大港油田低压高渗油藏保护修井液研究

发布时间：2018-07-13 20:16

【摘要】：大港油田已进入中后期开发阶段,随着地层能量的不断下降,已经有大约70%以上的油井在修井过程中出现了不同程度的修井工作液漏失现象。其中有20%-30%的井漏失是比较严重的(漏失量大于20m3),由于修井工作液的大量漏失导致很多井不能建立正常的工作循环。其结果是：①延长了修井作业时间,提高了修井成本；②冲砂不彻底,油井作业周期短；③开井后排废液时间长,产量恢复率低。本文通过对南部油田损害因素分析,敏感性评价,取得了损害油层的主要原因。一是地层能量低漏失严重造成损害,二是高压低渗水敏现象严重造成损害,三是原油物性差,四是洗井液与地层流体的配伍性差。同时针对低压高渗油藏通过协同效应、水合效应、流度控制技术形成了高效发泡技术、高效稳泡技术并创新性的形成了一套低成本充氮气配制工艺研制出了一套新型低密度氮气微泡修井液体系。该体系不仅可以降低液柱压力,减小压差,而且微泡本身还具有一定的强度和韧性,具有可变形性、可压缩性,能够自匹配各种漏失通道,适用于各种类型的低压漏失井,为低压漏失井冲砂洗井作业开辟了一条新径。通过综合性能评价,研制出的新型高效发泡剂以及高效稳泡剂,发泡量达到了760mL,半衰期达到了501秒,盐水中发泡量达到了495mL,半衰期为436秒且油水界面张力达到了10-1mN/m。稳泡剂稳泡时间达到了2天以上,且续航能力强,高温破坏后重复搅拌具备再发泡能力和稳泡能力,低密度氮气微泡修井液体系与同类技术相比无需发泡设备,密度0.6-0.95g/cm3,20MPa下微泡不破裂,应用井深从1000m提高到2000m,成本降低70%,解决了常规泡沫体系在井下一定温度压力下失稳消失的问题。
[Abstract]:Dagang Oilfield has entered the middle and late stage of development, with the continuous decline of formation energy, more than 70% of the wells in the workover process have appeared different degrees of workover fluid leakage phenomenon. Among them, 20% to 30% of the well leakage is serious (the leakage is greater than 20m3). Due to the large leakage of workover fluid, many wells can not establish normal working cycle. The result is that the workover time is prolonged, the workover cost is increased and the sand washing is not complete, the working cycle of oil well is short and the waste liquid time is long, and the recovery rate of production is low. Based on the analysis of damage factors and sensitivity evaluation of southern oil fields, the main causes of formation damage have been obtained in this paper. One is the damage caused by low leakage of formation energy, the other is the serious damage caused by high pressure and low permeability, the third is the poor physical property of crude oil, and the fourth is the poor compatibility of well washing fluid and formation fluid. At the same time, the high efficiency foaming technology has been formed for low pressure and high permeability reservoirs through synergistic effect, hydration effect and mobility control technology. A new low density nitrogen microbubble workover system was developed with high efficiency foam stabilization technology and a set of low cost nitrogen filling preparation technology. The system can not only reduce the pressure of the liquid column and the pressure difference, but also have certain strength and toughness, deformability and compressibility, and can match all kinds of leakage channels, which is suitable for various types of low pressure leakage wells. It opens up a new path for sand washing operation in low pressure leakage wells. Through comprehensive performance evaluation, a new type of high efficiency foaming agent and a high efficiency foam stabilizer were developed, the foaming amount reached 760mL, the half-life reached 501sec, the foaming capacity in brine reached 495mL, the half-life was 436s and the interfacial tension of oil and water reached 10-1mN / m. The foam stabilizer has been used for more than 2 days, and has a strong ability to survive. After high temperature damage, repeated stirring has the ability of refoaming and stabilizing foaming. Compared with the similar technology, the low density nitrogen microbubble workover system does not need foaming equipment. At the density of 0.6-0.95g / cm ~ 3 ~ 20MPa, the microbubble does not break, the application depth is raised from 1000m to 2000m, the cost is reduced by 70, and the problem of instability and disappearance of conventional foam system under a certain temperature and pressure is solved.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE358

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