测绘仪器测量不确定度中的灵敏系数

灵敏系数的计算是不确定度计算的关键.在测绘仪器的计量检定中,常对多个目标进行多测回的测量来采集的数据(输入量),通过公式间接求出测量结果(输出量).因而在测量不确定度的评定中.数学模型繁杂,致使求取(输入量到输出量的)灵敏系数困难,方法也各不相同.采用强行偏导法;传递继承法;方差比例法计算出几个典型的测绘仪器(经纬仪,经纬仪检定装置和全站型电子速测仪)的灵敏系数.解决了测绘仪器测量不确定度评定中的技术难题.     

Thermohydrodynamic investigations of horizontal oil wells

A method is developed for interpretation of the temperature variation curves obtained simultaneously by means of several deep-laid measuring devices located at different sites of a horizontal part of an oil well. The method enables one to estimate the filtration parameters of a nonuniform oil reservoir and to plot the inflow profile along the horizontal wellbore.     

弹载光纤陀螺旋转惯组误差自补偿技术

目前弹载惯性测量组合测试标定精度受外界干扰影响较大,特别是光纤陀螺温度稳定性低,易受环境温度影响参数变化,导致误差补偿效果不好。针对该问题,提出设计一种光纤陀螺旋转惯性测量组合。在惯性测量组合外加旋转轴,在导弹飞行过程中使惯性测量组合绕旋转轴连续旋转,将射前补偿不完全误差调制为周期项,从而达到误差自补偿的效果。理论分析和仿真结果表明,通过旋转不仅能自动补偿与转轴垂直方向惯性仪表的常值误差和部分安装误差,而且能补偿加速度计部分一次项误差、二次项误差和部分交叉轴耦合项误差,选择合适的旋转方案还可以完全消除旋转速度与陀螺仪标度因数误差、安转误差的耦合误差。     

Boundary-layer behaviour in a hydraulic theory of horizontal oil wells

In many cases, modern oil production occurs by means of long, more or less horizontally drilled cavities in an oil reservoir, so-called horizontal wells. Oil production by means of these horizontal wells is usually advantageous because the contact area between the well and the reservoir can be increased significantly, in particular for oil reservoirs with large aspects ratios. However, it turns out that the production profile along the length of a horizontal well may have boundary-layer-like characteristics with the consequence that a large fraction of the production comes from a small section of the well. In this paper the boundary-layer characteristics of the production profile are analysed. It is shown that different boundary layers with different characteristics can occur simultaneously. In particular it is shown that there may be a thin `annulus-induced' boundary layer and a thick `reservoir-induced' boundary-layer.     

Productivity model of horizontal wells in a sour gas reservoir

ABSTRACT

The utilization of a horizontal well has a great significance in the development of sour gas reservoir. The accurate prediction of the productivity of horizontal well will become more and more important in developing sour gas reservoir. In this paper, the effect of sulfur deposition on permeability is considered and a productivity prediction formula of the horizontal well is established. The effects of the length of horizontal well, the effective thickness of the reservoir, elemental sulfur deposition, and reservoir heterogeneity on productivity are analyzed and calculated. The theoretical results show that elemental sulfur disposition and the heterogeneity are the most important factors. According to the field case, the calculating results of improved Joshi’s equation approaches the real productivity, which means that it could be used to predict the productivity of horizontal well at initial stage during sour gas reservoir development. The results can be used as a reference for the development of similar sour gas reservoir.     

Operating charts for continuous sedimentation IV: limitations for control of dynamic behaviour

The nonlinear behaviour of a one-dimensional idealized model of continuous sedimentation has been investigated in this series of papers. The model is a scalar hyperbolic conservation law with a space-discontinuous flux function and a point source. Parameters in the equation are the two input variables (concentration and flux) and the control variable (a volume flow). The most desired type of solution contains a large concentration discontinuity and is referred to as ‘optimal operation’. Operating charts (concentration-flux diagrams) have proved to be a means for classifying the nonlinear behaviour. In this paper, some fundamental results on the dynamic behaviour are presented, which give information on the limitations of the range of the control variable. When this is used together with the previously introduced optimal control strategies for step inputs, the process can be controlled.     

聚能切割技术在水平井连续油管切割中的应用

将环形聚能切割技术应用于水平井连续油管遇卡事故处理中,可以解决连续油管在水平井中的遇卡事故。针对2英寸连续油管的特点,设计了一种聚能切割弹及连接装置马笼头,主要从切割弹结构设计、药型罩结构设计、装药选择、马笼头结构设计及施工工艺等方面进行了研究。通过地面切割试验、现场应用,设计的聚能切割装置,及电缆传输工艺实现了水平井中遇卡连续油管的切割解卡,操作简便、施工安全。     

聚能切割技术在水平井连续油管切割中的应用

将环形聚能切割技术应用于水平井连续油管遇卡事故处理中,可以解决连续油管在水平井中的遇卡事故。针对2英寸连续油管的特点,设计了一种聚能切割弹及连接装置马笼头,主要从切割弹结构设计、药型罩结构设计、装药选择、马笼头结构设计及施工工艺等方面进行了研究。通过地面切割试验、现场应用,设计的聚能切割装置,及电缆传输工艺实现了水平井中遇卡连续油管的切割解卡,操作简便、施工安全。     

Mathematical modeling of high-frequency electromagnetic heating of the bottom-hole area of horizontal oil wells

The results of theoretical investigations of the possibility of using intense high-frequency electromagnetic radiation in fields of high-viscosity oils with the aim of intensifying their production have been given. Expressions of the distribution of the electromagnetic field strength and the field of heat sources occurring in an oil bed under the action of high-frequency electromagnetic radiation transferred to the bed through a horizontal well have been obtained. A two-dimensional mathematical model of the process of production of oil through horizontal wells with simultaneous high-frequency electromagnetic action has been developed. The efficiency and profitableness of the method from the viewpoint of the energy balance have been evaluated.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 77, No. 6, pp. 105–111, November–December, 2004.     

Accuracy limitations on Brillouin lidar measurements of temperature and sound speed in the ocean

There are five mutually dependent variables relevant to Brillouin lidar measurements of temperature and sound speed in the ocean; they are (1) the Brillouin shift, (2) the sound speed, (3) the index of refraction, (4) the temperature, and (5) the salinity. We use three well-known relations to analyze rigorously the interdependence of these five variables. Clearly, a Brillouin shift measurement does not provide a stand-alone determination of temperature or sound speed; one more variable or one more relation must be known. The use of mean values of salinity that have been obtained by an analysis of a large set of historical in situ data is considered for this additional relation.     

Effect of nanoparticle behaviour on mud cake buildup for directional and horizontal wells: mathematical modelling and experimental study

The present study examined the effect of nanoparticle size and geometry on filter cake buildup during dynamic filtration using experimental and modeling approaches. A dynamic filtration setup was proposed and designed to test cross-flow circulation against a synthetic core at a constant differential pressure. The proposed mathematical model considers the critical deposition boundary of the porous media for particles along with drag, lift, friction, buoyancy, permeate, and electrostatic forces. The comprehensive model response allowed investigation of the aggregation and shape of nanoparticles at different cross-flow inclinations. The drag and lift force coefficients and moment of inertia of the nanoparticles were determined using cluster structures of nanoparticles identified using dynamic light scattering (DLS) and fractal theory. The deposition and erosion intensity index of all solid particles were experimentally determined and used in the model. Electronic microscope images of the mud cake surface confirmed the proposed cluster structure of the aggregated particles. The mud cake thickness measured by dynamic filtration tests and the nanoparticle-bentonite weight ratio acquired by DLS showed good agreement with the mathematical model results. The proposed approach allows selection of the optimum shape and size of the nano-solid particles as additives to minimize mud cake buildup along the borehole.     

靖边气田陕100井区马五1+2储层水平井开发优化

根据研究区实际的储层特点,对水平井开发的可行性进行了分析。结果表明,陕100井区马五1+2储层地质条件适合水平井开发。在对研究区三维精细地质建模的基础上,采用数值模拟对水平井的井网方式、水平段长度、井排距、开发指标等进行了预测。结果表明,最优的井网形式是水平段平行对称布置,采用同时穿越马五12和马五13的阶梯状水平段的水平井,井距和排距均为2 100 m。预测第10年年末,阶梯状水平井的采出程度为48.78 %,比直井的采出程度高16.6 %,研究结果可以指导研究区水平井的高效开发。