Simulation studies on optimizing oil productivity in oil rim reservoirs under gas cap blow down production strategy

Gas cap blow down strategy is normally deployed for Ultra-thin oil rim reservoirs with huge gas caps due to extremely high gas oil ratios from wells in such reservoirs.The current state leads to loss of production from the oil reserves due to high initial reservoir pressure thus,reducing its net present value.Data on important factors essential to the productivity of oil rim reservoirs are used to build a heterogeneous ultra-thin reservoir with a time step of 10,000 days using the Eclipse software and its embedded correlations.The reservoir is subjected to a gas cap blowdown via a gas well,then an oil well is initiated into the model at onset and after time periods of 2000 days,4000 days,6000 days and 8000 days to estimate the oil recovery.It is expected that due to the large nature of the gas cap,pressure decline will be drastic and leading to a low oil recovery,hence the injection of water and gas at different rates at the periods indicated.The results indicate an oil recovery of 4.3%during gas cap blow down and 10.34%at 6000 days.Peak oil recoveries of 12.64%and 10.80%are estimated under 30,000 Mscf/day at 4000 days and 1000 stb/day at 6000 days respectively.This shows an incremental oil recovery of 8.34%and 6.5%over that recorded during gas cap blow down.The results also indicate that the gas production at those periods was not greatly affected with an estimated increment of 257 Bscf recorded during 30,000 Mscf/day at 4000 days.All secondary injection schemes at the respective time steps had positive impact on the overall oil recoveries.It is recommended that extra production and injection wells be drilled,enhanced oil recovery options and injection patterns be considered to further increase oil recovery.

Hybrid model for BOF oxygen blowing time prediction based on oxygen balance mechanism and deep neural network

The amount of oxygen blown into the converter is one of the key parameters for the control of the converter blowing process,which directly affects the tap-to-tap time of converter. In this study, a hybrid model based on oxygen balance mechanism (OBM) and deep neural network (DNN) was established for predicting oxygen blowing time in converter. A three-step method was utilized in the hybrid model. First, the oxygen consumption volume was predicted by the OBM model and DNN model, respectively. Second, a more accurate oxygen consumption volume was obtained by integrating the OBM model and DNN model. Finally, the converter oxygen blowing time was calculated according to the oxygen consumption volume and the oxygen supply intensity of each heat. The proposed hybrid model was verified using the actual data collected from an integrated steel plant in China, and compared with multiple linear regression model, OBM model, and neural network model including extreme learning machine, back propagation neural network, and DNN. The test results indicate that the hybrid model with a network structure of 3 hidden layer layers, 32-16-8 neurons per hidden layer, and 0.1 learning rate has the best prediction accuracy and stronger generalization ability compared with other models. The predicted hit ratio of oxygen consumption volume within the error±300 m^(3)is 96.67%;determination coefficient (R^(2)) and root mean square error (RMSE) are0.6984 and 150.03 m^(3), respectively. The oxygen blow time prediction hit ratio within the error±0.6 min is 89.50%;R2and RMSE are0.9486 and 0.3592 min, respectively. As a result, the proposed model can effectively predict the oxygen consumption volume and oxygen blowing time in the converter.

Exploration and Practice of Nitrogen Addition Process for LF Refining Ladle Bottom Blowing Nitrogen Steel Liquid

This article discusses and analyzes the law of nitrogen increase in liquid steel and the main factors affect-ing the nitrogen increasing of molten steel,through the way of adding nitrogen to molten steel by bottom blowing nitrogen gas in LF refining process.It is considered that the main factors affecting the nitrogen increasing instability of molten steel are the initial temperature of LF refining,nitrogen relative element,surface active elements[O]and[S]of steel liquid,and bottom blowing rate of ladle.The large-scale production practice shows that T[O]not more than 50×10-6 and[S]is not more than 0.020 in LF refining at the initial temperature of not less than 1570.The liquid steel nitrogen enrichment test is carried out by ladle bottom blowing nitrogen gas after 20 min of refining,the flow rate is set as(6.0~7.0)NL/min per ton,and it is turned to 2 NL/min at 6 min before the end of refining,the nitrogen increasing rate of liquid steel is basically stable at(5~6)×10-6 per minute.

Effect of gas blowing nozzle angle on multiphase flow and mass transfer during RH refining process

A three-dimensional mathematical model was developed to investigate the effect of gas blowing nozzle angles on multiphase flow,circulation flow rate,and mixing time during Ruhrstahl-Heraeus(RH) refining process.Also,a water model with a geometric scale of 1:4 from an industrial RH furnace of 260 t was built up,and measurements were carried out to validate the mathematical model.The results show that,with a conventional gas blowing nozzle and the total gas flow rate of 40 L·min^(-1),the mixing time predicted by the mathematical model agrees well with the measured values.The deviations between the model predictions and the measured values are in the range of about 1.3%–7.3% at the selected three monitoring locations,where the mixing time was defined as the required time when the dimensionless concentration is within 3% deviation from the bath averaged value.In addition,the circulation flow rate was 9 kg·s^(-1).When the gas blowing nozzle was horizontally rotated by either 30° or 45°,the circulation flow rate was found to be increased by about 15% compared to a conventional nozzle,due to the rotational flow formed in the up-snorkel.Furthermore,the mixing time at the monitoring point 1,2,and 3 was shortened by around 21.3%,28.2%,and 12.3%,respectively.With the nozzle angle of 30° and 45°,the averaged residence time of 128 bubbles in liquid was increased by around 33.3%.

Successful treatment of a rare subcutaneous emphysema after a blow-out fracture surgery using needle aspiration:A case report

BACKGROUND Many cases of emphysema associated with blow-out fractures occur before surgery due to trauma.However,emphysema can occur even after surgery,and most of such cases are managed conservatively and allowed to resolve.Swelling in the periorbital area due to emphysema that occurs after surgery can make early recovery difficult.CASE SUMMARY Herein,we describe a case of postoperative subcutaneous emphysema that was treated using a simple needle aspiration method.A 48-year-old male patient visited the hospital with a blow-out fracture of the left medial orbital wall and nasal bone fracture.One day postoperatively,swelling and crepitus in the left periorbital area were observed,and follow-up computed tomography showed emphysema in the left periorbital subcutaneous area.Needle aspiration using an 18-gauge needle and syringe was used to relieve the emphysema.The symptoms of sudden swelling improved immediately,and no recurrence was observed.CONCLUSION We conclude that needle aspiration is a useful method that could help in relieving symptom,resolving discomfort,and enabling early return to daily life in patients with postoperative subcutaneous emphysema.

Eco-friendly physical blowing agent mass loss of bio-based polyurethane rigid foam materials

Through systematical experiment design, the physical blowing agent(PBA) mass loss of bio-based polyurethane rigid foam(PURF)in the foaming process was measured and calculated in this study, and different eco-friendly PBA mass losses were measured quantitatively for the first time. The core of the proposed method is to add water to replace the difference, and this method has a high fault tolerance rate for different foaming forms of foams. The method was proved to be stable and reliable through the standard deviations σ1and σ2for R1(ratio of the PBA mass loss to the material total mass except the PBA) and R2(ratio of the PBA mass loss to the PBA mass in the material total mass) in parallel experiments. It can be used to measure and calculate the actual PBA mass loss in the foaming process of both bio-based and petroleumbased PURF. The results show that the PBA mass loss in PURF with different PBA systems is controlled by its initial mass content of PBA in PU materials ω. The main way for PBA to dissipate into the air is evaporation/escape along the upper surface of foam. This study further reveals the mechanism of PBA mass loss: the evaporation/escape of PBA along the upper surface of foam is a typical diffusion behavior. Its spread power comes from the difference between the chemical potential of PBA in the interface layer and that in the outside air. For a certain PURF system, R1has approximately linear relationship with the initial mass content of PBA in PU materials ω, which can be expressed by the functional relationship R1= kω, where k is a variable related to PBA’s own attributes.

超临界CO_(2)管道瞬态输送工艺研究进展及方向

长距离超临界CO_(2)管道瞬态输送的核心技术还有待突破,相关模型和方法亟需工业规模示范工程的验证及修正。以成就型综述法,对超临界CO_(2)管道输送过程中停输、水击、泄漏和放空工况下形成的CO_(2)瞬态流加以描述、成果比较和综合评价。结果表明:超临界CO_(2)瞬态流的关键因素是温度、压力、相态变化、协同作用;超临界CO_(2)管道安全停输时间可定义为从停输开始至管内任一点流体即将进入气液共存区的时间;CO_(2)发生相变首先造成流速突变,进而是压力的突变,产生水击现象,引起新的瞬变流动;站场放空系统的设计目标是在放空过程不出现冰堵、材料冷脆、噪声污染、放空系统激振等问题的前提下,放空时间尽量短;埋地管道泄漏规律涉及到土壤渗流场、温度场、浓度场等多场耦合问题。研究结果可为超临界CO_(2)管道流动安全保障提供参考。

一类非线性扩散方程解的blow up速率估计

利用F riedm an-M cleod方法和变动尺度方法研究了一类具有非线性边界条件的非线性扩散方程解的b low up问题,证明了解在有限时间b low up,并且得到了b low up速率估计.

具有非线性记忆的抛物型方程解的Blow up

讨论了m(t)不具单调性的条件下,具有非线性记忆的抛物型方程解的Blow up.

一类非线性耗色散方程解的Blow-up

本文研究一类四阶非线性耗、色散波动方程的补边值问题,在一定条件下,得到了方程解的blow up性质。

具有非线性记忆的抛物型方程解的Blow up估计

讨论了 m( t)单调增加的条件下 ,具有非线性记忆的抛物型方程解的 Blow up,并给出了解的Blow

非线性拟抛物方程解的Blow-up

用特征函数法分别研究了非线性拟抛物方程u_t—Δu_t=f(u,D_xu,D_x^2u),u_-Δu_t=-△y(u) 与u_t-Δu_t=f(u)+Δg(u)的初边值问题整体解的不存在性与有限时间Blow-up。

某电厂循环冷却排污水达标排放方案设计与比较

针对某电厂的循环冷却系统排污水治理难题,提出了采用纳滤技术降低循环冷却系统排污水中含盐浓度和硫酸根浓度以满足地方环保标准实现达标排放的方案,并与采用反渗透技术的循环水旁路除盐处理方案进行了技术经济性比选。在方案比选中充分考量了2种方案对电厂脱硫废水零排放的影响,得出的结果表明经纳滤处理后达标排放的方案更具优势。

Bio-Based Rigid Polyurethane Foams for Cryogenic Insulation

Cryogenic insulation material rigid polyurethane(PU)foams were developed using bio-based and recycled feedstock.Polyols obtained from tall oil fatty acids produced as a side stream of wood biomass pulping and recycled polyethylene terephthalate were used to develop rigid PU foam formulations.The 4th generation physical blowing agents with low global warming potential and low ozone depletion potential were used to develop rigid PU foam cryogenic insulation with excellent mechanical and thermal properties.Obtained rigid PU foams had a thermal conductivity coefficient as low as 0.0171 W/m·K and an apparent density of 37-40 kg/m^(3).The developed rigid PU foams had anisotropic compression strength properties,which were higher parallel to the foaming direction.Moreover,the compression strength was also influenced by the type of applied bio-based polyol.The bio-based polyols with higher OH group functionality delivered higher crosslinking density of polymer matrix;thus,the mechanical properties were also higher.The mechanical strength of the foams increased when materials were tested at liquid nitrogen temperature due to the stiffening of the polymer matrix.The thermal properties of the developed materials were determined using differential scanning calorimetry,dynamic mechanical analysis,and thermogravimetric analysis methods.Lastly,the developed rigid PU foams had good adhesion to the aluminium substrate before and after applying cyroshock and an excellent safety coefficient of 4-5.Rigid PU foams developed using Solstice LBA delivered adhesion strength of~0.5 MPa and may be considered for application as cryogenic insulation in the aerospace industry.

含有Hénon项的非线性椭圆系统稳定解的Liouville定理

本文主要研究含有Hénon项的k-耦合椭圆系统-Δu_(i)=Σ_(j-1)^(k)β_(ij)|χ|^(α)|u_(i)|^(q-1)ui|uj|^(q+1),x∈R^(N)其中k是一个固定的正整数,i=1,2,…,k,q≥1,N≥3,B=(β_(ij))_(i,j=1)^(k)为实对称矩阵.首先使用Pohozaev恒等式构造单调公式,并发现其等价关系.当矩阵B严格余正时,联合使用Pohozaev恒等式、单调公式和爆缩序列方法证明了(无论是正的还是变号的)稳定解的Liouville定理.

一类退化抛物方程高初始能量下解的有限时刻爆破及整体存在性

We consider the initial-boundary value problem for finitely degenerate parabolic equation. We first give sufficient conditions for the blow-up and global existence of the parabolic equation at high initial energy level. Then, we establish the existence of solutions blowing up in finite time with initial data at arbitrary energy level. Finally, we estimate the upper bound of the blow-up time under certain conditions.

具非线性源的多孔介质方程解的Blow-up时间对初值的相依性

考虑多孔介质方程的Dirichlet问题,讨论在解的Blow-up时间T有限的情况下,当初值出现一个小的扰动函数h(x)时,相应方程的Blow-up时间Th随之发生的变化情况,证明了Blow-up时间|T-Th|和‖h‖L1(Ω)之间连续相依性的结果,其中QT=Ω×(0,T),0≤u0(x)∈L∞(Ω),h(x)∈L∞(Ω),ΩRN是一有界区域,其中对指标m,p的限制满足1<m<p.

半线性拟抛物方程解的Blow-up

研究一类半线性拟抛物方程的初边值问题.首先利用格林函数和最大值原理证明了解的正定性,而后,通过要求非线性项满足正定性条件和凹凸性条件,利用特殊函数法证明了方程正解的有限时间爆破.

高炉长期休风快速达产研究及应用

针对120 t炼钢转炉更换炉衬、煤气公共管道检修,会导致系统全停、影响产能的问题,采取了相应措施:休风前1#、2#高炉调节,包括渣、铁及产量调节;休风期焦炭、炉温、炉渣二元碱度及上休风料调节;复风前准备,1#、2#高炉复风及恢复炉况等操作。采取措施释放产能后3 d内恢复至检修前水平,实现炉况稳定及快速达产目标。

半线性拟抛物方程古典解的Blow-up问题

研究了半线性拟抛物方程的初边值问题ut-Δut=f(u)x∈Ω,t>0(1.1)u(x,0)=u0(x),x∈Ω(1.2)u|Ω=0,t≥0(1.3)古典解的blow-up性.讨论了正解的存在性.研究了(1.1)^(1.3)的古典解u(x,t)的blow-up性,即存在T0≤(1+λ0)∫α∞g-1(x)ds使得limt→T0-‖u‖p=∞对1≤p≤∞.