The imbibition law of the Jurassic continental shale in Fuxing area is not clear， which brings great challenges to the production test after well shut-in. In addition， studies on the imbibition law and influencing factors of continental shale are insufficient. Therefore， the experiment on the imbibition law of the Jurassic continental shale in Fuxing area was conducted based on the low-field nuclear magnetic resonance （NMR）. First， the differences in physical properties of shale of Lianggaoshan Formation and Dongyuemiao Member in Ziliujing Formation were tested and analyzed. Then， the changes in permeability and porosity before and after the imbibition were set as the evaluation indexes， and the influences of lithology， fluid， fluid pressure， and clay content on the imbibition law of the continental shale were analyzed. Besides， the wettability of the continental shale was evaluated. The experimental results show that compared with that of Dongyuemiao Member， the average porosity of shale of Lianggaoshan Formation is smaller， and the average permeability is larger； the average brittle mineral content is higher， and the average clay mineral content is lower. During the imbibition process of the Jurassic continental shale in Fuxing area， micro-fractures are induced by clay hydration， which provides additional imbibition channels. However， the imbibition ability of limestone is weaker than that of shale， and there are no micro-fractures during the imbibition； in addition， the shell limestone interlayer in the reservoir may inhibit the imbibition and micro-fracture propagation in the shale. The oil phase will enhance the micro-fracture propagation after the shale induces micro-fractures in the aqueous phase， and the complicated oil-water phase imbibition may be beneficial to the permeability improvement in the shale reservoir. Compared with atmospheric imbibition， pressureed imbibition has a limited effect on inducing micro-fractures and improving permeability， and the imbibition rate is larger； the imbibition equilibrium is earlier， but the imbibition amount is smaller. The influence of confining pressure on imbibition should be considered during well shut-in. The micro-fractures induced by hydration in shale with high clay mineral content are more significant， and the effect of improving permeability is more obvious. The imbibition rate and imbibition amount of shale in the oil phase are smaller than those in the aqueous phase， and the wettability of shale is hydrophilic. The experiment reveals the imbibition law and the characteristics of micro-fractures induced by the hydration of the Jurassic continental shale in Fuxing area， which provides a theoretical basis for the well shut-in and production test of continental shale during flowback.

Abstract Marine shale has been developed successfully in China, however, the exploration and development of the continental shale is still limited. Study about imbibition and influence factors of the continental shale is insufficient. The objective of the proposed paper is to design and conduct an imbibition experiment to research imbibition rate, imbibed volume, induced crack and influence factors in the Jurassic continental shale in Sichuan basin in China. The imbibition experiment is developed based on the low field Nuclear Magnetic Resonance(NMR) and accurate weighting. The permeability, porosity and mineral composition of shale samples of LU Formation and DD Formation are measured and the differences are analyzed. The change of permeability and porosity before and after the imbibition process is set as the evaluation index and the influence factors of imbibition in the continental shale are analyzed. The influence factors include lithology, imbibition fluid, imbibition pressure and clay content. Besides, the wettability of the continental shale is estimated in the experiment. The experimental results show that the imbibition capacity of the limestone sample is weaker than that of shale samples, and the shell limestone interlayer in the continental shale reservoir may inhibit the imbibition and crack propagation in the shale. Oil phase may enhance the crack propagation after the shale samples induced crack in aqueous phase, and the complicated phase imbibition in the continental shale reservoir may be beneficial to the permeability improvement. The forced imbibition has weaker capacity of crack induction and permeability improvement compared to the spontaneous imbibition, and the influence of the reservoir confining pressure on the imbibition should be considered during the well shut-in process after hydraulic fracturing. The higher clay content shale sample has stronger capacity of crack induction and permeability improvement compared to the lower clay content shale sample. The wettability of the continental shale sample is water-wet. The imbibition experiment reveals the imbibition law and the induced crack character of the continental shale samples, whose results fill the gap in existing studies and have a theoretical guidance for the shut-in and flowback design in the continental shale reservoir.

目前排水采气工艺选择采用现场经验法和宏观控制图版法,因考虑因素欠缺,工艺实施效果较差,文章根据压力供给与临界携液原则,结合经济效益分析,开展了页岩气井排水采气工艺综合优选.根据误差分析优选Mukherjee-Brill两相流模型用于计算页岩气井筒压力分布,确定排水采气工艺的压力适用界限;考虑产液量、液滴变形和造斜率变化引起的液滴碰撞,建立页岩气井全井筒临界携液流量模型,确定排水采气工艺的携液适用界限,最终建立页岩气井排水采气工艺综合优选方法.实例分析表明,页岩气井临界携液流量模型的预测精度达94.1％,页岩气井排水采气工艺综合优选方法能够实现"一井一策"的排水采气工艺定量优选,优选后的排水采气工艺具有良好的排液增产效果与经济效益.

To improve the safety of cluster perforating tubing strings in horizontal wells with unconventional oil/gas reservoirs, a passing capability analysis model for cluster perforation string in a wellbore is established, in which the friction between downhole tools and borehole wall, fluid resistance, wellbore geometric constraint, and tool variable cross section were accounted for. The model is solved via geometric analyses and the beam-column theory. Then, the cable pump thrust test is carried out in three shale gas wells in South Sichuan, and com-paring the measured data with the theoretical calculation results, the correctness of the theoretical model is verified. Based on that, the influences of the cluster numbers, the perforating gun types, the well section length, and the well types on the mechanical characteristics of the cluster perforation string are systematically analyzed. The results obtained demonstrate that, first, the number of perforating gun clusters should be as small as possible when the azimuth angle or well inclination angle changes greatly. In case of a small change of azimuth or deviation angle, the number of perforation gun clusters can be appropriately increased to improve the operation efficiency. Second, when the deviation angle and azimuth angle change greatly in field operation, it is recommended to use a small perforating gun to ensure the smooth running of the perforating string. When a large perforating gun is needed in the field, it is necessary to optimize the well trajectory (reduce the location of the big dogleg in wellbore) to ensure the safe running of the tubing string. Third, in the field well trajectory optimization design, the position of well inclination angle change and azimuth angle change should be staggered to improve the trafficability of perforating tubing strings on -site. Moreover, when increasing the well sections, the position of the knee point should be optimized to be smoother, and the change rate of the parameter value of the well trajectory should be reduced. The research results pro-vide a theoretically sound guidance for designing and practically sound approach for effectively improving the service life of perforating tubing strings in horizontal wells with unconventional oil/gas reservoirs.

Due to the mechanical structure and operating principle of sliding vane pump (SVP), an all-metal artificial lift equipment with high temperature resistance and high pump efficiency, an unbalanced radial hydraulic force always exists in it during oil recovery, which will cause damage on efficiency, safety and service life of production system. What's more, the flow behavior of fluid through the pump cannot be accurately characterized because current related works fails to capture the influence of the force mentioned. To bridge this knowledge gap, in this paper, the computational fluid dynamics method was introduced and used to analyze the radial hydraulic force under different operating parameters for the first time. On this basis, novel measures to reduce this unbalanced force were put forward, and a design scheme of concentric stator-rotor to completely eliminate the radial hydraulic force was proposed. Main results show that a) increase in eccentricity will contribute to the enhancement of discharge capacity, which will simultaneously aggravate the radial hydraulic force. And this force is proportional to the fluid viscosity, lifting pressure difference and rotation speed. b) The direction of radial hydraulic force of adjacent stages in multistage SVP is opposite. To reduce this unbalanced force, it is recommended to use even-numbered (odd-numbered) multistage pump when the number of total stages is small (large). c) The concentric design eliminates the radial hydraulic force at the expense of the function of self-regulating flow rate. Besides, the stator curve under concentric stator-rotor condition will degrade the kinetic characteristic of vanes.

针对水平井产出剖面测试需求和传统生产测井技术的局限性和建立数字化油田所需的单井生产数据不够精细,提出了量子点示踪剂产出剖面测试技术,对长水平井进行长时间生产动态监测.建立了瞬态监测阶段和稳态监测阶段量子点示踪剂产出模型,提出了量子点示踪剂产出剖面采样、检测和解释的流程.通过1口水平井的应用论证了智能示踪剂技术在监测水平井各段油水产量的有效性,说明了量子点示踪剂监测技术具有连续分相态、分段监测井下生产动态的功能.智能示踪剂产出剖面测试与解释技术可以实时监测一口井的生产健康情况,发现产水段,为见水井精细调剖堵水提供帮助,为数字化油井和油田的建立提供精细化的数据.

Multi-gas assisted steam huff and puff process is a relatively new thermal recovery technology for offshore heavy oil reservoirs. Some blocks of Bohai oilfield have implemented multi-gas assisted steam huff and puff process. However, the development mechanism still requires further study. In this paper, high-temperature high-pressure (HTHP) PVT experiments and different huff and puff experiments of sand pack were carried out to reveal the enhanced production mechanism and evaluate the development effect of multi-gas assisted steam huff and puff process. The results indicated that viscosity reduction and thermal expansion still were the main development mechanism of multi-gas assisted steam huff and puff process. Specifically, CO2 easily dissolved in the heavy oil that made it mainly play the role of reducing oil viscosity, N2 was characteristics of small solubility and good expansibility, and it could improve formation pressure, increase steam sweep volume and even reduce the heat loss. Meanwhile, injecting multi-gas and steam could break the balance of heavy oil component that made the content of resin reduce and the content of saturates, aromatics and asphaltene increase so as to further reduce the viscosity of heavy oil. Compared with steam huff and puff process, multi-gas assisted steam huff and puff process increased the recovery by 2–5%. The optimal water–gas ratio and steam injection temperature were 4:6 and 300℃, respectively. The results suggested that multi-gas assisted steam huff and puff process would have wide application prospect for offshore heavy oil reservoirs.

目前的临界携液流量模型均未完整反映页岩气井的复杂井身结构和返排液量变化特征,无法准确预测页岩气水平井积液.为此,通过对液滴动力学和能量分析,综合考虑井筒产液量、液滴变形和造斜率变化引起的液滴能量损失,建立了页岩气井全井筒临界携液流量模型.根据最大稳定变形液滴能量平衡关系,确定了最大稳定变形液滴长轴长度;选取了适用于页岩气水平井的曳力系数和表面张力公式;根据误差分析优选了Mukherjee-Brill两相流模型计算页岩气水平井井筒压力分布.实例分析表明,与现有临界携液流量模型相比,新模型对于页岩气水平井的积液预测符合率最高,预测精度达92.3％.新模型可以准确预测积液井和接近积液井,对不积液井的积液预测精度也能满足现场应用要求,可以有效指导页岩气井积液判断与排采工艺选择.

探讨塔河区块储层的应力敏感性,为制定合理生产制度提供依据.通过对目标区奥陶系储层碳酸盐岩开展不同温度下应力敏感评价实验,结果表明:碳酸盐岩应力敏感程度属于中等偏强型;碳酸盐岩试样渗透率随着有效围压增加呈指数型递减,卸压后试样渗透率难以恢复至加载前水平;试样渗透率与温度呈负指数关系,当试样从30℃升高至120℃时,渗透率损害率从0.53增长到0.65,温度敏感性增强23％.温度对塔河区块储层应力敏感有明显的影响.

Current critical flow rate models fail to accurately predict the liquid loading statuses of shale gas horizontal wells. Therefore, a new critical flow rate model for the whole wellbore of shale gas horizontal wells is established. The results of the new model are compared to those of current models through the field case analysis. The new model is based on the dynamic analysis and energy analysis of the deformed liquid-droplet, which takes into account the liquid flow rate, the liquid-droplet deformation and the energy loss caused by the change of buildup rate. The major axis of the maximum stable deformed liquid-droplet is determined based on the energy balance relation. Meanwhile, the suitable drag coefficient equation and surface tension equation applied to shale gas horizontal wells are chosen. Finally, the critical flow rate equation is established and the maximum critical flow rate of the whole wellbore is chosen as the criterion for liquid loading prediction. The precision of liquid loading prediction of the new model is compared to those of the four current models, including Belfroid's model, modified Li's model, liquid film model and modified Wang's model. Field parameters of 29 shale gas horizontal wells are used for the comparison, including parameters of 18 unloaded wells, 2 near loaded-up wells and 9 loaded-up wells. Field case analysis shows that the total precision of liquid loading prediction of the new model is 93.1%, which is higher compared to those of the current four models. The new model can accurately predict the liquid loading statuses of loaded-up wells and near loaded-up wells, while the prediction precision for unloaded wells is high enough for the field application, which is 88.9%. The new model can be used to effectively estimate the field liquid loading statuses of shale gas horizontal wells and choose drainage gas recovery technologies, which considers both the complex wellbore structure and the variation of flowback liquid flow rate in shale gas horizontal wells. The results of the new model fill the gap in existing studies and have a guiding significance for liquid loading prediction in shale gas horizontal wells.

储气库井生产制度设计不合理会导致管柱冲蚀而造成管柱失效,为储气库长期安全运行带来安全隐患.根据文23储气库井注采管柱结构与生产工况,建立文23储气库注采管柱冲蚀模型,研究了注气和采气过程管柱的冲蚀规律,同时分析了发生冲蚀的极限工况.结果表明,注气时管内实际流速与临界冲蚀流速均随井深的增加先增大后减小,在1300 m左右达到最大值;极限注气量随注气压力增加而增加.采气时管内实际流速与临界冲蚀流速均随井深变化先减小后增大,在1500 m左右达到最小值;管内实际流速与临界冲蚀流速均随井口压力减小而增大,最小井口压力与极限采气量均随地层压力减小而减小.

经长输管线输送的天然气注入到地下空间而形成的人工气藏称为地下储气库.国内外现有储气库大多数是枯竭气藏型地下储气库.中国石化储气库建设起步较晚,基础较为薄弱,同时与国内外已建成储气库相比,中石化储气库建设面临的地质条件和注采工况也较为复杂.以中国在建最大储气库项目中原文23储气库为例,其复杂地质条件以及面临的"快瞬变非稳态增压"注采难题需要进行专门研究.分析了目前中石化枯竭型气藏储气库建库现状,提出了建库技术挑战,总结了现阶段取得的注采关键技术研究成果,通过分析中国石化枯竭气藏型储气库注采技术研究现状和最新进展,提出了国产化技术完善、智能化注采营运、一体化模拟实验室的建设等方面的发展建议和要求,为持续加强规模化储气库群建设的支持提供参考.

为完善垂直上升管内气液过喷射旋流工具诱导螺旋环状流流压降计算方法,在前人单相螺旋环状流研究的基础上,结合螺旋体的结构特征,初步建立了垂直上升管内气液螺旋流压降计算模型,然后通过室内评价实验对模型进行了校验,对模型进行了修正,解决了单相螺旋环状流摩阻系数进行两相螺旋环状流压降计算的误差问题,最终得到了垂直上升管内气液两相螺旋环状流压降计算的数学模型.将新模型的螺旋环状流压差计算结果与实验结果进行误差分析,结果表明该模型压降预测精度达到97.5％,能够用来进行井下喷射旋流工具诱导螺旋环状流的压降计算.

There is no precedent for the application of rotary flow jetting tool in the drainage gas recovery under gas wells. Based on the motion principles of jet flow and vortex flow, this paper designs a downhole rotary flow jetting tool, and verifies the feasibility of the tool through fluid simulation. Next, an indoor experiment device was established for drainage gas recovery with rotary flow jetting tool by the principle of similarity, and the structural parameters of the tool were subject to multi-objective optimization through orthogonal experiments. The optimized tool can achieve ideal rotary flow height and discharge volume. The results show that the proposed rotary flow jetting tool can effectively separate gas from liquid, and produce a rotary flow. The optimal structural parameters were determined as follows: the pitch diameter of spiral body is 45mm, the throat pipe length is 247mm, the spiral angle is 55°-60°, the spiral wing width is 4-6mm, and the nozzle diameter is 15-25mm. In addition, the number of side holes of the throat pipe has little effect on the jetting effect.

随着水平井分段完井技术的发展,完井结构变得越来越复杂,为了准确模拟水平井分段完井流入剖面,研究了基于节点网络的水平井分段流入剖面预测方法.将完井结构简化为由地层、井壁与完井工具间的环空、完井工具构成的水平井井筒网络,基于物质守恒原理和动量守恒定理,建立了各类流动桥的压降模型;用桥流动指数来表征流体流动方向,建立了耦合地层、井壁与完井工具间的环空、完井工具三者之间的流体流入剖面预测模型,并采用Newton-Raphson迭代方法进行了求解.算例分析表明,应用该方法可预测水平井复杂完井结构的环空、油管中的压力和流量分布,准确反映完井方式和完井工具对井筒流体流入剖面的影响,且具有较高的预测精度.研究认为,建立的水平井分段流入剖面模型可为完井方式选择、参数优化设计提供理论支撑.

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.

To deal with low production,low liquid and low efficiency which occur after large-scale horizontal well fracturing has been carried out to develop tight oil reservoirs in Southern Ordos Basin,and to further determine oil reservoir performance and improve the development,a number of feasible solutions and production recovery measures were determined and implemented by evaluating the potential of under-performing wells.Based on the principle of remote intelligent control,a high-performance downhole intelligent switch was developed.A smart layering exploiting technology with a low cost and a simple operation procedure was developed by applying intelligent microelectronic technology to production strings based on mechatronics,by means of a string mechanics effect calculation method used for multiple-packer combination,the deformation of smart layering exploiting string and the load in the process of water packing were calculated to avoid movement and failure of packers.This technique was tested at 5 wells.It was shown that this smart layering exploiting technology could acquire production data effectively,decrease water cut and increase production rate.Therefore it was advantageous due to its low construction cost and a convenient layer control.Further,it may be an effective technique of water production control and oil production stabilization in tight oil reservoir horizontal wells.

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 .

产出剖面测试技术在涪陵地区页岩气井的应用还不成熟,面临着诸多技术难点和挑战.在分析各种技术难点的基础上,有针对性地提出了解决涪陵地区页岩气井产出剖面测试技术难题的技术思路和方法.分别论述了仪器输送方式的选取、井控设备的优选、测试仪器的优选、测试制度的制定和资料解释方法.通过1口页岩气水平井产出剖面测试的现场试验和资料解释,表明了测试工艺的可行性和资料解释方法的可靠性.