层序格架中用地球化学录井资料评价烃源岩的方法

在综述前人对海相盆地和陆相盆地烃源岩分布与层序地层格架关系研究的基础上,介绍了露头、地球物理资料层序地层研究与地球化学录井资料的有机质丰度评价相结合进行烃源岩评价的方法及步骤。并通过在准噶尔盆地侏罗系烃源岩评价中的具体应用,较为客观地说明了准噶尔盆地侏罗系烃源岩在纵、横向上的分布。实践证明该方法是行之有效的。     

Uncertainty analysis and the relative contributions of geological factors for the Qingshankou source rocks in the North Songliao Basin, northeastern China

Source rock evaluation is a critical factor in resource assessment of oil and gas. Models for evaluating source rocks are dependent on established geomathematical principles, the calculation of source-rock parameters, and geological data. The sensitivities and uncertainties associated with these models are a matter of concern. In this paper, the effects and relative contributions of 13 major geological factors, as well as their variations and distribution probabilities, have been analyzed for the source rocks in the North Songliao Basin in northeastern China. The geological factors include the time of formation of the regional caprock, composition of the regional caprock, the phases of hydrocarbons in migration, and those factors associated with the generation, retention, and expulsion of hydrocarbons and their effects on source-rock efficiency. Of the 13 factors analyzed, the most important are the source-rock depth, sedimentation rate, total organic content, and kerogen-type index; the relative contributions to the uncertainty of efficient gas/oil migration amounts for the most important factors are 37, 25, 19, and 1% for oil and 32, 17, 20, and 15% for gas, respectively. These most reflect the changes that have occurred in the Qingshankou source rocks.     

关于铀、金矿源层(岩)与地球化学负异常的讨论

借鉴成矿物质取源于矿源层(岩)的思想,作者提出了地球化学场成矿元素的正、负异常相匹配的地区是最有利于成矿的远景区。     

塔中原油超高二苯并噻吩硫特征及其控制因素

塔中相当部分原油具有高丰度芳香硫——二苯并噻吩(DBTs)特征,其在原油中的绝对丰度高达26 859μg/g,在芳烃中的相对丰度高达58.2%,主要分布在塔中I号构造带下奥陶统、塔中4(TZ4)和塔中1-6(TZ1-6)井区。采用综合地球化学研究途径,对该区原油的高DBTs特征及其主控因素进行初步探讨。分析表明,研究区母源岩较强地控制DBTs的丰度,纯泥岩、页岩中DBTs丰度不高,灰岩、云岩等烃源岩DBTs丰度偏高或超高;观察到在正常油窗范围内,烃源岩和相关原油随成熟度增加DBTs丰度增加,而塔中型高-过熟原油中DBTs丰度有先增加后减小的趋势,表明热成熟作用对该化合物有较强的控制作用;发现生物降解、水洗可使原油中DBTs丰度降低,但对塔中原油中DBTs影响较小;观测到塔中相当部分原油的DBTs含量与硫酸盐热化学还原作用——TSR的作用产物H2S、硫醇、长链烷基四氢噻烷有一定正相关性。对比研究认为,有多种因素控制塔中原油中DBTs丰度与分布,热成熟作用、TSR是导致塔中下奥陶统部分原油高DBTs特征的重要原因,前者可能是主要因素,特殊母源岩因素相对较少,尽管尚不能排除。TZ4井区等石炭系高DBTs原油主要来自深部地层,与下奥陶统抑或更深层高DBTS原油的混入有关。本研究对于该区深层油气勘探具有重要意义。     

On the chemical mechanism of kerogen thermal transformation. Study of the transformation of sporopollenin

Experiments were carried out on the thermal decomposition of sporopollenin, isolated from a marine algae (Lycopodium clavatum) at constant temperature (380°C) and pressure (around 200 atm), but for varying pyrolysis times.The decomposition products were separated into groups, analysed by chromatography and infra-red spectroscopy, and their elemental composition determined. The thermal evolution of sporopollenin proceeds in three distinct steps: first, a partial decomposition of the initial substance occurs with the formation of soluble materials. This is followed by a full decomposition of the sporopollenin and disappearance of the non-soluble residue. Finally, a non-soluble material reappears. It is proposed that, due to secondary reactions, the evolution of kerogen of the sapropelic type is similar to what has been observed in mild pyrolysis experiments.     

云南省中部富碱斑岩成矿机理探讨

云南富碱斑岩由地壳深部的源岩分离熔融形成，该源岩则由早期侵入陆壳的幔源超基性岩与陆壳组分混合而成。斑岩成矿作用的成矿物质主要来源于岩浆，铅同位素资料表明它们有深部流体相、早期陆壳和幔源岩浆三种来源，但归根结底可能本区存在异常上地幔。地质地球化学综合分析认为，铜金等元素主要来源于幔源组分，铅锌等元素来源于陆壳组分，源岩重熔和岩浆演化使成矿元素得到进一步的富集。在不同的构造单元中，源岩的壳幔组分比、重熔程度等存在差异，因而富碱斑岩特征及成矿作用有别，出现两个成矿亚系列。     

Evaluation of burial history, thermal maturity and source-rock assessment of the Upper Paleozoic succession of the eastern Taurus region, southern Turkey

The regional burial history pattern, thermal maturity variations and source rock assessment of the sedimentary succession in the eastern Taurus region, in the southern part of Turkey, have been studied on surface samples collected from the six different sections which represent the entire region. Organic petrography (Thermal Alteration Index) and geochemical data (TOC content, T_max and HI values) were obtained from transmitted-light microscopy and Rock-Eval pyrolysis.The Lower Paleozoic (Cambrian, Ordovician and Silurian) strata were not investigated and modeled in terms of the maturity and hydrocarbon source rock potential, because of their poor organic matter content and their over maturity resulting from great burial depth (more than 7630 m). Other Paleozoic strata, except the Lower Devonian Ayitepesi Formation, generally have the values of more than 0.5% TOC. Organic matter of the Middle Devonian Safaktepesi sediments are composed of highly terrestrial organic material (type III kerogen), while samples from other three formations (Gumusali, Ziyarettepe and Yigilitepe Formations), while samples from other organic matter (type II and type III kerogen). The average TAI values are as high as 3.4 (equivalent to 1.42 of R₀%) for Ayitepesi and as low as 2.75 (equivalent to 0.77 of R₀%) for Yigilitepe Formations. Time-temperature index values (TTI) indicate that Ziyarettepe and Yigilitepe sediments are marginally mature to mature, while the Devonian strata are overmature. There are minor discrepancies between ΣTTI values and geochemical data in terms of the organic maturity for Devonian strata. In contrast, the e is a consistency between those values for the Ziyarettepe and the Yigilitepe Formations. The onset of oil generation time in the region was initiated from as early as the Norian (216 Ma) to as late as the Lutetian (45 Ma).Regional variations in the level of thermal and source-rock maturities of the Upper Paleozoic sediments in the eastern Taurus region largely depend on burial depth.     

东营凹陷沙四中亚段盐湖相烃源岩研究

东营凹陷下第三系沙河街组沙四中亚段蒸发岩十分发育,其中与泥岩共生的含盐系地层在胜坨南部及中央隆起带等地区厚逾千米。通过大量样品的分析测试和对这套蒸发岩沉积体系的研究,认为沙四中沉积时期湖盆充填呈现出欠补偿的饥饿状态,并建立了深水蒸发成盐的沉积模式。蒸发岩夹层中的深灰色泥岩和页岩的地球化学特征充分体现了盐湖沉积环境标志。高盐环境有利于有机质的富集和保存,沙四中亚段的灰色泥岩和页岩为东营凹陷的一套有效烃源岩。