Due to the particularity of the Bohai oilfield steam stimulation Wells and steam injection wellhead temperature above 350, conventional downhole monitoring method cannot be effectively applied to the steam stimulation Wells in Bohai oilfield, steam stimulation current Bohai oilfield downhole long-term long-term monitoring techniques are mainly distributed optical fiber temperature monitoring technology has been in the steam stimulation Wells in Bohai oilfield, successful application of multiple wells. For further research and application of long-term monitoring data of downhole wellbore fluid thermal enthalpy change of effective calculation model for wellbore heat loss calculation considering continuous nitrogen injection for oil casing annulus wellbore heat radial heat distribution and the influence of axial heat absorption along the wellbore of heterogeneity, homework heating radius of horizontal well steam stimulation calculation model is established by using the mathematical model and distributed optical fiber wellbore measured data, the simulation calculation of Bohai oil field L well steam stimulation wellbore heat loss is about 22

注蒸汽开采是稠油强化开采的主要开发方式,传统的地面注蒸汽开采综合热效率低,锅炉出口的蒸汽干度低,有效气体大量浪费,开采成本高.将传统的地面蒸汽发生器移置到井下,这种新兴的井下蒸汽发生器技术可大大减少蒸汽在井筒内的热量损失,不受井深变化的影响,尤其适合海上油田深层稠油的开采.在对国内外井下蒸汽发生器研究资料整理的基础上,提出适用于海上稠油热采井下蒸汽发生器设计的基本原则及技术指标,形成渤海油田稠油注蒸汽开发的新思路.

针对浅层稠油油藏蒸汽驱后期采收率低、地层能量亏空严重的问题,通过室内实验探究了尿素作为蒸汽驱添加剂在地层条件下的增压作用以及其在三次采油中的提采效果.结果表明:氨水与原油中的酸性物质反应生成表面活性剂,导致岩石润湿性反转、油水界面张力降低、流体黏度降低,且降黏率可以达到93％以上,有效地改变了流体及油藏性质.PVT实验中,低压条件下尿素增压至原来的3倍,高压条件下增压至原来的1.5倍,同时二氧化碳在原油中的溶解也减弱了二次增能效果.岩心驱替实验中,当蒸汽驱含水率达到98％以后,注入尿素溶液,驱替系统压力增加,低压条件下的压力增幅是高压条件下的2倍;含水率降低,低压条件下降幅是高压条件下的2倍;最终驱油效率提高10％～20％,其中低压较高压条件高4.7％.综合来看,低压条件下,尿素辅助蒸汽驱增压效果、驱油效果更好.

为建立与实际非线性渗流一致的试井解释模型,在考虑低渗透油藏变渗透率渗流效应的基础上,建立了二维低渗透油藏变渗透率非达西试井模型,给出了差分方程组数值求解方法,绘制了考虑不渗透边界影响的试井典型曲线,进行了不渗透边界与低速非达西对低渗透油藏试井曲线的敏感性分析.研究结果表明,对于非达西流动情形,压力导数曲线在径向流动阶段便开始偏离0.5水平线而逐渐上翘,非达西作用越强,上翘幅度越大,在遇到不渗透边界后上翘幅度加快;对于低渗透油藏,井附近存在不渗透边界时,非达西流动有可能掩盖不渗透边界的影响.该模型可以有效的解决低渗透油藏试井曲线非达西上翘与不渗透边界上翘难以区分的问题,对低渗透油藏的试井解释具有较大的实用意义.

为防止海上稠油热采作业中井筒管柱出现腐蚀现象,加快稠油热采规模化应用进展,对海上热采现场作业后的井筒管柱进行形貌观察、机械性能检测、能谱检测以及室内模拟试验等方法进行腐蚀分析,结果表明:井筒管柱在热采井中的腐蚀主要由于高温、氯离子和氧离子共同作用.针对腐蚀原因,优化工艺方案和提高设备性能,降低井筒中氧、氯含量.现场应用表明,优化后可有效减缓井筒管柱腐蚀速度.

The thermal recovery wells in Bohai Oilfield have been subjected to multiple rounds of thermal recovery, and optimizing wellbore insulation technology has become one of the most critical technologies in thermal recovery steam injection. At present, the A23 well in the L oilfield of Bohai Oilfield has carried out three rounds of steam stimulation on-site operation, and the third round of steam injection has been optimized and improved on the basis of the second round of steam injection, using 4-1/2″ aerogel insulated tubing steam injection. Comparing with high vacuum insulated tubing used in the second round of Well A23, the second steam injection effectively reduces the heat loss per kilometer of insulated tubing from 14.24% to 10.21%. Meanwhile, the intermittent nitrogen injection process in the empty wellbore reduces the heat loss in the wellbore annulus and effectively reduces the total nitrogen injection volume by 11.86% compared with the previous round. By using aerogel insulated tubing and annulus intermittent nitrogen injection technology, the heat loss of steam injection is reduced and the cost of steam injection for offshore thermal recovery wells is effectively saved.

为了监测蒸汽吞吐作业中油套环空及水平段注汽管内的蒸汽温度变化,为现场蒸汽施工作业提供井下数据支持,采用分布式光纤温度监测技术DTS,通过将光缆捆绑在隔热油管外和Y管穿越到水平段油管内部的工艺管柱结构,对油套环空和水平段温度进行监测,成功录取了注汽前期、注蒸汽、焖井、放喷4阶段全井段温度数据.测量数据分析结果显示,注汽期间水平段温度最高可达368.22℃,根据环空温度的变化趋势,对蒸汽上返开展实时监测并采取措施进行控制,为注汽提供安全性保障.现场试验表明,通过监测注汽过程中的油套环空温度可以对隔热油管的隔热性能进行评价,通过监测焖井、放喷期间水平段的温度变化可以为后续的注汽效果分析及油藏数值模拟提供更为准确的测试数据支持.

渤海海上油田蒸汽吞吐试验井A1井第一轮出现注汽压力高,注汽能力受限,热损失大,井底注汽干度没有达到预期,影响热采效果.为了降低注汽压力,改善蒸汽吞吐实施效果,采用正交试验方法对蒸汽吞吐试验井A1井注汽压力高的原因进行分析,认为影响A1井注汽压力高的敏感因素按影响程度依次是地层能量、渗透率以及原油黏度.该区块后续热采实施应先冷采降低地层能量或注汽前采取降黏增注预处理措施,以改善注汽实施效果.研究结果可为全区热采实施及类似油田热采开发提供指导.

针对金县1-1油田稠油井因结蜡导致产液量下降的情况,结合该油田的工艺管柱、地质油藏及生产特点设计了一套空心电加热杆清防蜡管柱工艺.阐述了空心电加热工艺管柱的系统构成和工作原理、免拆井口投捞电缆的采油树及配套环空安全阀的设计、优选了工艺中的加热设备,对整体管柱建立二维温度场非稳态数学模型和电加热杆增温效果进行了研究,对整体工艺现场应用进行了评价,证实电加热清防蜡工艺对稠油井具有增产效果.

The control of rheological property and filtration of drilling fluids at high temperature was the technical problem for high temperature-resisting drilling fluids.A high temperature stabilizer was used as a treating agent,a set of water-based drilling fluid systems,which could resist against 200℃,were developed,the stability,rheological property and inhibition and its pollution resisting performance at high temperature were evaluated.The result indicates that the high temperature resisting water-based drilling fluid has a good stability,after it is aged at 200℃,it has a low filtration rate at high temperature and high pressure,good rheological property,good inhibition and salt resistance and good resistance against poor soils.