摘要
南里海盆地是中、新生代发育的弧后裂谷—前陆复合盆地,其中下库拉凹陷具有快速巨厚沉积、异常高压、泥火山发育、低地热梯度的特点。探讨了下库拉凹陷异常高压形成条件、发育特征及其对油气成藏的影响。异常高压的形成主要与该区快速沉积、巨厚塑性沉积、构造挤压、泥火山活动、富含蒙脱石厚层泥岩发育有关,而温热膨胀、烃类生成、黏土矿物脱水对该区异常地层压力的贡献不大。凹陷内2000多米深度已经具有国内罕见的异常高压。由于地层岩性不同,异常高压引起的欠压实在部分构造的泥岩压实曲线和密度曲线上十分明显,而在部分构造中没有反映,并依此把下库拉凹陷中异常高压地层的泥岩压实划分为3种类型。异常高压利于该区储集层物性的保存、油气藏的封闭,控制该区油气分布,促使该区构造和圈闭形成,但也产生了严重的工程难题。
South Caspian Basin is a backarc rift and foreland combination basin developed in the Mesozoic and Cenozoic. The lower Kura Sag in the basin is characterized by great thickness and rapid sedimentation, abnormally high formation pressure, widespread mud volcanos, and low heat flow and formation temperature. This paper studies the forming condition and distribution feature of the abnormally high pressure in the lower Kura Sag and its effects on hydrocarbon accumulation. Its formation is related to tectonic compression; mud volcanism; widely thick, rapid, plastic sedimentation; and massive clays with smectite. Thermal expansion, hydrocarbon generation and clay dehydration contribute little to the high pressure formation. Formation pressure is universally higher in Lower Kura than that in China＇s basins, with pressure coefficient up to 2. 14 in 2 412 m. Compaction trend lines of under-compaction clay in different structures are various because of different lithology, according to which the abnormal clay compaction is divided into 3 types. Abnormally high pressure is favorable for reservoirs preservation and formation of structures and traps, controls hydrocarbon distribution, but also causes severe engineering problems.
出处
《石油勘探与开发》
SCIE
EI
CAS
CSCD
北大核心
2009年第4期487-493,共7页
Petroleum Exploration and Development
基金
中国石油天然气集团公司"海外重点战略大区勘探潜力及新项目快速综合评价技术研究"项目(06B60101)
关键词
南里海盆地
异常高压
形成条件
快速沉积
油气成藏
South Caspian Basin
abnormally high pressure
forming condition
rapid deposition
hydrocarbon accumulation
