奥连特盆地斜坡带原油地化特征、充注模式及勘探实践

doi:10.13745/j.esf.sf.2020.6.38

摘要/Abstract

摘要：

奥连特盆地斜坡带原油油品分布复杂,重质原油开发难度大、不经济,中轻质原油分布规律不清,严重制约斜坡带油气勘探。本文从原油地化分析入手,通过分析原油分布特征和地化特征,明确重油成因机理,建立原油充注模式,指出中轻质油有利发育区,以有效指导油气勘探。研究结果如下:(1)斜坡带原油正构烷烃具有前峰型碳分布形式,表明原油主要为海相母源;(2)原油具有“双低+双高”族组成,表明原油为烃源岩低熟-成熟阶段产物;(3)重油主要为生物降解成因,证据1为:饱和烃总离子流图发育UCM现象,证据2为:检测发现25-降藿烷标志性化合物;(4)地化分析表明同一样品中同时存在降解原油和未降解原油特征,表明原油为两期充注成因;(5)据此建立油气两期充注模式:早期常规原油充注,中期原油普遍遭受生物降解,原油变重,晚期常规原油充注与降解原油混合控制平面原油油品分布特征,并指出斜坡带砂岩尖灭条带下倾方向是常规油有利分布区,部署探井、评价井获得了成功。

关键词: 地化特征, 重油成因, 生物降解, 混合充注成藏

Abstract:

The slope zone of the Oriente Basin has a complex crude oil distribution according to °API. Heavy oil extraction in the basin is difficult and costly, accompanied by unclear distribution of medium and light crude oil, which greatly hinders oil and gas exploration in this area. In this paper, starting with geochemical analysis of crude oil, we clarified the formation mechanism of heavy oil and established a charging model for crude oil by analyzing its distribution and geochemical characteristics. We also identified the favorable prospecting areas for medium and light crude oil to provide effective guidance for oil and gas exploration. The results show: (1) Crude oil samples from the slope zone had a front peak in their n-Alkane distribution, indicating marine source. (2) The group composition of crude oil displayed a “double low+double high” feature, suggesting the crude oil comes from the low maturity-maturity stage of source rocks. (3) Biodegradation is the major reason for heavy oil formation, evidenced by (i) the well developed UCM phenomenon in the total carbon ion flow chart; and (ii) the detection of 25-norhopane marker compounds. (4) Degraded and normal crude oil co-exist in the same oil sample according to geochemical analysis, indicating crude oil is the results of mixing two stages of oil charging. Based on the results, a two-stage oil filling model is established: After early oil charging, crude oil is generally degraded and becomes heavier in the mid-stage; then after late-stage oil charging, the mixing of later stage normal oil and degraded crude oil controls the planar distribution of crude oil. The area in the down dip direction of shale belt in the slope zone is the favorable area for normal oil exploration as proved by successful drilling of exploration wells.

Key words: geochemical feature, heavy oil formation mechanism, biodegradation, mixed oil charging

中图分类号:

P618.130.2

张志伟, 马中振, 周玉冰, 阳孝法, 王丹丹, 刘亚明, 赵永斌. 奥连特盆地斜坡带原油地化特征、充注模式及勘探实践[J]. 地学前缘, 2021, 28(4): 316-326.

ZHANG Zhiwei, MA Zhongzhen, ZHOU Yubing, YANG Xiaofa, WANG Dandan, LIU Yaming, ZHAO Yongbin. Crude oil geochemical features, charging model and exploration practice in slope zone of the Oriente Basin[J]. Earth Science Frontiers, 2021, 28(4): 316-326.

图/表 10

图1 奥连特盆地位置及采样点分布

Fig.1 Distribution of sampling sites in the Oriente Basin

图2 T区块原油API纵向层位分布特征

Fig.2 Vertical distribution features of crude oil API in T block

图3 奥连特盆地油藏平面展布图(据文献[6]补充修改)

Fig.3 Layout map of oil reservoirs in the Oriente Basin. Modified after [6].

图4 T区块M1ss段油藏及原油API分布

Fig.4 Distribution of oil reservoir and crude oil API in M1ss section of T block

图5 T区块原油样品饱和烃总离子流图

Fig.5 Total ion chromatograms (TIC) of saturated hydrocarbon for crude oil samples from T block

图6 C7井原油色谱质谱图(检测到25-降藿烷标志化合物)

Fig.6 GC/MS spectra of crude oil from Well C7 identifying 25-norhopane biomarker compound

图7 Piuntza-1X井热演化史及有机质成熟度

Fig.7 Thermal evolution history and organic matters maturity for Well Piuntza-1X

图8 不同光照射下的斜坡带砂岩样品中不同类型流体包裹体图 a,b图为Au30井第1号照片的石英次生加大包裹体;c,d图为G1-3井第16号照片观测到的切穿石英微裂隙的包裹体;a,c两图为透射光;b,d两图为荧光。

Fig.8 Photomicrographs of different types of fluid inclusions in sandstone samples from slope belt under different lights

图9 流体包裹体均一化温度分布

Fig.9 Distribution of homogenization temperature for fluid inclusions

图10 奥连特盆地斜坡带油气充注模式剖面位置见图4。

Fig.10 Hydrocarbon charging model for the Oriente Basin slope belt

参考文献 27

[1]	MATHALONE J M P, MANUEL M R. Petroleum geology of the sub-Andean basins of Peru[M]//TANKARD A J, SUÁREZ R S, WELSINK H J. Petroleum basins of South America. Tulsa: AAPG Press, 1995: 423-444.
[2]	刘池洋, 王建强, 赵红格, 等. 沉积盆地类型划分及其相关问题讨论[J]. 地学前缘, 2015, 22(3):1-26.
[3]	温志新, 童晓光, 张光亚, 等. 全球沉积盆地动态分类方法: 从原型盆地及其叠加发展过程讨论[J]. 地学前缘, 2012, 19(1):239-252.
[4]	温志新, 童晓光, 张光亚, 等. 全球板块构造演化过程中五大成盆期原型盆地的形成、改造及叠加过程[J]. 地学前缘, 2014, 21(3):26-37.
[5]	HIGLEY D K. The Putumayo-Oriente-Maranon Province of Colombia, Ecuador, and Peru: Mesozoic-Cenozoic and Paleozoic petroleum systems[R]. Reston: USGS, 2001: 1-31.
[6]	马中振, 陈和平, 谢寅符, 等. 南美Putomayo-Oriente-Maranon盆地成藏组合划分与资源潜力评价[J]. 石油勘探与开发, 2017, 44(2):225-234.
[7]	谢寅符, 季汉成, 苏永地, 等. Oriente-Maranon盆地石油地质特征及勘探潜力[J]. 石油勘探与开发, 2010, 37(1):51-56.
[8]	马中振, 谢寅符, 陈和平, 等. 南美典型前陆盆地斜坡带油气成藏特征与勘探方向选择: 以厄瓜多尔Oriente盆地M区块为例[J]. 天然气地球科学, 2014, 25(3):379-387.
[9]	YANG X F, XIE Y F, ZHANG Z W, et al. Hydrocarbon generation potential and depositional environment of shales in the Cretaceous Napo Formation, eastern Oriente Basin, Ecuador[J]. Journal of Petroleum Geology, 2017, 40(2):173-193. DOI URL
[10]	DASHWOOD M F, ABBOTTS I L. Aspects of the petroleum geology of the Oriente Basin, Ecuador[J]. Geological Society, London, Special Publications, 1990, 50(1):89-117. DOI URL
[11]	刘畅, 张琴, 谢寅符, 等. 厄瓜多尔Oriente盆地东北部区块白垩系层序地层格架及发育模式[J]. 沉积学报, 2014, 32(6):1123-1131.
[12]	傅家谟, 盛国英. 环境有机地球化学初探[J]. 地学前缘, 1996, 3(2):127.
[13]	童晓光, 郭建宇, 王兆明. 非常规油气地质理论与技术进展[J]. 地学前缘, 2014, 21(1):9-20.
[14]	PETERS K E, MOLDOWAN J M. Effects of source, thermal maturity, and biodegradation on the distribution and isomerization of homohopanes in petroleum[J]. Organic Geochemistry, 1991, 17(1):47-61. DOI URL
[15]	LARTER S, HUANG H P, ADAMS J, et al. A practical biodegradation scale for use in reservoir geochemical studies of biodegraded oils[J]. Organic Geochemistry, 2012, 45:66-76. DOI URL
[16]	FRYSINGER G S, GAINES R B, XU L, et al. Resolving the unresolved complex mixture in petroleum-contaminated sediments[J]. Environmental Science & Technology, 2003, 37(8):1653-1662. DOI URL
[17]	王汇彤, 张水昌, 翁娜, 等. 稠油中饱和烃复杂混合物成分解析及其意义[J]. 中国科学: 化学, 2012, 42(10):1469-1478.
[18]	常象春, 王铁冠, 李启明, 等. 哈拉哈塘凹陷新垦区块奥陶系油气成藏的地球化学证据[J]. 中国石油大学学报(自然科学版), 2013, 37(3):44-49.
[19]	柳广弟, 杨伟伟, 冯渊, 等. 鄂尔多斯盆地陇东地区延长组原油地球化学特征及成因类型划分[J]. 地学前缘, 2013, 20(2):108-115.
[20]	BENNETT B, FUSTIC M, FARRIMOND P, et al. 25-Norhopanes: formation during biodegradation of petroleum in the subsurface[J]. Organic Geochemistry, 2006, 37(7):787-797. DOI URL
[21]	徐锋, 李贤兵, 胡健, 等. 乍得Bongor盆地Ronier油田油气成因特征与生烃演化史分析[J]. 地学前缘, 2018, 25(2):130-139.
[22]	李威, 窦立荣, 张光亚, 等. 苏丹Muglad盆地Fula坳陷油气地球化学特征与成藏意义[J]. 地学前缘, 2018, 25(2):121-129.
[23]	李儒峰, 陈莉琼, 李亚军, 等. 苏北盆地高邮凹陷热史恢复与成藏期判识[J]. 地学前缘, 2010, 17(4):151-159.
[24]	高先志, 陈发景. 应用流体包裹体研究油气成藏期次: 以柴达木盆地南八仙油田第三系储层为例[J]. 地学前缘, 2000, 7(4):548-554.
[25]	郑有业, 李晓菊, 马丽娟, 等. 有机包裹体在生油盆地研究中的应用[J]. 地学前缘, 1998, 5(2):325.
[26]	王飞宇, 肖贤明, 何萍, 等. 有机岩石学在油气勘探中应用的现状和发展[J]. 地学前缘, 1995, 2(4):189-195.
[27]	倪培, DUBESSY J, 丁俊英, 等. 低温原位拉曼光谱技术在流体包裹体研究中的应用[J]. 地学前缘, 2009, 16(1):173-180.