摘要
哈拉哈塘油田是塔里木盆地重要的油气产区之一,原油成藏期次复杂、部分单井原油密度多变.通过原油物性特征及分布规律、碳同位素值、饱和烃色谱特征、包裹体均一温度、原油成熟度等研究表明：原油来源于下古生界海相烃源岩,具有北东构造高部位密度高、降解程度强、成熟度低,南部构造低部位原油密度低、降解程度低、成熟度高的特征.哈拉哈塘油田经历了3期成藏过程,分别为加里东晚期、海西晚期和喜马拉雅期.加里东晚期原油成熟度较低（4-/1-MDBT＜3.0）,遭受强烈降解,在志留系以残余沥青为主,在奥陶系为重质油,一间房组烃类伴生盐水包裹体均一温度为55～85℃,主要分布在哈拉哈塘地区西侧的艾丁地区.海西晚期原油成熟度中等（4.0＜4-/1-MDBT＜5.5）,以中质油为主,一间房组烃类伴生盐水包裹体均一温度为85～115℃,在哈拉哈塘油田东北地区与加里东晚期原油混合,同时也是哈得逊油田和东河塘油田东河砂岩油藏的主要油源.喜马拉雅期原油成熟度较高（4-/1-MDBT＞6.0）、密度低,一间房组烃类伴生盐水包裹体均一温度为115～135℃,主要分布在哈拉哈塘地区南部.导致单井原油密度多变的原因主要有3种：①多期充注与降解.不同期次原油成熟度和密度差异明显,且降解程度不同,混合不均匀导致原油密度多变.此类型单井较为常见,多分布在大型断裂附近.②“轻质油洗作用”.轻质油与重质油混合导致原油胶体失稳,产生组分分异,沥青质沉淀,据此提出了“轻质油洗作用”概念以解释此现象.沉淀物中沥青质主要来源于早期重质油,而混染的饱和烃和芳烃组分主要来源于晚期轻质油.此类井主要分布于轻质油和重质油混合带.③原油乳化.原油与地层水混合形成油包水,为假稠油.在中质油井和重质油井区多有发现.
Halahatang oilfield,with complicated hydrocarbon accumulation periods,is one of the most important petroleum producing areas in Tarim Basin.The oil densities of some single wells are changeable obviously.Based on the study of petroleum physical characteristics and distribution,the carbon isotope values,saturated hydrocarbon chromatogram,homogenization temperature of fluid inclusions as well as oil maturity,it＇s shown that：the petroleum are originated from the Lower Paleozoic marine source rocks.The oil samples are characterized by high density,high degradation and low maturation degree in the northeastern part of this oil field,where is the high part of the structure.Whereas in the southern part of the oil field,where is the low part of the structure,the oil samples are characterized by low density,low degradation and high maturation degree.Halahatang oilfield has experienced three periods of hydrocarbon accumulation：late Caledonian,late Hercynian and Himalayan period.With low maturation degree （4-/1-MD-BT＜3.0）,the late Caledonian period petroleum was degraded seriously,remaining sand bitumen and heavy oil in Silurian and Ordovician respectively.The homogenization temperature of brine inclusions associated with this period of hydrocarbon in Yijianfang Formation is 55-85°C.This period petroleum mainly distributed in Aiding region,the west side of Halahatang area.The late Hercynian period petroleum is characterized by normal maturation degree （4.0＜4-/1-MDBT＜5.5） and homogenization temperature of 85-115℃ in Yijianfang Formation.It was mixed with the late Caledonian oil in the northeast part of Halahatang oilfield.This period of petroleum is also the main source of Donghe sandstone reservoir in Hadexun oilfield and Donghetang oilfield.The third hydrocarbon accumulation stage is Himalaya period with high maturation degree and low density,the petroleum mainly located in the southern part of Halahatang oilfield.The homogenization temperature of brine inclusions formed in this period in Yijiangfang
出处
《石油学报》
EI
CAS
CSCD
北大核心
2015年第4期405-415,共11页
Acta Petrolei Sinica
基金
中国石油天然气股份有限公司重大科技专项(2014B-0307)资助
关键词
哈拉哈塘
成藏期次
密度多变
原油乳化
轻质油洗作用
生物降解
4-/1-MDBT
Halahatang
hydrocarbon accumulation period
highly variable oil density
emulsification of crude oil
light oil-washing
biodegradation
4-/1-MDBT
