Facies logging identification of intermediate-basic volcanic rocks in Huoshiling Formation of Songliao Basin

Volcanic oil and gas reservoirs are generally buried deep,which leads to a high whole-well coring cost,and the degree of development and size of reservoirs are controlled by volcanic facies.Therefore,accurately identifying volcanic facies by logging curves not only provides the basis of volcanic reservoir prediction but also saves costs during exploration.The Songliao Basin is a‘fault-depression superimposed’composite basin with a typical binary filling structure.Abundant types of volcanic lithologies and facies are present in the Lishu fault depression.Volcanic activity is frequent during the sedimentary period of the Huoshiling Formation.Through systematic petrographic identification of the key exploratory well(SN165C)of the Lishu fault-depression,which is a whole-well core,it is found that the Huoshiling Formation in SN165C contains four facies and six subfacies,including the volcanic conduit facies(crypto explosive breccia subfacies),explosive facies(pyroclastic flow and thermal wave base subfacies),effusive facies(upper and lower subfacies),and volcanogenic sedimentary facies(pyroclastic sedimentary subfacies).Combining core,thin section,and logging data,the authors established identification markers and petrographic chart logging phases,and also interpreted the longitudinal variation in volcanic petro-graphic response characteristics to make the charts more applicable to this area's volcanic petrographic interpretation of the Huoshiling Formation.These charts can provide a basis for the further exploration and development of volcanic oil and gas in this area.

Factors controlling the formation and evolution of source rocks in the Shahezi Formation,Xujiaweizi fault depression,Songliao Basin

The types and quality of source rocks in the Shahezi Formation are the key factors affecting the distributions of various deep gas reservoirs in the Xujiaweizi fault depression in Songliao Basin.To clarify the quality differences and origins of different types of source rocks in the Shahezi Formation,this study reconstructed the sedimentary and water environment,determined the controlling effects of fault activity,sedimentary facies,and paleo-sedimentary environment on the quality of various source rocks,by making full use of seismic,logging,core,organic geochemical and element geochemical analysis.The results show that two types of source rocks developed in the Shahezi Formation,namely,mudstones and coals.The mudstones have a relatively high abundance of organic matter,which consists of type-Ⅱ kerogen and partial type-Ⅲ kerogen,and are concentrated in Sha-I Member.The coals have a high abundance of organic matter,which consist of type-Ⅲ kerogen,and are mainly distributed in Sha-Ⅱ Member.During the deposition of Sha-I Member,intense fault activity formed arrow,deep-water lacustrine basins with high salinity and strong reducibility on the downthrow sides of faults.During the deposition of Sha-II Member,fault activity progressively weakened,and the areas of lacustrine basins enlarged to their maximum values and became wide,shallow-water basins with low salinity and low reducibility.The development of source rocks was controlled by fault activity,sedimentary facies,and paleo-sedimentary environment.Fault activity formed accommodation space on the downthrown sides of faults for mudstone accumulation,thus determining mudstone thickness.The sedimentary environment controlled the organic matter input and determined the distribution of mudstones and coals.The paleo-sedimentary environment,which consisted of paleo-salinity,as well as paleo-water depth and redox conditions,affected the accumulation and preservation of organic matter and is the main controlling factor for the quality difference of various source rocks in the Shahezi Formation.

Latest Zircon U-Pb Geochronology of the Huoshiling Formation Volcanic Rocks in the Southeastern Margin of the Songliao Basin

Objective The Huoshiling Formation is the earliest volcanic stratum in the Songliao Basin,composed mainly of intermediate-basic volcanic rocks,with rare fossils.The geological age of this formation has been controversial for long.

Accumulation and exploration of continental shale gas resources of Cretaceous Shahezi Formation in Lishu fault depression,Songliao Basin,NE China

Distribution characteristics,organic matter development characteristics,gas-bearing characteristics,reservoir characteristics,and preservation conditions of the Shahezi Formation shale of Lower Cretaceous in the Lishu fault depression,Songliao Basin,NE China,are analyzed using organic geochemical,whole rock,and SEM analysis data,and CO_(2)and N_(2) adsorption and high-pressure mercury injection experiment data in combination with the tectonic and sedimentation evolution of the region to reveal the geological conditions for enrichment and resource potential of continental shale gas.The organic-rich shale in the Lower Cretaceous of the Lishu fault depression is mainly developed in the lower submember of the second member of the Shahezi Formation(K_(1)sh_(2)^(1) Fm.)and is thick and stable in distribution.The shale has high TOC,mainly types II_(1) and II_(2) organic matter,and is in the mature to the over-mature stage.The volcanic activity,salinization,and reduction of the water environment are conducive to the formation of the organic-rich shale.The shale reservoirs have mainly clay mineral intergranular pores,organic matter pores,carbonate mineral dissolution pores,and foliated microfractures as storage space.The pores are in the mesopore range of 10–50 nm,and the microfractures are mostly 5–10μm wide.Massive argillaceous rocks of lowland and highstand domains are deposited above and below the gas-bearing shale separately in the lower submember of the K_(1)sh_(2)^(1) Fm.,act as the natural roof and floor in the process of shale gas accumulation and preservation,and control the shale gas enrichment.Based on the above understandings,the first shale gas exploration well in Shahezi Formation was drilled in the Lishu fault depression of Songliao Basin.After fracturing,the well tested a daily gas production of 7.6×10^(4) m^(3),marking a breakthrough in continental shale gas exploration in the Shahezi Formation(K1 sh Fm.)of the Lishu fault depression in Songliao Basin.The exploration practice has reference significance for the exploration of continental shale gas in the Lower Cretaceous of Songliao Basin and its periphery.

Methane adsorption effected by pore structure of overmature continental shale:Lower Cretaceous Shahezi Formation,Xujiaweizi Fault,Songliao Basin

Overmature continental shale is commonly developed,but few studies have given insight into its pore structure and sorption capacity.Various techniques,including SEM,helium porosity and permeability,N_(2)/CO_(2)adsorption,MICP,and NMR,were used to detect the pore structure of shale from the Shahezi Formation,Xujiaweizi Fault,Songliao Basin.The excess methane adsorption volumes were measured by the volumetric method and modeled by the Langmuir model.Based on the findings,the most developed pores are intraparticle pores in clay minerals,followed by the dissolution pores in feldspar,but organic pores are uncommon.The selected shales have low helium porosity(mean 1.66%)and ultralow permeability(mean 0.0498×10^(−3)μm^(2)).The pore throats are at the nanoscale,and the pore-throat size distributions are unimodal,with most less than 50 nm.The studied shales are characterized by the lower specific surface area(SSA)and pore volume(PV)but the larger average pore diameter.The total SSA is contributed by the micro-and mesopores,while the PV is dominated by meso-and macropores.The pore structures are more complex and controlled by multiple factors,such as mineral compositions and diagenesis,but organic matter is not critical.The maximum absolute adsorption methane volume(VL)is 0.97−3.58 cm^(3)/g(mean 1.90 cm^(3)/g),correlating well with the total SSA,SSA,and pore volume of micropores,which indicates that methane is mainly adsorbed and stored in micropores,followed by mesopores.

徐家围子断陷沙河子组烃源岩形成古环境及主控因素

【目的】明确沙河子组优质烃源岩形成的主控因素,为松辽盆地深层天然气勘探方向优选提供地质依据。【方法】综合利用岩心、有机地球化学和元素地球化学等多种资料,系统研究沙河子组沉积环境和水体环境,明确了断裂活动、沉积相和古沉积环境对烃源岩有机质丰度、类型的控制作用。【结果】沙河子组发育暗色泥岩和煤岩两种类型烃源岩,沙Ⅰ段沉积期断裂活动强,水体相对局限、深度大,形成的“深水窄盆”盐度高、还原性好,以半深湖相泥岩为主,沙Ⅱ段时断裂活动弱,湖盆面积达到最大,形成的“浅水宽盆”盐度低、还原性变差,烃源岩以滨浅湖相煤岩为主。【结论】断裂活动在下降盘为泥岩堆积提供可容纳空间,控制了泥岩厚度;沉积环境影响有机质输入,决定了泥岩有机质类型和煤岩分布;由古盐度、古水深和氧化还原组成的古沉积环境影响有机质的富集和保存,是导致现今烃源岩质量差异的主要原因。

徐家围子断陷沙河子组煤岩气成藏条件及突破方向

为明确徐家围子断陷煤岩气勘探有利区,综合地震、岩心和地球化学等多种资料,系统分析了煤岩气成因、烃源岩类型、储层特征和储盖组合等有利成藏条件。结果表明:(1)沙河子组1号、2号煤层是形成于三角洲前缘和滨浅湖沼泽环境的稳定煤岩,煤岩厚度为3~10m,TOC平均约为29.65%,正处于高—过成熟阶段;(2)沙河子组煤层气以甲烷为主,为自生自储的高—过成熟煤型气;(3)煤岩储集空间类型多样,以张性微裂隙、原生植物组织孔、气孔和矿物质孔为主,孔隙度和渗透率分别平均为4.74%和4.42mD,是深层有利储层;(4)沙河子组顶部发育泥岩、泥质粉砂岩2种盖层和3种储盖组合,顶底泥岩型和顶泥底砂型储盖组合封闭性高,与煤层内广泛分布的超压封存箱一起,为煤岩气的保存创造了有利条件;(5)在煤层气藏地质特征研究基础上,通过生烃模拟估算研究区各生烃洼槽的资源量,并结合煤岩厚度、埋藏深度、成熟度等多种参数,优选宋站洼槽1号煤层和徐西洼槽2号煤层2个有利区,泥质盖层厚度大于5m的区域为近期煤层气勘探突破方向。

松辽盆地北部全油气系统成藏模式与勘探潜力

松辽盆地作为一个多套优质烃源岩大面积发育的大型陆相叠合盆地,由于受多期构造与沉积的复合控制和改造,油气藏富集规律复杂多样。为进一步落实松辽盆地北部油气成藏条件与勘探潜力,基于全油气系统新概念,将松辽盆地北部划分为2个全油气系统:以青山口组为生油岩,嫩江组为区域盖层的储盖组合,形成了常规油、致密油、页岩油多类型有序成藏的上部石油系统;以沙河子组为烃源岩,登娄库组为区域盖层的储盖组合,形成了营城组火山岩、沙河子组砂砾岩等多种气藏差异富集的下部天然气系统。以此为基础,研究了松辽盆地北部油气藏的基本油气地质条件、常规-非常规油气的共生特征与油气分布情况。上部石油系统青山口组源岩经过生烃增压、幕式排烃后,地层压力释放,页岩储层形成自封闭体系,内部干酪根持续生烃、油气原位成藏,形成大规模连续分布的“立体式”页岩油藏;扶余油层致密油受生烃增压作用的控制、油气向下“倒灌”,形成断裂下排-横向运移、源-储侧向对接充注成藏。下部天然气系统沙河子组源岩持续生烃,受源储关系、储层特征和输导通道等成藏要素的耦合控制,形成中央古隆起“源储叠置、不整合输导、淋滤层聚气、高部位富集”,营城组火山岩气藏“下生上储、深断裂通源、高部位聚气”和沙河子组致密气“自生自储、断裂控砂、超压控富”等3种成藏模式。研究成果对松辽盆地不同类型油气资源分布预测和勘探具有重要指导意义。

松辽盆地徐家围子断陷沙河子组沉积相类型及演化模式

【目的】徐家围子断陷沙河子组致密砂砾岩储层具有非常大的天然气勘探潜力,有望成为大庆油田深层火山岩气藏勘探的重点接替领域。【方法】综合运用岩心、录井、测井及地震等资料,对徐家围子断陷沙河子组沉积相展布及沉积演化模式开展了研究。【结果与结论】徐家围子断陷沙河子组发育辫状河三角洲、扇三角洲、具供给水道的远岸浊积扇、近岸水下扇、扇三角洲前端滑塌浊积扇以及浅湖—半深湖、深湖相等沉积相。安达凹陷、徐东凹陷以及肇州凹陷东侧的缓坡带接受来自肇东—朝阳沟基底古隆起的碎屑物质而发育辫状河三角洲沉积,局部发育由远源供给水道形成的湖底浊积扇沉积体;安达凹陷、徐东凹陷、徐西凹陷以及肇州凹陷西侧等徐西陡坡带接受来自中央隆起带粗碎屑物而发育扇三角洲沉积体系,以近源短流为基本特征,局部发育近岸水下扇沉积,且由于湖盆边缘发育的扇三角洲沉积体不稳定,在扇三角洲沉积体前方形成滑塌浊积扇沉积。

徐家围子断陷沙河子组主干断裂形成演化与地层剥蚀特征

主干断裂的活动控制着徐家围子断陷沙河子组的建造与改造。为了明确断裂活动,运用位移距离曲线方法系统分析了徐家围子断陷主干断裂的生长活动特征,通过不整合面下的同向轴特征分析了徐家围子断陷沙河子组沉积末期的剥蚀改造作用。结果表明:徐家围子断陷主干断裂分段特征明显,徐西断裂与宋西断裂在火石岭组沉积时期分别是数条分段的小断裂,在沙河子组沉积时期连通为整条断裂并持续控陷活动;徐中断裂在沙河子组沉积时期弱伸展弱控陷,在沙河子组沉积末期作为薄弱带发生压扭反转;徐东断裂带中的徐东正断层在沙河子组沉积时期弱控陷,徐东逆断层在营城组一段沉积末期的反转作用下形成;沙河子组沉积末期的反转作用对沙河子组厚度与构造格局产生明显改变,沿徐西断裂与宋西断裂存在较强的剥蚀,徐西断裂北端升平凸起尤为强烈,徐中断裂压扭反转产生一定的走滑分量并遭受剥蚀,徐东逆断层在营城组一段沉积末期的反转中形成,对沙河子组厚度无明显改变,但对徐东构造带构造格局产生明显影响。研究成果可为徐家围子断陷古构造恢复与进一步勘探提供理论参考。

长岭断陷查干花次凹火石岭组火山岩喷发模式新认识

长岭断陷查干花次凹火石岭组火山岩岩石类型及岩性组合与典型火山碎屑岩存在差异,其岩心、薄片见火山灰球、淬碎角砾等特殊构造,储集层物性较差,无典型的火山岩丘状包络机构,火山岩可能形成于特殊的喷发环境。根据地震波反射特征、岩心描述、薄片特征及分析化验资料,识别不同喷发环境的典型标志,结合已钻井岩性组合、区域构造背景等,建立该区的火山喷发堆积模式。研究表明:该区火山岩经历了3个喷发期次,分别处于陆上、水陆交替和水下喷发环境。水下喷发火山岩纵横比小,常呈宽缓盾状,原生孔隙不发育,溶蚀孔、脱玻化孔等发育,储集空间整体以中—小孔隙为主。陆上喷发火山岩孔隙较发育,物性较好,为油气勘探开发的主要目标。

松辽盆地德惠断陷白垩系烃源岩特征及其控藏作用

基于烃源岩、天然气、储层流体包裹体等实验分析,系统研究了松辽盆地德惠断陷白垩系烃源岩地球化学特征、发育环境、天然气成因与来源、油气成藏期次以及烃源岩的控藏作用等。研究结果表明:①德惠断陷白垩系烃源岩TOC普遍大于1%,有机质类型以Ⅲ型为主,Ⅱ型样品主要分布在农安南洼陷,总体处于成熟—高成熟的大量生气阶段;火石岭组与营城组烃源岩形成于还原—弱还原、水体盐度较高的沉积环境,农安南洼陷火石岭组烃源岩中浮游生物、藻类等低等生源贡献较大,生油能力更强。②白垩系天然气组成差异大,烷烃气体积分数为2.0%~98.5%,CO_(2)体积分数为0.1%~96.5%;天然气主要为煤成气,受不同期次天然气充注影响,部分气样呈碳同位素倒转特征;郭家、华家与农安南洼陷的油气源岩以火石岭组为主;鲍家洼陷的天然气可能主要来自营城组;CO_(2)主要为无机成因,随埋深增大,碳酸盐胶结物碳同位素组成表现为正偏移,指示深部存在钻遇高无机CO_(2)气层的风险。③农安南洼陷的烃源岩正处于大量生油阶段,由南部至北部,烃源岩热演化程度逐渐增高,控制了“南油北气”的相态分布,也控制了油气成藏期次;工业油气流井主要分布在烃源岩厚度较大地区及附近,烃源岩的分布控制了油气藏的分布。

致密砂砾岩成储界限及分级评价标准——以松辽盆地徐家围子断陷白垩系沙河子组为例

徐家围子断陷下白垩统沙河子组砂砾岩储层是松辽盆地深部重要的致密气藏储层,其孔渗关系复杂,给成储界限的厘定和储层分级评价带来挑战。针对沙河子组砂砾岩储层,采用水膜厚度法、充注动力法、试气产能法和力学平衡法厘定了理论下限、成藏下限、有效渗流下限和成储上限,根据不同成岩作用主控因素下的孔渗关系确定成储界限物性值。在此基础上,结合储层微观孔隙结构差异划分储层类型,建立致密储层分级评价标准,并利用测井资料将分级评价标准进行应用,为研究区致密气甜点区优选提供依据。将沙河子组砂砾岩分为常规储层、Ⅰ—Ⅳ级致密砂砾岩储层和非储层,成储界限与分级评价结果具有很好的匹配关系。其中,常规储层孔隙度大于9%,渗透率大于0.05×10^(-3)μm^(2);Ⅰ级致密储层孔隙度为8%~9%,渗透率为(0.01~0.05)×10^(-3)μm^(2);Ⅱ级致密储层孔隙度为5%~8%,渗透率为(0.001~0.01)×10^(-3)μm^(2);Ⅲ级致密储层孔隙度为3.5%~5%,渗透率为(0.2~1)×10^(-6)μm^(2);Ⅳ级致密储层孔隙度为2%~3.5%,渗透率为(0.05~0.2)×10^(-6)μm^(2);非储层的孔隙度小于2%,渗透率小于0.05×10^(-6)μm^(2)。致密砂砾岩气产量受控于致密储层类型;Ⅰ级、Ⅱ级致密储层是致密气高产的有利层段;徐家围子断陷北部安达—宋站地区有利储层厚度较大,为致密气勘探开发甜点区。

火山断陷型湖盆细粒沉积岩有机质富集模式——以松辽盆地梨树断陷下白垩统沙河子组二段下亚段为例

以松辽盆地梨树断陷下白垩统沙河子组二段下亚段(简称沙二下亚段)沉积特征为例,采用有机岩石学、主微量元素及生物标志化合物分析等方法,探讨火山断陷型湖盆细粒沉积岩有机质富集条件及富集模式。研究结果表明,沉积古环境的变化控制沙二下亚段不同岩相类型的垂向分布,并将其划分为上、下两部分,下部主要发育块状长英质泥岩夹含生屑长英质泥岩,上部主要发育纹层状长英质页岩和纹层状细粒混积页岩;下部有机质干酪根类型以Ⅱ2—Ⅲ型为主、上部以Ⅰ—Ⅱ1型为主,且总体呈现出上部有机碳含量较下部增高的特征。分析认为,火山断陷型湖盆有机质富集的主要条件为:①持续增强的裂陷作用是导致古水深加大的直接因素,基准面上升使深水沉积范围随之扩大,泥页岩发育规模相应增大;②相对强烈的水下火山喷发与裂陷作用具有同时性,火山活动可为湖盆提供大量营养物质,有利于藻类的勃发,并导致Ⅰ—Ⅱ1型干酪根生产力较高;③相对干旱的古气候导致河流淡水及陆源物质(包括陆源高等植物Ⅲ型干酪根)输入减少,形成高盐度、缺氧分层的水体,咸水湖盆有利于有机质保存。在此基础上,建立的火山断陷型湖盆细粒沉积岩有机质富集模式,对深化松辽盆地沙河子组乃至中国东北地区同期火山断陷型湖盆细粒沉积岩有机质富集机制的地质认识,具有一定的参考借鉴意义。

松辽盆地德惠断陷白垩系火石岭组凝灰岩储层预测及成藏主控因素

基于钻井岩心分析、测井曲线、地震等资料,运用模型正演、多参数反演体融合技术等,对松辽盆地德惠断陷白垩系火石岭组凝灰岩储层分布特征及油气富集条件进行了研究,预测了优质储层分布。研究结果表明:(1)松辽盆地德惠断陷白垩系火石岭组凝灰岩为裂隙式喷发形成的火山碎屑岩,主要为含角砾熔结凝灰岩、含角砾晶屑凝灰岩和沉凝灰岩。地震反射特征总体表现为低频、差连续、中强振幅或弱振幅,多参数反演体融合体技术预测的凝灰岩储层“甜点”分布与钻井证实结果的符合率高,凝灰岩储层平均钻遇率达92.8%,气层平均钻遇率为81.0%,其中12口井获得了工业气流;华家构造带与郭家断阶带储层岩性分别以含角砾熔结凝灰岩和含角砾晶屑凝灰岩为主,断裂发育,是2个优质储层发育区。(2)研究区凝灰岩的测井和地震相特征相匹配形成的岩性-岩相模板可有效指导凝灰岩的地震相识别,振幅属性刻画出的火山口相、近火山岩相为有利岩性分布区。(3)研究区发育火石岭组、沙河子组、营城组3套优质烃源岩厚度均超过300 m,TOC值分别为0.26%~5.08%,0.10%~5.55%,0.10%~9.74%,S1+S2分别为0.24~8.23 mg/g,0.12~18.15 mg/g,0.25~2.86 mg/g,Ro分别为0.6%~1.3%,1.1%~1.6%,1.0%~2.2%,具有丰度高,成熟度中等的特征,为大规模成藏奠定了良好的物质基础。(4)研究区凝灰岩气藏是一套源储侧向对接、高位富集的致密气藏,成藏主要受构造样式、断裂发育程度和供烃窗口控制,其中拉张和伸展作用形成的叠瓦状断弯褶皱控制了油气富集程度,断裂发育程度及供烃窗口的大小决定了气藏规模。

松辽盆地北部中央古隆起基岩气藏形成条件与有利勘探区

为寻找松辽盆地中央古隆起基岩天然气富集区,分析了其天然气成因和有利成藏条件,优选了基岩气藏有利勘探区块。研究结果表明:①松辽盆地北部中央古隆起天然气组分和成因与徐家围子断陷类似,均是以甲烷为主的高—过成熟的煤型气,显示基岩气藏气源主要来自古隆起东侧徐家围子断陷。②优质烃源岩、有利储层、立体输导通道和优良盖层等有利条件耦合是形成基岩气藏的关键,沙河子组烃源岩泥岩和煤岩TOC平均分别为4.33%和32.56%,处于高过成熟阶段,宋站和徐西等生烃洼槽生烃强度普遍大于180×10^(8)m^(3)/km^(2),是基岩重要的气源;受风化和破裂作用影响,基岩顶、底形成的风化壳孔缝层、内幕裂缝层等有利储层孔隙度分别为4.3%和1.3%,渗透率分别为0.45 mD和6.3 mD;风化壳、断层和裂缝耦合形成“S”型、“T”型和“断缝体”型输导通道,促进了天然气的侧向运移;登娄库组泥岩厚度大、突破压力高,且其形成时间早于天然气大规模运移和充注成藏期,使得基岩气藏得以保存。③中央古隆起带可分为3个有利勘探区,北部汪家屯凸起和昌德凸起主要为风化壳气藏,发育“S”型、“T”型输导通道,气藏受输导通道和保存条件联合控制,南部肇州凸起则以基岩内幕气藏为主,发育“断缝体”型输导通道,气藏受储层厚度、物性和圈闭影响明显。

松辽盆地梨树断陷沙河子组页岩与泥岩差异与成因

松辽盆地下白垩统沙河子组泥页岩是松辽盆地深部断陷层主力烃源岩,也是松辽盆地陆相页岩气最具潜力的层系。中国地质调查局在松辽盆地钻探了松科2井和吉梨页1井均证实了沙河子组页岩气具有可观的资源潜力,尤其是吉梨页油1井首次在松辽盆地梨树断陷沙河子组陆相页岩中获得直井日产7.6×10^(4)m^(3)的高产页岩气流.

松辽盆地徐家围子断陷白垩系沙河子组深层致密气成藏机理及勘探突破

松辽盆地徐家围子断陷沙河子组砂砾岩埋深大、岩性致密,目前对其成藏控制因素认识不足,且受投资成本和勘探开发技术的制约,沙河子组一直未能实现储量和产量的突破。使用地震、岩心、测井、录井及地质分析化验资料,从煤系烃源岩生烃潜力、致密砂砾岩展布、储集物性、地层超压等方面分析了沙河子组致密气成藏控制因素,力图寻找富气甜点、指导井位部署。结果表明,沙河子组储层与烃源岩叠置,致密非浮力成藏动力过程致使异常高压的出现,并造就了满盆含气的格局。沙河子组致密砂砾岩储层在纵横向上叠置发育,储层内部发育的多层高孔渗带成为致密砂砾岩气藏的“甜点”。在致密气成藏理论的指导下,精准刻画了优质富气“甜点”的分布并设计了最优气井轨迹,充分发挥地质工程一体化优势,以优快钻井和最优改造体积为目标,部署了宋深9-平5井,测试产量达106×10^(4)m^(3)/d,取得了沙河子组致密气藏的重大突破,为后期松辽盆地沙河子组致密气藏勘探开发带来了广阔的前景。

Formation mechanism of high-quality reservoirs of Lower Cretaceous volcaniclastic sedimentary rocks in Songliao Basin

High abundance gas reservoirs were discovered in the volcaniclastic sedimentary rocks of Wangfu faulted depression in Songliao Basin,but the distribution pattern and formation mechanism of this type of high-quality reservoirs were not clear.In the Shahezi Formation of Well Block CS6 in Wangfu faulted depression,the void space type,reservoir property,pore throat and pore diameters were studied by means of the casting thin section,helium intrusion porosimetry,mercury intrusion porosimetry(MIP)and nuclear magnetic resonance(NMR)methods,moreover,formation mechanism and main controlling factors of the high-quality reservoirs were discussed.Results showed that lithology of high-quality reservoirs consisted of the volcaniclastic sedimentary agglomerate and the volcaniclastic sedimentary breccia,and exhibited the coarsening-upward characteristics.Furthermore,three types(seven subtypes)of void spaces were identified,among which the intragranular vesicles with primary abundant pores were uniquely developed in the high-quality reservoirs of volcaniclastic sedimentary rocks,indicating this high-quality reservoir belonged to the large-pore and small-throat reservoir;porosity and permeability of volcaniclastic sedimentary agglomerate were slightly higher than those of volcaniclastic sedimentary breccia,and both were significantly higher than those of sedimentary rock in the Shahezi Formation,the porosity was closely related with the burial depth.Formation mechanisms of reservoirs in the volcaniclastic sedimentary rocks were release of volatile matters in parent rocks,grain support,dissolution and tectonic modification,among which the former two were the main controlling factors.The high-quality reservoirs over the study area were mainly distributed in the central part of the fan of volcaniclastic sedimentary rocks,among which the grain-supported,coarse-grained volcaniclastic sedimentary rocks with high content of intragranular vesicular detritus and burial depth less than 3000 m were the most favorable area for development of the high-quality reservoirs.

湖盆水下喷发火山岩相类型、特征与储集意义——以松辽盆地南部查干花地区白垩系为例

为解决传统的陆上和海域火山碎屑岩岩相及相模式难以反映湖盆水下火山机构特征的问题,以松辽盆地长岭断陷查干花地区白垩系火石岭组凝灰岩丘为研究对象,探讨水下喷发火山碎屑岩岩相并建立相模式。研究表明,水下喷发火山碎屑岩可分为2种相4种亚相,其中2种相为水下爆发相和喷发间歇期形成的火山沉积相。水下爆发相可进一步分为气携水下热碎屑流、水携火山密度流和水下降落3种亚相;火山沉积相由含外碎屑火山碎屑沉积岩1种亚相构成。松辽盆地水下喷发形成典型的凝灰岩丘相模式,凝灰岩丘通常由多个水下喷发堆积单元叠加构成,可分为近源和远源两个相组。近源相组完整的堆积单元从下到上依次由含外碎屑火山碎屑沉积岩亚相-气携水下热碎屑流亚相-水携火山高密度流亚相和水下降落亚相构成;远源相组的堆积单元以发育水下降落亚相为主,夹有多个薄层水携高密度流亚相沉积。气携水下热碎屑流亚相和火山沉积相含外碎屑火山碎屑沉积岩亚相是陆相湖盆水下喷发有利储集层发育的优势岩相。