This study aims to address the issue of ultra-deep well, high H 2 S content and the completion of permanent packer string in Yuanba gas field, which leads to difficult recovery of gas wells in Yuanba gas field after flooding. Based on the investigation and analysis on the applicable conditions of conventional drainage gas recovery process, a new combined process of “water injection nitrogen+foam drainage” for the recovery of flooded wells is proposed. Then the calculation model of gas injection pressure is optimized. The quick chart of the relationship between the amount of nitrogen needed to fill the wellbore and the pump pressure and the relationship between the amount of nitrogen injected and the height of nitrogen column for process design is drawn. Furthermore, a new type of high temperature sulfur-resistant foaming agent with good compatibility with corrosion inhibitors and defoamers commonly used in gas fields was developed. The field application of well YB29-1 and well YB121H shows that the new combined process of “water injection nitrogen+foam drainage” can effectively evacuate the wellbore effusion and restore the production of water flooded wells, which can be promoted in the completion wells with high sulfur permanent packer string of the same nature.

深层页岩气井投产初期能量充足,大多采用套管快速排液,当井口压力降至带压作业能力范围内或气井出现携液困难时再下入油管生产,油管下入时机、下入深度及油管尺寸等参数设计基本依据作业进度或现场经验而定.目前,下入时机对气井产能的影响鲜有研究材料供参考,因此,基于川南深层页岩气在套管生产阶段的53井次井筒动态监测资料,优选了井筒压降计算模型.通过分析气井生命周期内井筒流型、井底流动压力、临界携液能力的变化规律,确定油管最佳下入时机;基于探明的不同油管深度下的井筒压降变化规律,提出了以井筒最小压降为目标的油管最优下入深度;综合携液、压力损耗敏感性研究,得到最优管柱尺寸.结果表明:川南深层页岩气井在井口压力降至15～25 MPa时,为油管最佳下入时机,油管最优下深井斜介于70°～85°,最优管径为62 mm.该设计在现场应用良好,通过油管参数设定,气井压降速度降低了50％,单位压降产量增长2倍,对有效地指导川南深层页岩气水平井油管设计及实施具有重要意义.

The shale gas fields in Southern Sichuan are developed in an integration mode of testing, production and transmission,which has realized the development goals of cost reduction, emission reduction, fast production commissioning and early returns.However, a lot of empirical practices serve as reference of decision-making during implementation of integration practices. There is a lack of general guidance. In order to study the post-frac soaking, the flowback system and the drainage measures, the experiments of overpressured NMR imbibition, permeability stress sensitivity and gas-liquid two phase percolation are conducted, the flow regime and the distribution of pressure profile are simulated, and the discharge and production effect of more than 30 wells in Southern Sichuan shale gas field has been evaluated. The results show that the entry of fracturing fluids into reservoir through imbibition is beneficial to increasing the complexity of shale cracks, and the optimal shut-in time of Southern Sichuan shale gas field is 4～10 days. Meanwhile, a six-staged flowback system is formed, and a post-frac drainage guide chart is established. It is determined that tubing and manual lifting should be implemented when the flow regime changes and the tube should be installed at the well deviation of 70° ～ 85°. Besides, the drainage strategy is also proposed. In general, the research results are of great significance for guiding post-frac production control and drainage technology.

近年来,超音速雾化成了低压低产井排液新工艺的热点,但从矿场应用情况来看,效果不尽人意.利用Fluent仿真模拟手段,建立了拉法尔管模型和普通喷嘴模型,数值模拟了两种模型在相同生产条件下的流动状态.通过对比分析,从机理角度回答了超音速雾化排水工艺是否能提升排液效果,为该工艺是否具备推广价值提供理论决策依据.分析结果表明,基于拉法尔喷管原理的超音速雾化装置能达到超音速状态,出口流速相对于普通喷嘴有大幅提升,但是这种效果的作用距离非常有限,相对于1000～2000 m井深来说显得效果很微弱.

In order to clarify the drainage effect of the foam drainage process under various flow patterns and effectively guide the well selection, we design a set of visual air-water-foam three-phase pipe flow simulation experimental apparatus. At first we determine the foam concentration by surface tension experiment, and then we conduct different foam lifting experimental tests with different gas superficial velocities and liquid superficial velocities. We obtain the following results. Firstly, adding the surfactant to the gas-water two-phase flow can effectively reduce the two-phase flow pressure drop and significantly suppress the flow fluctuation. Secondly, the degree of decrease in pressure drop and liquid holdup in the wellbore increases first and then decreases with increasing of the gas flow rate. Thirdly, in the effective range of the foam lift, gas and water in the wellbore are vigorously agitated, prompting the added surfactant to fully contact with the water, thereby generating a large amount of foam, reducing the wellbore pressure drop and liquid holdup. Fourthly, the critical gas flow rate to carry the liquid is taken as the upper limit of the effective range of the foam lift. The lower limit in this range is the transition boundary from bubble flow to slug flow, and the optimal flow rate of the foam lift is determined as the transition boundary from slug flow to churn flow. In conclusion, limits of foam drainage application connect the two-phase flow pattern transition boundary with the results of foam experiments. The clarification of limits of foam drainage application will help reduce the cost of gas well deliquification and provide a theoretical basis for the efficient application of the foam drainage technology in gas fields.

Deliquification is an important means for controlling the flooding of gas wells and maintaining the even advancement of the edge and bottom waterline in high-sulfur gas fields. First, according to the characteristics of the completion structure of the Puguang and Yuanba deep high-sulfur gas fields, the adaptability of the existing deliquification technology is analyzed. The suitable deliquification technology is selected. Then, the high temperature resistant ternary composite foaming agent is developed. A high-sulfur gas well bubble agent wellhead safe filling process is established. A solid foaming agent anti-sulfur delivery device is developed. The coiled tubing + nitrogen step-by-step gas lift process is proposed. The gas injection method, gas injection volume, gas injection pressure is optimized.The field applications of bubble deliquification and gas lift technology in high-sulfur gas wells are carried out. The results show that the new foaming agent has good foaming and foam stabilization performance in simulated formation water aged at a salinity of 10×104 mg/L, pH of 3～8, and high temperature of 180 ℃. The foam deliquification process has successfully achieved short-term stimulation of 2 wells with accumulated liquid. The effective period of single operation stimulation is 3～5 d. The coiled tubing + nitrogen step-by-step gas lift technology controls the lifting pressure of deep high-sulfur gas wells within 35 MPa, with the maximum gas injection depth reaches 6 150 m. 6 water-flooded wells are successfully resumed to produce with the effective period of stable production per single operation of 1 to 2 months. The tubing filling bubble deliquification technology and coiled tubing nitrogen lift technology are temporary measures to eliminate liquid accumulation at one time, and do not meet the long-term deliquification requirements of high-sulfur gas wells, and it is necessary to explore more long-term new deliquification technology.

为解决气井积液预警不及时、排采介入滞后、劳动强度大、制度优化难等问题,通过分析收集21井次的井底测压数据,建立了中江气田气井积液程度3级分类标准,形成了多指标的井筒积液数字综合识别方法,对158口井进行诊断,正确率达92.4％.结合各排采工艺应用界限和经济分析,创建了智能决策系统,并借助计算机编程、工业自动化控制、物联网互联等将智能决策系统与智能排液采气技术一体化,在JS 203-7 HF、JS 104-3 HF井成功应用,实现了井口压力数据自动收集、气井积液程度自动识别、排液采气措施自动判断、排液采气参数自动调整.JS 203-7 HF井及时介入智能泡排后产能递减率由76.00 m 3/d降低到6.37 m 3/d,JS 104-3 HF井及时介入智能柱塞后实现稳定排液且日增产天然气3000 m 3/d.智能决策系统和智能排液采气装置,能有效降低气井产量递减速度,提高最终气藏采收率,对致密砂岩气藏、页岩气藏的智能化排采技术具有借鉴意义.

针对传统人工泡沫排水采气方式劳动强度大、泡排效率低、管理不精细等问题,通过设计自动化泡沫排水采气注剂流程,开发注剂装置远程监控软件,提出手动加注、自动定时加注、智能加注3种运行模式,并配套开发了自动报警与安全切断系统.为满足不同井场条件,自主研制了3个系列的自动泡沫排水采气注剂装置(简称自动泡排注剂装置),该装置具有智能加注、远传远控、自动报警、多井轮注、多源供电、小型手抬等功能.2019年,该装置在川西老区推广应用16口井,累计自动运行2374井次,累计采出天然气1879.881×104 m3.该工艺与前期人工泡排相比,产量增加约10％,最多实现1泵对8口井同时泡排,创造了川西气田泡排工艺"自动化、智能化、网联化、8分支"四项记录,满足无人值守井、丛式井组、偏远井智能泡排作业要求,在气井排水采气提质增效方面具有推广潜力.

页岩气井水力压裂过程中注入液量大,但压裂后返排率往往较低,滞留压裂液对储层的影响仍不清晰.针对该问题,选取永川新店子构造YY1井龙马溪组的岩心,开展压裂液渗吸实验,并对比渗吸前后岩心物性、孔隙结构特征及电子显微镜下微观结构等参数的变化规律.实验结果表明:永川新店子构造岩心压裂液渗吸后,岩心平均孔隙度增大了50％,平均渗透率增大了25％,气体吸附量减少了35％,比表面积降低了40％;岩心沿层理方向产生了新的裂缝,并随着渗吸的持续进行,裂缝发生扩展和延伸,逐步沟通裂缝网络,增大了液体的渗吸面积;通过YY1HF井的现场试验发现,焖井30 d后再控产(6万m3/d)试采,产液量大幅度降低,气井生产稳定.研究认为,压裂后焖井有利于改善储层物性,增加渗流通道,压裂后返排应由小到大逐级控制油嘴排液,以提高气井采收率.

Since the production started in late 2014, there have been 11 relief wells that have been blocked, which seriously affected the normal production of gas wells. On the basis of analyzing blocked well, according to wellhead pressure, wellhead temperature variation characteristics and hydrate formation depth prediction of different plugging, rapid diagnostic methods for hydrate plugging and composite plugging have been established. Through verification, the diagnosis accordance rate is 100%. At the same time, the comprehensive evaluation method of fuzzy diagnosis is used to evaluate the influence factors, and the source of blockage is analyzed.

从国内外的对比分析来看,不同页岩区块的返排特征差异很大,其中原因有储层本身的因素,也有工程方面的因素.通过对比国内外在页岩气返排机理方面的一些研究认识,结合开展的龙马溪组岩心实验,对影响页岩气井返排的因素,诸如储层岩石的层理发育状况,矿物组成,相对渗透率,毛管力,裂缝的应力敏感,以及压裂液性能、地面返排控制等进行分析,对页岩气井返排模式的合理制定和优化有一定借鉴意义.

The Xujiahe formation gas well is prone to be flooded production suspension after produce water,the characteristics of high temperature,high pressure and ultra-deep of the gas reservoir restrict the application of common drainage gas recovery technology.Through the introduction of electric submersible pump drainage gas recovery technology in the DY1 well,the design and workover process optimization of the highly deviated well gas well was developed,the drainage effect was evaluated and also the fault cause was analyzed.Finally,it could be concluded that the ESP drainage technology is fit the demand of the continuous high strength liquid discharge,but influenced by the factors such as unit vibration and corrosion,the ESP technology has greater risk in the application of the deep and high water production gas well.

对于页岩气开发方面的研究,人们一直都将注意力放在如何通过压裂形成大规模缝网上,而忽略了对压后返排模式的研究.但是近年发现有些泥页岩在液体浸泡后不仅渗透性不会变差,甚至还有变好趋势,因此压后到底是直接返排还是焖井后返排成为争论焦点.针对这一问题,采用岩心驱替实验分析的方法,研究了降阻水浸泡后对黏土组分和储层物性的影响.准备两块YY1HF井岩心和500mL降阻水,对岩心进行预处理后,开展页岩脉冲覆压物性测试、氮气吸脱附测试和电镜扫描实验.测试结果表明,降阻水浸泡后,岩石样品的孔隙度、渗透率等参数均有所改善,同时岩心的氮气吸附量降低了33％,比表面积降低了40％.适当的焖井不仅改善了岩石物性参数,还改变了天然气渗流通道,使天然气更容易采出,有利于吸附气向游离气转化,提高气井初期产量和极限采收率.

元坝气田长兴组气藏是高含硫气藏,单井测试产量高,传统的产能评价方法需足够的放空测试时间,不利于安全环保,为此,在二项式产能方程的基础上,通过统计分析长兴组气藏9口井的系统试井资料总结得到经验公式,即一点法产能快速评价公式,可用于快速评价元坝长兴组气藏的产能,提高了评价效率,同时也减轻了环保的压力.

气田开发作为一项系统性工程，涵盖了气藏动态、井筒举升和地面集输等各个生产环节，但目前气藏研究基本上是逐点分析，难以保证系统分析的准确性和及时性，已不能完全满足生产的需要。为此，结合马井蓬莱镇组气藏开发现状和系统整体研究的实际需求，开展了IPM软件生产一体化数值模拟研究。该软件主要包括地面管网优化设计、井筒动态分析、生产动态综合分析、高压物性分析、油气藏数值模拟、控制连接器等功能模块，利用该软件可进行气井生产历史拟合、气井产能递减分析、气井合理生产管柱研究、气藏稳产预测、气藏生产动态预测、气藏生产方案优化等，弥补了气藏工程软件单一分散的缺陷。

At present,there is a shale gas exploration and development boom. However,the study of shale gas are mainly concentrated in the geological and drilling and completion,and the study of shale gas well test dynamic aspects is almost blank. The infinite diversion multi-stage fractured horizontal well in Shale gas reservoir is established evaluation model,which discussed the influence of parameters on the dynamic pressure such as diffusion, adsorption,and analyzed the homogeneous infinite diversion multi-staged fracturing in shale gas reservoir pressure dynamic characteristics of horizontal well,to solve the uncertain problem of shale gas reservoir multi-staged fracturing horizontal well dynamic parameter analysises. It is formed a homogeneous typical curve of shale gas reservoir multi-staged fracturing horizontal wells. Research results provide technical support for the development of shale gas reservoir staged fracturing of horizontal well which is reasonable and efficient.

At present,many commercial softwares are basically a gas reservoir study point by point analysis.Systematical analysis is difficult to guarantee the accuracy and timeliness.It has been unable to fully meet the production needs.Therefore,according to the production status and the actual needs of overall study,integration of gas reservoir is simulated numerically by IPM software,Which includes ground pipe network optimization,wellbore dynamic analysis,production dynamics comprehensive analysis,PVT analysis,reservoir simulation,control connectors and other functional modules.With this software,gas-well production history fitting,production decline analysis,reasonable production string research,stable yields prediction,production performance prediction and production decision optimization can be carried out.It overcomes the disavantages of unity and dispersion for the engineering software.It is of great significance for improving the overall system efficiency and economic benefits of gas and oil exploration.

The efficiency of β nucleating agent PA-01 and PA-03 of isotactic polypropylene（iPP） was investigated by wide angle X-ray diffraction（WAXD）,differential scanning calorimetry（DSC）,polarizing optical microscope and mechanical testing.The results showed that the impact strength of iPP nucleated with 0.2% of PA-01 and PA-03 increase 3.4 and 3.3 times than that of pure iPP respectively.The mass fraction of β crystal of iPP nucleated with PA-01 and PA-03 can reach 87% and 88% respectively.Compared with pure iPP,the crystallization peak temperature of iPP nucleated with PA-01 and PA-03 increase 10.8 ℃ and 6.2 ℃ respectively.Meanwhile,the addition of PA-01 and PA-03 significantly decrease the size of spherulite.Finally,impact resistance PP was prepared by the use of PA-01,and then processing condition was optimized and the properties were tested.

油气井产能评价需要知道井底流压,而井底流压数据的准确性与油管尺寸、油管粗糙度有关。通过实例计算表明,油管内壁的粗糙度是影响产能评价的一个重要参数,粗糙度越大,评价的产能越大,粗糙度越小,评价的产能可能越小。

川西中浅层低压、低产气井开发已步入中后期,存在携液困难、堵塞严重等问题,从开发效益角度来讲,采用井下节流工艺能达到节能降耗、降本增效的目的。结合川西地区的实际生产特征,开展了井下节流技术中压力、产水量和井眼轨迹的适应性评价,并在11口井中进行了现场应用。结果表明,该适应性评价技术有效的指导了选井工作,提高了施工成功率。