Prediction of wax precipitation region in wellbore during deep water oil well testing

During deep water oil well testing, the low temperature environment is easy to cause wax precipitation, which affects the normal operation of the test and increases operating costs and risks. Therefore, a numerical method for predicting the wax precipitation region in oil strings was proposed based on the temperature and pressure fields of deep water test string and the wax precipitation calculation model. And the factors affecting the wax precipitation region were analyzed. The results show that: the wax precipitation region decreases with the increase of production rate, and increases with the decrease of geothermal gradient, increase of water depth and drop of water-cut of produced fluid, and increases slightly with the increase of formation pressure. Due to the effect of temperature and pressure fields, wax precipitation region is large in test strings at the beginning of well production. Wax precipitation region gradually increases with the increase of shut-in time. These conclusions can guide wax prevention during the testing of deep water oil well, to ensure the success of the test.

Survey-Based Analysis of Water Consumption Law in High-Rise Public Buildings and Water-Saving Performance of Pressure-Reducing Measures

Facing the contradiction of water scarcity and water wastage in most cities of China, this study aims at probing into the factors influencing water-use efficiency and assessing water-saving potential by adopting pressure control measures based on field survey conducted in 23 high-rise buildings in Suqian, China and laboratory tests. Results showed that per capita water consumption (PCWC) exceeding water consumption norms is common in these buildings. The hourly water consumption variation law is quite different among different types of buildings. These differences should be considered in designing building water supply systems to lower water and energy consumption. On the basis of correlation analysis, the order of factors influencing the PCWC follows average tap water pressure, percapita building area, and building age, suggesting pressure management in high-rise buildings is a key water-saving measure. Field tests of outflow characteristics under different water pressures indicated that over-pressure outflow (OPO) is a common cause of water wastage in buildings, however, no branch pipe pressure control measures were found in all the surveyed buildings. Laboratory tests showed that branch pipe pressure-reducing measures can lower water consumption and improve the comfortability of use as well. Therefore, in addition to applying high efficiency water-saving devices, we strongly recommend that branch pipe pressure-reducing measures should be strictly implemented in designing new building water supply systems and reconstruction of existing old building water supply systems, thereby, promoting water, energy saving and development of green building.

Dynamic modelling and engineering simulation of fluid mechanics in water injectors

To study the fluid dynamic response mechanism under the working condition of water injection well borehole,based on the microelement analysis of fluid mechanics and the classical theory of hydrodynamics,a fluid microelement pressure-flow rate relationship model is built to derive and solve the dynamic distribution of fluid pressure and flow rate in the space of well borehole.Combined with the production data of a typical deviated well in China,numerical simulations and analyses are carried out to analyze the dynamic distribution of wellbore pressure at different injection pressures and injection volumes,the delayed and attenuated characteristics of fluid transmission in tube,and the dynamic distribution of wellbore pressure amplitude under the fluctuation of wellhead pressure.The pressure loss along the wellbore has nothing to do with the absolute pressure,and the design of the coding and decoding scheme for wave code communication doesn’t need to consider the absolute pressure during injecting.When the injection pressure is constant,the higher the injection flow rate at the wellhead,the larger the pressure loss along the wellbore.The fluid wave signal delay amplitude mainly depends on the length of the wellbore.The smaller the tubing diameter,the larger the fluid wave signal attenuation amplitude.The higher the target wave code amplitude(differential pressure identification root mean square)generated at the same well depth,the greater the wellhead pressure wave amplitude required to overcome the wellbore pressure loss.

Research progress and application prospect of functional adhesive materials in the field of oil and gas drilling and production

By summarizing the composition,classification,and performance characterization of functional adhesive materials,the adhesion mechanisms of functional adhesive materials,such as adsorption/surface reaction,diffusion,mechanical interlocking,and electrostatic adsorption,are expounded.The research status of these materials in oil and gas drilling and production engineering field such as lost circulation prevention/control,wellbore stabilization,hydraulic fracturing,and profile control and water plugging,and their application challenges and prospects in oil and gas drilling and production are introduced comprehensively.According to the applications of functional adhesive materials in the field of oil and gas drilling and production at this stage,the key research directions of functional adhesive materials in the area of oil and gas drilling and production are proposed:(1)blending and modifying thermoplastic resins or designing curable thermoplastic resins to improve the bonding performance and pressure bearing capacity of adhesive lost circulation materials;(2)introducing low-cost adhesive groups and positive charge structures into polymers to reduce the cost of wellbore strengthening agents and improve their adhesion performance on the wellbore;(3)introducing thermally reversible covalent bond into thermosetting resin to prevent backflow of proppant and improve the compressive strength of adhesive proppant;(4)introducing thermally reversible covalent bonds into thermoplastic polymers to improve the temperature resistance,salt-resistance and water shutoff performance of adhesive water shutoff agents.

Outflow of Pacific water from the Chukchi Sea to the Arctic Ocean

Pacific water exits the Chukchi Sea shelf through Barrow Canyon in the east and Herald Canyon in the west, forming an eastward-directed shelfbreak boundary current that flows into the Beaufort Sea. Here we summarize the transformation that the Pacific water undergoes in the two canyons, and describe the characteristics and variability of the resulting shelfbreak jet, using recently collected summertime hydrographic data and a year-long mooting data set. In both canyons the northward-flowing Pacific winter water switches from the western to the eastern flank of the canyon, interacting with the northward-flowing summer water. In Barrow canyon the vorticity structure of the current is altered, while in Herald canyon a new water mass mode is created. In both instances hydraulic effects are believed to be partly responsible for the observed changes. The shelfl）reak jet that forms from the canyon outflows has distinct seasonal configurations, from a bottom-intensified flow carrying cold, dense Pacific water in spring, to a surface-intensified current advecting warm, buoyant water in summer. The current also varies significantly on short timescales, from less than a day to a week. In fall and winter much of this mesoscale variability is driven by storm events, whose easterly winds reverse the current and cause upwelling. Different types of eddies are spawned from the current, which are characterized here using hydrographic and satellite data.

Key Technology of Ground Grouting Treatment for Inclined Shaft under Condition of Super Thick Water-Rich Loose Layer

Shaft is one of the important links of mine production. In recent years, wellbore deviation has occurred many times in various regions of China, especially under the condition of thick water-rich loose layer, wellbore deviation has become an important factor that seriously affects the safety of mine production and miners’ life. Taking the serious deviation of shaft in Guotun Coal Mine in Shandong Province as an example, this paper analyzes the causes of wellbore deviation from the aspects of wellbore geological conditions and wellbore construction methods, and grouting treatment engineering carried out on the deviated shaft under the condition of mine production. Through on-site grouting construction, repair and treatment are remarkable, which provides reference for the subsequent surface grouting treatment engineering of wellbore deviation.

井筒举升工艺在稠油冷采开发中的应用

针对草古1潜山稠油油藏注汽热采效果不佳的状况,根据不同区域地质、油藏特点,先后应用井筒电加热、电喷泵及阀式泵泵上掺水等以井筒降粘为主要目的的新工艺开展了冷采试验,取得了较好的生产效果,实现了该区块的高效规模开发,同时也形成了适合油藏特点的草古1冷采系列技术,为制定企业相关生产工艺标准,奠定了必要的基础。

近井地带高含水饱和度对火驱开发效果影响的实验

火驱技术是注蒸汽开发后的有效接替技术,然而注蒸汽后近井地带储层形成的高含水饱和度对火驱的点火、火线推进和开采效果的影响尚未明确。利用燃烧管实验装置将高含水饱和度的油砂填充到注气端附近,以模拟近井地带储层的高含水饱和度,并研究了近井地带储层的高含水饱和度对火驱的点火、火线推进特征及开发效果的影响。结果表明:近井地带储层的含水饱和度高达91.7%时,依然可以实现成功点火,形成有效驱替。近井地带储层的水能起到蒸汽驱油作用,加快火线的推进速度,缩短油墙的形成时间,从而导致火驱受效时间提前,但也会降低火驱过程中的燃料消耗量和氧气利用率,导致火线前缘的燃烧效果变差和原油采收率的降低。研究成果可为蒸汽吞吐后转火驱技术的现场应用提供理论参考。

基于PIPEPHASE的苏南采出水外输系统模拟研究

采出水外输是各大气田生产过程中保证气田产量和完善气田开发效果的重要途径。苏南气田采出水外输系统是一个复杂的流体网络系统,系统需要在不同状态下对外输方式进行调整。基于集气站、输水阀室、输水管线、处理厂的空间分布和拓扑结构关系,利用PIPEPHASE稳态多相流模拟计算软件,建立包含管网设施和参数的气田采出水外输系统模型;通过黏密度检测分析、阴阳离子色谱实验等明确了外输系统中的介质组分,进而开展仿真模拟;通过误差修正后的模型开展模拟计算,得出不同状态下各节点单元的压力和流量。结果表明:外部气温变化造成的介质温度改变会对外输系统产生小幅影响,通过对比不同分配分输方式的模拟计算结果与现场生产数据,验证了模型的合理性。研究结果可以为苏南气田现场生产提供参考。

Sensitivity Analysis of Thermal Equilibrium Parameters of MIKE 11 Model:A Case Study of Wuxikou Reservoir in Jiangxi Province of China

Sensitivity analysis of thermal equilibrium parameters in the reservoir module of MIKE 11 model was conducted for the Wuxikou Reservoir in Jiangxi Province of China in order to apply the module to the environmental impact assessment to accurately predict water temperature of reservoirs.Results showed that radiation parameter A and evaporation-first parameter were much more sensitive than other parameters.The values of the radiation parameter A ranged from 0.10 to 0.34.The values of evaporation-first parameter varied from 0 to 10.The sensitivity of solar absorption parameters was less than that of evaporation parameter,of which light attenuation values ranged from 0.5 to 0.7,and this parameter would not impact model results if it was more than 2.Constants in Beer's law ranged from 0.2 to 0.7.Radiation parameter B was not more sensitive than evaporation parameter and its reasonable range was higher than 0.48.The fitting curves showed consistent changing tendency for these parameters within the reasonable ranges.Additionally,all the thermal equilibrium parameters had much more important effects on surface water temperature than deep water temperature.Moreover,if no observed data could be obtained,the local empirical value would be used to input to the MIKE 11 model to simulate the changes in the discharged outflow-water temperature qualitatively.

塔里木盆地深部寒武系复杂地层钻井液技术

塔里木盆地寒武系复杂地层具有超深、超高温、超高压及岩性、流体和应力复杂等地质特征,钻井过程中白云岩破碎性地层垮塌、薄层膏岩溶解导致井壁失稳及钻井液污染、钻井液高温稳定性差等问题突出。基于理论分析,提出了“合理密度支撑、随钻多级封堵及封闭浆静态强化”破碎性地层防塌、“欠饱和、低滤失”含膏白云岩地层防卡、“聚合物、磺化材料协同抗温”调控钻井液高温性能的钻井液技术对策。采用抗高温封堵防塌剂、抗高温抗盐聚合物降滤失剂、多尺度宽尺度粒径随钻封堵防塌处理剂、磺化处理剂和抗高温高效润滑剂作为关键处理剂,通过室内试验优选了SMDP-2抗高温抗盐降滤失剂,确定了封堵防塌材料配方和SMJH-1润滑剂最优加量,构建了耐温200℃的抗高温强封堵欠饱和盐水钻井液。该钻井液在QSH1井等3口井进行了应用,表现出良好的抑制性、封堵防塌性和高温稳定性,实现了复杂地层快速钻进。其中,QSH1井下丘里塔格组及阿瓦塔格组井段日平均渗漏量较邻井降低45.6%,井眼扩大率为9.52%,电测、下套管均一次顺利到底,钻井周期缩短30.32%。研究结果表明,该钻井液技术可有效解决温度200℃以内的塔里木盆地寒武系复杂地层钻井液技术难点,为该类地层安全快速钻井提供了技术保障。

煤矿斜井过动水砂层帷幕注浆扩散封堵机理及应用

我国西部煤矿斜井井筒在富水松散层段大多发生渗漏水现象,有时甚至存在涌水溃砂风险,影响煤矿安全生产。为科学指导斜井过动水砂层防治水工作,以曹家滩煤矿主副斜井过动水砂层帷幕注浆为工程背景,借助有限元数值模拟软件建立了动水砂层帷幕注浆扩散封堵模型,探究了煤矿斜井过动水砂层帷幕注浆扩散封堵机理,结合具体治理区域,优化了动水砂层帷幕注浆参数及工艺,并进行了现场效果检验。研究结果表明:随着动水流速和注浆压力的增大,浆液顺水流方向扩散特征明显;注浆压力0.5MPa,动水流速0.3m/s时,顺水流方向浆液扩散半径增至1.83m;随着帷幕内壁与井筒外壁间距的增大,井筒围岩变形破坏范围逐渐远离井筒外壁,治理区域间距设置应不小于12.5m;注浆参数及工艺优化后,主副斜井治理段水量分别衰减85.6%和82.7%,治理效果显著。本文研究成果有助于解决动水砂层斜井井筒渗漏水问题,保障斜井井筒安全运营,保护矿山地下水资源。

Effects of instantaneous shut-in of high production gas well on fluid flow in tubing

As the classical transient flow model cannot simulate the water hammer effect of gas well, a transient flow mathematical model of multiphase flow gas well is established based on the mechanism of water hammer effect and the theory of multiphase flow. With this model, the transient flow of gas well can be simulated by segmenting the curved part of tubing and calculating numerical solution with the method of characteristic curve. The results show that the higher the opening coefficient of the valve when closed, the larger the peak value of the wellhead pressure, the more gentle the pressure fluctuation, and the less obvious the pressure mutation area will be. On the premise of not exceeding the maximum shut-in pressure of the tubing, adopting large opening coefficient can reduce the impact of the pressure wave. The higher the cross-section liquid holdup, the greater the pressure wave speed, and the shorter the propagation period will be. The larger the liquid holdup, the larger the variation range of pressure, and the greater the pressure will be. In actual production, the production parameters can be adjusted to get the appropriate liquid holdup, control the magnitude and range of fluctuation pressure, and reduce the impact of water hammer effect. When the valve closing time increases, the maximum fluctuating pressure value of the wellhead decreases, the time of pressure peak delays, and the pressure mutation area gradually disappears. The shorter the valve closing time, the faster the pressure wave propagates. Case simulation proves that the transient flow model of gas well can optimize the reasonable valve opening coefficient and valve closing time, reduce the harm of water hammer impact on the wellhead device and tubing, and ensure the integrity of the wellbore.

青海油田风西区块长水平段水平井钻井液技术

青海油田为实现稀井高产开发技术方案,在柴达木盆地大风山地区风西构造部署五口长裸眼水平井,并同时应用水基、油基钻井液进行施工对比,总结完善风西长裸眼长水平段水平井钻完井工艺技术模板。以优质复合盐水基钻井液在风西ⅠH1-5井的现场应用实例进行总结,并对相关钻井工艺技术应用、工程参数控制、流变性与携带等进行分析。风西ⅠH1-5井完钻井深为5478 m,水平段长2541 m,创青海油田水平段最长、油层钻遇率最高(100%)、水平井单趟进尺最多(1566 m)、水平段短程起下钻井段最长(达1000 m)、首次采用漂浮下套管技术等多项施工新纪录,该井的成功钻探对于超长水平段水平井的钻完井工艺在青海油田应用具有里程碑意义。与应用油基钻井液施工的邻井就钻井周期进行了对标分析,该优质复合盐水基钻井液施工井均优于油基钻井液施工井,对今后钻探长裸眼、长水平段水平井钻井液体系优选有较好的指导借鉴。

油气钻采领域功能胶黏材料研究进展及前景

通过概述功能胶黏材料的组成、分类及性能表征,阐述了功能胶黏材料的吸附/界面反应、扩散、机械互锁和静电吸附等黏结作用机理,综述了其在防漏堵漏、井壁稳定、水力压裂和调剖堵水等油气钻采工程领域的研究现状、应用挑战及应用展望。依据现阶段功能胶黏材料在油气钻采领域的应用,提出了功能胶黏材料在油气钻采领域的重点研究方向:(1)对热塑性树脂进行共混改性或设计可固化热塑性树脂,提高黏结堵漏剂的黏结性能和承压能力;(2)在聚合物中引入低成本黏附性基团和正电荷结构,降低黏结固壁剂成本,提高其在井壁的黏附性能;(3)在热固性树脂中引入热可逆共价键,预防支撑剂回流,提高黏结支撑剂抗压强度;(4)在热塑性聚合物中引入热可逆共价键,提高黏结堵水剂的抗温抗盐能力和堵水性能。

纳米材料提高水基钻井液页岩稳定性研究进展

维持井壁稳定一直是油气钻探过程中的技术难题。由于页岩微纳米孔缝与层理发育、水敏性高,井壁失稳问题在页岩层尤为突出。提高钻井液的性能是减少井壁失稳的重要途径。纳米材料因其独特的尺度和性质,可作为水基钻井液添加剂以提高页岩的稳定性。通过对国内外技术的跟踪与分析,阐述纳米材料提高页岩稳定性的评价方法、纳米材料类型及其作用机制。开展纳米材料在非均质地层的基础理论研究,开发在高温高压及高盐环境下稳定有效的新型纳米材料,建立纳米材料提高页岩稳定性的微观评价方法,是纳米材料的重要发展方向。

GY5-1-4H页岩油水平井提高固井质量关键技术研究与实践

针对页岩油水平井水平段长、井眼条件复杂、套管居中难度大、顶替效率低、水泥体系性能要求高等制约固井质量提高的难题,开展钻井参数与钻具组合协同优化技术研究,优化钻具组合,满足提高固井质量对井眼清洁的要求,通过顶替效率模拟研究设计了理想套管居中度,并以此优选了整体冲压螺旋半刚性扶正器和清水顶替预应力固井技术,基于韧性化改造技术提高水泥石强度,降低杨氏模量,改性水泥石可以满足页岩油井水力压裂要求。使用上述页岩油水平井固井工艺配套技术,确保了GY5-1-4H井固井质量合格,为长水平段水平井固井提供了一套可借鉴的固井关键技术。

Limit analysis of extended reach drilling in South China Sea

Extended reach wells （ERWs）, especially horizontal extended reach well with a high HD （horizontal displacement） to TVD （true vertical depth） ratio, represent a frontier technology and challenge the drilling limitations. Oil and gas reservoir in beaches or lakes and offshore can be effectively exploited by using extended reach drilling （ERD） technology. This paper focuses on the difficult technological problems encountered during exploiting the Liuhua 11-1 oil field in the South China Sea, China. Emphasis is on investigating the key subjects including prediction and control of open hole limit extension in offshore ERD, prediction of casing wear and its prevention and torque reduction, φ244.5mm casing running with floating collars to control drag force, and steerable drilling modes. The basic concept of limit extension in ERD is presented and the prediction method for open hole limit extension is given in this paper. A set of advanced drilling mechanics and control technology has been established and its practical results are verified by field cases. All those efforts may be significant for further investigating and practicing ERD limit theory and control technology in the future.

流域水资源配置方法研究

流域水资源配置解决的主要问题是确定不同天然来水情况下的省际规划出境水量,以及平原地下水规划开采量和入海水量。省际规划出境水量是流域水资源管理的基础指标,平原地下水规划开采量和入海水量是反映生态状况的指标。结合严重缺水的海河流域,研究并提出采用典型年法进行水资源配置的技术路线,提出2010规划水平年满足各项控制指标条件下省际配置分区经济社会发展的可利用水量。