储层裂缝识别与评价方法新进展

裂缝发育程度决定着低渗储层的渗流和产出能力,但由于裂缝发育机制的复杂性,故裂缝性油气藏一直是勘探的重点和难点.目前裂缝评价方法多以常规测井资料为主,结合其它分辨率较高的诸如FMI测井、地层倾角测井等.本文列举的计算机层析成像技术、ANN技术、灰色系统评判法是在裂缝研究领域相对有效的识别和评价方法,在油田的现场应用中取得了良好效果.     

含裂缝地层的过套管电阻率测井响应特征研究

由于石油压裂开采等开发措施的实施,会使在套管周围存在着许多被油气等高阻流体填充的微裂缝.尽管这些裂缝或孔隙可能很小,但对套管井电阻率测量会有非常大的影响,甚至会改变原地层的电阻率测井特征,因此裂缝测井响应的计算及考察对过套管电阻率测井十分重要.为解决裂缝测井响应的计算问题,本文提出了计算等效电阻的电流通量管模型,利用该电流通量管模型给出了含垂直裂缝地层横向电阻的计算方法,基于传输线方程法及地层电阻的过套管测量方法实现了含裂缝地层的过套管电阻率测井响应的数值计算,通过计算实例考察了地层裂缝对过套管电阻率测井响应的影响.算例表明:裂缝中的高阻流体对地层视电阻率测量结果会有较大的影响;环形裂隙比垂直裂缝有更大的电阻率测井响应.本文的研究为解决微裂缝过套管电阻率测井响应的计算这一关键技术问题提供了一种可行的计算与考察方法.     

碳酸盐岩裂缝性储层测井识别及评价技术综述与展望

由于碳酸盐岩裂缝发育机制的复杂性,开展碳酸盐岩裂缝性储层的识别与评价一直是测井分析的热点和难点.本文基于大量文献调研,梳理了碳酸盐岩裂缝的定义、成因和分类,系统归纳了碳酸盐岩裂缝性储层的测井响应特征及评价方法,并进行了实例分析.研究表明,常规测井方法对碳酸盐岩裂缝均有不同程度的揭示,基于不同原理的常规测井方法对碳酸岩盐裂缝的响应程度差异显著,利用常规测井方法对碳酸岩盐储层裂缝识别应遵循综合识别原则;碳酸盐岩裂缝成像测井识别方法中,电阻率成像测井、偶极声波测井和核磁共振测井反映裂缝较为直观,但成本高;基于常规测井资料的灰色关联识别方法、神经网络识别方法、小波多尺度识别方法等非线性数学方法,弥补了常规测井和成像测井识别碳酸盐岩裂缝的不足,并且取得较好的应用效果.     

裂缝的双侧向测井响应的数学模型及裂缝孔隙度的定量解释

根据裂缝双侧向测井响应的特征，裂缝分３种状态：低角度裂缝、倾斜裂缝和高角度裂缝，给出了判断裂缝状态的方法；建立了裂缝的双侧向测井响应与裂缝孔隙度、裂缝内流体电导率、基岩电导率之间的函数关系；得出人工估算和计算机精确计算裂缝孔隙度的两套反演公式及相应计算方法．     

大岩心电阻率测量响应的数值模拟

根据电极法岩心电阻率测量原理及准静态电场理论,用三维有限元法编制了大直径岩心电阻率测量数值模拟程序,并运用该程序计算考察了裂缝对大岩心电阻率的影响。得出大岩心的电阻率随着裂缝与电场方向夹角的增大而增大,随着裂缝宽度的增加而降低。该结果可供大岩心实验系统和大岩心实验的研发参考。     

裂缝性地层方位侧向测井响应数值模拟

为研究井周裂缝发育特征,本文提出一种新型方位侧向测井方法,利用三维有限元法,模拟裂缝的方位侧向测井响应.结果显示,深浅侧向电阻率幅度差异受裂缝倾角的控制,低角度缝为负差异,高角度缝为正差异;倾斜裂缝张开度的增大使测井响应值减小,方位电阻率差异增大;井周方位电阻率可反映裂缝方位产状,单一缝或裂缝密度较小时,沿裂缝走向的方位电阻率小,沿裂缝倾向的方位电阻率大;裂缝发育地层的测井响应显示宏观各向异性特征,但方位电阻率的差异显示发生反转现象,即沿裂缝走向/层理方向的方位电阻率大,沿裂缝倾向/垂直层理方向的方位电阻率小;对方位电阻率测井响应进行井周成像,直观显示了裂缝的产状和发育特征.     

塔河油田碳酸盐岩缝洞型储层的测井识别与评价方法研究

塔河油田奥陶系以碳酸盐岩为主，油气的主要储渗空间为裂缝和溶蚀孔洞，具有很强的非均质性．本文利用常规及成像测井资料，对碳酸盐岩缝洞型储层的识别与评价方法进行研究．为了综合各种测井方法识别裂缝，建立了综合裂缝概率模型，计算综合裂缝概率指示裂缝的发育程度．利用地层微电阻率扫描成像测井资料进行裂缝和溶蚀孔洞的定性、定量解释．定量计算的裂缝参数为：裂缝密度、裂缝长度、裂缝平均宽度、平均水动力宽度、裂缝视孔隙度；定量计算的溶蚀孔洞参数有：面孔率、孔洞密度．根据缝洞型储层孔隙空间类型及其中子孔隙度、补偿密度、声波、双侧向电阻率的测井响应物性特征，建立缝洞型碳酸盐岩储层复杂孔隙介质解释模型，用于确定裂缝、溶蚀孔洞孔隙度和评价储层．     

裂缝性岩石低频下复电阻率与饱和度关系研究

储层中裂缝的发育影响着油气运移和储存,因此识别裂缝以及得到裂缝性储层的表征参数与物理性质对于预测天然气的产量有重要的意义.本文主要通过实验和数值模拟研究了低频段(100 Hz～1 MHz)内均质岩样和不同裂缝参数的裂缝性岩样的复电阻率频散特性.利用有限元模拟计算简易岩样模型的复电阻率,研究了完全饱和水状态下均质岩样与裂缝岩样复电阻率频散特性的区别.并重点研究了100 Hz、1 kHz和10 kHz下均质岩样以及不同裂缝宽度、密度、倾角岩样含水饱和度SW与电阻增大率TR、含水饱和度SW与介电常数变化率Iε的变化关系.实验结果显示完全饱含水的情况下裂缝的出现,使得岩样的复电阻率实部降低,复电阻率虚部的幅值减小;不同频率(100 Hz、1 kHz和10 kHz)下IR-SW曲线发生分离.裂缝密度和裂缝倾角的增加,导致岩样的复电阻率实部降低,复电阻率虚部的幅值减小;并使得不同频率下的IR-SW和Iε-SW分离程度变大.讨论了阿尔奇公式中饱和度指数n与系数b以及仿阿尔奇公式中介电饱和度指数n '与系数b与裂缝参数的关系,说明在高含水饱和度时,导电与介电的幂指数规律基本一致.通过对裂缝性岩石上述参数的研究,为多频复电阻率测井仪的研发提供理论与实验支撑,进而提高裂缝性储层含气性识别以及定量评价含气饱和度的可靠性.     

测井及地震裂缝识别研究进展

测井及地震裂缝识别方法是解决裂缝预测难题的主要手段.通过大量的学术调研,对常用的测井和地震裂缝预测方法的原理及技术特点进行详细的分析,并说明其优劣性.在测井方法中,成像测井仍是目前最为可靠的裂缝识别依据,常规测井、三孔隙度比值法、侵入校正差比法和概率密度法容易实现、效果较好,且能够通过与地震反演的结合来预测裂缝的区域分布特征,横波测井和放射性测井效果较好,但资料难于收集,与数值统计分析相关的测井裂缝识别法局限于井点处的裂缝研究.在地震方法中,纵波各向异性应用最为广泛,且能准确得到裂缝的空间分布特征,叠前远近偏移距属性差法、相干体及倾角检测法、叠后融合属性法、多尺度边缘检测法及地震反演方法能够得到裂缝的分布特征数据体,但无法预测裂缝方向,构造应力场分析法经常用于预测某个地层界面构造缝的分布特征,横波与转换波裂缝预测方法受成本限制,VSP裂缝预测受横向延伸限制,均未广泛应用.     

裂缝预测技术在砾岩体气藏评价中的应用

裂缝是砾岩体油气藏重要渗流通道.对裂缝分布规律及发育特征的正确识别,是砾岩体油气藏勘探开发成功的关键.大兴断层下降盘砾岩体裂缝储层天然气蕴藏量丰富、勘探评价潜力大.但储层裂缝成因的复杂性、控制和影响的多因素性在一定程度上增加了裂缝储层的研究难度.为了解决砾岩储层横向变化大,砾岩体内部沉积特征复杂,非均质性强等难题,本次...     

A numerical oil spill model based on a hybrid method

The purpose of this paper is the development of a hybrid particle tracking/Eulerian-Lagrangian approach for the simulation of spilled oil in coastal areas. Oil discharge from the source is modeled by the release of particles. When the oil slick thickness or the oil concentration reaches a critical value, particles are mapped on slick thickness or node concentrations, and the calculations proceed in the Eulerian-Lagrangian mode. To acquire accurate environment information, the model is coupled with the 3-D free-surface hydrodynamics model (POM) and the third-generation wave model (SWAN). By simulating the oil processes of spreading, advection, turbulent diffusion, evaporation, emulsification, dissolution and shoreline deposition, it has the ability to predict the horizontal movement of surface oil slick, the vertical distribution of oil particles, the concentration in the water column and the mass balance of spilled oil. An accidental oil release near Dalian coastal waters is simulated to validate the developed model. Compared with the satellite images of oil slicks on the surface, the numerical results indicate that the model has a reasonable accuracy.     

Cracking conditions of crude oil under different geological environments

There are mainly 3 kinds of existing states of oil generating from source rocks, that is, dispersive liquid hydrocarbon inside of source rock, dispersive liquid hydrocarbon outside of source rock and concentrated liquid hydrocarbon outside of source rock. Because of the differences in thermal history and medium conditions around, and the interaction of organic and inorganic matter, the liquid hydrocarbon with 3 kinds of existing state has different cracking conditions. The gas generation dynamics experiments of crude oil matching different mediums indicate that the distribution of activation energy of methane changes a lot according to medium difference. The carbonate has a main influence on oil cracking conditions and can largely reduce its activation energy, which reflects the lower cracking temperature of crude oil. The mudstone takes a second place and the sandstone is the smallest. The catalytic cracking function to the oil of the carbonate, of the mudstone and of the sandstone changes weaken in turn. The corresponding R _o values of main gas generation period in different mediums are as follows: 1.5%–3.8% with pure crude oil, 1.2%–3.2% with dispersive crude oil in carbonate, 1.3%～3.4% with dispersive crude oil in mudstone and 1.4%–3.6% with dispersive crude oil in sandstone. The influence of pressure to crude oil cracking is relatively complicated. In the low heating speed condition, pressure restrains the oil cracking and gas generation, but in the high heating speed condition, pressure has an indistinctive influence to the oil cracking and gas generation. Pressure also makes a different effort in different evolvement stage. Taking the middle and lower Cambrian source rocks in the Tarim Basin as an example, primary oil generating quantity is 2232.24×10⁸t, residual oil and oil cracking gas quantity is 806.21×10⁸t and 106.95×10¹²m³ respectively.     

石油双机(有机+无机)混合成因的研究与探索

石油与天然气的成因问题关系到我国乃至世界各国能源结构的配置及其能源在社会与经济发展中的地位和导向.自从17世纪展开对石油的有机与无机成因的争论以来,至今已有约300~400年的历史.尽管有机成因论占据了统治地位,但是无机成因论亦不断地在兴起!通过对这二者的理解和研究,从理论上讲他们都具有一定的物质基础和论据.基于对国内、外一些特异油田的生储环境,原油中所富含的微量金属元素的聚集与散失,某些油田中并未找到卟啉分子这样的生物标志物,碳、氢、氧化学合成实验等方面取得了一定的成效,故全盘否定无机生油的论点和论据确尚感为时过早或欠妥!显然,在以有机物成油为主体的前提下,无机物亦可生成部分石油,并通过运移、渗透到各油田的储集层中应是完全可能的.基于这样的分析、研究和探索,现提出石油的双机(a有机+b无机)混合成因的新理念.诚希能在今后的石油工业发展中,从理论、技术、实验和实践中强化对双机混合成因新理念的深化研究与探索,以达深切理解和扩展石油生、储空间环境等是不无裨益的!     

基于EEI反演的储层油气识别研究

埕岛油田是我国极浅海地区第一个投入开发的大油田,其馆陶组上段属河流相砂泥岩沉积,油气富集程度高。该层段分为五套砂组,其中三砂组和四砂组是主要的含油储层。此次研究的目标工区内主要的烃类是重质油,含油储层与含水储层的物性差异较小,通过反演常规的弹性参数无法准确指示油气。基于测井曲线和岩石物理交汇分析,本文构建了敏感的油气指示因子,通过扩展的弹性阻抗反演技术反演该指示因子从而进行油气展布预测。该方法在工区得到了良好的应用效果。      

An oil spill-food chain interaction model for coastal waters

An oil spill-food chain interaction model, composed of a multiphase oil spill model (MOSM) and a food chain model, has been developed to assess the probable impacts of oil spills on several key marine organisms (phytoplankton, zooplankton, small fish, large fish and benthic invertebrates). The MOSM predicts oil slick thickness on the water surface; dissolved, emulsified and particulate oil concentrations in the water column; and dissolved and particulate oil concentrations in bed sediments. This model is used to predict the fate of oil spills and transport with respect to specific organic compounds, while the food chain model addresses the uptake of toxicant by marine organisms. The oil spill-food chain interaction model can be used to assess the environmental impacts of oil spills in marine ecosystems. The model is applied to the recent Evoikos-Orapin Global oil spill that occurred in the Singapore Strait.     

A rapid field method for detecting oil in sediments

A rapid thin-layer chromatographic technique for estimating the relative concentration of crude oil in sediments has been developed. The limit of detection on the chromatogram is 2 μg of Empire Mix or Saudi Arabian crude oil. The technique has been tested on 335 sediment samples collected from 67 stations in the Gulf of Mexico and has been utilized in assessing the location of oil entering the sediments from the Argo Merchant spill incident.     

电场差分法理论研究

对均匀大地和二层大地的频率域电场差分法理论曲线进行的计算和研究表明,电场差分法是一种以目标地质体和围岩在电阻率和极化率方面的差异为基础,根据测量到的能明显反映激电响应与电磁耦合响应的比值随频率变化的P参数曲线在性态上的差异来圈划油气藏的一种电法勘探方法. 因为它圈划油气藏的物理基础是油气藏上方与围岩上方测量到的电磁耦合响应和激电响应的差异,所以在圈划油气藏方面,该方法与复电阻率法类似,同样具有找油气的优良性能. 此外,该方法与复电阻率法相比,具有对目标地质体和围岩的电阻率和极化率差异反映灵敏、效率高、成本低等优点,所以它是一种值得推广的找油气的电法勘探方法.     

雄关漫道真如铁——论中国油气二次创业

半个多世纪以来，中国经历了油气资源的第一次创业，在祖国大陆和近海大陆架地区的新生代陆相碎屑岩沉积盆地中，发现了一批油气田，使原油年产量达1．67亿吨，位居世界第五，天然气疸这241亿立方米，居世界第十五位，成绩是巨大的，但是，1993年开始进口原油3000万吨，2000年进口原油7200万吨，严重影响国家经济建设，而且这种趋势还在不断发展，预测2010年将进口原油1亿吨，天然气200亿立方米，那么，中国油气资源的出路何在？作者指出，从中国大地构造演化来看，前新生代海相残留盆地还有巨大的油气潜力，尽管其勘探的难度是世界级的，但是，只要我们切实地依靠科学技术，进行油气资源的二次创业，困难上，在实践中克服困难，就可以发现更多的石油天然气，支持国家经济建设的持续发展。     

南海油气资源潜力及勘探现状

南海的油气资源极为丰富,享有“第二个波斯湾”的美誉.南海地貌类型多样,地形复杂,其战略位置极为重要,是东亚及相邻各国必经之路.资源之争,使得周边各国使出浑身解数,发展海洋经济与技术,1981年至2002年,越南就从南沙海域的油田中开采了1亿吨石油、15亿多立方米的天然气,获利250亿美元,南海石油已成为越南国民经济的第一大支柱产业.近半世纪中国南海油气勘探工作取得巨大的成就,发现了26个新生代盆地,取得了南海海域的基本石油地质成果,为南海的勘探开发奠定了基础.南海具有巨大的勘探空间及技术发展空间,每一次的技术进步,都会带来南海油气勘探的质的飞跃.     

Persistence of 10-year old Exxon Valdez oil on Gulf of Alaska beaches: the importance of boulder-armoring

Oil stranded as a result of the 1989 Exxon Valdez spill has persisted for >10 years at study sites on Gulf of Alaska shores distant from the spill's origin. These sites were contaminated by "oil mousse", which persists in these settings due to armoring of underlying sediments and their included oil beneath boulders. The boulder-armored beaches that we resampled in 1999 showed continued contamination by subsurface oil, despite their exposure to moderate to high wave energies. Significant declines in surface oil cover occurred at all study sites. In contrast, mousse has persisted under boulders in amounts similar to what was present in 1994 and probably in 1989. Especially striking is the general lack of weathering of this subsurface oil over the last decade. Oil at five of the six armored-beach sites 10 years after the spill is compositionally similar to 11-day old Exxon Valdez oil. Analysis of movements in the boulder-armor that covers the study beaches reveals that only minor shifts have occurred since 1994, suggesting that over the last five, and probably over the last 10 years, boulder-armors have remained largely unmoved at the study sites. These findings emphasize the importance of particular geomorphic parameters in determining stranded oil persistence. Surface armoring, combined with stranding of oil mousse, results in the unexpectedly lengthy persistence of only lightly to moderately weathered oil within otherwise high-energy wave environments.