Development and prospect of downhole monitoring and data transmission technology for separated zone water injection

This article outlines the development of downhole monitoring and data transmission technology for separated zone water injection in China.According to the development stages,the principles,operation processes,adaptability and application status of traditional downhole data acquisition method,cable communications and testing technology,cable-controlled downhole parameter real-time monitoring communication method and downhole wireless communication technology are introduced in detail.Problems and challenges of existing technologies in downhole monitoring and data transmission technology are pointed out.According to the production requirement,the future development direction of the downhole monitoring and data transmission technology for separated zone water injection is proposed.For the large number of wells adopting cable measuring and adjustment technology,the key is to realize the digitalization of downhole plug.For the key monitoring wells,cable-controlled communication technology needs to be improved,and downhole monitoring and data transmission technology based on composite coiled tubing needs to be developed to make the operation more convenient and reliable.For large-scale application in oil fields,downhole wireless communication technology should be developed to realize automation of measurement and adjustment.In line with ground mobile communication network,a digital communication network covering the control center,water distribution station and oil reservoir should be built quickly to provide technical support for the digitization of reservoir development.

A New Heat Transfer Model for Multi-Gradient Drilling with Hollow Sphere Injection

Multi-gradient drilling is a new offshore drilling method.The accurate calculation of the related wellbore temperature is of great significance for the prediction of the gas hydrate formation area and the precise control of the wellbore pressure.In this study,a new heat transfer model is proposed by which the variable mass flow is properly taken into account.Using this model,the effects of the main factors influencing the wellbore temperature are analyzed.The results indicate that at the position where the separation injection device is installed,the temperature increase of the fluid in the drill pipe is mitigated due to the inflow/outflow of hollow spheres,and the temperature drop of the fluid in the annulus also decreases.In addition,a lower separation efficiency of the device,a shallower installation depth and a smaller circulating displacement tend to increase the temperature near the bottom of the annulus,thereby helping to reduce the hydrate generation area and playing a positive role in the prevention and control of hydrates in deepwater drilling.

Throttle characteristics of multi-stage circumfluence nozzle during the separate-layer injection of CO_(2)

Separate-layer injection of CO2 is an important method to improve oil and gas production and recovery.Conventional single-stage nozzle is usually blocked by impurities,and the ice-barrier phenomenon is very common.To solve this problem,large-diameter multi-stage circumfluence nozzle was designed to release pressure stage by stage.In order to illuminate the throttle characteristics of the CO2 multi-stage circumfluence nozzles,numerical simulation was performed to test several nozzles with different diameters and stage numbers.Furthermore,we tested the throttle characteristics through laboratory experiments and obtained the effects of several critical parameters such as nozzle diameter,number of stage and pressure drop on the throttle characteristics.The results show that the flow rate decreases as the nozzle stage increases on the condition of constant pressure and nozzle diameter.And pressure difference increases as nozzle stage number increases under the constant flow rate.The throttle capability of multi-stage circumfluence nozzles was much better than the concentric nozzles.Large-diameter multi-stage nozzle is recommended rather than small-diameter single-stage nozzle during the process of separate-layer injection,which can efficiently prevent impurities and ice blocking.The results are expected to provide a theoretical support for the nozzle choice of separate-layer injection of CO2.

A Novel Statistical Analysis for Residual Stress in Injection Molding

Residual stresses can reduce the reliability of plastic injection molding parts. This work is an attempt to model the residual stresses as a function of injection molding parameters. More stress is placed on reducing the number of input factors and to include all possible interactions. For this purpose, two-stage experimentation is suggested: a factor screening stage and Response Surface optimization stage. In screening stage Taguchi 3 level experimental design is used to classify the input parameters as significant and non-significant factors. Eight input variables were classified into 3 non-significant and 5 significant factors using this screening stage. Thus for the Response Surface optimization stage: instead of doing 160 experiments in Central Composite, 56 are only needed after the screening stage in half Central Composite Design. The best subset and regression model fitting tools in addition to model verification using randomly selected input setting were used to select a model for predicting residual stresses with a verified Root Mean Square Error (RSME) of nearly 0.93 MPa.

Study on Water Injection Formula by Grey Correlation Method for Offshore Water Flooding Reservoir

Based on the development of the offshore water drive reservoir, the determination of reasonable water injection of monolayer and single well affects the distribution of remaining oil and development effect of oil field water flooding, so this paper, using the grey correlation analysis method, studies the main factors influencing the dividing coefficient of water-injection and weight. This method takes into account the effective thickness, permeability, injection-production well spacing, the number of injection-production wells, and the direction of formation coefficient factors such as the influence of the dividing coefficient for injection. The formula for water-injection multi-factor controlled is established, at the same time, applying water injection formula of this article and the conventional on injection allocation of A-platform offshore injection wells. And the difference of single-well injection-allocation quantity in layers is analyzed. Based on a platform offshore, layers exist in the process of water flooding and the problems such as the contradiction between the layers, put forward the necessity of layered water injection through this article to determine water injection formula and injection allocation on a platform of injection wells by implementing effect which can be found. A platform for water flooding development of water cut under control, natural decline rate reduced to verify the reliability and practicability of the formula to determine injection in this paper. It has certain guiding significance to the offshore for the water-injection development oilfield.

Optimum development options and strategies for water injection development of carbonate reservoirs in the Middle East

Through the research on several carbonate reservoirs developed in the Middle East, the basic characteristics of different types of carbonate reservoirs are determined, and a set of high-efficiency water injection development options and strategies are presented. Hidden baffles and barriers exist in carbonate reservoirs in the Middle East, so the reservoirs could be divided into different separated development units based on the baffles and barriers characteristics. Flexible and diverse profile control techniques such as high angle wells and simple and applicative zonal water injection have been introduced to improve the control and development degree of reservoirs. Three principal water injection development methods suitable for different carbonate reservoirs in the Middle East are proposed, including the combination of crestal gas injection and peripheral water injection, bottom interval injection and top interval production(buoyancy underpinning), and "weak point and strong plane" area well pattern. Based on the characteristics of very low shale content, fast and far pressure transmission in the Middle East carbonate reservoirs, a large well-spacing flood pattern is recommended, and reasonable development strategies have been made such as moderate water injection rate and maintaining reasonable production pressure drawdown and voidage replacement ratio, so as to maximize the recovery of reservoirs in the none or low water cut period.

井下旋流分离管柱的振动特性研究

为研究旋流分离管柱在注入泵和采出泵两螺杆泵抽吸条件下的振动特性,对其进行模态分析和瞬态动力响应分析。结果表明,不同工况下,旋流分离管柱的固有频率有所不同;固定注入泵一端和固定采出泵一端相比,固定采出泵一端各阶固有频率较小;螺杆泵转动引起的激振力和内部流量变化都会导致管柱变形,其中螺杆泵转动对旋流分离管柱变形影响较大;相对于固定采出泵,固定注入泵条件下旋流分离管柱产生的振动位移更大,是旋流分离管柱自身结构和注入泵转速产生更大激振力综合作用导致的结果;控制两个螺杆泵工作状态的时间差,理想情况下可以控制旋流分离管柱的总变形。

CO_(2)分注井气嘴节流特性及矿场应用

为了解决CO_(2)分注井节流压差建立困难,气嘴易冲蚀的技术难题,通过构建CO_(2)物性变化的流动-传热耦合模型,揭示2级和3级节流气嘴的流场演化机制,优化设计气嘴结构、建立了绕流气嘴节流图版并开展现场应用。结果表明:流量为10 m3/d时,2级嘴径1.4 mm和3级嘴径1.6 mm的绕流气嘴分别能产生将近6 MPa和8 MPa的节流压差,证明绕流气嘴结构合理、性能可靠、能够达到调整层间压差的技术要求;参照气嘴图版优选的节流气嘴,现场应用20口井,节流压差可达4 MPa左右,调整后注入压力上升2.4 MPa,加强层相对吸气比例由9.7%上升至50.7%,有效调整了层间差异,解决了分注井小层吸气不均的问题。研究结果指导现场测调,为CO_(2)分注规模化应用提供技术支撑。

榆树林油田CCUS采油工程方案优化设计与实践

大庆榆树林油田扶杨油层属低孔、特低渗透储层,针对以往开发过程中存在注水困难、压裂有效期短、水驱开发难以有效动用的问题,开展CO_(2)驱油技术现场试验。从经济性、技术适应性、配套工艺成熟性等角度对采油工程方案进行综合评价,优选出单、双管分层注入工艺、高气液比举升工艺、注采两端个性化防腐工艺及物理化学组合解冻堵工艺等CCUS采油工程技术。结果表明:试验区投产初期及目前生产情况均达到了油藏预测指标;采出井平均泵效及检泵周期与外围油田平均水平相持平,注气井与采出井腐蚀速率小于行业指标;实现CO_(2)有效埋存108.9×10^(4) t,比水驱预测采出程度提高采收率4.39百分点,取得较好的驱油开发效果。研究成果为CCUS示范区的高效建设提供了技术支撑,开辟了大庆油田外围难采储量有效动用的新途径。

一种优化高频注入法PMSM无位置传感器控制

传统高频信号注入法采用带通滤波器分离信号,龙伯格观测器利用所得信号计算出转子位置,考虑到带通滤波器设计复杂且使高频信号幅值产生衰减,同时龙伯格观测器需要电机转矩反馈、转动惯量等多种机械参数,这些因素干扰电机控制系统的动态性能等。采用基于低通滤波器的信号分离方法可在不损失高频信号得到含转子位置信号;利用电机的转速、转子位置角以及其角加速度之间关系构建扩张状态观测器,可以避免测量负载转矩和对不确定扰动的估计。仿真及实验结果表明,该优化策略能够使电机在低速控制时稳定运行,且具有更好的低速动态性能。

井下油水分离装置现状与展望

油田进入开发中后期,采出液含水率急剧上升,如何降低含水率并提高采收率是开发后期需要解决的首要问题。井下油水分离技术利用水力旋流技术、重力分离技术或其他油水分离工艺实现在井下对采出液进行预分离,从而采出较低含水率的油水混合液,此项技术对于高含水油田具有很大应用前景。通过对井下油水分离装置的研究现状进行简要分析与总结,并指出目前井下油水分离装置存在的问题与挑战,同时做出展望,为其发展提供一定的参考。

采用非共沸制冷剂的双喷气增焓两级压缩热泵循环研究

提出一种采用非共沸制冷剂的双喷气增焓两级压缩热泵循环(DVIC),该循环在普通喷气增焓循环(VIC)的基础上采用分液冷凝技术,并增加一组闪蒸器,减少系统不可逆损失,改善热力性能。采用R290/R1336mzz(Z)非共沸制冷剂,对DVIC进行研究,并与VIC进行比较。结果表明:在设定工况下,DVIC比VIC拥有更优的循环性能,系统COP和(火用)效率分别提高5.82%和8.41%,压缩机功耗降低6.39%;在较低蒸发温度或较高冷凝温度的运行工况下,DVIC性能的改善效果更加明显。

海上油田分层防砂分层注聚技术工艺优化

针对胜利油田已有的双管分层防砂分层注聚技术无法满足其海上低剪切、防堵塞、长效注聚需求的现状,对注聚筛管、环空安全阀及液控封隔器等核心工具进行了优化改进,形成了双管宽流道分层防砂分层注聚技术。优化研究结果表明:形成的注聚筛管采用倒梯形缝状结构,表面双疏涂层,自洁不堵塞,流通量提高25%~40%;优化环空安全阀过流通道使内外管环空过流面积增加3.3倍;优化液控封隔器结构,使胶筒肩部受力减小12.6%,坐封活塞面积增加0.78倍,解封后环空面积增大1.5倍。该技术已在海上油田成功应用35井次,井筒黏度保留率达93%,提高5%,平均注入压力下降1.1 MPa。该技术对油田海上、陆地化学驱区块的长效注采开发具有一定的示范指导作用。

海上油田电液联控单管分层注聚技术研究

针对传统单管细分注聚技术存在因聚合物吸附等造成测调仪投捞不到位、配聚器调配困难及有效期短等问题,研发了一种电液联控单管分层注聚技术。该技术包含电液复合分控装置、液控多级配聚器、非接触式热传导流量计等核心工具。电液复合分控装置通过1根主控电缆,实现1根液控管路分控多个液控工具,大大简化了井筒管线数量;液控多级配聚器解决了注聚过程中流量调节困难的问题,实现变排量调节和大压差注入;非接触式热传导流量计实现聚合物流量井下长效在线监测。目前该技术已成功应用3井次,分注层数2~3层,最大单层配注量130 m^(3)/d,测调次数达21次,测试准确率达85%以上,在井时间约600 d依然有效。该技术满足了海上油田“保黏、细分、长效”的注聚需求,具有较高的推广应用价值。

注汽锅炉过热及提效改造技术的研究

随着油田开采深度的增加,被广泛使用的湿饱和蒸汽和高干度蒸汽注采方法将受到限制,由于管线和井筒输送损失,到达井底的干度较低,降低了加热效果,因此需提高锅炉出口蒸汽干度,以改善开发效果。辽河油田注汽锅炉平均热效率约89%,距离国家标准规范热效率(92%以上)有一定的差距,还有提效空间。目前热注站汽水分离器产生的25%高温分离水与给水换热后直接外排至联合站,不仅造成了约15%热量的浪费,而且还增加联合站的污水处理费用。为了解决上述问题,采用注汽锅炉过热及提效改造技术,主要包括新增过热段,改造对流段、过渡段保温改造、汽水流程调整以及自控系统升级,其节能降耗效果显著,具有一定的推广价值。

高产水气井同井采注技术研究及应用

高产水气井因产水量大而存在井筒连续排液难、地面气水混输难及产出水处理成本高等问题。为此,基于“潜油电泵深抽+采出水不出地面处理”研究思路,研制了一种井下气液流道转化关键装置,实现井下气水流道空间转换及产层与回注层有效封隔;创新形成高产水气井潜油电泵同井采注工艺技术,确保气井油管稳定采气、油套环空产出水不出地面直接井下回注。潜油电泵同井采注工艺技术在42口高产水关停气井中推广应用,累计增产3350万m3,产出水全部实现井下回注,节省污水处理成本926万元,实现高产水气井经济有效排采。

朱家峁煤矿3#煤层导水裂缝带发育高度分析研究

根据朱家峁煤矿三盘区煤层赋存条件及工作面巷道布置与开采状况,为研究3#煤层开采后覆岩导水裂缝带发育高度及形态规律,在理论分析与详细探测设计基础上,采用钻孔分段注水测漏法对3301综采面采后覆岩导水裂缝带高度进行了现场探测。通过系统资料整理与分析,得到了该条件下的两带高度实测资料,3301综采面观测站处导水裂缝带最大高度为55.4m,为采厚的19.8倍。建议在后续矿井突水危险性评价时,采用本次实测裂采比20倍作为依据。

Numerical simulations of single and multi-staged injection of H_(2) in a supersonic scramjet combustor

Computational fuid dynamics(CFD)simulations of a single staged injection of H_(2) through a central wedge shaped strut and a multi staged injection through wall injectors are carried out by using Ansys CFX-12 code.Unstructured terahedral grids for narow channel and quarter geometries of the combustor are generated by using ICEM CFD.Steady three dimensional(3D)Reynods averaged Navier-stokes(RANS)simulations are carried out in the case of no H_(2) injection and compared with the simulations of single staged pilot and/or main H2 injections and multistage injection.Shear stuess transport(SST)based on k-ω turbulent model is adopted.Flow field visualization(omplex shock waves interactions)and static pressure distribution along the wall of the combustor are pradicted and compared with the experimental schlieren images and measured wall static pressures for validation.A good agreement is found between the CFD predicted results and the measured data.The narow and quarter geometries of the combustor give similar results with very small differences.Multi-staged injections of H_(2) enhance the turbulent H_(2)/air mixing by fomming vortices and additional shock waves(bow shocks).

Research on performance testing of radio fuse based on virtual separation technology

The conception of virtual separation technology about high low frequency of electronic module was put forward based on the analysis of tactical performance testing of radio fuse.By means of the principle of fuse Doppler signal acquisition and injection,the high low frequency of electronic module was virtually separated,and one of important parameters—burst height of radio fuse is tested precisely.

Removal of Silica and Alumina as Impurities from Low-Grade Iron Ore Using Wet High-Intensity Magnetic Separation and Reverse Flotation

This study investigates the removal of silica and alumina as impurities from hematite based low-grade iron ore containing 34.18 mass% iron, 31.10 mass% of silica and 7.65 mass% alumina. Wet high-intensity magnetic separation (WHIMS) and reverse flotation (RF) were investigated. In WHIMS process, 93.08% of iron was recovered with a grade of 53.22 mass% at an optimum magnetic density of 10,000 mT, and pulp density of 2% used the L-4 machine. In RF experiments, optimal results showed 95.95% of iron recovered with 51.64 mass% grade using 1 kg/t of 1% alkaline starch as iron depressant and 1:1 mixture ratio of 0.75 kg/t DAA and NaOL as silica and alumina collectors. The designed multi-stage process involving feeding the concentrate from WHIMS into RF process reduced silica to 2.02 mass%, alumina to 1.04 mass% whilst recovering 81.94% of the iron with 67.27 mass% grade. As a result of this research, a process to produce high quality iron concentrate from hematite based low-grade iron ore with high iron recovery rate was constructed.