Study of inter-well interference in shale gas reservoirs by a robust production data analysis method based on deconvolution

In order to overcome the defects that the analysis of multi-well typical curves of shale gas reservoirs is rarely applied to engineering,this study proposes a robust production data analysis method based on deconvolution,which is used for multi-well inter-well interference research.In this study,a multi-well conceptual trilinear seepage model for multi-stage fractured horizontal wells was established,and its Laplace solutions under two different outer boundary conditions were obtained.Then,an improved pressure deconvolution algorithm was used to normalize the scattered production data.Furthermore,the typical curve fitting was carried out using the production data and the seepage model solution.Finally,some reservoir parameters and fracturing parameters were interpreted,and the intensity of inter-well interference was compared.The effectiveness of the method was verified by analyzing the production dynamic data of six shale gas wells in Duvernay area.The results showed that the fitting effect of typical curves was greatly improved due to the mutual restriction between deconvolution calculation parameter debugging and seepage model parameter debugging.Besides,by using the morphological characteristics of the log-log typical curves and the time corresponding to the intersection point of the log-log typical curves of two models under different outer boundary conditions,the strength of the interference between wells on the same well platform was well judged.This work can provide a reference for the optimization of well spacing and hydraulic fracturing measures for shale gas wells.

Inter-well internal resonance analysis of rectangular asymmetric cross-ply bistable composite laminated cantilever shell under transverse foundation excitation

The chaotic dynamic snap-through and complex nonlinear vibrations are investigated in a rectangular asymmetric cross-ply bistable composite laminated cantilever shell,in cases of 1:2 inter-well internal resonance and primary resonance.The transverse foundation excitation is applied to the fixed end of the structure,and the other end is in a free state.The first-order approximate multiple scales method is employed to perform the perturbation analysis on the dimensionless two-degree-of-freedom ordinary differential motion control equation.The four-dimensional averaged equations are derived in both polar and rectangular coordinate forms.Deriving from the obtained frequency-amplitude and force-amplitude response curves,a detailed analysis is conducted to examine the impacts of excitation amplitude,damping coefficient,and tuning parameter on the nonlinear internal resonance characteristics of the system.The nonlinear softening characteristic is exhibited in the upper stable-state,while the lower stable-state demonstrates the softening and linearity characteristics.Numerical simulation is carried out using the fourth-order Runge-Kutta method,and a series of nonlinear response curves are plotted.Increasing the excitation amplitude further elucidates the global bifurcation and chaotic dynamic snap-through characteristics of the bistable cantilever shell.

Inter-well interferences and their influencing factors during water flooding in fractured-vuggy carbonate reservoirs

Based on the characteristics of injection-production units in fractured-vuggy carbonate reservoirs,nine groups of experiments were designed and performed to analyze the interference characteristics and their influencing factors during water flooding.Based on percolation theory,an inversion model for simulating waterflooding interferences was proposed to study the influence laws of different factors on interference characteristics.The results show that well spacing,permeability ratio,cave size,and cave location all affect the interference characteristics of water flooding.When the cave is located in high permeability fractures,or in the small well spacing direction,or close to the producer in an injection-production unit,the effects of water flooding are much better.When the large cave is located in the high-permeability or small well spacing direction,the well in the direction with lower permeability or smaller well spacing will see water breakthrough earlier.When the cave is in the higher permeability direction and the reserves between the water injector and producer differ greatly,the conductivity differences in different injection-production directions are favorable for water flooding.When the injection-production well pattern is constructed or recombined,it’s better to make the reserves of caves in different injection-production directions proportional to permeability,and inversely proportional to the well spacing.The well close to the cave should be a producer,and the well far from the cave should be an injector.Different ratios of cave reserves to fracture reserves correspond to different optimal well spacings and optimal permeability ratios.Moreover,both optimal well spacing and optimal permeability ratio increase as the ratio of cave reserves to fracture reserves increases.

Inter-Well Coupling and Resonant Tunneling Modes of Multiple Graphene Quantum Wells

We investigate the inter-well coupling of multiple graphene quantum well structures consisting of graphenesuperlattices with different periodic potentials.The general form of the eigenlevel equation for the bound states of thequantum well is expressed in terms of the transfer matrix elements.It is found that the electronic transmission exhibitsresonant tunneling peaks at the eigenlevels of the bound states and shifts to the higher energy with increasing the incidentangle.If there are N coupled quantum wells,the resonant modes have N-fold splitting.The peaks of resonant tunnelingcan be controlled by modulating the graphene barriers.

Theoretical and experimental study of a bi-stable piezoelectric energy harvester under hybrid galloping and band-limited random excitations

In the practical environment,it is very common for the simultaneous occurrence of base excitation and crosswind.Scavenging the combined energy of vibration and wind with a single energy harvesting structure is fascinating.For this purpose,the effects of the wind speed and random excitation level are investigated with the stochastic averaging method(SAM)based on the energy envelope.The results of the analytical prediction are verified with the Monte-Carlo method(MCM).The numerical simulation shows that the introduction of wind can reduce the critical excitation level for triggering an inter-well jump and make a bi-stable energy harvester(BEH)realize the performance enhancement for a weak base excitation.However,as the strength of the wind increases to a particular level,the influence of the random base excitation on the dynamic responses is weakened,and the system exhibits a periodic galloping response.A comparison between a BEH and a linear energy harvester(LEH)indicates that the BEH demonstrates inferior performance for high-speed wind.Relevant experiments are conducted to investigate the validity of the theoretical prediction and numerical simulation.The experimental findings also show that strong random excitation is favorable for the BEH in the range of low wind speeds.However,as the speed of the incoming wind is up to a particular level,the disadvantage of the BEH becomes clear and evident.

非均质气藏井间地层压力计算方法及应用

中国陆相沉积气藏储层普遍存在非均质性,常规地层压力计算方法具有很大局限性,难以准确评价井间地层压力。本文以均质地层中的点源解为基础,采用边界元思想,建立了一种可用于非均质气藏井间地层压力计算的半解析方法。基本思想是将非均质储层进行分块处理,分别建立单个均质区域的压力方程,通过各区交界面处的压力和流量连续条件,将各区压力方程耦合求解,并将求解结果回代至单个区域的压力方程,从而计算地层中任意一点的压力。建立了理论模型,对所提出的井间地层压力计算方法进行了数值验证,并将其应用于长庆靖边气田某区块。结果表明,本文所建立的非均质气藏井间地层压力半解析计算方法与数值模拟计算结果相吻合,仅在早期和井筒附近存在微小差异;半解析方法能很好地预测实际气藏中单井及井间的地层压力变化,与实测数据趋势一致。

威荣深层页岩储层水力压裂多井压窜现象及机理

威荣深层页岩气田五峰组—龙马溪组储层埋藏深,地质构造复杂,强非均质性天然裂缝发育,地应力高且水平地应力差大,非连续性构造在高临界应力环境下易出现扰动失稳。在储层局部连续裂缝带发育和高应力环境的共同作用下,前期400 m井距条件下出现邻井压窜和多井巷道压窜现象,导致大量生产井产能下降、续建井井壁失稳及套变问题。针对以上问题,文中基于地质-工程一体化思路,考虑了多种复杂天然裂缝分布特征和复杂裂缝扩展应力干扰效应,建立了基于DFN-FEM的井组压裂复杂裂缝扩展模型。研究发现:1)天然裂缝带和大型断裂是多井巷道压窜的主要地质因素;2)天然裂缝面法向刚度越小,压裂应力扰动范围越大,压窜越严重;3)内摩擦角和内聚力越小,岩石越容易破裂并诱发压窜;4)井组压裂顺序对压窜类型和程度均有显著影响,交错压裂最优。该研究结果可为威荣页岩储层水平井井间干扰防治与产能恢复提供依据,进而有效支撑以威荣为代表的深层页岩气田的安全高效开发。

海上油田井间连通性识别方法研究

与陆上油田相比,海上油田油水分布更复杂、储层非均质性更严重,注水开发中后期出现存水率低、注水效率低的问题,亟需精准高效的水驱调控技术改善水驱开发效果、提高油气采收率。井间注采连通性的精确识别与表征,是海上油田潜力分析和综合治理方案制定的重要基础,基于井间连通性定量评价的动态分析和流场表征能够为解决注采井网不完善、存水率和储量动用程度低等瓶颈问题提供有力的依据。分析了连通性识别方法的基本原理和特点,论证了其在海上油田的适用性,提出了基于注采数据的反演模型法在海上油田条件下的技术优势,明确了该方法未来的改进方向。

海上特超稠油油藏小井距蒸汽吞吐汽窜堵调工艺

渤海某大规模热采开发的特超稠油油藏在一轮次注热期间井间汽窜率超70%,严重影响油田产能。针对该情况,基于探井、测井认识,先后开展药剂性能评价、单/双管驱替实验及现场堵调应用,对高含水层物性得到了进一步认识,随后开展泡沫调剖、井组同注数值模拟及现场试验,井间汽窜得到有效控制。研究结果表明,局部高含水低渗储层经蒸汽冲刷后平均渗透率或高于探井阶段测量值,对于已汽窜井开展井组同注措施,对于未汽窜井及井组边部井采用强化泡沫调剖,该措施不仅可以有效控制和预防汽窜,同时可均匀动用储层,优势层段吸汽剖面级差降低46.8%。泡沫调剖辅助井组同注的工艺策略实施后单井产能提高12%~33%,对海上特超稠油高效开发具有指导意义。

煤层气直井储层堵塞原因分析及解堵措施应用

针对煤层气直井储层堵塞后气量难以恢复的问题,开展了储层堵塞原因及恢复措施的研究。通过对煤层气直井储层堵塞成因及生产特征分析,将储层堵塞分为三种类型:层间干扰型、排采不连续型、井间干扰型,针对不同原因导致的储层堵塞在进行压裂车解堵时应根据各自的是适应性进行选井和施工,同时尽可能增大措施规模和排量,提高措施见效率和单井产气量。本文提供的压裂车解堵技术,能够有效解决储层堵塞问题,提高储层堵塞井单井产气量。

水驱油藏优势渗流通道识别及其效果分析

油藏中优势渗流通道的存在及其分布,显著影响着油藏开发对策与开发效果。本文综合运用多相渗流和储层地质理论,建立表征注采井间小层连通性及识别优势渗流通道存在的方法。基于小层对比法、地质建模法和示踪剂法,详细解剖某油田一个代表性井组的砂体连通性和优势渗流通道的发育特征。研究结果表明:在研究区实例井组的注采井间,三种方法得到的储层连通率差异较大,其中精度较高的示踪剂法确定的连通率为40%;并在重点解剖小层中识别出三条优势渗流通道,依据示踪剂见剂速度与回采率,对三条优势渗流通道的发育程度进行了分级。对比实际监测结果,小层对比分析法得到的连通率明显偏高,地质建模法与示踪剂法得到的连通率比较接近,两种方法得到的连通率均受到开发小层的储层沉积与相变规律、非均质性及实测资料精细度的影响。示踪剂法识别优势渗流通道效果最佳,比地质建模法的识别精度提高了25%。

渤海JZ-X油田气顶窄油环油藏井位优化和挖潜策略

针对气顶底水窄油环油藏易气窜水锥、剩余油分布复杂的生产难题,在渤海矿区逐渐探索出利用水平井开发的井位优化与挖潜策略。基础井网阶段:水平井段垂直构造线穿多层来提高储量动用程度,并匹配智能滑套分采管柱以缓解层间矛盾;基础井网平行于流体界面,部署于油水界面之上1/3油柱高度避气控水。综合调整阶段:通过油藏数值模拟研究,油田开发进入中—后期,剩余油平面上主要富集于井间滞留区,纵向上后期水体能量驱动逐渐发挥主要作用,剩余油主要富集于油层上部。对比井间侧钻、气顶注气和屏障注水方案增油量指标,当前剩余油挖潜策略以井间侧钻与气顶注气为主。井间侧钻通过低产低效井平面侧钻至井间,纵向高部位部署挖潜剩余油,单井净增油量为3.4×10^(4)~4.2×10^(4)m^(3);气顶注气通过采气井转天然气回注,补充气顶能量,气驱水平井上部剩余油,提高原油采收率,预测净增油量为5.2×10^(4)m^(3)。

基于EEM-PARAFAC的荧光示踪剂检测方法的研究

在油田的注水开发中,利用化学示踪剂进行井间连通性测试是了解出水优势通道特征、制定提高采收率方案的必要前提。但常见的荧光示踪剂在现场应用中易受原油中荧光物质的干扰导致识别率和检测精度较低,严重影响测试结果的准确性。采用三维荧光光谱法与平行因子分析法相结合的分析方法,对在多种荧光物质干扰下的模拟采出液中的荧光示踪剂进行定性分析与定量分析,成功得出模拟采出液中荧光示踪剂浓度,经计算平均相对误差约为12.75%。该方法用三维荧光光谱的数据处理代替传统的荧光背景测试,去除模拟采出液中不同荧光物质对待检测示踪剂的干扰,具有操作简单、准确性高、成本低、检测速度快的特点,可广泛应用于复杂背景条件下荧光示踪剂的快速检测。

基于FEM-DFN的页岩气井复杂裂缝扩展与优化——以长宁页岩气藏X1水平井组为例

对长宁页岩气示范区水平井裂缝扩展形态认识不清、井间干扰频繁等问题严重制约了页岩气藏的高效开采。对此,文中基于地质-工程一体化思想,结合适用于多井压裂分析的有限元-离散裂缝网络(FEM-DFN)方法,分析了水平井组体积裂缝扩展形态及天然裂缝对水力裂缝扩展的影响,厘清了井间干扰因素。结果表明:在天然裂缝带发育区域,天然裂缝带对水力裂缝的诱导、捕获和阻隔作用主导了水力裂缝的扩展行为;天然裂缝带导致的水力裂缝不对称扩展、非均匀起裂是造成井间干扰的重要原因;天然裂缝带中各类裂缝的发育程度对水力裂缝扩展有重大影响。该研究成果可为长宁页岩气藏高效水力压裂参数设计提供支撑和依据。

煤层气井整体压裂及排采技术研究:以余吾煤业为例

综合国内煤层气井在压裂及排采技术上的相关研究,从余吾煤业S6、 S7井区的S6102、 S7101、 S7102、 S7103工作面入手,对50口地面瓦斯抽采井进行了探索,针对压前作业情况、压裂施工情况、压裂过程评价、裂缝监测结果及压裂效果评价,对压裂工程质量及整体压裂试验展开研究,同时对排采技术及整体排采制度的建立进行了分析,对煤层气井整体压裂及排采技术的发展具有一定的借鉴和指导意义。

混合式三稳态压电能量俘获器动力性能分析

为了提高压电能量俘获器在低强度外界激励下的俘能表现,基于三稳态压电悬臂梁能量俘获器模型,在U形框架和基底之间以及压电悬臂梁固定端与U形框架之间分别装置一个弹性放大器,提出一种混合式三稳态压电能量俘获器(TPEH+DEM)模型。基于Hamilton原理建立了TPEH+DEM系统的非线性力电耦合运动方程,并利用谐波平衡法分析了弹性放大器的质量和弹簧刚度、磁铁之间相对距离、负载电阻等对TPEH+DEM系统能量收集水平的影响。结果表明:在一定的外界激励频率范围内,TPEH+DEM系统的响应输出功率存在两个峰值,合理调节弹性放大器的质量和刚度能使系统在较低的外界激励强度下进入阱间运动,产生很高的输出功率。相比于仅带有弹性基底的传统三稳态压电能量俘获器,TPEH+DEM模型在低频外界激励下具有更好的俘能表现。

城市海岸带沿线规划设计提升策略研究——以烟台市蓬莱区段为例

在海洋文明发展的时代背景下,城市海岸带沿线区域不仅是连结陆海的重要纽带,也是空间联动的重要载体。而现今,我国海岸带沿线的发展仍在功能串联、价值转化、韧性生态等方面面临着极大挑战。文章将以烟台市蓬莱区段为例,研究分析规划策略,重点突出陆海统筹布局、全域联动升级的规划路径,以期为城市海岸带沿线区域现阶段的提升发展提供具有实践意义的策略思考。

新生育政策背景下隔代照料随迁老人主观幸福感现状研究

目的调查新生育政策背景下隔代照料随迁老人的主观幸福感,分析其影响因素,旨在丰富我国老年人中特殊人群的研究结果,弥补我国对隔代照料随迁老人研究不足的缺口,为今后对这一群体的政策制定、社区工作和学术研究提供借鉴。方法采用整群随机抽样法,采用一般人口学资料问卷及中国老年人主观幸福感量表对湘潭市宝塔街道盘龙社区湖工花园小区等多个小区的隔代照料随迁老人进行问卷调查。结果隔代照料随迁老人主观幸福感总均分(2.03±0.41)分,家庭适意感维度条目均分最高、自我完满感次之、生活完满感最低。主观幸福感的主要影响因素为子女个数、身体状况、文化程度、居住状况(P<0.05)。结论从政府、社会、家庭、个体层面制定提升新生育政策背景下隔代照料随迁老人主观幸福感的策略。

大型河流──三角洲沉积储层精细描述方法

概括地论述了大庆油田应用现代沉积和露头研究中的层次分析思想和自创的模式预测描述法，成功地研制出依据油田密井网测井资料和大型河流—三角洲特有的沉积规律与模式，由大到小、由粗到细分层次逐级解剖砂体几何形态和内部建筑结构，精细地建立储层地质模型，系统描述储层宏观非均质体系的研究方法。该方法将整套储层划分为岩相段、单一族回层（或单砂层）、沉积微相（或相对均质单元）、单砂体、建筑结构单元、层内非均质等6个描述层次，并对砂体井间连续性、几何形态与边界位置、厚度与渗透率的平面非均质性采用模式化预测性描述，较好地解决了储层复杂非均质体系描述和井间砂体预测的难题。

辫状河储集层夹层发育模式及其对开发的影响--以准噶尔盆地风城油田为例

通过对露头原型模型、岩心和测井综合分析,基于砂体构型,研究准噶尔盆地风城油田辫状河储集层内部夹层类型、形成机理和分布模式,并对夹层进行井间分布预测。风城油田辫状河储集层内部夹层分为4类:坝内夹层、坝间夹层、道坝转换夹层和串沟,岩性上可分为泥质砂岩夹层和细粒夹层两种类型。利用岩心刻度测井进行单井夹层识别,应用多点统计学方法建立夹层训练图像,进行井间夹层分布预测,结果表明,夹层整体上大小不一、分布零散,呈薄厚不等的透镜状分布。应用夹层三维模型指导B试验区水平井设计,实践表明夹层预测对提高原油产量具有重要意义。