大牛地气田盒1段气藏水平井分段压裂工艺研究与实践

针对大牛地气田盒1段气藏低压、低渗、储层品质差、气井控制半径小、单井无法经济有效建产、储量动用率低等问题,采用中长水平段+三维地震预测+分段压裂设计优化及管外封隔分段压裂工艺技术实现了盒1储层的有效建产,通过现场应用效果对比表明,水平井施工成功率达到99.2%,措施有效率93.3%,压后产能达到直井产能的5.2倍,实现了难动用储量的高效开发,为大牛地气田盒1段气藏的有效动用提供了技术保障。

川东北清溪场构造飞三段气藏录井特征及解释评价

川东北碳酸盐岩天然气储层所赋存的层位众多,其中上组合海相地层中三叠系飞仙关组储层由于埋深适中,是重要的勘探目标。江汉录井在川东北清溪场构造XQX1井飞仙关组飞三段发现高产、高压、裂缝型气层,测试产量达106.8×104m3/d,控制储量超过30×108m3,是在川东北及鄂西渝东地区继河坝2井后又一口单层测试产量超百万方,且不含硫化氢的碳酸盐岩气井。

安岳气田高石梯区块上震旦统灯四段气藏动态监测及认识

四川盆地安岳气田高石梯区块上震旦统灯影组灯四段气藏受地层剥蚀尖灭、岩性及构造等控制,为构造背景下的高温常压大型岩性—地层复合圈闭气藏。为了深化认识复杂气藏特征及气藏开发动态规律,实现气藏高效合理开发,以高石梯区块灯四段气藏为研究对象,从气藏试井、生产测井和流体分析等多方位开展动态监测。分析了气藏动态监测典型事例,并结合气藏地质认识及开发动态指出了气藏流体性质及分布特征、气藏储渗模式及开发方式。研究结果表明:①灯四段气藏为中含硫化氢、中含二氧化碳气藏,气藏划分为高石3储渗区、高石2储渗区和高石9储渗区3个储渗单元;②气藏未见明显的边水底水,高石1井产出液体来自于灯二段,部分气井存在井底污染;③气藏存在孔隙型、孔洞型、裂缝孔洞型3种不同的储渗模式;④利用动态监测调整配产工作制度合理。结论认为,对于大型岩性—地层复合圈闭气藏,全方位及多角度、多阶段及多类型地进行动态监测是正确认识复杂类型气藏开发特征及开发规律的有效手段,所形成的分析方法可以为类似气藏开发提供借鉴和参考。

大牛地气田中二叠统盒1段气藏产液特征及控制因素

为了明确鄂尔多斯盆地大牛地气田北部中二叠统下石盒子组盒1段气藏的产液特征及控制因素,以该气藏地层水赋存状态、生产动态特征及分布规律为研究对象,分析了产液井储层地质特征、生烃强度、泥岩隔夹层发育状况、局部砂体构造等对气水分布的影响,指出了含水气藏的控制因素。研究结果表明:①大牛地气田盒1段气藏属于浅水低能辫状河沉积体系,储层物性差,气体以气水混生为主;②气藏产液类型主要为孔隙中的自由水和毛细管水,基于生产特征将气田北部划分为低产液、中产液、高产液3个区域;③生烃强度控制了产液井的分布范围,生烃强度大的区域有着充足的气源补给,易于天然气富集;④储层内部泥岩隔夹层及泥质含量发育情况决定了天然气的富集程度,对于储层泥岩隔夹层薄、泥质含量低、储层物性好、孔隙度大、渗透率高的连通心滩厚砂体,储层多以气层为主,表现为低产液区;⑤整个大区域构造对气水的分布控制作用不显著,但在同一期连通的砂体内部表现为上气下水的特征,局部构造高点仍是天然气的相对富集区。结论认为,通过气水分布特征及控制因素的探析,可以对气田开发调整与气井管理提供指导。

大牛地气田盒3段气藏开发调整对策分析

大牛地气田盒3段气藏采用直井开发,具有初期产量高、稳产期长、累计产量高,生产效果好的特点,采收率已达40%。为了进一步提高气藏采收率,针对盒3段气藏开展了生产效果分析及井网评价研究。结果表明,盒3段气藏井网部署总体较为合理,局部存在可加密调整空间。其中,复合型心滩发育区连通性好,累计产量高,加密空间小;中等型心滩与孤立型心滩发育区井网具有一定的调整空间,是下步开发挖潜的重要方向。

炉气、下段气管线中氨的回收

纯碱生产过程中炉气、下段气含有一定量的氨。为减少这部分氨外排,一是将下段气直接换热,改变成间接换热,冷凝该部分氨;二是对炉气和下段气冷凝水工艺流程进行改造。通过两次改造,对该部分氨进行回收利用,又通过工艺查定,修改了部分操作参数及方法。

大牛地气田大17井区太1段气藏产能主控因素及开发调整对策

为了明确鄂尔多斯盆地大牛地气田大17井区石炭—二叠系太原组1段气藏产能主控因素,以11口水平井为研究对象,分析了该区太1段气藏生产动态特征,明确了沉积、构造对气井生产的影响情况,并有针对性地制定了开发调整对策。研究结果表明:(1)太1段气藏11口水平井中Ⅰ类井共8口,初期产能高,稳产期长,液气比低,生产效果较好;Ⅱ类井共3口,初期产能较低,稳产期短,液气比相对较高,生产效果较差。(2)Ⅰ、Ⅱ类井储层厚度无明显区别,但储层物性存在差异,Ⅰ类井自然伽马曲线以低幅平滑箱形为主,电阻率较高,孔隙度、渗透率均较高,物性较好;Ⅱ类井自然伽马曲线齿化严重,电阻率较低,物性较差,含水量较高。(3)沉积模式不同导致Ⅰ、Ⅱ类井储层物性存在明显的差异,Ⅰ类井处于迎水面,储层物性好,产量高,液气比低,累计产量高;Ⅱ类井处于背水面,物性差,内部泥岩夹层发育、电阻率低,束缚水含量高导致液气比高,影响气井产能释放。结论认为:(1)太1段气藏气井产能主要受沉积控制,障壁砂坝迎水面储层物性好,气井产能高,为老区开发调整的有利区;(2)通过在砂坝迎水面部署加密井,优化老井生产制度,可以有效提高气藏采收率。

Monitoring of Summer High Temperature Damage by Using MODIS Data to Estimate Air Temperature

[Objective] This study was to monitor the hot damage of high temperature on rice in summer by using MODIS data to estimate air temperature. [Method] A new statistical algorithm was introduced for daytime air temperature （Ta） retrievals over east China by using the Moderate Resolution Imaging Spectroradiometer （MODIS） data, and the high temperature monitoring for rice in south China in 2007 summer was used to demonstrate. [Result] High temperature plays a key role in rice production during rice heading stage in summer in southern China. Using MODIS data to monitor the hot damage of high temperature is a feasible way to relieve agricultural disasters. [Conclusion] The result of this study provided a method to monitor hot damage of high temperature tn rice in summer of China.

Pyrolysis-Gas Chromatography/Mass Spectrometry for Microstructure and Pyrolysis Pathway of Polyester-Polyether Multiblock Copolymer

The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.

A contrast study on different gasifying agents of underground coal gasification at Huating Coal Mine

To optimize the technological parameter of underground coal gasification （UCG）, the experimental results of air gasification, air-steam gasification, oxygen-enrichment steam gasification, pure oxygen steam gasification and two-stage gasification were studied contrastively based on field trial at the Huating UCG project. The results indicate that the average low heat value of gas from air experiment is the lowest （4.1 MJ/Nm3） and the water gas from two-stage gasification experiment is the highest （10.72 MJ/Nm3）. The gas productivity of air gasification is the highest and the pure oxygen steam gasification is the lowest. The gasification efficiency of air gasification, air-steam gasification, oxygen-enriched steam gasification, pure oxygen steam gasification and two-stage gasification is listed in ascending order, ranging from 69.88% to 84.81%. Described a contract study on results of a field test using steam and various levels of oxygen enrichment of 21%, 32%, 42% and 100%. The results show that, with the increasing of O2 content in gasifying agents, the gas caloricity rises, and the optimal O2 concentration range to increase the gas caloricity is 30%-40%. Meanwhile, the consumption of O2 and steam increase, and the air consumption and steam decomposition efficiency fall.

Development of Liquid Slug Length in Gas-Liquid Slug Flow along Horizontal Pipeline: Experiment and Simulation

The liquid slug length distribution is crucial for designing the downstream processing system with mul-tiphase pipeline. Experiments were conducted in a 133m long horizontal test loop. The measurements were per-formed by conductivity probes to determine the liquid slug length distribution. The data covered both the slug and plug flow regimes. From experimental results, the mean liquid slug lengths were relatively insensitive to gas and liquid flow rates in the higher mixture velocity range. But in the lower mixture velocity range, the mean liquid slug length decreased and then increased with mixture velocity. It shows that the development length of slug flow was longer than x/D=1157. A slug tracking model was adapted to study the evolution of liquid slug length distribution in a horizontal pipeline. In the present model, the wake effect of elongated bubble and the pressure drop due to accel-eration are taken into account and random slug lengths are introduced at the entrance. The results of the model are compared with the measured slug length distributions of slug flow regime. It shows that the predicted mean and maximum slug lengths are in agreement with the experimental data at x/D=1157 and the form of the slug length distributions is also predicted well by the model.

Three-dimensional nonlinear flutter analysis of long-span suspension bridges during erection

In this work, the aerodynamic stability of the Yichang Suspension Bridge over Yangtze River during erection was determined by three dimensional nonlinear flutter analysis, in which the nonlinearities of structural dynamic characteristics and aeroelastic forces caused by large deformation are fully considered. An interesting result obtained was that the bridge was more stable when the stiffening girders were erected in a non symmetrical manner as opposed to the traditional symmetrical erection schedule. It was also found that the severe decrease in the aerodynamic stability was due to the nonlinear effects. Therefore, the nonlinear factors should be considered accurately in aerodynamic stability analysis of long span suspension bridges during erection.

Experimental Investigation of Slug Development on Horizontal Two-phase Flow

Slug initiation and subsequem evolution along a 5.0 cm ID, 16m long horizomal pipe are experimentally studied. The transient characteristics of interfacial structures are described by using simultaneous measuremeres of the liquid height at multiple locations along the pipe. Various effects of superficial gas and liquid velocities and pressure oscillation on the slug initiation and evolution along the pipe are illustrated. It is found that the slug is initiated by a deterministic orocess with reolenishmem and deoletion of liquid near the inlet for the superficial gas velocity USG〈3.0m·s^-1 and by a stochastic process with wave coalescence along the pipe for USG〉3.0m·s^-1.The evolution of the slugs is strongly attected by superhclal gas and liquid veloclties for USG〈3.0m·s^-1 but weakly affected by the superficial gas velocity for USG〉3.0 m·s . The suppression of pressure oscillation at the pipe inlet significantly delays the onset of slugging, with slugs forming postponed further downstream. The slug frequency at the outlet is, however, not affected by the variation in the pressure oscillation.

Simulation of the western North Pacific subtropical high in El Ni?o decaying summers by CMIP5 AGCMs

The performances of CMIP5 atmospheric general circulation models （AGCMs） in simulating the western North Pacific subtropical high （WNPSH） in El Nino decaying summers are examined in this study. Results show that most models can reproduce the spatial pattern of both climatological and anomalous circulation associated with the WNPSH in El Nino decaying summers. Most CMIP5 AGCMs can capture the westward shift of the WNPSH in El Nino decaying summers compared with the climatological location. With respect to the sub-seasonal variation of the WNPSH, the performances of these AGCMs in reproducing the northward jump of the WNPSH are better than simulating the eastward retreat of the WNPSH from July to August. Twenty-one out of twenty-two （20 out of 22） models can reasonably reproduce the northward jump of the WNPSH in El Nino decaying summers （climatology）, while only 7 out of 22 （8 out of 22） AGCMs can reasonably reproduce the eastward retreat of the WNPSH in El Nino decaying summers （climatology）. In addition, there is a close connection between the climatological WNPSH location bias and that in El Nino decaying summers.

Simulations of Aerosol Optical Properties to Top of Atmospheric Reflected Sunlight in the Near Infrared CO_2 Weak Absorption Band

Over the Asian continent,high aerosol loading is critical to ensure the high accuracy of CO_2 retrieval in the near infrared absorption band.Simulations were performed to explore the effect of light path modification by aerosol son the atmospheric CO_2 near infrared band(6140-6270 cm^(-1)).The Vector LInearized Discrete Ordinate Radiative Transfer(VLIDORT) model and the Line-By-Line Radiative Transfer Model(LBLRTM) were used for forward calculations.The U.S.standard atmosphere was used for atmospheric profiles.The results indicate that the aerosols caused similar effects to increases in CO_2 in the planetary boundary layer and became more significant with aerosol layer rising while aerosol optical depth was 0.1.This effect will cause an over estimation of the CO_2 mixing ratio in the retrieval process and an under estimation in the aerosol layer.The results also indicate that the effect of urban and industrial aerosols is smaller than that of non-absorbing and dust aerosols because of the nearly constant absorption properties in the near infrared band.

Superposability of unsteady aerodynamic loads on bridge deck sections

The 2-dimensional unsteady aerodynamic forces,in the context of both a thin airfoil where theory of potential flow is always applicable and a bluff bridge-deck section where separated flow is typically induced,are investigated from a point of view of whether or not they conform to the principle of linear superposition in situations of various structural motions and wind gusts.It is shown that some basic preconditions that lead to the linear superposability of the unsteady aerodynamic forces in cases of thin airfoil sections are no longer valid for a bluff section.Theoretical models of bridge aerodynamics such as the one related to flutter-buffeting analysis and those concerning aerodynamic admittance(AA)functions,however,necessitate implicitly this superposability.The contradiction revealed in this work may throw light on the perplexing problem of AA functions pertaining to the description of buffeting loads of bridge decks.Some existing theoretical AA models derived from flutter derivatives according to interrelations valid only for thin airfoil theories,which have been employed rather extensively in bridge aerodynamics,are demonstrated to be illogical.Finally,with full understanding of the preconditions of the applicability of linear superposability of the unsteady aerodynamic forces,suggestions in regard to experiment-based AA functions are presented.

Requirement for cyclin D3 in germinal center formation and function

Germinal centers （GC） of secondary lymphoid tissues are critical to mounting a high-affinity humoral immune response. B cells within the GC undergo rapid clonal expansion and selection while diversifying their antibody genes. Although it is generally believed that GC B cells employ a unique proliferative program to accommodate these processes, little is known about how the GC-associated cell cycle is orchestrated. The D-type cyclins constitute an important component of the cell cycle engine that enables the cells to respond to physiological changes. Cell type- and developmental stage-specific roles of D-type cyclins have been described but the cyclin D requirement during GC reaction has not been addressed. In this study, we report that cyclin D3 is largely dispensable for proliferation and Ig class switching of in vitro activated B cells. In contrast, GC development in Ccnd3^-/- mice is markedly impaired, as is the T cell-dependent antibody response. Within the GC, although both switched and unswitched B cells are affected by cyclin D3 inactivation, the IgM^- pool is more severely reduced. Interestingly, despite a compensatory increase in cyclln D2 expression, a significant number of Ccnd3^-/- GC B cells accumulate in quiescent GO state. Lastly, although cyclin D3 inactivation did not disrupt BCL6 expression in GC B cells, it completely blocked the GC promoting effect of BCL6 overexpression, suggesting that cyclin D3 acts downstream of BCL6 to regulate GC formation. This is the first demonstration that cyclin D3 plays an important and unique role at the GC stage of B cell development.

The gas reservoir response in PP- and PS-wave frequency sections

Spectral decomposition using the method of Matching Pursuit Decomposition （MPD） for PP- and PS-wave data has higher resolution and higher consistency over the entire time-frequency plane. The MPD algorithm avoids the problems of inaccurate analytic time point and the time window size choice that may occur during a Fourier transform. The PP-wave attenuation is greater than the PS-wave attenuation while propagating through gas reservoirs. There are some stronger amplitude low-frequency shadows on the PP-wave single frequency sections beneath gas reservoirs which are not seen on corresponding PS- wave single frequency sections. Therefore, hydrocarbons are predicted from comparing the behavior on both frequency sections. The time-frequency analysis for multi-component data is decomposed by MPD for data from northeast China containing rich gas reservoirs. The gas response character is analyzed on different wave mode single frequency sections. We describe the MPD algorithm, compare it to other spectral decomposition methods, and show some examples of detecting low-frequency shadows beneath gas reservoirs.

Dot Size Thermal Objects Detection in Atmosphere of Infrared Range

The article deals with the experimental studies of atmosphere indistinct radiation structure. The information extraction background of dot size thermal object presence in atmosphere is reasonable. Indistinct generalization of experimental study regularities technique of space-time irregularity radiation structure in infrared wave range is offered. The approach to dot size thermal object detection in atmosphere is proved with a help of threshold method in the thermodynamic and turbulent process conditions, based on the indistinct statement return task solution.

Pressure transient analysis of a finite-conductivity multiple fractured horizontal well in linear composite gas reservoirs

Faulted gas reservoirs are very common in reality,where some linear leaky faults divide the gas reservoir into several reservoir regions with distinct physical properties.This kind of gas reservoirs is also known as linear composite(LC)gas reservoirs.Although some analytical/semi-analytical models have been proposed to investigate pressure behaviors of producing wells in LC reservoirs based on the linear composite ideas,almost all of them focus on vertical wells and studies on multiple fractured horizontal wells are rare.After the pressure wave arrives at the leaky fault,pressure behaviors of multiple fractured horizontal wells will be affected by the leaky faults.Understanding the effect of leaky faults on pressure behaviors of multiple fractured horizontal wells is critical to the development design.Therefore,a semi-analytical model of finite-conductivity multiple fractured horizontal(FCMFH)wells in LC gas reservoirs is established based on Laplace-space superposition principle and fracture discrete method.The proposed model is validated against commercial numerical simulator.Type curves are obtained to study pressure characteristics and identify flow regimes.The effects of some parameters on type curves are discussed.The proposed model will have a profound effect on developing analytical/semi-analytical models for other complex well types in LC gas reservoirs.