New perspective of Miocene marine hydrocarbon source rocks in deep-water area in Qiongdongnan Basin of northern South China Sea

Drilling wells reveal that the organic matter abundance of Miocene marine source rocks in shallow water area of the Qiongdongnan Basin is relatively low with poor hydrocarbon generation poten- tial. However, in some drilling wells of deep water area close to the central depression belt, Miocene marine source rocks with better organic matter abundance and hydrocarbon generation have been found, which have achieved better source rock standard based on the analysis of geochemical charac- teristics. Although there are no exploratory wells in deep water area of the research region, through the comparative analysis of geochemical data of several typical exploratory wells respectively from shallow water area in the basin, central depression belt margin in deep-water area of the basin and Site 1148 of deep sea drilling in the South China Sea Basin, it reveals that the tendency of the quality of source rocks becomes positive gradually from delta to bathyal environment, which then becomes negative as in deep oceanic environment. Owing to the lack of terrestrial organic matter input, the important controlling factors of Miocene marine source rocks in the Qiongdongnan Basin are ocean productivity and preservation conditions of organic matter. The element geochemistry data indicate that the tendency of the paleoproductivity and the preservation conditions of organic matter become positive as water depth increase from shallow area to bathyal area close to central depression belt. So it is speculated that there must exist high quality source rocks in the central depression area where the preservation conditions of organic matter are much better. Besides, in theory, in oxygen-poor zone of oceanic environment at the water depth 400–1 000 m, the preservation conditions of organic matter are well thus forming high-quality marine source rocks. The result- ing speculation, it is reasonable to consider that there are high hydrocarbon generation potential source rocks in bathyal environment of the Qiongdongnan Basin, especially at the water depth 400– 1 000 m.

Hydrocarbon expulsion model and resource potential evaluation of high-maturity marine source rocks in deep basins:Example from the Ediacaran microbial dolomite in the Sichuan Basin,China

Hydrocarbon expulsion features and resource potential evaluation of source rocks are crucial for the petroleum exploration.High-maturity marine source rocks have not exhibited a hydrocarbon expulsion mode owing to the lack of low-maturity source rocks in deep petroliferous basins.We considered the Ediacaran microbial dolomite in the Sichuan Basin,the largest high-maturity marine gas layer in China,to exhibit a method that quantitatively characterizes the hydrocarbon expulsion of high-maturity marine source rocks.The experiment of fluid inclusion,rock pyrolysis,and vitrinite reflectance(Ro)of 119 microbial dolomite core samples obtained from the Dengying Formation were performed.A hydrocarbon expulsion model of high-maturity source rock was established,and its resource potential was evaluated.The results showed that the Ediacaran microbial dolomite in the Sichuan Basin is a good source rock showing vast resource potential.The hydrocarbon expulsion threshold is determined to be vitrinite reflectance at 0.92%.The hydrocarbon expulsion intensities in the geologic history is high with maximum of 1.6×10^(7)t/km^(2).The Ediacaran microbial dolomite expelled approximately 1.008×10^(12)t of hydrocarbons,and the recoverable resource was 1.5×10^(12)m^(3).The region can be categorized into areasⅠ,Ⅱ,Ⅲ,andⅣ,in decreasing order of hydrocarbon expulsion intensity.Areas with a higher hydrocarbon expulsion intensity have a lower drilling risk and should be prioritized for exploration in the orderⅠ>Ⅱ>Ⅲ>Ⅳ.Two areas,northern and central parts of Ediacaran in the Sichuan Basin,were selected as prospects which had the drilling priority in the future gas exploration.The production data of 55 drilled wells verified the high reliability of this method.This model in this study does not require low-maturity samples and can be used for evaluating high-maturity marine source rocks,which has broad applicability in deep basins worldwide.

Basin-filling processes and hydrocarbon source rock prediction of low-exploration degree areas in rift lacustrine basins:a case from the Wenchang Formation in low-exploration degree areas,northern Zhu I Depression,Pearl River Mouth Basin,E China

Hydrocarbon source rocks, as a main geologic factor of petroliferous systems in a sedimentary basin, play a key role in the accumulation of oil and gas and the formation of hydrocarbon accumulations. This study, which focuses on difficulties in prediction of hydrocarbon source rocks in basins or sags with low exploration degree and insufficient hydrocarbon source rock indicators, taking the Wenchang Formation of northern Zhu I Depression, Pearl River Mouth Basin as an example, proposed a hypothesis of “finding lakes and hydrocarbon source rocks”. Detailed steps include, first, determination of the lacustrine basin boundary according to analysis of seismic foreset facies, determination of the depositional area based on the compilation of strata residual thickness maps, determination of the lacustrine basin shape according to deciphering slope break belt system, determination of the fluctuation of paleo-water depth according to biogeochemical indicators of mature exploration areas, determination of the lacustrine basin scale based on analyses of tectonics intensity and accommodation space, which prove the existence of the lacustrine basin and identify the range of semi deep-deep lake;second, further analyses of tectonopalaeogeomorphology, paleo-provenance,palaeoclimate and paleo-water depth to reconstruct the geologic background of the original basin and semideep-deep lacustrine facies, to determine the distribution of semi-deep/deep lacustrine sediments in combination with studies of logging facies, core facies, seismic facies and sedimentary facies, and to rank the sags’ potential of developing hydrocarbon source rocks from controlling factors of source-to-sink system development;third, on the basis of regional sedimentary facies analysis, through identification and assessment of seismic facies types of semi-deep/deep lacustrine basins in mature areas, establishing “hydrocarbon source rock facies” in mature areas to instruct the identification and depicting of hydrocarbon source rocks in semideep/deep lacustrine basins with low exploration degree;fourth, through systematical summary of hydrocarbon-rich geological factors and lower limit index of hydrocarbon formation of the sags already revealed by drilling wells(e.g., sag area, tectonic subsidence amount, accommodation space, provenance characteristic, mudstone thickness, water body environment, sedimentary facies types of hydrocarbon source rocks), in correlation with corresponding indexes of sags with low exploration degree, then the evaluation and sorting of high-quality source rocks in areas with sparsely distributed or no drilling wells can be conducted with multi-factors and multiple dimensions. It is concluded that LF22 sag, HZ10 sag and HZ8 sag are II-order hydrocarbon rich sags;whereas HZS, HZ11 and HZ24 are the III-order hydrocarbon-generating sags.

Hydrocarbon Generation and Expulsion of the Upper Triassic T3x5Source Rocks in the Western Sichuan Depression: Assessment for Unconventional Natural Gas

Tight-sand gas in the Jurassic and shale gas within the fifth member of Xujiahe Formation （T3xs） in the Western Sichuan Basin （WSD） are currently regarded as the most prolific emerging unconventional gas plays in China. This study conducted a conventional evaluation of T3x5 source rocks in the WSD, and investigated their hydrocarbon generation and expulsion characteristics, including intensity, efficiency and amount. The results show that, the T3x5 source rocks are thick （generally 〉200 m）, and have a high total organic content （TOC）, ranging from 2.5 to 4.5 wt%. It is thus indivative of a great hydrocarbon generation potential when they underwent high thermal evolution （Ro〉1.2%） in the area. In addition, an improved method of hydrocarbon generation potential is applied, indicating that the source rocks reached a hydrocarbon expulsion threshold with vitrinite reflectance （Ro） reaching 1.06%. and that the comprehensive hydrocarbon expulsion efficiency is about 60%. The amount of hydrocarbon generation and expulsion from Tax5 source rocks is 3.14x10^10 t and 1.86x10^10 t, respectively, with a residual amount of 1.28x10^10t within them. Continuous-type tight-sand gas is predicted to have developed in the Jurassic in the Chengdu Sag of the WSD because of the good source-reservoir configuration; the Jurassic sandstone reservoirs are tight, and the gas expelled from the T3xs source rocks migrates for very short distances vertically and horizontally. The amount of gas accumulation in the Jurassic reservoirs derived from T3x5 source rocks is up to 9.3x10s t. Geological resources of shale gas are up to 1.05x10TM t. Small differences between the amounts calculated by the volumetric method and those obtained by hydrocarbon generation potential method may be due to other gas accumulations present within interbedded sands associated with gas shales.

Evaluation of abundant hydrocarbon-generation depressions in the deepwater area of Qiongdongnan Basin,South China Sea

It has been confirmed that the key source rocks of Qiongdongnan Basin are associated with the Yacheng Formation, which was deposited in a transitional marine-continental environment. Because the distribution and evolution patterns of the source rocks in the major depressions are different, it is important to determine the most abundant hydrocarbon-generation depressions in terms of exploration effectiveness. Based on an analysis of organic matter characteristics of the source rocks, in combination with drilling data and seismic data, this paper establishes a model to evaluate the hydrocarbon-generation depressions in the deepwater area of Qiongdongnan Basin. First of all, by using the method of seismic-facies model analysis, the distribution of sedimentary facies was determined. Then, the sedimentary facies were correlated with the organic facies, and the distribution of organic facies was predicted. Meanwhile, the thickness of source rocks for all the depressions was calculated on the basis of a quantitative analysis of seismic velocity and lithology. The relationship between mudstone porosity and vitrinite reflectance（Ro） was used to predict the maturity of source rocks. Second, using the parameters such as thickness and maturity of source rocks, the quantity and intensity of gas generation for Yacheng and Lingshui Formations were calculated. Finally, in combination with the identified hydrocarbon resources, the quantity and intensity of gas generation were used as a guide to establish an evaluation standard for hydrocarbon-generation depressions, which was optimized for the main depressions in the Central Depression Belt. It is proposed that Lingshui, Ledong, Baodao and Changchang Depressions are the most abundant hydrocarbon depressions, whilst Songnan and Beijiao Depressions are rich hydrocarbon depressions. Such an evaluation procedure is beneficial to the next stage of exploration in the deep-water area of Qiongdongnan Basin.

准噶尔盆地上三叠统烃源岩评价与有效烃源灶分布预测

准噶尔盆地蕴含丰富的油气资源,已于多个层位取得油气勘探发现。然而,上三叠统厚层泥岩能否作为盆地有效烃源岩一直没有明确的定论,亟需开展全盆范围内上三叠统烃源岩评价工作并进行有效源灶分布预测,为该层系下一步勘探部署提供依据。为进一步明确准噶尔盆地上三叠统烃源岩时空分布特征及其生烃潜力,落实有效烃源灶分布范围内生烃强度,基于资料收集、剖面实测、钻孔岩屑观察采样和有机地球化学测试,利用多个地化参数开展了全盆范围上三叠统烃源岩有机质丰度、类型、成熟度评价,优选关键参数利用多层次模糊数学评价方法,圈定有效源灶范围。结果表明,上三叠统烃源岩分布范围广(基本全盆分布)、厚度大(可达350 m)、腹部埋深大(最大埋深11 km);烃源岩TOC含量为0.75%~8.3%,平均值为1.74%;S_(1)+S_(2)平均为2.78 mg/g,氯仿沥青“A”平均为0.354%;有机质类型以Ⅲ型和Ⅱ2型为主,陆源高等植物输入占优,相对较好的母质类型主要沿盆1井西凹陷—阜康凹陷方向分布,有机质成熟度处于低成熟—成熟热演化阶段,局部达高—过成熟阶段。按照中国煤系泥岩生烃潜力评价标准,上三叠统泥岩整体为一套差—中等质量烃源岩,烃源岩总体上具有一定的生烃潜力,特别是生气潜力。有效烃源灶分布于中央坳陷腹部的阜康凹陷西部—沙湾凹陷东部一带以及南缘冲断带的霍玛吐背斜带,有效烃源灶范围内烃源岩Ro大于1.3%,生油强度在50×10^(4)t/km^(2)以上,生气强度在3×10^(8)m^(3)/km^(2)以上。

鄂尔多斯盆地南缘长7烃源岩地球化学特征与沉积环境

鄂尔多斯盆地南缘出露多处典型长7段页岩剖面,为了加深该区域烃源岩的研究,对35个烃源岩样品开展有机碳含量测定、岩石热解分析、饱和烃气相色谱-质谱分析、微量元素含量测定等测试分析,研究其地球化学特征,分析其有机质来源及沉积环境。结果表明:暗色页岩发育于淡水和还原的半深湖—深湖环境,沉积期气候温暖湿润,适宜生物发育,Mo元素高度富集,指示湖泊富营养化,初级生产力高;物质来源为藻类等低等水生生物和陆地植物的混合来源,但藻类等低等水生生物是主要来源;源岩有机质高度富集,总有机碳(TOC)平均值为23.51%,高于陆相优质烃源岩的丰度标准;有机质以腐泥—混合型为主,生烃潜量S1+S2均值为112.93 mg/g,生烃潜力良好;岩石热解峰温及生物标志化合物参数,指示达到成熟热演化程度,具有勘探潜力。

鄂尔多斯盆地庆阳-镇原地区长8原油地球化学特征研究

文章以庆阳-镇原地区中生界三叠系延长组长8油藏原油和长7暗色泥岩为研究对象,借助岩石热解、烃源岩有机质镜鉴、色谱-质谱等分析测试手段,开展长8油藏原油地球化学特征、长7烃源岩综合评价和油源对比研究.结果表明:庆阳-镇原地区长8原油物性较好,低碳数正构烷烃在原油中占优势,其原油母质构成既有陆生植物,又有低等水生生物,而且低等水生生物对于原油的贡献相对较大.原油中Ts/Tm值处于适中水平,已达到成熟原油的标准.对庆阳-镇原地区的油源进行对比分析,表明长8原油主要来自于长7烃源岩.

南海北部陆缘盆地深水区油气勘探新认识及攻关方向

南海北部陆缘盆地深水区已成为我国海洋油气勘探增储上产的重要领域,但由于构造演化史复杂,该区不同凹陷的沉积—构造特征、烃源岩生烃—储层成岩演化和成藏模式均存在明显差异。为准确认识该区油气勘探潜力和方向,基于前人研究成果和勘探实践,在综合分析烃源岩、储层、差异成藏等地质条件的基础上,剖析了南海北部陆缘盆地深水区成藏特征、油气勘探作业面临的挑战,并指出了下一步油气攻关研究方向。研究结果表明:①受地壳拆离作用及强烈薄化影响,该区地层沉积特征特殊,岩石地球物理性质多样;②软流圈差异抬升形成深水区独特的高热流背景,促使区域性湖相、煤型及叠合型等3类烃源灶快速、高强度生烃,生烃门限变浅;③深水盆地群的演化和成盆规模差异大,构造演化控制了盆地几何形态和储集体时空展布,深水区独特的板块构造位置、复杂的构造演化史、温压变化剧烈的地质特征等控制了油气成藏模式。结论认为:①该区油气勘探面临地震资料解析度低、规模有效储层预测困难、勘探成本高等技术与经济的双重挑战;②需要创新形成高地温背景下优质储层差异化分布规律的研究思路;③亟需提升勘探设备能力建设,攻关高效地震采集、“重磁电震”地球物理一体化采集处理、双井架钻探作业、多井段“一趟钻”等勘探关键技术,为我国海洋深水油气勘探开发的高质量发展做好理论和技术支撑。

珠江口盆地惠州凹陷惠东新区恩平组烃源岩生烃特征及成藏贡献

珠江口盆地惠州凹陷惠东新区恩平组厚度达3000 m,沉积特征整体表现为陆相浅水广盆环境,恩平组烃源岩生烃特征和成烃规模一直是困扰研究区勘探的基础问题之一。为厘清上述两个关键问题,以构造学、沉积学以及有机地球化学相结合的研究思路为指导,在化验分析数据基础之上,重新认识本地区恩平组烃源岩特征、生烃潜力及主要成藏贡献区。研究表明:惠东地区恩平组主体发育三角洲—浅湖相沉积,烃源岩包括煤、碳质泥岩和暗色泥岩;暗色泥岩有机质丰度中等—好,有机质类型为II型,具有早期生油,晚期持续生气的特征;盆地模拟计算原油地质资源量近3×108t,天然气资源量近500×108m3,资源潜力较大;油气源对比表明恩平组烃源岩来源的油气藏主要发育在惠东地区,惠东地区下一步最有利勘探方向为邻近烃源岩的深层恩平组圈闭以及“源-断-脊-圈”匹配较好的浅层珠江、珠海组圈闭。

珠江口盆地超深水区LW21-A井烃源岩分子地球化学特征与油气成因

珠江口盆地超深水区勘探程度低,珠四坳陷仅LW21-A井有油气发现,通过对其进行系统地特征分子地球化学测试与分析,揭示了所钻遇烃源岩的类型和发现油气的成因。该钻井揭示,文昌组和恩平组发育海相(海侵)泥岩和微咸水浅湖相(近海湖盆)泥岩;LW21构造气藏中存在海相(海侵)和湖相2类凝析油;LW21构造气藏中天然气主要成分为CO_(2),属于CO_(2)气藏,含一定量烷烃气;CO_(2)主要是无机幔源型成因气,烷烃气主要是油型气与海相生物气的混合型干气。这一认识对珠江口盆地超深水区珠四坳陷带的进一步评价和勘探决策具有重要意义。

鄂尔多斯盆地吴起地区长7页岩油烃源岩特征及生排烃潜力

目前吴起地区开发的主力层位侏罗系延安组下组合(延7—延10层)和三叠系延长组上组合(长4+5层和长6层)已到中后期,亟需寻找新的接替层位和接替能源满足油田持续高效稳产的战略目标,三叠系延长组长7段页岩油作为吴起采油厂新的接替层位,具有较大的勘探开发价值。为探明长7页岩油烃源岩的特征及勘探潜力区,进行了岩心分析、测井曲线研究、岩石热解分析、镜检显微组分分析、镜体反射率(R_(o))测试和生排烃潜力计算。结果表明:长7烃源岩的丰度总体上较高,有机碳含量(TOC)主要分布在0.49%~41.02%。长7层有机质类型以Ⅰ型和Ⅱ型为主,生油能力强。烃源岩镜质组表明吴起地区处在成熟阶段,并且以生油为主,反射率R_(o)样品分布集中在0.50%~1.15%,长7段烃源岩生烃强度为(200~600)×10^(4)t/km^(2),排烃强度大多为(200~300)×10^(4)t/km^(2)。综合吴起地区烃源岩厚度和生排烃强度,将长7段页岩油勘探潜力区划分为Ⅰ类、Ⅱ类和Ⅲ类,吴页平1井勘探钻探试油结果证明,烃源岩勘探潜力区是有利的页岩油开发层系和接替层。该研究结果将为吴起地区页岩油下一步勘探开发指明方向。

东营凹陷民丰地区沙四段下亚段烃源岩特征

东营凹陷民丰地区在沙四段下亚段油气勘探中获重要突破。但其烃源岩生烃潜力、生物标志物特征及其环境意义以及膏盐岩对烃源岩成熟度的影响仍缺乏系统研究。基于岩石有机碳、热解.于酪根显微組分鉴定、饱和烃色谱-质谱等实验结果。结合地质条件。系统评价了沙四段下亚段烃源岩。研究结果表明:①烃源岩有机质以腐泥型的Ⅰ和Ⅱ_(1),型干酪根为主,生烃母质优质,盐间和扇间泥岩均具生烃能力,含有中等-优质烃源岩,可作为潜在页岩油气发育区;基于多元回归分析模型分岩性建立了TOC测井评价模型,其预测值与实测值吻合度高。②上部烃源岩相对下部具有高C_(27),重排甾烧C_(27)规则甾烷、高规则甾烧/17α-蕾烷等特征;上部烃源岩多为盐间泥岩,沉积于威水还原-强还原环境,下部烃源岩多为盐下扇间泥岩。为微咸水淡水还原环境.二者以垂深4180~4200m为界,均在古冲沟附近较为发育。③烃源岩处于成熟-高成熟阶段,上部、下部烃源岩大致以镜质組反射率等于1.0%为界,上部生油为主,下部有利于裂解生气;盐上地层(以砂砾岩储层为主)的地温梯度和烃源岩镜质组反射率明显大于盐下和无盐相应参数。

歧口凹陷沙三段烃源岩评价及生排烃特征

以桂源岩热解分析数据为基础,结合PetroMod盆地模拟技术,明确研究区痊源岩特征及热演化史,运用生桂潜力法建立生排痊模式,分析生排痊史及排痊强度,揭示歧口凹陷沙三段痊源岩热演化与生排痊作用对油气运聚与分布的影响。结果表明:研究区痊源岩普遍处于成熟-高成熟演化阶段,在镜质组反射率约为0.53%和0.83%时分别进入生坯和排痊门限,其排痊率达250mg/g,排痊效率达65%。晚始新世末一早渐新世开始短暂生痊,因构造抬升运动而中止,在中渐新世开始排坯,至中渐新世末达到生排桂高峰期,之后于晚渐新世末再次因构造运动生排疑中止,整个生排坯过程与桂源岩热演化阶段基本一致。排坯中心沿歧北次凹一歧口主凹周缘分布,排妊强度达90x10^(6)t/km^(2),具有强排妊特征。广泛式的生排分布特征为歧口凹陷邻近隆起和斜坡部位提供了丰富的油气来源和运移动力,油气同时具有近源成藏及远距离侧向运移成藏的特征。

石钱滩地区石炭系石钱滩组烃源岩发育特征

石钱滩凹陷夹持于克拉美丽山、奇台凸起、黑山凸起、黄草湖低凸起之间,为个相对独立的成藏单元。2013年,中石化胜利油田为探索石钱滩凹陷部署钻探钱1井,二叠系芦草沟组312.00~337.40米井段测试获原油0.5 L,证实了石钱滩凹陷中石化矿权区具有较大的油气勘探潜力。近源勘探阶段,2019年吐哈油田介入该区勘探,按下洼探索石炭系近源成藏组合的含油气性,部署石钱1井,该井揭示了套新的含油气系统.

柴达木盆地干柴沟地区下干柴沟组上段烃源岩特征

为解决柴达木盆地干柴沟地区下干柴沟组上段(E32)烃源岩评价标准尚未建立、烃源岩研究程度偏低的问题,通过大量岩心化验分析进行有机岩石学、有机地球化学、正构烷烃及类异戊二烯烷烃为代表的生物标志化合物研究,对干柴沟地区下干柴沟组上段进行了烃源岩评价及母质沉积环境探讨。结果表明:依据烃源岩有机质类型、TOC、氯仿沥青“A”含量、游离烃S1指标可确定Ⅰ、Ⅱ、Ⅲ类烃源岩的评价标准;烃源岩有机质来源为藻类等低等水生浮游生物和微生物;有机质类型为Ⅱ1-Ⅰ型;烃源岩成熟度介于低成熟-成熟生烃阶段。该研究对确定下一步有利勘探目标具有一定的指导意义。

十三间房水西沟群煤系烃源岩生烃条件及资源潜力

据录井和岩样分析化验等资料,结合ΔLogR技术和油气资源评价方法(成因法),对十三间房水西沟群煤系烃源岩生烃条件和油气资源潜力进行分析和预测。结果表明:研究区水西沟群泥岩有机质丰度随埋深由好变差,并受控于古水深变化,有机质类型为Ⅱ2-Ⅲ型,煤为中等烃源岩,了墩以北处于成熟阶段且拟合古地温梯度达3.8℃/100 m;水西沟群山前带发育滨浅湖-沼泽相,发育较厚有效烃源岩。产烃率图版、烃源岩厚度和资源量预测结果分析表明,该区泥岩生烃能力强于煤并受控于烃源岩厚度;西山窑组为该区主力生烃层,八道湾组天然气资源贡献不低。水西沟群石油和天然气预测资源量分别为(52.20~85.183)×10^(6)t、(77.94~118.89)×10^(8)m^(3),证实十三间房水西沟群生烃条件优越,资源量丰富,可为油气藏形成提供强有力的物质基础。

Kinetic study of the hydrocarbon generation from marine carbonate source rocks characterization of products of gas and liquid hydrocarbon

The kinetic parameters of hydrocarbon generation from the marine carbonate source rocks were determined and calibrated through kinetic simulating experiment. The kinetic parameters of hydrocarbon generation then were extrapolated to geological condition by using the relative software. The result shows that gaseous hydrocarbons (C_1, C_2, C_3, C_(4-5)) were generated in condition of 150℃<T< 220℃(1.0%<Ro <3.0% ). Light hydrocarbons (C_(6-13)) and heavy hydrocarbons ( C_(13)^+ ) were generated in condition of 100 ℃ <T<170 ℃ (0.5%<Ro<1.5%). A quantitative reference to examine the natural evolution of hydrocarbon of marine carbonate source rocks can be established through the results. It also provides a new method for evaluating the highly mature marine carbonate source rock more reasonably.

少井区烃源岩叠前地震反演预测方法

少井区烃源岩难以通过井震标定提取准确子波、构建精细低频模型。为此,提出根据盲信号理论的少井区烃源岩叠前地震反演预测方法。首先,根据盲信号理论,利用地震数据高阶统计量提取地震盲子波,再根据贝叶斯理论在复频域内估计模型参数的低频分量;然后,利用得到的地震盲子波及复频域低频模型在复频域内进行弹性阻抗反演;最后,利用烃源岩地震岩石物理模型构建弹性阻抗与烃源岩物性参数之间的关系,并通过弹性阻抗反演得到烃源岩的泥质含量、烃源岩指示因子等物性参数,从而预测少井区烃源岩的空间分布特征,定量评价烃源岩。该方法中,地震子波盲提取是一种统计性子波提取方法,不需要井数据参与,可为少井区烃源岩的叠前地震反演提供先验约束,解决了无井或少井区无法进行确定性子波提取的问题。模型试算和实际资料应用结果均表明该方法可靠、准确。

基于测井资料的烃源岩有机碳含量测井评价方法研究——以鄂尔多斯盆地甘泉地区山西组为例

烃源岩有机碳含量是烃源岩评价的重要参数之一,受岩心样品数量和分析化验成本的限制,仅通过实验室测定烃源岩有机碳含量评价烃源岩有机质丰度的方法已经无法满足非常规油气精细勘探的需求。通过大量的文献调研,系统总结了烃源岩有机碳含量测井评价方法原理及其局限性,结合鄂尔多斯盆地甘泉地区山西组地质特征与烃源岩测井响应特征,建立了烃源岩有机碳含量预测模型,对比分析了不同模型预测精度及其适用性。研究认为:自然伽马测井法、密度测井法、改进ΔLog R法和多元回归法对研究区山西组烃源岩有机碳含量定量评价均具有较强的适用性,其中多元回归法适用性最好,这可为今后基于测井资料计算鄂尔多斯盆地甘泉地区山西组烃源岩有机碳含量提供一定的方法和思路。