Numerical Simulation on Production Trials by Using Depressurization for Typical Marine Hydrate Reservoirs:Well Type and Formation Dip

Natural gas hydrate has huge reserves and is widely distributed in marine environment.Its commercial development is of great significance for alleviating the contradiction between energy supply and demand.As an efficient research method,numerical simulation can provide valuable insights for the design and optimization of hydrate development.However,most of the current production models simplify the reservoir as a two-dimensional(2D)horizontal layered model,often ignoring the impact of formation dip angle.To improve the accuracy of production prediction and provide theoretical support for the optimization of production well design,two three-dimensional(3D)geological models with different dip angles based on the geological data from two typical sites are constructed.The vertical well,horizontal well and multilateral wells are deployed in these reservoirs with different permeabilities to perform production trial,and the sensitivity analysis of dip angles is also carried out.The short-term production behaviors in high and low permeability reservoirs with different dip angles are exhibited.The simulation results show that 1)the gas and water production behaviors for different well types in the two typical reservoirs show obviously different variation laws when the short-term depressurization is conducted in the inclined formation;2)the inclined formation will reduce the gas production and increase the water extraction,and the phenomena becomes pronounced as the dip angle increases,particularly in the low-permeability reservoirs;3)and the impact of formation dip on hydrate recovery does not change significantly with the variation of well type.

Characteristic analysis of bleeding effect on standing column well (SCW) type geothermal heat exchanger

Thermal performance is the most important factor in the development of a borehole heat exchanger utilizing geothermal energy.The thermal performance is affected by many different design parameters and different operating conditions such as bleeding.This eventually determines the operation and cost efficiency of the borehole heat exchanger system.The thermal performance of an open standing column well (SCW) type geothermal heat exchanger was assessed under the influence of bleeding.For this,a thermal response test rig was established with line-source theory.The test rig also had a bleeding function by releasing fluid while taking additional underground water through the heat exchanger.The thermal response test was performed with an additional constant input heat source.Effective thermal conductivity and thermal resistance were obtained from the measured data.From the measurement,the effective thermal conductivity is found to have 1.47 times higher value when bleeding is applied.The thermal resistance also increases by 1.58 times compared to a non-bleeding case.This trend indicates enhanced heat transfer in the SCW type heat exchanger with a bleeding function.Bleeding,therefore,could be an effective method of achieving a high heat transfer rate in the SCW type heat exchanger with sufficient underground water supply.

The First Hybrid Wells-Dawson-type Polytungstate Monosupported by Cd-coordination Complex via Di-bridging O-atom

Polyoxometalates（POMs） with Cd-coordination complexes acting as supporting units are rarely reported. The linkage of the supporting units with inorganic building block（polyanion） is generally established on terminal O-atoms, but scarcely via bridging O-atoms. By introducing liquid small organic molecule（pyridine, C5NH5） as assistant ＂structure-directing agent＂, we obtained a novel organic-inorganic hybrid polytungstate,（Hpy）4[Cd（phen）2（P2W18O62）]·nH2O（1, n ≈ 3, py = pyridine, phen = 1,10-phenanthroline）, under hydrothermal conditions. The single-crystal X-ray diffraction analysis shows that 1 is the first compound containing an asymmetric heteropolyanion, [Cd（phen）2（P2W18O62）]4–, a Wells-Dawson-type polyanion monosupported by Cd-coordination complex via di-bridging O-atoms.

Blasingame production decline type curves for analysing a multi-fractured horizontal well in tight gas reservoirs

Production decline analysis has been considered as an important method to obtain the flow parameters, reservoir properties and original gas in place. Although advanced Blasingame production decline analysis methods for vertical wells, fractured wells and horizontal wells are widely used, limited study has conducted on Blasingame production decline type curves for multi-fractured horizontal well(MFHW). Based on the perpendicular bisection(PEBI) grids, a numerical model was developed and the solution was obtained using control volume finite element method and the fully implicit method. Blasingame production decline-type curves of the infinitely conductive MFHW were plotted through computer programming. A field case was presented to analyse and verify the model developed. Five flow regimes, including early formation linear flow, early radial flow, compound linear flow, transient flow and pseudo-radial flow, are recognized. Fracture spacing is the main factor that affects early radial flow, compound linear flow and transient flow, the distance from the well to the circular boundary affects the pseudo-radial flow, and the type curves are also significantly affected by the formation permeability, fracture number and fracture half-length. The validation of field case suggests that the Blasingame production decline type curves proposed in this work can be applied to the production decline analysis for MFHW in tight gas reservoirs.

Electron tunneling effects on radiative recombination in modulation n-doped ZnSe/BeTe type-II quantum wells

We have studied the cyclotron-resonance absorption and photoluminescence properties of the modulation n-doped ZnSe/BeTe/ZnSe type-Ⅱ quantum wells. It is shown that only the doped sample shows electron cyclotron-resonance absorption. Also, the undoped sample shows two distinctive peaks in the spatially indirect photoluminescence spectra, and the doped one shows only one peak. The results reveal that the high concentration electrons accumulated in ZnSe quantum well layers from n-doped layers can tunnel through BeTe barrier from one well layer to the other. The electron concentration difference between these two well layers originating from the tunneling results in a new additional electric field, and can cancel out a built-in electric field as observed in the undoped structures.

Direct Analytical Method to Calculate Photopeak Efficiency and Photopeak Attenuation Coefficient of NaI(Tl) Well-Type Detector

In this paper full-energy peak (photopeak) efficiency and photopeak attenuation coefficient of 3'' × 3'' NaI(Tl) well-type scintillation detector were calculated using gamma-rayisotropic radiating point sources (with photon energy: 0.245, 0.344, 0.662, 0.779, 0.964, 1.1732, 1.333 and 1.408 MeV) placed outside the detector well. These energies were obtained from 152Eu, 137Cs and 60Co. The relations between the full energy peak efficiency and photopeak attenuation coefficients, were plotted vs. photon energy at different sources to detector distance, and it found that the full energy peak efficiency decreased by increasing the distance between the source and the detector.

Type Curves Relating Well Spacing and Heterogeneity to Oil Recovery in a Water Flooded Reservoir—A Case Study

The design of an optimum spacing between oil wells entails both reservoir characterization and economics considerations. High hydrocarbon recovery requires short distances between wells. However, higher well density leads to a greater development cost. Accordingly, determination of an optimum well spacing is primordial in the development of oil fields. As a matter of fact, the identification of optimum well spacing for heterogeneous sandstone reservoirs undergoing waterflooding requires extensive analytical and numerical studies. The intent of this work is therefore to develop type curves as a quick tool in estimating ultimate recovery and reduce excessive reservoir simulation cost in analog reservoirs. These type curves utilize reservoir heterogeneity and well spacing in the estimating of oil recovery. In this work, we investigated numerically the effects of heterogeneity and well spacing on ultimate recovery using Eclipse black oil simulation and PEEP economic software 2015 and 2009 versions, respectively. The study involved a 50-ft thick Middle Eastern reservoir with porosity variability ranging from 0.2 to 0.9. Corresponding average matrix permeabilities of 1, 10 and 100 md were considered. Type curves relating well spacing and heterogeneity to ultimate oil recovery were developed. Type curves and net present value calculations indicated that there is exists an ultimate well spacing for each of the considered matrix permeabilities.

Electronic band structure of a type-II 'W' quantum well calculated by an eight-band k·p model

In this paper, we present an investigation of type-II ＇W＇ quantum wells for the InAs/Ga1-xInxSb/A1Sb family, where ＇W＇ denotes the conduction profile of the material. We focus our attention on using the eight-band k. p model to calculate the band structures within the framework of finite element method. For the sake of clarity, the simulation in this paper is simplified and based on only one period--A1Sb/InAs/Ga1-xInxSb/InAs/A1Sb. The obtained numerical results include the energy levels and wavefunctions of carriers. We discuss the variations of the electronic properties by changing several important parameters, such as the thickness of either InAs or Cal_xInxSb layer and the alloy composition in Ga1-xInxSb separately. In the last part, in order to compare the eight-band k·p model, we recalculate the conduction bands of the ＇W＇ structure using the one-band k·p model and then discuss the difference between the two results, showing that conduction bands are strongly coupled with valence bands in the narrow band gap structure. The in-plane energy dispersions, which illustrate the suppression of the Auger recombination process, are also obtained.

Improvement of TE-polarized emission in type-Ⅱ InAlN–AlGaN/AlGaN quantum well

The optical properties of the type-Ⅱ lineup InxAl1-xN-Al0.59Ga0.41N/Al0.74Ga0.26N quantum well(QW) structures with different In contents are investigated by using the six-by-six K-P method.The type-Ⅱ lineup structures exhibit the larger product of Fermi-Dirac distribution functions of electron fc^n and hole(1-fv^Um) and the approximately equal transverse electric(TE) polarization optical matrix elements(|Mx|^2) for the c1-v1 transition.As a result, the peak intensity in the TE polarization spontaneous emission spectrum is improved by 47.45%-53.84% as compared to that of the conventional AlGaN QW structure.In addition, the type-Ⅱ QW structure with x^0.17 has the largest TE mode peak intensity in the investigated In-content range of 0.13-0.23.It can be attributed to the combined effect of |Mx|^2 and fc^n(1-fv^Um) for the c1-v1, c1-v2, and c1-v3 transitions.

40 K双波段长波探测器冷箱封装技术研究

冷光学技术是弱目标及多光谱红外探测的重要支撑技术。为了实现低温光学系统温度精确控制和防污染,一般多将低温光学与探测器集成在冷箱内。某高光谱相机需要1个320×64量子阱探测器和1个320×64 II类超晶格探测器共面拼接,集成双波段微型滤光片,形成长波双波段探测杜瓦组件,探测器工作所需的40 K低温环境由脉管制冷机提供。杜瓦采用无窗口设计,并通过柔性波纹管将杜瓦外壳与冷箱外壳集成,以实现气密性集成和光校调节。针对40 K温区双波段探测器封装的三维拼接、探测器及滤光片的低应力封装、制冷机与探测器的高效热传输等难点,对探测器的三维拼接、40 K温区高效热传输、探测器低应力集成的热层结构、低应力滤光片支撑、杜瓦与制冷机耦合等进行研究,创新性提出了三点Z向调节拼接方法、探测器Al2O3载体复合钼基板和钼冷平台的热层结构、双波段滤光片集成的钼支撑结构、带应力隔离的冷平台与制冷机过盈装配的耦合方法,最终实现了40 K温区下双波段探测器平面度优于±2.06μm(RMS)、探测器的低温应力小于22.06 MPa、双波段滤光片低温形变小于8.55μm、探测器与制冷机温度梯度为2.6 K。40 K长波双波段红外探测器冷箱杜瓦组件经过2000 h通电老练和300次开关机试验验证,试验前后组件性能未发生明显变化,满足工程化应用的要求。

考虑漏层性质的漏失压力剖面确定方法

目前矿场上常用破裂压力当量密度剖面作为钻井液安全密度窗口上限。由于大多数井漏是在地层未破裂的情况下发生的,该做法容易误导现场钻井液密度的使用。漏失压力剖面是合理设计和使用钻井液密度的关键参考数据。归纳了不同性质漏层的漏失压力计算方法;总结出一套漏失压力剖面确定方法,应用该方法能有效识别井漏类型,进而选用相应的漏失压力模型,得出准确的漏失压力剖面。

“三类六区”单井效益评价方法在油田配产中的应用

油气田上游企业单独配置产量与成本造成资源配置长期不均衡的现象,传统按油井能力配产已无法满足油田高质量、可持续发展的需求,投资、成本、产量等资源如何合理配置是油田生产经营中需要解决的难题。为此,以油井为单元建立“三类六区”效益评价方法,引入最低变动成本识别无效益产量,在此基础上通过最低变动成本及单井效益贡献值的统一优化排序,利用盈亏平衡、成本最低及利润最大三种模型测算经济产量规模,以指导高成本及无效益产量进行效益优化,提出分类治理措施。此研究应用于制定XJ油田效益配产方案,基于油田能力配产方案及成本预算方案,以油田盈亏平衡产量、成本最低产量及利润最大产量为参考,调整产量规模、优化配置成本,得到量效兼顾产量方案,为油田生产经营决策提供依据。

煤层气L型水平井电潜螺杆泵井清防砂工艺技术创新及应用

套管完井压裂投产的煤层气L型水平井出砂严重,倒置式电潜螺杆泵举升工艺受压裂砂影响故障频繁,影响了连续稳定排采,因此确定了倒置式电潜螺杆泵排采过程中由于压裂砂导致的故障点,并针对性创新应用了井筒内、导流罩及泵内清砂工艺技术,同时优化防砂管柱设计,确保了连续稳定排采。

水工筒井式超深地下连续墙施工关键技术研究

为提高软土、中风化泥质粉砂岩和高地下水位地层的水工筒井式超深地下连续墙施工技术水平,通过对超深地下连续墙的重点如成槽、钢筋笼吊放及对接、混凝土绕流等3个关键环节进行技术把控,找到各环节的技术难点,根据施工中遇到的实际问题,分析原因并提出对应防控改进措施。通过实践证明这些措施操作简便、行之有效,可为类似超深地下连续墙项目提供指导和借鉴。

探采结合技术在新疆砂岩型铀矿中的应用

以新疆蒙其古尔P0线以西的矿床为研究对象,针对其矿体变化系数大、埋藏深、赋存条件复杂、规模化开发困难等问题,采用勘探钻孔与生产钻孔相结合的“探采结合”一体化模式,使勘探钻孔的利用率达到了61%,节约了钻孔投入成本,提高了资源质量,缩短了矿床建设周期,减少了植被破坏,做到了矿山绿色可持续发展。该技术经济效益及环境效益显著,为复杂砂岩地浸铀矿开发提供了新思路、新方法。

对FETKOVICH(费特科维奇)典型曲线的质疑与评论

FETKOVICH(费特科维奇,以下简称为费氏)于1971年和1980年,分别提出的有限水域水侵量方程和定压典型曲线,受到国内外专家的重视和引用。由于费氏典型曲线可以通过实际数据的拟合,确定井的驱动半径和驱动面积,因此,受到业内专家的青睐。通过推导表明,费氏有限水域水侵量方程,是一个指数递减方程。费氏将该方程直接应用于定容封闭边界油井的产量递减分析,并基于初始递减率的关系式,得到了费氏典型曲线的无因次时间。费氏利用无因次压力的倒数作为无因次产量,得到了典型曲线的无因次产量。然而,由于费氏典型曲线的无因次时间和无因次产量之间没有直接的函数关系,无法建立费氏的无因次典型曲线,因此,对费氏的有限水域水侵量方程和典型曲线的无因次时间和无因次产量进行了推导,并对存在的问题提出了质疑和评论。

孕妇生育动机与主观幸福感及母胎依恋的关系研究

目的分析孕妇生育动机的潜在类别,探讨生育动机与母胎依恋的关系及主观幸福感的中介作用,为提高母胎依恋水平提供参考。方法运用母胎依恋关系量表、总体幸福感量表和生育动机量表对413名妊娠中晚期孕妇进行调查。采用潜在类别分析探讨孕妇的生育动机,多分类自变量中介效应分析检验不同类别生育动机对母胎依恋的直接效应和主观幸福感的中介效应。结果孕妇的生育动机可以分为自主型(23.7%)、控制型(23.7%)、混合型(26.4%)和消极型(26.2%)4个潜在类别。中介效应分析发现,与自主型生育动机相比,控制型和消极型生育动机对母胎依恋的相对直接效应显著(β=-0.519、-0.612,均P<0.05),主观幸福感的相对间接效应显著(β=-0.262、-0.221,均P<0.05),主观幸福感起部分中介作用;而混合型生育动机对母胎依恋的相对直接效应不显著(β=0.176,P=0.117),主观幸福感的相对间接效应显著(β=-0.118,P<0.05),主观幸福感起完全中介作用。结论孕妇生育动机具有明显的分类特征,其对母胎依恋的预测价值及主观幸福感的中介作用也与分类有关,应针对不同人群进行精准干预。

社区老年脑卒中病人精神幸福感现状及影响因素

目的:调查社区老年脑卒中病人精神幸福感现状并分析其影响因素。方法:便利选取山西省汾阳市3个社区的257例老年脑卒中病人为研究对象,采用一般资料调查表、精神幸福感指数量表(SIWB)、D型人格量表(DS14)、接纳与行动问卷第2版(AAQ⁃Ⅱ)对病人进行调查。结果:社区老年脑卒中病人精神幸福感总分为31.00(23.00,42.00)分。回归分析结果显示,D型人格量表总分、接纳与行动问卷总分、居住方式和慢性病数量是社区老年脑卒中病人精神幸福感的影响因素(P<0.05)。结论:社区老年脑卒中病人精神幸福感处于中等偏下水平,社区卫生保健人员应重点关注存在D型人格、心理灵活性差、独居、合并慢性病数量多的病人,针对性采取措施以提高病人的精神幸福感。

塔里木盆地西南部晚白垩世——早古新世沉积环境演化:来自皮山PBX1井的地化证据

【研究目的】白垩纪与古近纪之交发生过地质历史上重大的灾变和异常事件,致使K/Pg界线成为全球最重要的地质界线之一。通过对塔里木盆地晚白垩世—早古新世沉积环境的研究,有助于重建特提斯北部盆地群塔里木盆地的古环境。【研究方法】本文通过塔里木盆地西南部PBX1井岩心的地球化学元素敏感指标研究K/Pg上下环境的变化。【研究结果】晚白垩世晚期古气候属于干热型,早古新世呈现短暂温湿型。古盐度由晚白垩世正常海洋环境向早古新世半咸水、海陆过渡盐湖环境转换,K/Pg界线位置处,古盐度达到最低值。氧化-还原环境由晚白垩世富氧→贫氧的弱氧化-弱还原环境经历了K/Pg事件之后短暂向早古新世富氧环境转化,而后整体上由贫氧的弱氧化-弱还原环境向极贫氧的还原环境演化。【结论】PBX1井地球化学元素敏感指标揭示了中生代—新生代之交灾变异常事件在塔里木盆地响应特征,也是特提斯洋北部盆地群晚白垩世—早古新世沉积环境演化的有效证据。

沉井式机械立体停车库火灾风险及防治策略研究

在充分调研的基础上,结合电动汽车火灾案例和他人研究成果,对某在用沉井式机械立体停车库的消防设计进行详细分析,发现存在防火单元无法分、消防联动易失准、灭火效能不确定、事故处置难度大的主要风险。通过理论研究和对比数据分析,提出预警探测、防火分隔、分级响应、结构抗火、消防救援方面的策略。本研究为下一步开展相关实体试验、消防设计、规范修订提供了基本思路。