裂缝发育程度对低孔隙度岩石渗流特性的影响

低孔隙度岩石中的裂缝对储层渗透率具有重要影响,但裂缝的存在导致岩心代表性样品选取和高精度岩石物理参数测量困难。为研究裂缝对低孔隙度岩石渗透率的影响,通过高精度电子计算机断层扫描(computed tomography, CT)实验构建了低孔隙度岩石的三维数字岩心模型,采用添加平板裂缝的方法构建了不同裂缝参数的低孔隙度岩石数字岩心,并利用格子玻尔兹曼(lattice Boltzmann method, LBM)方法计算了不同裂缝参数数字岩心模型的渗流场分布和绝对渗透率。结果表明,尽管低孔隙度岩石的数字岩心模型基质渗透率低,但裂缝的存在对岩石渗透率有一定程度的提高。然而,裂缝发育程度对渗透率影响规律不同：当单条裂缝孔隙度在0～0.4%时,裂缝对模型渗透率影响不明显;当单条裂缝孔隙度大于0.4%时,裂缝对模型渗透率具有显著影响;模型渗透率随裂缝开度增大而增大,随裂缝倾角增大而减小,随裂缝数量增加而增大。另外,裂缝与基质存在耦合作用,与裂缝相连的孔隙中流体流速明显提高,显示裂缝对基质孔隙的强连通作用。本研究结果对含裂缝的低孔隙度储层渗透率精确计算及储层压裂后的油气产能评价有指导意义。     

低渗透油藏动态渗吸机理实验研究及数字岩心模拟

在低渗油藏的开发过程中,渗吸作用对于产量提升起到重要作用.传统的岩心渗流实验难以从微观的角度较为清晰地描述岩石物性、孔喉分布、岩石组分构成等特征.利用数字岩心技术建立孔隙网络模型,对真实岩心孔隙结构进行渗吸模拟分析具有重要意义.对松辽盆地某区域岩心样品通过综合微计算机断层扫描技术(micro computed tomography,Micro-CT)、数字岩心分析技术,实现低渗储层数字岩心渗吸过程的模拟,与实验室岩心自发渗吸实验对照,结果表明,利用数字岩心技术模拟得到的孔隙度、渗透率参数与实验室测量结果相差较小,提取的孔隙网络模型与真实岩心误差较小,从而可以保证数字岩心得到的两相渗流模拟结果具有较高的可信度,为油藏渗吸作用的机理研究提供了新的思路,对指导实际油藏开发具有重要意义.     

应用核磁T2谱与数字岩心技术计算粒度分布方法

提出一种利用核磁T2谱结合数字岩心技术计算岩石粒度分布的方法。岩石粒度分布近似符合Weibull分布,改变分布参数可得到不同粒度分布。给出初始Weibull分布后采用过程法构建数字岩心,并用随机行走法对构建的数字岩心进行核磁数值模拟,遍历分布参数区间使模拟得到T2谱与试验T2谱逼近,误差最小时获得的Weibull分布即为岩石粒度分布。最后根据实际核磁测井资料对井下岩石粒度进行连续计算,粒度计算结果与实验室粒度分析结果对比良好,验证了方法准确性。     

基于砂岩数字岩心的地层参数模拟与粗化方法研究

基于micro-CT成像的数字岩心技术的发展,拓展了岩石物性参数的测量和分析方法。基于三维数字岩心的物性参数模拟,可较为准确的反应岩石的物性,针对砂岩三维数字岩心图像的地层参数模拟与粗化,对研究岩心的流体分布等具有十分重要的意义。首先,基于三维数字岩心图像,采用闵可夫斯基泛函和K-means聚类法对岩心进行精细分层;其次,采用驱替模拟法,模拟岩心在不同驱替状态下湿相和非湿相的分布,针对不同的湿相分布状态,对各个小层在不同方向上的地层参数进行模拟;最后,采用数学平均法、曲线回归法和去除薄层后的曲线回归法对岩心的地层参数进行粗化并对比分析各种粗化方式结果的差异。     

砂岩数字岩心的地层参数模拟与粗化方法研究

基于micro-CT成像的数字岩心技术的发展,拓展了岩石物性参数的测量和分析方法。基于三维数字岩心的物性参数模拟,可较为准确地反应岩石的物性,针对砂岩三维数字岩心图像的地层参数模拟与粗化,对研究岩心的流体分布等具有十分重要的意义。首先,基于三维数字岩心图像,采用闵可夫斯基泛函和K-means聚类法对岩心进行精细分层;其次,采用驱替模拟法,模拟岩心在不同驱替状态下湿相和非湿相的分布,针对不同的湿相分布状态,对各个小层在不同方向上的地层参数进行模拟;最后,采用数学平均法、曲线回归法和去除薄层后的曲线回归法对岩心的地层参数进行粗化并对比分析各种粗化方式结果的差异。     

加压时间对储层岩心渗透率的影响

目前储层应力敏感性研究仅限于有效覆压对渗透率的影响,忽略了加压时间对岩石变形的作用.在高压孔渗仪上用拟三轴岩心夹持器和天然岩心,考察了加压时间对岩石渗透率的影响,提出并计算了单位覆压下渗透率绝对变化速率和相对变化速率.结果表明,岩石变形或渗透率变化与时间有关,渗透率随加压时间的延长而降低.在加压初期渗透率变化幅度较大,随着时间的延长,渗透率变化逐渐变缓;幂函数在总体趋势上能拟合渗透率随时间的变化,其拟合误差在工程应用的合理范围内;基础渗透率大于4.6×10-3 μm2的岩心,渗透率下降主要发生在4 h内;渗透率绝对变化速率随时间的延长而降低;渗透率绝对变化速率和相对变化速率与岩石物性有关,岩心基础渗透率越高,渗透率绝对变化速率越大,相对变化速率越小.渗透率相对变化速率的建立,为储层应力敏感性评价提供了一个新的定量参数.     

基于Kozeny-Carman方程的水相相对渗透率计算方法

岩石孔隙中流体的相对渗透率是储层评价、油气田开发的关键参数之一,与流体性质、岩石的润湿性、孔隙结构等有关。一般通过稳态法与非稳态法实验获得。由于相渗实验的周期长、成本高,且条件较为苛刻,难以在现场中进行大量的应用。以Kozeny–Carman方程和阿尔奇公式为基础,将复杂的孔隙结构及流体分布进行简化,得到了毛管渗流中外油内水和外水内油状态下水相的相对渗透率模型。并通过G油田4块岩心的实验数据对模型进行了分析。研究表明:外油内水状态下的水相相对渗透率模型与孔隙中油水渗流规律相符,用该模型计算的水相相对渗透率与实测数据较为吻合。     

考虑渗透率张量的各向异性油藏流线模拟方法

针对各向异性油藏,考虑全张量形式渗透率,建立三维两相不可压缩流体流线模拟方法。采用十九点差分格式对压力方程差分离散并进行求解得到压力场,对全张量渗透率下运动方程求解得到速度场,采用Pollock方法确定并追踪流线,最后根据一维水驱油理论得到任一流线内的含油饱和度分布。不同渗透率张量油藏模型计算结果表明:油藏压力沿最大主渗透率方向传播较快;由于流速计算时交叉项的引入,流线与压力梯度方向一般不一致;注采井方向与最大主渗透率方向垂直布置可有效减轻注入水沿最大主渗透率方向的突进,使流线在整个油藏中分布更加均匀,改善水驱开发效果。     

数字岩心物性数值模拟

针对岩心物性实验周期长且实验结果难以复现等缺点,利用数字岩心对储层岩石物性进行数值模拟。使用计算机断层扫描(CT)技术,获得CT序列图;并由序列图构建三维岩心图像。利用最大内切球方法建立岩心图像的孔隙网络模型,计算岩心渗透性以及岩心中孔喉参数;利用分形维数描述岩心图像的均质性。将数字岩心物性模拟结果和毛管压力曲线数据进行对比,分析了当前物性数值模拟和真实物性实验之间的差距。利用多组岩心样本进行了实验。结果表明,由于成像设备的原因,岩心图像只能表征岩石中的大尺寸孔隙特征;此外,CT图像得到的均质性和物性实验具有很好的一致性,渗透性和物性实验具有一定的出入。     

利用泥质含量与孔隙度计算砂岩渗透率

砂岩储层的渗透率受多个因素的影响,单相关模型往往有其局限性,为保证渗透率模型具有优良的解释能力和预测效果,本文提出一种综合利用岩心粒度分析与物性分析资料,根据泥质含量与孔隙度计算渗透率的方法,并且通过实际井资料的试处理验证,说明其计算方法是可靠的。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.