The effects of total organic carbon content (TOC) on the migration of polycyclic aromatic hydrocarbons (PAHs) in the soil were investigated. This study analyzed the vertical properties of the concentrations and distributions of PAHs and TOC at various soil profiles from functionally different environmental regions including nature reserves, ploughs, orchards, farmlands, metropolitan areas, and industrial parks. The vertical migration properties of PAHs in soils were examined by conducting leaching experiments in soil columns. The concentrations of PAHs varied from region to region and showed strong, positive correlations with TOC in the same region. Furthermore, based on the leaching experiments, the transport abilities of PAHs were significantly influenced by TOC, although they could all be transported to the deep layers by TOC in soil columns. The downward migration of PAHs decreased with the increase in TOC and vice versa. The properties of the composition and structure of PAHs also had an obvious influence on their residues and migration in soil profiles at the same TOC conditions. In addition, the transport of PAHs was related to the amount of leaching water, the leaching time, and the additional PAHs.

随XN区块油藏不断开发,井组高回压已成为制约油区发展的一个不容忽视的因素,井组回压升高关系着单井产能、泵效、抽油机及其井下管杆使用寿命、集输管线跑冒滴漏等一系列问题。为合理优化原油生产系统及技术系统,本文以XN区为例重点分析了回压对抽油泵泵效、油井产量、抽油机耗电量的影响,并对高回压井组制定相应对策并从而降低井口回压。

Taking Chang 6 oil layers of Yanchang Formation as an example,and on the basis of the comparative study of multiple models,the saturation interpretation model for freshening factors was proposed by "three-low" oil reservoirs with tight reservoir,small pore throat radius,high mudstone content,weak oil-water differentiation,and complex contradiction of water-out mechanism.The mean value of dilution correction factor D was determined to be 0.25~0.3.The new method was utilized to carry out comparative interpretation in 20 production wells of the studied area.The coincidence rate of water-out degree is over 88%,and the mean differential of water production rate is 7.91%.As a result of high coincidence rate of the interpretation and good adaptability,the method can be used as the saturation interpretation model for water flooded reservoirs in the studied area.

以安塞长6微裂缝性特低渗透油藏为例,基于物质平衡原理及定态水侵模型,建立考虑无效注水的注采比、总压降与产液量差之间的关系,利用实际开发资料拟合,计算出无效注水比例及有效注采比,分析影响低效注水循环的因素,评价注水利用情况,结果表明中高含水期后注水低效循环主要受裂缝、大孔道影响,王窑、坪桥区无效注水比例分别达到35.9%、71.6%,水驱效率低,建立的评价方法与实际状况较为符合,为油藏综合调整提供依据。

Based on the exploration of the studied area in Ansai Oilfield,the development of bottom water in the reservoir and the distribution characteristics of barriers were discussed,the influence of bottom water and barrier on exploration effect was systematically analyzed. The distribution of residual oil and oil-water interface were also investigated systematically. The results indicate that bottom water growes stronger in the west of the studied area than in the east,whereas the barriers present the contrary characteristics. The barriers between layers are located under the oil-water interface,which has insignificant effect on elimination of bottom-water coning. Therefore,the oil-water interface is raised at the different speeds of different wells,which leads to no uniform oil-water interface and the distribution of residual oil among different layers is uneven.

A sound pressure displacing system is crucial to the effective development of low permeable oil reservoirs while water flooding parameters,flooding methods and the selection of integrated injection-production monitoring measures which could affects displacing system are closely correlated to multiple pressure monitoring data in the process of flooding exploration.In the development lasting as long as 20 some years,Wangyao district the earliest block in Ansai Oil Field to implement flooding exploration had gradually developed an empirical method with pressure monitoring data its main source while also combining updated info to determine adjustment measures which posed great significance in instructing development of Ansai Oil Field and lent experiences to similar reservoir explorations.

Based on the analysis of the geo-chemical characteristics of the oil samples collected from Chang 10 member of G52 well in Ansai oilfield,the distribution characteristic of the biomarkers and the oil source of the samples are systematically studied.The results show that n-alkane of the oil samples is characterized by unimodal distribution without even or odd n-alkanes predominance,and main carbon peak is at nC21.The distribution C27∶C28∶C29 ααα20R steranes presents L shaped,and ββ-steranes has high abundance.The abundance of tricyclic terpane is medium,and Ts,C29Ts and 18a(H)-rearranged hopanes have higher abundance and lower gammacerane index.The lower abundance of C31-C35 homohopanes indicates that the oil has high maturity.The compositions and parameters of the biomarkers indicate that the mature crude oil is generated from the lacustrine source rock mainly enclusing lower hydrobionts and lacustrine algaes under the environments of fresh-brackish lacustrine.According to the comparison of the distribution and related parameters of the biomarkers in Chang 10 crude oil with those in the hydrocarbon source rock of Chang 6-Chang 9,it is shown that the characteristics of the biomarkers in Chang 10 crude oil is similar to those in Chang 9 hydrocarbon source rock,so it is held that the Chang 10 crude oil is mainly from the Chang 9 hydrocarbon source rock.

<正>第一采油厂地处革命圣地延安,是中国石油天然气股份有限公司长庆油田分公司下属的一个主力采油单位,管理着我国陆上最早开发的特低渗亿吨级整装油田—安塞油田。因成功开发了世界罕见的"低渗、低压、低产"油田,实现了高效经济开发,被中国石油天然气集团公司确立为"安塞模式"而享誉石油界。

通过室内土柱模拟试验研究了石油烃在土壤剖面中的纵向迁移特点及影响因素.结果表明,淋滤后多环芳烃（PAHs）主要富集在土柱表层,w（PAHs）随深度增加而明显降低,但不同土柱w（PAHs）降幅不同.饱和烃类化合物组成特征表明,土柱不同深度下饱和烃化合物的组成特征与原土样有明显不同,表明这些化合物在土壤剖面上发生了迁移,但不同化合物（正构烷烃、甾萜类和烷基环己烷）纵向迁移的深度不同,说明饱和烃中不同组分化合物的迁移能力不同.石油烃组成及质量分数随深度变化特征表明,影响石油烃在土壤中纵向迁移的因素主要有土壤总有机碳（TOC）的质量分数和原油黏度.

Based on waterflood development simulated experiment and field data analyses,core was analyzed by mercury injection experiment and physical-mechanical test,characteristics of Chang-6 Oil-bearing Formation changes after long term waterflood development in Ansai Oilfield was discussed.The result showed that permeability evidently decreased with the increase of water injection rate as a whole,the average rate of change was 4.72%;porosity increased by an average of 0.15% and there was no apparent change in the type of pore combination;efficiency of mercury withdraw decreased by an average of 4.39%;the median radius of throats diminished,however,there was no significant change of distribution characteristics;reservoir wettability transformed from lipophile to hydrophile on the whole.Characteristics of low-permeability reservoir varied after long term waterflood development.The mechanisms were that the clay particle and interstitial material in reservoir dissolved,crushed and moved by the action of injected water washing,one part was carried away by injected water,and the another part still stayed in thin pore-throat,caused the pore connectivity worse and the heterogeneity of reservoir was stronger;the variation of the properties of reservoir rock and pore-throat surfaces caused the change of reservoir wettability.

安塞油田属于低渗、低压、低产的"三低"油藏,针对安塞油田开发实际情况,从经济极限产能方面定义了低产低效井,并对其进行了分类,从地质因素和后期开发方面分析了不同类型低产低效井的成因。通过对开发地质资料的研究分析,结合采油工艺技术,针对不同的低产低效井制定了合理的治理技术。实践证明,低产低效井治理取得了显著的效益,同时也为同类油藏提供了经验。

Analyses have shown that the concentrations and the compositions of polycyclic aromatic hydrocarbons (PAHs) in the representative soil profiles of Beijing and Tianjin change obviously with depth. In order to reveal the migration behavior and critical factors affecting PAH concentrations in soil profiles, laboratory simulations of soil columns were designed to determine the factors, especially soil organic matter content, which affect migration behavior of PAHs. Three soil matrices with different textures and TOC, pre-saturated with deionized water, were loaded into columns. Pollutants (including PAHs and d10-flu) were added to the surface soil and then the columns were leached with deionized water. The results indicate that the concentration distribution of PAHs in each column showed similar trends with depth; mainly accumulating at the surface, and decreasing sharply with depth, but depending on the various compounds in the different columns. The concentrations were still higher than those of the original soil samples. Compared to the original soil profiles, the distributions of the PAHs with different rings along the soil column profile were different; the relative contents of d10-fluorene and fluorine etc., increased obviously over those of the originals. The concentrations of the multiring PAHs also increased obviously and migrated somewhat, but had a weaker migration compared to low molecular weight PAHs (≤3 rings). Moreover, the migration depth of PAHs or any individual PAH changed obviously with different TOC: both increased more at lower TOC concentrations, which indicates the effect of soil organic matter on the migration of the target compounds.

Vertical distribution of both the concentration and composition of polycyclic aromatic hydrocarbons (PAHs) in ten profiles in Beijing has been investigated. The results showed that PAH concentrations and compositions in topsoil from different sampling sites were different. PAH concentrations were much higher in topsoil of the investigated urban area, industrial region, and paddy field with wastewater irrigation than in other areas. Moreover, PAH concentrations in topsoil were much higher than those at greater depth, where the concentrations were relatively consistent in most soil profiles. The fingerprints of PAHs in the samples from topsoil (0-30 cm) in the same profiles were similar and were obviously different from those at greater depth, suggesting that PAH sources were consistent in topsoil samples and were discriminating between topsoil and deeper soils. PAHs in topsoil mainly arose from mixed sources of combustion of liquid fuel, coal, and/or wood, as well as wastewater irrigation, while those at greater depth were derived from soil genesis and the process of soil formation.

The contents and distribution of 20 polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic hydrocarbons (HAHs) were investigated in 16 soil profiles of Beijing and Tianjin region. Transport of high molecular weight PAHs (HMWPAHs) and the correlation between total organic carbon (TOC) and their concentrations were also discussed. The results indicated that highly contaminated sites were located at urban or wastewater irrigation areas and pollutants mainly accumulated in topsoil (< 40 cm), with a sharp content decrease at the vertical boundary of 30-40 cm. Total PAHs/HAHs concentrations in soils from Tianjin were markedly greater than those from Beijing. Even the contents at bottoms of soil profiles in Tianjin were higher than those in topsoils of Beijing soil profile. HMWPAHs dominated the PAH profiles, exhibiting a uniform distribution of pyrogenic origin between topsoils and deep layers. Furthermore, the percentages of HMWPAHs remained relative constant with the depth of soil profiles, which were consistent with the distribution of particulate matter-associated PAHs in the local atmospheric environments. Therefore, HMWPAHs transport with particulates might be the predominant source found in soil profiles.

Base on the measured results of the such as hopanes,steranes and aromatic steranes in 10 soil profile samples collected from various environment domains in Beijing,the chemical composition,distribution and pollution sources in the soil profiles were investigated.Different concentration of hopanes and steranes are detected in all soil profiles,with lawn in city area and rice seeding bed in Changping having the highest content,where triaromatic steroid hydrocarbons were also detected.Concentrations changes of hopanes and steranes in each profile showed similar trend with depth,declined rapidly down to 30 cm and trend consistent in the deep part(30 cm),and their fingerprint chromatogram are similar in different deep soils.The content of hopanes has with steranes in Beijing soil profiles,and they are mainly affected by oil combustion whereas coal combustion takes a smaller proportion.Hopanes and steranes in deep soil mainly come from the surface,and atmospheric particulates may have great impact.

Soil samples were collected from ten soil profiles with different environmental conditions in Beijing for saturated hydrocarbons (SHs) analysis. The vertical distribution of the both concentration and composition of SHs in ten soil profiles were investigated. Concentration of SHs in different profiles is significantly different, ranged from 1.5 microg x g(-1) to 54.1 microg x g(-1). The higher concentrations are found in the samples from B7, B9 and B10. A series of SHs including n-alkanes, isoprenoid alkanes, terpenoids and steranes, alkyl hexamethylene were detected in all samples. The order from higher content to lower in most profiles (except B7) is: n-alkanes, isoprenoid alkanes, terpenoids and steranes, alkyl hexamethylene, and the relative content of n-alkanes is obviously dominant in the upper horizons. Concentrations of SHs and content of soil organic carbon in each profile show similar trend with depth, declined rapidly down to 30 cm and trend consistent in the deep part( > 40 cm). CPI1, CPI2, (C25 + C27 + C29 + C31) / Sigma alkanes, terpenoids and steranes, and biomarker parameters suggest that pollutants are mainly from fossil fuel in B7, high plant-derived n-alkanes dominated in other profiles and fossil fuel contamination to different extent. The sources of n-alkanes in deep part of soil profiles are different from those in topsoil samples, which are related to the soil itself, such as soil parent material and process of soil formation, but the sources of alkyl hexamethylene, terpenoids and steranes between topsoil and deep part are constant.

Vertical distribution of the concentration and composition of some sulfur and oxygen heterocyclic aromatic hydrocarbons (SOHAHs), such as, fluorene, dibenzofuran, dibenzothiophene and their alkyl homologues in 10 soil profiles in Beijing have been investigated. The results showed that the concentrations and composition of SOHAHs in topsoil (0–30cm) from different profiles are different. The concentrations of SOHAHs in topsoils are much higher than that in bottom soils where the concentrations are relatively constant. The fingerprints of SOHAHs from same profile are similar in topsoil samples, which are obviously different at the deep part, which suggested that the sources of these compounds are consistent in topsoil and are discriminating between surface and bottom soils. The main sources of SOHAHs in surface soil were fossil fuel combustion, petroleum and wastewater irrigation, while those at deep part were likely derived from the degradation products of soil organic matters.