【作者】 张家政；

【导师】 郭建华；

【作者基本信息】 中南大学 ， 矿物学、岩石学、矿床学， 2009， 博士

【摘要】 火山岩作为盆地基底的一部分几乎见于所有盆地。构造一火山活动对原有油气藏具有破坏、改造和建造等多重效果。经过近百年的勘探与开发,在国内外含油气盆地中不断有火山岩油气藏被发现,其中不乏高产油气藏。2006年5月,中科院院士刘嘉麒在大陆火山作用国际会议上提出“沿着火山岩找油气是我国石油界的第三次创新”。可以预见,火山岩有着广阔的勘探开发前景和空间,将成为我国石油工业增储上产的一个重要的领域。火山岩油藏因储层分布规律复杂,准确认识和客观评价难度大而且往往开发效果不佳。如何精细刻画火山岩油藏储层分布规律,深入剖析控制因素,是该类油藏能否成功开发的关键所在。本论文以准噶尔盆地红山嘴油田石炭系火山岩油藏作为研究对象,利用工区新采集的精细三维资料进行精细构造解释,针对火山岩地层划分对比、岩性岩相、裂缝识别与评价、储集空间类型及组合、储层成岩演化、储层控制因素、储层综合评价及储层地质建模等诸多难点,制定了多学科综合研究的技术路线。对火山岩油藏岩性、岩相、孔隙、裂缝、成岩作用、地质建模等方面进行了综合研究。在精细描述火山岩储层分布规律的基础上,对研究区的火山岩油藏成藏条件、圈闭类型、成藏规律及控制因素等方面进行了仔细研究并提出了评价井位的部署建议。研究表明,控制准噶尔盆地红山嘴油田火山岩油藏储集层的关键因素有三:第一、岩性岩相是决定火山岩储集性能的物质基础本次研究优选了火山岩复杂岩性识别技术,认为Fisher判别分析方法根据投影原理将多个变量的特征差异表现在几个主要的判别函数中,通过对四亚类九小类的岩性识别,识别符合率高。以此为基础进行了火山岩岩相研究,研究区火山岩岩相由侵入相、溢流相、爆发相、火山沉积相和冲积扇相组成,大部分地区发育火山沉积相,东部发育溢流相、爆发相,南部发育火山沉积相与冲积扇相。储层综合研究表明:岩性上安山岩、凝灰岩和凝灰质砂砾岩易形成良好的次生孔隙和裂缝,是有利油气储集岩性;岩相上溢流相、爆发相及冲积扇相是有利油气储集相,主要分布在工区的东部和东南部。第二、构造运动形成的裂缝是影响火山岩储集性能的关键因素精细三维地震资料研究表明,C-P期断层是改善储集层储集空间的关键,T-J期断层是形成高角度缝和斜交缝的关键。裂缝系统控制了次生孔缝的形成和分布,同时裂缝系统形成了油气运移的有利疏导体系,是制约油气富集的重要原因。本次研究探索性建立了裂缝孔隙度和裂缝角度解释模型,对44口井进行解释。研究认为裂缝的发育规律为:类型上以构造缝为主,成岩缝次之,溶蚀缝不发育;岩性上以安山岩、凝灰岩为主,凝灰质砂砾岩、沉凝灰岩次之,火山角砾岩较差;产状上以斜交缝和网状缝为主,高角度缝次之,水平缝最差:有效性上以晚期构造缝为主,大部分未被充填,有效性最好,中期和早期构造缝则多被充填;剖面上裂缝主要集中在距风化壳300m的范围内,尤其是150m的距离内最为发育;平面上裂缝主要发育在区域大断裂附近,成带状分布;裂缝发育方向上,红56A井区裂缝走向约25~0、车72井区约330~0、红18井区约300~0-340~0,裂缝走向与T-J期主断裂基本平行。第三、溶蚀溶解作用是影响裂缝性储层有效性的重要条件研究区石炭系火山岩储集层基质具有低孔特低渗的特点,对储集层改造起关键作用的另一因素为溶蚀溶解作用。溶蚀溶解作用发生的条件:(1)良好物质基础:火山岩主要以基性安山岩和火山碎屑岩组成,是溶蚀溶解作用发生并形成次生孔缝的物质基础。(2)充足流体介质:①无机酸性流体来源:a.火山在喷发过程中释放出大量二氧化碳、二氧化硫和硫化氢气体形成的酸性流体.b.深大断裂使地壳深部富含二氧化碳、硫化氢的酸性流体上升至浅层,从而发生溶蚀,这种溶蚀作用主要发生在深大断裂两侧。②有机酸性流体来源:二叠系烃源岩具有有机碳含量高、干酪根类型好,在三叠纪末期白碱滩组沉积时达到生油高峰,有机质热演化产生了有机酸,干酪根成熟过程中裂解也形成了大量的有机酸。(3)多重流体通道:研究区流体通道主要为不整合面、区域性断裂及次级断层和裂缝性储集层。溶蚀溶解作用的主要类型:①玻璃基质溶蚀作用;②沿长石解理缝的溶蚀作用;③沿长石边缘的溶蚀作用;④岩屑(包括浆屑)的溶蚀作用;⑤颗粒内的溶蚀作用;⑥方解石充填裂缝后,再被溶解形成的溶蚀缝;⑦颗粒和基质均被溶蚀形成的溶蚀孔洞。溶蚀溶解作用发生较普遍且主要集中在区域性断裂及次级断层附近,对研究区储层改造起到关键作用。油气成藏规律研究表明,来自昌吉凹陷的二叠系风城组和乌尔禾组烃源岩的油源沿断层、不整合面和火山岩裂缝型储集层,在裂缝、溶蚀孔缝发育的有利构造、地层圈闭中聚集成藏,是典型的新生古储油气组合。其油气成藏主控因素为:断裂和不整合面对油气运移聚集以及再分配起到了重要的控制作用;局部盖层直接控制了油气藏的分布范围、丰度和规模;有利的岩相(或沉积相)带控制了油气藏的形成规模。在地质认识的基础上,建议部署的红019井在石炭系用5mm的油嘴测试获日产油110t、气2.527×10~4m~3的重大突破,取得了良好的经济效益和社会效益。更多还原

【Abstract】 Volcanic rocks are distributed in almost all basins as a base.Volcanic activities have multiple effects on petroleum reservoirs such as destruction,alteration and reconstruction.Over the past few decades,lots of prolific volcanic reservoirs have been discovered in hydrocarbon-bearing sedimentary basins.During the International Conference on Terrigenous Volcanics in May,2006,Jiaqi Liu,an academician of the Chinese Academy of Sciences,advocated that the exploitation of petroleum in volcanic rocks would be the third innovation in petroleum industry.It is anticipated that petroleum exploration and development in volcanic rocks are very promising and will be very important to increase petroleum reserves and production.Volcanic reservoirs are very complex because of their distribution style and heterogeneity.Our limited knowledge in volcanic reservoirs and the difficulties in objective evaluation of these reservoirs lead to undesirable development.The key factors of volcanic reservoir development include how to describe reservoir distribution in detail and how to analyze controlling factors profoundly.This study focuses on Hongshanzui volcanic reservoirin the Jungar Basin.The subtle structures have been interpreted using high resolution 3-D seismic data in the new exploration areas.Comprehensive technological routes integrated with multi-disciplines have been made based on the other work,such as volcanic strata division and correlation, lithology,lithofacies and crack reorganization,pore space types and association of reservoir,diagenesis evolution of reservoir,controlling factors of reservoir,comprehensive assessments of reservoir and geology modeling of reservoir,and so on.Lithology of volcanic reservoir, lithofacies,pore,crack,diagenesis,and geological modeling have been comprehensively studied in this paper.The drilling positions of appraisal wells have been recommended based on detailed description of reservoir distribution,accumulation condition,trap types,accumulation laws and controlling factors.This study shows that there were three key controlling factors for petroleum reservoir in the Hongshanzui oilfield in Junggar basin.The first factor is lithofacies that is the basis for the reservoir properties of volcanics.Recognition methods of volcanic reservoirs are optimally selected in this study.The Fisher method uses the differences of multiple variables in several major discriminant functions based on projection theory.The probability of recognition tends to be high through lithology reorganizations of four subclasses and nine subgroups.On this basis, volcanic lithofacies have been studied.The lithofacies of study consist of invasion facies,effusive facies,burst facies and facies associated with volcanic and alluvial fan.The volcanic facies are distributed in most of study area.Effusive facies are distributed in the east,and volcanic facies and alluvial fan in the south.Andesite,tuff and tuffaceous sandy conglomerate are prone to forming secondary pore and crack,and those are favorable reservoir,mainly distributed in east and southeast.Secondly,fractures formed by structure activity have significant effects on volcanic reservoir quality.Subtle 3-D seismic data show that faults formed during C-P are critical to improve reservoir space and faults formed during T-J are important to form high-angle fractures and miters.Fracture system is very important in controlling petroleum accumulation because fracture system controls the formation and distribution of secondary pore space and also acts as oil and gas migration pathways.Schematic models of fracture porosity and angle have been established and used in the interpretation of 44 wells in this study.Our study shows that the fracture is characterized by predominance of structural fractures,secondary diagenesis fractures and minor dissolving fractures.In addition,andesite and tuff are main reservoir rock,and tuffaceous conglomerate and tuffite are minor,volcanic breccia is the poorest.The fractures are mainly miter and netted fracture in attitude,and high angle fractures are minor, horizontal fractures are poorest.The later are the main fractures,which have not been in-filled effectively.The fractures formed during middle and early periods have been filled mostly.The fractures in the section are mainly distributed in the region about 300m apart from weather crust, especially about 150m apart from weather crust.The fractures in the plane are distributed band-like in nearby large rapture.The fractures distributed in the nearby Hong56A well have a trend about 25°,330°nearby Che72 well,and 300-340°nearby Hong18 well.The trends of fractures are consistent with major fractures formed during T-J.Dissolution is another important factor to improve the quality of fracture reservoirs.Volcanic reservoirs are characterized by lower porosity and extra-lower permeability in study area.Dissolution plays an important role in improve the volcanic reservoir quality.Dissolution occurs in the following conditions:（1） Good material base:volcanics mainly consisted with andesite and volcanic clastics,which were material base for forming secondary resolved porosity;（2） Sufficient fluid media such as（ⅰ） inorganic acid which is formed by the following ways,e.g.,forming by CO₂,SO₂,H₂S that are released during volcanic eruption and risen up from the deep crust through discordogenic fault（this kind of inorganic dissolution happens along the discordogenic fault）,（ⅱ） organic acids which come from thermal evolution of organic matter and thermal decomposition of kerogen from the Permian source rocks with high TOC and Late Triassic source rocks with oil-prone kerogen having good hydrocarbon-generating potential（e.g.,Baijiatan formation）;（3） Multi fluid pathways:the main fluid pathways are unconformity,regional crack and secondary faults and fractural reservoirs.The main types of dissolution are:（ⅰ） glassy matrix dissolution,（ⅱ） feldspar dissolution around the cleavage fissure,（ⅲ） feldspar dissolution around the fringe, （ⅳ） debris dissolution,（ⅴ） grain dissolution,（ⅵ） calcite re-dissolution after filling the fracture,and（ⅶ） secondary porosity and cavity from dissolution of grains and matrix.The dissolution has significant effect on improvement of crack reservoir in the study area.In general,dissolution occurs mainly around the regional fractures and secondary faults.This study on oil and gas reservoir accumulation shows that the oil generated from the Permian Fengcheng and Wuerhe formation accumulated in favorable structure trap and stratigraphic trap with good fracture and resolved porosity through the fault,unconformity and fracture reservoir.The play is a typical new source and old bearing pool. The main controlling factors of oil accumulation are:（ⅰ） the crack and unconformity controlling hydrocarbon migration,accumulation and redistribution;（ⅱ） the local seals controlling the distribution,abundance and scale of petroleum reservoirs,and（ⅲ） favorable lithofacies（or sedimentary facies） controlling the scale of petroleum reservoirs.Significant breakthrough has been accomplished in oil production from the Hong 019 Well that was recommended to due to improvements in our knowledge in geology.The Hong 019 well proposed for drilling had produced oil 110t and gas 2.527×10⁴m³ based on the well test using 5mm choke in Carboniferous,which had significant impact on economic gains.更多还原