【作者】 申家年；

【导师】 卢双舫； 迟元林；

【作者基本信息】 大庆石油学院 ， 油气田开发工程， 2005， 博士

【摘要】 松辽盆地是我国最大的中新生代淡水湖泊相含油气盆地,齐家-古龙凹陷是盆地内的一个二级构造带,北部为齐家凹陷,南部为古龙凹陷。松辽盆地的形成大致经历了五个阶段,其中的裂陷阶段、沉陷阶段和萎缩平衡阶段沉积了齐家古龙凹陷的主要沉积盖层。青一段(qn1)、青二三段(qn23)、嫩一段(n1)泥岩是凹陷内的三套主要烃源岩,有机质类型以腐泥型为主,均为大型淡水(有海侵过程)深湖、半深湖相沉积;有机质丰度高、分布广、厚度大;嫩江组基本处于热催化生油气阶段,青山口组有相当部分进入热裂解生凝析油气阶段;生烃门限1200m 左右,生凝析油气门限1900m 左右。估计凹陷内现今地层温度与最高古地温相当。地层温度、压力皆南高北低,超压主要发育于南部葡萄花以下油层。齐家古龙地区有相当多的探井油气同产,绝大部分气油比较低。先用经验法对这些井进行初步筛选并考虑有无原始地化资料等因素,选择5 口井6 个油气层用经验法、计算相图法、实验相图法判别,最终认为英51 井葡萄花油层和古109 井葡萄花油层为凝析气藏,古31 井黑帝庙油层为产冷凝油的气藏。英51 井共有5 个油气层(F、qn1、G2、G1、P),顶部的葡萄花油层是凝析气,G2 层经相态判别为带气顶的油层。英51 井的5 个产层油气样品都进行了多项地化分析。根据英51 井和古109井的地质背景和油气组分分析,发现用业以提出的相态成因(如原生型、分异型、气洗型、气侵型)都难以给出圆满解释。与黑油相比,凝析油和和冷凝油的突出特征是以轻质组分为主,绝大部分为汽油馏分;油油对比和油源对比使用生标参数常难奏效。考虑到热蒸发是一种物理过程,性质相近的化合物之比值在热蒸发过程可能变化不大。本文尝试使用色谱指纹技术进行油油对比,根据热蒸发实验选择色谱图上相邻、分离效果,峰高相当的16 对化合物比值做为指纹。据色谱指纹、气体同位素、尤其是单体烃同位素的综合对比认为,英51 井葡萄花油层凝析油、气与下伏油层油、气同源,且与G2 层油气关系密切。由于沉积环境的相似性,常规的甾萜参数区分三套主要源岩效果不佳。对源岩色谱数据整理后建立了Pr/nC17、Ph/nC18区分青山口组和嫩江组的标准。由此标准判别,英51 井5 个油气层的油气皆来自青山口组。定量评价烃源岩生油气量在平面上的分布是凝析油气预测的基础。在比较了各种方法的优缺点后,选择了高压釜加水模拟实验法和有限平行一级反应化学动力学模型来评价源岩的油气生成量。由于凝析油以轻质组分为主,常用的两分法不能体现这一特征,为此进行了专项实验,标定了三分法(C1~5、C6~13、C14+)化学动力学参数,为定量评价区内烃源岩生气量,生“轻质油”量,生“重质油”量奠定了基础。英51 井、古109 井凝析气相态由热蒸发作用形成,是本文的重要观点之一,对此从地质、模拟实验、理论分析等多个方面进行了论证。(1) 凝析气分布在同源油的顶部且与下部含气油层关系密切,表明热蒸发作用的可能性。(2) 英51 井P凝析油与G2 黑油之间和古109 井区冷凝油与黑油之间的组分关系、甲苯/正庚烷和正庚烷/甲基环己烷参数关系,与蒸发实验所表现出来的规律一致。(3) 根据英51 井G2 层、P层温度、压力及两层油气的平均组分,计算了P层源自G2 层热蒸发的正构组分对(C1/C2～nC22/nC23)和部分常用化合物对(如Pr/nC17、正庚烷/甲苯等共7 对)的相对挥发度。实测G2、P层油气样品的这些组分含量比值与由相对挥发度在理论上所约束的关系具有很好的一致性;对古109 井也进行了类似的比较,同样与也支持热蒸发分馏机制。(4) 不同分区甲烷含量的垂向趋势也为热蒸发作用的存在提供了补充证据。经过分区成图,表现为热蒸发分馏模式的区块皆位于古龙凹陷内。(5) 蒸发出来的烃类需要通过油层顶部盖层向上部泄漏,这种更多还原

【Abstract】 In China, the Songliao Basin is the biggest petroliferous basin with Cenozoic fresh water lacustrine facies. Qijia-Gulong sag is a second-order structural zone in the basin, in which the north is Qijia sag, and the south is Gulong sag. As known, formation of the Songliao Basin has approximately undergone five stages, in which the rift stage, the downpunching stage and the atrophy balance stage deposit the main deposition cover strata in Qijia-gulong sag. And the mudstones of Qingshkou 1st member (qn1), Qingshkou 2-3nd member (qn23) and Nenjiang 1st member (n1) are three sets of main hydrocarbon source rocks, in the sag, whose organic matter type is sapropelic, and the deposition is large scale fresh water semideep-deep lacustrine facies (with sea ingression process).And the organic matter is abundant, distribution is wide, the thickness is great. In general, the Nenjiang formation is at the thermo-catalysis stage, and the considerable proportion of Qingshankou formation has entered pyrolysis stage as condensate oil-gas generating; the depth threshold is about 1200m, and the condensation oil gas threshold is around 1900m. The nowadays geotemperature in sag may be equal to the maximum paleogeotemperature. Formation temperature and pressure is all high in south and low in north. And overpressure mainly develops in the south below Putouhua oil layer. In the Qijia-Gulong area, there are quite many exploratory wells which produce oil and gas synchronously; most of the gas/oil ratio is low. In this paper, first, by the experiential rule, primarily choose wells and consider some factors, such as the primitive geochemical material, and then pick out 5 wells 6 oil layers, with the experiential rule, the computation phase diagram method, and the experimental phase diagram method from the various distinction, finally obtain the result that the English 51 well Putouhua oil layer and the Gu 109 well Putouhua oil layer are condensate gas pools, the Gu 31 well Heidimiao oil layer is a gas pool with condensation oil . The Ying 51 well has 5 oil-gas layers (F, qn1, G2, G1, P), the top Putouhua oil layer is the condensate gas reservoir, the G2 layer, by the phase state distinguish, is a oil layer with gas cap. The samples from 5 oil-gas layers of Ying 51 well are all carried on many geochemical analyses. According to the Ying 51 well and the Gu 109 well geological backgrounds and the oil gas component analysis, find that it is difficult to explain perfectly by the phase state origins that have been proposed (such as primary, differentiation, gas washing, gas irruption). Compared with the black oil, the prominent characteristic of condensate and condensation oil is mainly of the light quality components, and most is gasoline fraction. For the oil-oil correlation and the oil-source correlation, using the biomarkers parameter is often difficult to be effective. Considering thermo-evaporation is physical process, in thermo-evaporation process, ratios of the compounds whose natures are close cannot change greatly. In this article, we attempt to use chromatograph fingerprint technology to carry on the oil-oil correlation. Based on thermo-evaporation experiment, choose 16 pairs of compound ratio as the fingerprint, which are neighboring, have separate effect, and considerablely high peak in the spectrogram. According to the synthesis contrast between chromatograph fingerprint, the gas isotope, especially monomer hydrocarbon isotope, believe that in Ying 51 well, Putouhua condensate oil and gas and underlying oil and gas are from the same source, also are relative to the G2 level oil gas closely. As a result of the environment of deposition similarity, the conventional parameters, steroid and terpene, can not differentiate three sets of main source rocks effectively. After the analysis of source rocks chromatograph data, the paper has established Pr/nC17, Ph/nC18 standard for distinguishing Qingshankou Formation and Nenjiang Formation. And by the standard, find that the oil-gas of Ying 51 well 5 oil layers all comes from the Qingshankou Formation. Evaluating source rock hydrocarbon generation quantificationally in the horizontal distribution is the foundation of condensation oil gas forecast. After comparing the merits and demerits of each method, choose the high pressure vessel watering simulation method and the limited parallel first level reacted the chemical kinetics model appraises the oil gas quantity generated by source rock. Due to the condensate makeup the light oil, the common dichotomy cannot reflect this characteristic, as a result, carry on the special experiment, demarcate the trichotomy (C1~5, C6~13, C14+) the chemical kinetics parameters, which lays the foundation for the quantitative evaluation of gas generation quantity, "the light oil" generation quantity, and "the heavy oil" generation quantity of the hydrocarbon source rocks in the area. The thermo-evaporation fractionation is the reason for condensation gas phase state in Ying 51 well and the Gu 109 well, which is one important view of this article. Demonstrate it from the geology, the modeling, the theoretical analysis and many other aspects. (1) The condensation gas layer distributes in oil layers top of homologous source and has close relation with lower part oil-gas layer, which indicates the possibility of thermo-evaporation function. (2) The oil component relations between the Ying 51 well P condensate and the G2 oil, and between the Gu 109 well area condensation oil and black oil, the parameter relations between toluene/ heptane and heptane/methyl cyclohexane, are consistent with the law displayed in evaporation experiment. (3) According to the temperature, pressure and average components of the two oil-gas reservoirs, G2 , P reservoirs in Ying 51 well, relative volatility of C1/C2～nC22/nC23 and the partial commonly used compound (for example Pr/nC17, the normal heptane/toluene and so on, altogether 7 pairs) are calculated if P layer hydrocarbons component accumulation from the G2 layer thermo-evaporation. The component content ratios measured from G2, P oil gas samples are well consistent with the theoretical relations which is restrained by relative volatility. And carry on the similar comparison in the Gu 109 well, in the same way, support the thermo-evaporation fractionation mechanism. (4) Trend of methane content variety with depth in different districts also has provided the supplement evidence for the existence of thermo-evaporation function. After districting, become the charts, all sub-areas displayed by the thermo-evaporation fractionation pattern are located in the Gulong sag. (5) Evaporated hydrocarbon compound needs to divulge through the top of cap rock to upside, this kind of micro leakage channel may be cap rock itself micropore, also can be the cap rock existence micro crack even some minor faults. The former studies indicate that there is the existence of this kind of micro crevasse, in mudstones of the Gulong sag Qingshankou Formation, which can be vapors channel for upward migration. This article has proven the existence of oil cracking into gas from 4 aspects: (1) Oil cracking gas andkerogen degradation gas have different component characteristics, Puxi oilfield and the Gu 6 well area Putouhua oil layer mainly manifest the mixing effect for oil cracking gas and kerogen degradation gas. (2) The simulation experiment for oil heating indicates that when the crude oil is heated up to the point, Ro=1.2～1.6%, oil starts to crack into gas, and δ13C1 generated by oil cracking obviously change to be lighter in the early stage of oil cracking. (3) In this article, Qijia-Gulong nature gas δ13C1 becoming lighter just may explain that the kerogen degradation gas mixes up with the gas from early oil cracking. (4) Combining hydrocarbon generated section with bury history, it is could be know that qn1 and qn23 mainly generate and exclude the mature oil, but the light hydrocarbon parameters indicate that most Qijia-Gulong crude oil is high-mature oil. The author believes that majority of high-mature oil results from continuing mature, which can qualitatively interpretate why placanticline is the mature oil distribution area, but the Gulong sag is the high-mature oil distribution area. It could be obtained that the oil cracking is at the early stage according to Qingshankou Formation’s Ro situation and the hydrocarbon generating section. The oil cracking gas provides the supplement matter for the thermo-evaporation. Meanwhile, based on the preliminary analysis, believe that the oil to gas is the main reason for the unusual pressure in the Gulong sag. The gas washing is another origin for which the condensation oil gas forms. This article defines concepts of the relative solubility, α, and the residual ability, h, deduces the equations to express component change relations related to αand h; examines the influence of gas-oil ratio, temperature and pressure on αwhen gas washes occurs, and the changes of partial geochemical parameters in different gas wash condition. In terms of the above theoretical achievement, analyze the component characteristics and the main relations between geochemical parameters of three oil gases in Gu 31 well (to be upward, in turn P, H2, H1), and believe that in Qingshankou Formation, natural gas washes the H2 reservoir which has already formed along the fault upward migration and gathers at upside and forms H1 gas reservoir. As gas washing occurs at low temperature, low pressure, small oil enters in the gas phase, moreover, the temperature and pressure of H1 reservoir are lower, therefore H1 contains few condensation oil. According to the chemical kinetics achievement and the source rock growth situation, calculate the C14+ oil generated mass of n1, qn23 and qn1 in Qijia-Gulong area, in turn, is163.1×108t, 191.4×108t, 156.3×108t, the C6～13 oil generated mass is 28.2×108t, 90.0×108t, 104.8×108t, the C1～5 gas generated mass is 3.51×1011m3, 33.83×1011m3, 108.15×1011m3; the expelled oil mass is 95.3×108t, 167.1×108t, 197.9×108t, the expelled gas mass is 0.66×1011m3, 22.0×1011m3, 103.3×1011m3, total generated light oil mass is 223.0×108t, and total expelled oil mass and gas mass is 460.4×108t and 126.0×1011m3. We see that the light oil mass is less than half of the total oil mass, comparing with the condensate major part for the gasoline fraction, there is great difference. Even if make use of qn1 which the expelled gas mass is the biggest to calculate, the gas-oil ratio can not reach the general requirement for the condensation gas pool formation, in fact, which is the internal cause for the Qijia-Gulong area difficult to form the primary condensation gas pool. In general, although the condensate gas mainly is composed of light oil and gas, at most conditions,light oil and gas cannot always form the condensate gas pool, only in the middle of the sag where temperature and pressure are higher, and only when the component composition and the gas-oil ratio is proper, there is the possibility to form the condensate gas pool. Thephase state origin of Ying 51 well and the Gu 109 well condensate furtherly show the strict conditions to be needed to form the condensation gas pool in the Qijia-Gulong area. Based on the former experience and the Qijia-Gulong realities, regard the natural gas transport-gather coefficient as 5‰～3%, in the area natural gas resources quantity is situated between 730～4370×108m3. Considering the practice of condensation gas formation in the area, it is reasonable to believe that 10% of natural gas resources can form condensate gas, and use medium condensate content gas-oil ratio 5000m3/m3 to caluclate, then in the region of interest the condensate resources quantity is situated between 150～870×104m3, and the corresponding the condensate gas is 73～437×108m3. The superimposition shows the primary factors which may possibly affect the condensation gas pool to form and distribute, that is, the light oil generating intensity isoline, the natural gas generating intensity isoline, the Putouhua oil layer temperature isoline and n1 section mudstone percentage isoline which is regarded as important region cap rock in area(reflecting preserving condition), It is observed that, the Gu 124-Gu 86 well area should be the most advantageous distribution area for growing the condensation gas pool, while Ying 8 well area and the Gu 933-Jin 45 well area might be better areas where light oil and natural gas generating intensity are higher but other conditions are not synchronously best. Considering the thermo-evaporation fractionation as the main mechanism to formed the condensation gas pool in the area, the areas whose faults grow better, through which can link upper and lower oil layers in the advantageous area, are good target for exploring condensate gas pool, which need more work on the geology and the geophysics.更多还原