are giant fields. The current exploration is in its early stages of a new exploration phase with initial success, in which 10 operators plan to drill 40 wells between 1985 and 1992. The Oriente Basin has been deposited from the Paleozoic up to the present day with important commercial petroleum limited to Jurassic sedimentary cycles. Oil is produced from fluvial deltas and marine sandstones of the Hollin Formation and the Napo Formation. The vast majority of oil-producing structures are low-amplitude north-south anticlines with two types of anticlines (Type 1) associated with the normal fault and the anticlines (Type 2) associated with the thrust faults. Evidence of pre-Miocene tectonic development is evidenced by the revival of the Early Cretaceous “basement ” fault during the Early-Middle Cretaceous and the tectonic setting of the “Type 2” structure in the Early Cretaceous - Oligocene) extrusion. The small number of fields discovered in the structures related to the “Late Andean” crust (Miocene to Pliocene) is mainly due to the fact that these structures are later than the major stages of hydrocarbon generation and migration. The source of oil is still problematic due to the fact that marine mudstones and limestones in the potential source rock, the Cretaceous Napo Formation, are generally immature or marginal in the current Oriente basin. Oil sample analysis shows that they are a single petroleum group. Available evidence and tectonic and geochemical data support that the pre-Andean period was the main speculation of hydrocarbon generation and migration stages. The type of oil varies widely, including the 37 ° API, a 250 to 300 GOR oil-to-10 ° API heavy oil. Not only are there significant differences between oil fields, but also significant changes have taken place in different reservoirs of the same well. Most of the observed trends can be explained as follows: Early hydrocarbon generation, migration and traps. Subsequent tectonic evolution included local biodegradation, washing and / or water intrusion, and re-migration.