Abstract The packer is a key component of the downhole sealing system during well completion stage, and its sealing reliability is directly related to the effectiveness of the downhole sealing system. The reliability assignment of the packer should meet the multi-level and multi-factor requirements, and it has the coexistence of quantity and quality analysis. Thus, how to achieve the reasonable reliability allocation of the packer is very important. This article introduced the reliability allocation for a typical compression packer based on the fuzzy analytic hierarchy process (FAHP) method. The structure of analytic hierarchy process for compression packer’s reliability allocation was established, which include the target layer, criterion layer and object layer. To quantitatively calculate the weights of the main part of the compression packer system, the FAHP method was performed, which consist of the sealing unit, anchoring unit, locking and anti-retreat unit, seating unit, unseating unit and anti-open unit. The three-scale judgment matrix scale was conducted to make the fuzzy consistency matrix meet the consistency conditions. Based on the weight analysis results and the preset reliability, the reliability allocation of the compression packer system was performed. The obtained distribution results satisfy the preset requirements and consistent with the actual operation of the packer, which proves the feasibility and validity of FAHP method. The proposed method reasonably solves fuzzy decision-making problem in the process of reliability allocation, and provides an efficient and reasonable way for the reliability allocation of the packer.

针对提高连续管井下作业延伸极限的振荡减阻工具,根据水击效应建立了振荡减阻器工作时的水击方程,采用渐近线法对水击方程组进行求解,得到装有振荡减阻器的管路内流体压力与流速分布.同时,根据动量定理计算了水击振荡器引起的管柱轴向力和径向力变化,此径向力将改变管柱的法向接触力,进而改变摩阻力.计算结果表明:流体流速幅度从振荡器位置向水平井跟端位置呈阶梯式降低,压力幅度呈阶梯式上升,在阀的每一个开关周期内流体流速和压力都会陡然变化.当流体通过振荡器时,由于流体流速变化,单位质量流体将产生瞬时轴向拉力,将管柱静摩擦转化为动摩擦,有助于连续管在井眼内移动.

为研究形状记忆筛管在出砂井井底发生膨胀后的工作性能,对膨胀后的形状记忆充填层进行取样,通过实验分析其性能特征.结果表明:采用自主研发的聚合物复合材料制备的形状记忆充填层的岩心样品的力学性能符合温敏型材料的变化规律;不同位置的3块岩心的绝对渗透率基本相同,形状记忆充填层的均质性好;岩心的压差变化小,形状记忆充填层的抗堵塞性能好;该形状记忆充填层具有良好的渗透性能、挡砂性能和耐酸碱性能,能够满足指定出砂井的生产要求.形状记忆充填层膨胀后的性能测试实验能够直观地分析形状记忆筛管膨胀后的工作性能,为环空自充填防砂完井技术的材料选择与现场应用提供实验方法和依据.

由单一相对分子质量多元醇制备的多孔隙形状记忆聚合物的性能无法满足完井的要求,需要采用不同相对分子质量多元醇制备多孔隙形状记忆聚合物.为给制备适用于不同井下条件的多孔隙形状记忆聚合物提供依据,通过改变不同相对分子质量多元醇的质量比,制备了不同的多孔隙形状记忆聚合物,并测试其力学性能、玻璃化温度、热敏性能和观察其孔隙结构,分析了不同相对分子质量多元醇的质量比对其性能的影响规律.低相对分子质量与高相对分子质量多元醇的质量比越大,多孔隙形状记忆聚合物的硬度、压缩强度和弯曲强度越高,玻璃化温度、热形变温度、形变恢复温度和开孔率越低,泡孔尺寸越大,孔型系数和泡孔壁厚越大,结构的各向异性越强.研究表明,通过调整制备原料中不同相对分子质量多元醇的质量比,可获得具有一定力学强度,同时满足不同井下温度条件形状恢复、对不同粒径地层砂具有滤砂过流功能的完井用多孔隙形状记忆聚合物.

Abstract In response to the borehole instability problems such as wellbore collapse and sand production, which often occur in drilling and completion, a thermosensitive screen technology that can expand spontaneously at a specific temperature has been developed. The radial expansion of the screen allows for annulus filling and borehole strengthening. This paper provides a theoretical evaluation of the comprehensive performance of the thermosensitive screen on wellbore collapse. The results show that the thermosensitive screen barely expands before reaching the conversion temperature, which facilitates the screen's descent into the target depth. After reaching the destination depth, it can be stimulated to expand under the influence of conditions such as formation temperature. The extruding stress after screen expansion contacting the wellbore wall can effectively improve the stress distribution around the near-wellbore and reduce the shear instability caused by the difference between the maximum and minimum principal stress of the formation, while at the completion stage of production, it can effectively improve the flowing downhole pressure, thus increasing the drawdown pressure.

为了解形状记忆筛管在井下环境的膨胀性能,根据该筛管在井下的膨胀原理,研发了能够模拟井下环境的形状记忆筛管膨胀性能测试系统,进行了形状记忆筛管样机膨胀性能测试,分析了循环流体排量和温度对响应温度、膨胀速度和膨胀力的影响.研究结果表明:随着循环流体排量增大,响应温度随之升高,膨胀速度降低;当循环流体温度不低于初始响应温度时,随着循环流体温度升高,膨胀速度增大;循环流体的排量和温度对最终膨胀力的影响较小.测试结果为形状记忆筛管的设计和应用提供了依据.

随着油田精细化作业的需要,井下分层作业任务多,急需开发自动化的井下作业工具.为了实现井下多任务作业机器人的远距离控制,提出了一种以电力线载波通信技术为核心的异构通信系统.通过现场试验,上位机可以准确有序地控制井下多任务作业机器人的动作,井下状态参数可以正确无误的显示在上位机交互界面上,实现了对井下多任务作业的合理管控.整个异构通信系统经济实用,误码率低,运行可靠,满足井下多任务作业机器人的控制要求.

针对独立筛管防砂完井无法支撑井壁、有效期短的问题,以及砾石充填防砂完井工艺复杂、易砂堵、费用高的不足,提出了利用一趟管柱实现长裸眼环空充填的形状记忆筛管完井技术.在优化设计形状记忆筛管机械结构的基础上,研究了形状记忆筛管生产工艺,研制了形状记忆防砂筛管,并对其性能进行了试验评价,形成了形状记忆筛管自充填防砂完井工艺.现场试验结果表明,形状记忆防砂筛管膨胀性能优越、能完全充填环空和炮眼,且膨胀后的渗透性好、挡砂精度高.形状记忆筛管自充填防砂完井技术施工工艺简单、能适应不规则井眼,具有很好的推广应用价值.

To address the problem of ultra-high pressure ultra-high temperature and difficult completion string design in the ultra-deep horizontal wells in Shunnan in the north slope of Tazhong, a set of optimization design methods for ultra-deep horizontal well multistage completion string is proposed. The wellbore pressure, temperature distribution and production casing safety factor of an ultra-deep horizontal well in Shunnan are calculated. The parameters including the completion string size, the completion fluid density and the position of the packer are optimized. The countermeasures for address the design problem of the completion string are formulated in a targeted manner. The design of the completion string is optimized and the operation control parameters under different working conditions are obtained:under the pressure of 50 MPa balanced casing pressure, the maximum pump pressure should not exceed 74 MPa during low acid squeezing. When the fracturing displacement is 7 m3/min, the predicted pump pressure is 110 MPa. Assuming daily gas production of 20×104 m3, the predicted tubing pressure is 53 MPa, presenting no need to balance the casing pressure. The production capacity is exhausted in the late development stage, and the pure gas tubing pressure should be no less than 14 MPa. Based on the optimized completion string, the packers are stress checked, and the performance of the liner hanger packer and the multistage open-hole packer under all working conditions meets the design requirements. The study could provide references for similar designs.

The Shuntuo and Shunnan areas in Tahe Ordovician reservoir belong to ultra-high temperature ,ultra-high pressure and ultra-deep fracture-vug gas reservoir .Horizontal well staged stimulation technology was applied to achieve mufti-stages fracturing and improve cave conductivity for economical and efficient development of oilfield . For the high temperature , high operation pressure and complex stress characteristics of ultra-deep horizontal well staged fracturing string , the mechanic analytic model of the ultra-deep horizontal well multistage fracture string was established .The mechanic analysis method for various fracturing conditions was proposed according to the charac -teristics of different fracturing stages .Based on the model established , taking a Shunnan well as an example , the force analysis for the staged fracturing string was conducted for various fracturing conditions .The sting optimization design was carried out for solving the problems and improving the safety performance .The calculation results also showed that the model established could provide theoretical basis and method for the safety check and optimization design of ultra-deep horizontal well staged fracturing string .

Downhole flow automatic control is an important means to realize the stratification and control of oil layers. The downhole flow automatic control valve is an important equipment of modern intelligent well technology. In order to realize the opening control of the downhole flow control valve, the DC motor is used as the actuator to drive the valve mechanism to reach the predetermined position. The opening control system of the downhole intelligent flow control valve is designed with the high performance and low cost STM32 series chip as the core controller. The hardware and software design scheme and control strategy of the control system are proposed. Aiming at the opening control system of the flow control valve, the fuzzy PID control algorithm is studied. The experimental results show that the developed opening control system has simple structure and high control precision, which can meet the requirements of downhole application.

针对地热井的保温增效问题,根据地热井井身结构特点,建立井筒温度计算模型,并利用A地热井现场测试数据对模型进行验证,应用该模型对地热井热损失影响因素进行了敏感性分析.结果表明,通过有效洗井等措施,将局部井段产水转化为全井段产水,可使井口产液温度由61.2℃增加至65.7℃;井口产液温度随着日产量的增加而增高,但增幅逐渐减少;改变井身结构能显著提高井口产液温度,但需要进行系统的井身结构优化;采用保温材料的泵管带泵下深400 m时,井口产液温度达到70.9℃,比常规泵管提高2.7℃.分析结果为地热井保温增效开发提供了理论依据.

For geothermal wells in China, heat preservation and cost saving are critical to amplify industry scale, upgrade industrial structure, and optimize energy structure.Therefore, a wellbore temperature calculation model was established considering the characteristics of geothermal well bore configuration.The model was valida-ted through the test data of a case well,and the deviation of wellhead fluid temperature was only 1℃compared with the real data and simulated date.For sections with severe heat loss in geothermal well, a new completion string structure was proposed based on heat transfer coefficient models and temperature calculation methods.Field appli-cations show that wellbore heat loss was reduced significantly by changing the completion string and annulus media, for example, the temperature of wellhead fluid production raised 6.1℃by changing completion string and 10.1℃by using the insulation tubing.Completion string was optimized considering construction and material cost.The re-sults are meaningful for the development of geothermal wells.

针对水平井作业机器人的结构特点,采用分布式结构理论,设计了基于PIC18F2620微控制器的1个上位机和多个分布式下位机的2层分布式控制系统。上位机通过电力线向下位机发送控制指令,控制相应的下位机控制模块完成特定的功能,同时实时接收下位机反馈的状态监测参数,并在人机交互界面上实时显示和判断水平井作业机器人的工作状态;上位机与下位机之间采用电力线载波通信技术实现电力传输和数据通信。通信试验和综合测试结果表明,水平井作业机器人分布式控制系统运行稳定,通信实时性强,满足水平井作业机器人的控制要求。

针对海上稠油热采水平井对热采封隔器密封件性能的特殊要求，设计了检测热采密封件性能的试验方案，制定了试验标准，检测了国内目前常用的热采密封件耐高温高压和适应温差变化的性能，优选试制了新型的密封组件，满足了热采生产井对热采封隔器的要求。文中主要介绍了试验检测所用高温高压系统、评价的方法、工艺流程、常用热采封隔器密封件检测情况、新型密封组件检测情况、试验结果的分析等。

AHR packer retrieval by normal overpull can be difficult when they have been set in highly deviated or horizontal sections ,or when improper operations have caused workover problem .The axial force of tubing in horizontal well was analyzed based on structure and mechanism analysis of the AHR packer , and the over pull force that transmitted to the packer was simulated .Within the rated tensile strength of tubing if the overpull was not sufficient to overcome the preset releasing force of the packer ,coil tubing could be utilized to evacuate the tubing by pumping nitrogen through positive circulation ,and release for‐mation pressure to push the packer upwards ,at the same time ,tubing could be pulled for shearing off the pins and releasing the packer .Taking Well S22 in Y field as an example ,when the pulling force reached a tensile strength of 921 kN ,the force transmitted to the packer was only 236 kN ,then 1 650 m was tubing was e‐vacuated and 205 kN upwards force was released ,the total force applied to the pins of the packer was 441 kN ,the packer was successfully released .The study demonstrated that the evacuation of partial fluid to release the forma‐tion pressure can compensate for the insufficient releasing force on the packer ,and the approach can provide refer‐ence of theory and practice for releasing packers in highly deviated or horizontal wells .

热采水平井蒸汽吞吐时水平段吸汽不均衡,造成水平段动用不均。鉴于此,对热采水平井改善吸汽剖面技术进行研究。首先,建立油藏-井筒流动耦合模型及储层热-流-变形三场耦合模型,定量分析了油层物性参数、非均质性及注汽口位置对吸汽剖面的影响。然后,根据上述分析结果,设计了均衡注汽完井工艺管柱。该管柱可实现注采一体化及均匀注汽以及长水平段、非均质储层的均匀注采。现场应用结果表明,热采水平井改善吸汽剖面技术可以改善热采水平井长水平段的吸汽剖面,实现均衡注汽,提高水平井的动用程度。

Abstract Nowadays, the annual heavy oil production is more than 15 million tons in China and more than 60% of which are developed by cyclic steam stimulation (CSS) technology. Vacuum insulated tubing (VIT) with thermal packer is the mostly adopted thermal insulation manner during steam injection progress. This usually leads to two major problems. One is casing integrity issues like casing crack, casing collapse, and cement sheath damage induced by thermal packers's failure or cyclic casing as Well as cement heating. Another problem is frequent injection and production strings transformation, and this leads to operation cost increasing and high temperature production time wasting especially when CSS is of short cycle in super-heavy oil or thin thickness reservoirs. In order to solve the two problems, the vacuum insulated casing (VIC) and relevant integral completion technique are researched taking well completion, heat insulation and hereafter production into consideration simultaneously rather than separately. This completion technique injects steam by VIC while not by VIT and produces in normal tubing, thus eliminates the thermal packer's failure problems, meanwhile, simplifies the injection and production pipe conversion process and saves production time. VIC's heat loss and steam quality along wellbore are compared with that of VIT. The related techniques like cementing, perforation while adopting VIC are also studied. Field trials in Henan oilfield in China verify this completion's suitability for CSS in heating insulation, production performance and economics compared with normal method of CSS. The completion provides a long-term Well integrity solution for thermal Well recovery not only by CSS, also by other thermal manners like SAGD. Also, it can play an important role in heat proof exploitation of other resources like gas hydrate and geothermal energy.

针对常规分抽混出泵上泵环形固定阀可靠性差的问题,通过采用桥式通道,改进了流道结构,将上泵固定阀置于下泵下面,实现了上泵的单泵阀结构,提高了分抽泵的可靠性。改进后的分抽泵设计了流道交叉接头,可实现上下泵流道交叉互换,使上下泵对上下层的抽汲互换,从而可以满足多种地质配产需要。针对分抽混出泵整体管柱采用机械坐封造成管柱弯曲、加剧杆管偏磨的问题,配套了丢手插管工艺管柱。改进后的分抽混出泵在河南油田推广应用37井次,平均检泵周期由124 d延长到242 d,平均泵效提高8.8%,累计增油4 322.7 t。

The drillable pumping bridge plug is the key tool for the piecewise completion of unconventional oil-gas resource horizontal wells.A kind of bridge plug was developed studying the current situation of domestic and foreign shale gas well completion and bridge plug technology.The bridge plug consists of two groups of anchor mechanism,cuneiform packer rubber of multi-stage shoulder protection,external self-locking mechanism,and meshing anti-rotary mechanism.The matching tools and the test device were analyzed and the systematic laboratory test and the major testing of the key technology were carried out.The testing results show that the designed bridge plug is reasonable in structure,reliable in sealing,and high in indexes and properties.It can satisfy the requirement of piecewise fracture completion of shale gas.Finally,it is suggested that the bridge plug and the matching technology should be improved through field test on the basis of improving the comprehensive performance of the material in the later stage.