针对川西致密砂岩气藏近井带储层污染的问题,首先,开展了污染物特征及组分全分析,明确了川西致密砂岩气藏近井带主要的污染类型;其次,研发了多功能复合解堵剂,开展了新药剂物理特性、溶垢能力、破乳降黏、岩芯驱替等评价测试;再次,建立了压裂井近井带污染模型,提出了"大液量注入、液氮强顶替、放喷助排"的深度净化工艺;最后,在新场气田、中江气田及洛带气田10 口井进行推广应用.结果表明,新工艺措施有效率90％,增产天然气1 923×104 m3,取得了明显的经济效益.结果表明:(1)川西致密砂岩气藏近井带污染为液锁、起泡剂乳化、压裂液伤害、结垢结晶的复合型伤害;(2)多功能复合型解堵剂具有溶解无机垢、破乳降黏及解水锁等多项功能,驱替污染岩芯后渗透率提升1.74～2.40倍;(3)"大液量注入、液氮强顶替、放喷助排"的深度净化工艺,能够提高净化剂在致密储层的穿透深度,提高污染物返排效率,在同类气藏中具有推广价值.

针对川西气区含油气井泡排低效的问题,通过物理实验模拟发现,含油气井中油套环空存在油水分层,且油套环空内流体搅动较弱,起泡剂扩散速度慢,这是导致泡排效果不佳的主要原因.采用小直径管将起泡剂加注到油水界面以下,使起泡剂直接与地层水作用,提高了药剂的利用率,具有加快气井排液、提高起泡剂携液量、降低井筒回压的作用.实验结果显示,小直径管加注起泡剂较环空加注气井泡排出液时间提前了52％,泡排携液量提高了73％,且加注位置越深、加注频率越高,泡排效果越好.为此,本文提出了深注剂、勤加注的含油气井起泡剂加注技术措施,在川西气区开展了两口井的现场试验,气井平均产气量提高了24％,产液量提高了52％,累计增产天然气82×104m3,经济效益显著,有效解决了含油气井泡排低效的问题.

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.

针对川西气田低压低产井长期注入起泡剂,造成井底污染和排液双重难题,研制了井底净化药剂,实验表明驱替致密砂岩天然裂缝岩心后,渗透率提高44％,启动压力降低了11％,净化效果明显.配套了"小液量泵注+措施排液+多次净化"一体化作业技术,现场应用10口井,措施有效率达到80％,单井平均产量上涨49％,措施有效期达到138 d,累计增产天然气59×104m3,经济效益显著,为同类气井治理提供了借鉴意义.

国有企业传统的科技项目管理制度自上而下,缺乏灵活性,研究人员创新主动性不足,研发效率与成果转化率不高.中国石化西南油气分公司石油工程技术研究院将新技术孵化制与项目负责制相结合,营造创新氛围,激发全员创新热情.项目启动阶段,建立动态点子库,实行项目长竞聘制,明确项目长权利与义务,激励措施到位;项目攻关阶段,打破行政界限,自建虚拟团队,自主管理,实施项目终身负责制,有助于创新工作可持续发展.两种管理模式优势互补,使科技资源效用最大化,提高了创新速度和质量.自2018年起试点推广新技术孵化负责制,项目研发周期缩短54％,申报专利数量增加440％,成果转化率提高70％,技术人员综合能力得到提升.

针对中江气田水平井柱塞下入深度不足、在低压井中运行效率低、在结蜡井中易卡堵的问题,首先从A靶点处存在球座台阶面的井身特点出发,研制了免钢丝作业直投式水平井柱塞限位器,将柱塞下死点深度拓展至A靶点附近;其次基于Lea矿场经验法,引入载荷因子和柱塞上升速度,制作了“四线五区”柱塞气举运行工况诊断图版,提出了以Ⅰ区高效运行区为优化目标的柱塞运行提效方法,并且形成了“通井刮蜡,挤注热水,闷井强排”的结蜡井柱塞防卡方法,以及针对扩径井口的柱塞捕捉简易方法;最后在JS104-3HF井开展了现场应用,柱塞顺利下至A靶点附近,成功克服了井筒结蜡卡堵,柱塞运行平稳,产气量增加明显,有助于该技术在中江气田水平井中的推广.新图版直观判断柱塞工况,快速优化柱塞工艺,方便一线工程师使用,具有较好的实用性.

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.

针对川西致密砂岩气藏反凝析作用导致气井产量下降的问题,基于反凝析伤害室内实验和产能拟合计算,认识到生产中后期会出现反凝析现象,凝析油一旦在储层内析出,气井渗透率下降38.44％～54.07％,气井产能将下降19.09％～37.26％.反凝析治理对策主要通过合理控制气井配产,提高露点压力以上天然气采收率,气井生产后期通过"注表面活性剂+注气"措施进行解除.

The application effect of the foam deliquification technology in horizontal wells is poor because the foaming agent fails to reach the target location. In view of this, the adaptability of the capillary foam deliquification technology in the Western Sichuan Gas Field in the Sichuan Basin was analyzed from the aspects of gas flow rate, liquid flow rate and casing program of gas wells, and the design of injection depth and the selection of capillary size, tool string parameters (the maximum length and the minimum counterweight) and foam deliquification parameters (foaming agent type selection, ground injection concentration and rate) were optimized. Then, a standardized capillary operation process was developed. Finally, a field application test was carried out. And the following research results were obtained. First, the capillary foam deliquification technology has a popularization potential in the horizontal wells of middle–shallow depth, low pressure and low liquid flow rate, but it is not suitable for the wells with too low gas flow rate, too high liquid flow rate or too high condensate content. Second, the well deviation angle at the injection depth shall be between 70° and 80°, the selection of capillary size shall satisfy the requirement for tension strength by the well depth, the foam deliquification parameters shall be optimized based on the specific well conditions and the liquid loading characteristics, and the capillary operation shall comply with the standardized process. Third, by the end of July 2017, the capillary foam deliquification technology had been successfully applied in 9 horizontal wells in the Western Sichuan Gas Field with a cumulative gas increment of 295 × 104 m3. Fourth, 4 supporting technologies of the capillary foam deliquification are formed, including capillary sticking prevention, integrated agent injection and pressure measurement, combined cleaning and deliquification and capillary wellhead suspension. In conclusion, the capillary foam deliquification technology provides a technological support for the deliquification and production stabilization of horizontal wells with middle–shallow depth, low pressures and low liquid flow rates in the Western Sichuan Depression, and also provides technological reference for the deliquification of horizontal wells in the similar type of gas reservoirs.

为进一步认识页岩气储层岩石中压裂液等外来流体的影响,选择四川某页岩气藏岩样完成了不带压和带压下渗吸核磁共振响应特征实验.结果 表明,不带压自发渗吸过程中,岩样的T2谱曲线峰值增加、两翼扩展,从单峰特征变成了双峰特征,表明页岩岩样中的渗吸量随时间的增加不断地增加,并形成了新的孔缝系统,这与扫描电镜实验观察的渗吸前后孔隙结构变化结果一致.带压渗吸过程中,岩样的T2谱曲线表现为单峰特征,且基本上不发生变化;当卸载应力后完成不带压自发渗吸实验时,岩样的T2曲线表现出了与之前不带压自发渗吸实验观察一致的结果,这说明岩样上作用的应力影响页岩的渗吸特征.因此,在页岩渗吸实验评价及应用中应考虑应力敏感性的影响.

中江沙溪庙组低渗砂岩气藏孔喉细小,易受到因钻井液、完井液、地层析出水、凝析油等液体无法返排而造成的水锁伤害,严重影响气井正常生产.从气田水锁伤害机理及气田水锁伤害评价出发,采用表面活性剂作为解水锁药剂,通过对氟碳类、柠檬烯(CnF)和乙二醇等3类解水锁药剂的性能对比试验,评价其解水锁性能.室内评价结果表明:采用氟碳复配体积分数为0.1％的解水锁药剂,岩心试样的吸水量和吸油量分别降低63.5％和30.0％,与地层水的接触角增大至32.61°,与凝析油的接触角增大至5.15°,具有憎水憎油性能.氟碳类药剂具有表面张力低、复配浓度低的特点,与岩心作用后能显著降低岩心吸水吸油能力,可以达到解除水锁伤害的目的,可将氟碳类药剂作为解除低渗气田水锁伤害的主要复配药剂.

川西坳陷东坡沙溪庙气藏属于低渗致密气藏,随着气藏开发进入中后期,为解决储层反凝析油、水锁等问题采用"投产初期合理配产,提高露点压力以上的采出程度;生产中期保持气井平稳生产,尽量避免关井和提产;生产后期采用化学药剂解除储层伤害"的生产治理技术,储层伤害治理效果显著.针对井筒堵塞和积液问题,同时推导出了全新的凝析油气井泡排剂加量公式,优化了起泡剂加注方式,制定了一井一策井筒解堵措施,成功开展20余口井井筒解堵作业,实现经济效益400余万元.

病态气井是指由于受到非地质因素影响,导致产量、压力异常递减的气井.病态井诊断是开展问题井治理的前提,只有正确地诊断出“病因”,才能“对症下药”解决问题.起源于我国春秋时期的“望闻问切”四诊法,由于其全面、客观的诊断方法,在油气井生产管理方面也有应用.从病态井诊断与病人诊断的共性出发,巧妙地将四诊法与现代信息技术结合,利用气井日常管理资料、生产动态分析资料、气井产出物组分分析数据,并辅以模糊决策软件,通过录取的与单井生产息息相关的38个参数(包括钻井参数、储层改造参数、地质参数、测试参数和生产数据),全面掌握气井地质、工程资料,再通过逻辑链接,形成各种参数对气井生产特征的影响关联,达到准确判断气井污染类型、污染原因的目的.利用该方法对川西气田100余口气井进行了跟踪分析,筛选并确诊其中的23口井,开展了40余井次的病态井治理施工,累计增产天然气320×104m3.

中江气田具有低孔低渗、储层厚度薄、气水分布复杂、非均质性强等地质特征,随着气田开发的不断深入,产量、压力异常的气井逐年增多,直接产量损失达到30× 104m3/d以上.经分析,主要是由生产制度不合理,导致凝析油过早析出,储层反凝析、水锁以及泡排乳化液堵塞等储层污染问题造成的.储层污染治理对策主要有生产制度控制法和化学药剂解除法:针对凝析油污染问题,制定合理配产指标,提高露点压力以上天然气采出程度;针对后期液锁、乳化液堵塞、无机堵塞等问题,向储层泵注以表面活性剂为主的复配药剂,降低储层孔喉毛管力,提高液相流动性,有利于解除生产后期污染问题.结合中江气田储层污染的类型和特点,研发了一套配方为3％HCl+0.5％表面活性剂+1％破乳剂+铁稳剂+黏稳剂+增效剂的储层污染解除药剂,并应用于2口储层污染井,施工后2口井产量上涨了10％-30％,措施有效期为6～7个月,累计增产30× 104mm3.

Aiming at the issue of poor performance of 66 oil and gas wells in Zhongjiang gas field, it is found through the experimental study on the mechanism and flowability of oil and gas wells, because of the existence of condensate oil, some of the foaming agent with liquid loading form emulsion structure and will be consumed.Only part of foaming agent can play the role of carrying liquid.Condensate oil content increases by 10, liquid carrying volume of foam drainage decreases by 40 to 60.The effect of foam drainage can only be improved by increasing the amount of foam agent.The formula of the filling agent of condensate oil gas wells is deduced and the results of the field test show that the formula is in line with the actual situation.Liquid carrying volume of two test wells increases by 80 or more and gas production increases by 45 or more, which has the value for promotion and application.

井下节流工艺可降低站场建设成本,稳定气井生产,减少温室气体排放.川西气田从2006年开始引入井下节流工艺,但丛式井开发模式造斜点浅、井斜角大以及流体节流后温度必须大于水合物形成温度的理论,导致井下节流工艺应用程度不高,且因维护工艺存在不足,造成井下节流器投放失效率达22％,打捞失败率达35％.为克服以上技术难题,基于地层加热和流体冲蚀理论,优化节流器设计下深,解决了大斜度井实施井下节流工艺难的问题;优选了多胶筒棘刺节流器,制定了合理的井下节流器维护制度:活动式打捞周期为半年1次,固定式打捞周期为1年1次,提出地面安全防护措施:油压→针阀→油嘴套→井口高低压截断阀→地面流程,从而提高节流器可靠性,解决了井筒卡堵、打捞困难.2016年川西气田共对12口井实施井下节流,工艺施工成功率100％,打捞成功率100％.

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.

井下节流是采气井最佳的降本减排工艺之一.在投产前下入井下节流器面临以下问题:井下节流油嘴尺寸的合理选择;新井压力高、产量大、井筒脏物多导致井下节流工具下入难;部分新区块气井压裂测试与输气管线建设时间衔接不上,导致下入节流器后无法利用测试流程完成泄压.经分析认为:利用IPR曲线结合邻井生产特征统计可计算出合理的井下节流油嘴尺寸;施工前向井筒中泵注解堵剂、在节流器活动部件处涂黄油等措施可提高井下节流器投放成功率;测试与投产衔接不上的气井尽量采用井筒气直接节流泄压进输气管网的模式,直接泄压地面管线冰堵风险较大的气井建议安装临时水套炉加热节流泄压;无法满足输气泄压的气井采取测试流程配合泄压后导入输气流程的思路.综合利用上述方法,川西气田实现了多口高压高产井投产即下井下节流器后的顺利开井.

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.