【作者】 邓敦夏；

【导师】 赵金洲；

【作者基本信息】 西南石油大学 ， 油气田开发工程， 2009， 博士

【摘要】 近年来,随着世界对能源需求量的不断增加和勘探技术的进步,油气资源勘探开发不断向纵深发展越来越多的主要勘探目的层呈现全面下沉的趋势,井深大于4500m,温度超过170℃的异常高温深井数日益增多。压裂作为这类储层最为有效的增产措施,也受到国内外越来越为广泛的关注。然而深部层系的高温高压也给油气层改造带来了更多地困难,耐高温压裂液（180℃以上）、超高温储层的压裂设计理论与技术不配套及大型压裂规模优化等一系列问题,已经成为制约这类油气田勘探开发效益实现的“瓶颈”。本文针对制约深层超高温储层的一些关键理论和技术展开较为系统和深入的研究,取得了以下主要成果:1、在调研剖析国外超高温压裂液体系的配方特征与性能指标的基础上,完成了超高温压裂液的单剂开发和实验综合评价,研究了满足深层、超高温储层压裂要求的低伤害压裂液体系,形成了满足190℃的压裂液配方。（1）在0.1%～0.6%交联比条件下:高温压裂液样品温度上升至40～50℃后,交联速度加快,粘度增加。温度达到120℃后,其粘度有大幅度提升,在中温区间显示出与常规压裂液体系相反的粘温特征。（2）HAAKE RS600流变测试最佳交联比搜索结果显示,该超高温压裂液最佳交联比范围为0.2%～0.3%。（3）180～200℃压裂液的粘度-温度实验结果显示,180℃时,0.55%GHPG粘度为164.5mPa.s,0.60%GHPG粘度为332.8mPa.s。（4）180～200℃压裂液的粘度-时间实验结果显示,在最佳交联比下,180℃、170s^-1连续剪切120min后其粘度仍然保持在90～100 mPa.s;190℃、170s^-1连续剪切120min后其粘度仍然保持在70～80mPa.s;198℃、170s^-1连续剪切120min后其粘度仍然保持在60-90mPa.s。实验显示出极其优异的抗温抗剪切性能,完全能满足超高温、超深层储层的加砂压裂改造施工要求。（5）超高温压裂液冻胶在180℃、50ppm破胶剂作用下:剪切50min后,粘度降低至20mPa.s:剪切70min后,粘度降低为10mPa.s。（6）破胶液表面张力为28.4mN/m,固相残渣为587 mg/L,残渣含量略高于普通压裂液。2、延迟交联实验表明,GHPG冻胶粘度第一拐点在4min左右,此时体系为局部交联呈线性结构,具有较强的流动性和低摩阻特性。第二拐点为8～10min左右,体系为网状结构,粘弹性很高,呈现“挑舌”特征。3、LOOP环流摩阻实验测试结果表明,80℃、76mm施工管柱、4～6m³/min排量条件下,超高温压裂液摩阻与清水摩阻相比,降阻率为30%-46%。4、闭合压力为20.7～82.7MPa下,破胶液对支撑裂缝伤害率小于20%。5、基于井筒温度场和裂缝温度场计算模型,完成了超高温压裂改造的破胶剂用量优化设计。6、利用测井资料、岩石力学实验参数和实际施工资料,获得了丰深区块纵向地应力剖面,建立了超深储层地层破裂压力预测方法和超深储层井口压力预测模型。7、建立了压裂液返排中的支撑剂回流力学模型和裂缝闭合后的临界返排流速模型,实现了定量确定压裂返排参数和放喷油嘴尺寸的优化选择,并提出了支撑剂回流的控制技术和方法。更多还原

【Abstract】 In recent years, with the growing demand and improvement of exploration technology, the exploratory development of hydrocarbon resources further develop in depth. More and more main exploration targets have the overall trend of sinking, the well depth is more than 4500m, the number of the abnormal high temperature deep wells which are more than 170℃is increasing. As the most effective stimulation for this type of reservoir, fracturing has got comprehensive attention both here and abroad. But the high temperature and high pressure of the deep layer bring more difficulty to the improvement of reservoir. High temperature fracture fluid(more than 180℃), the discrepancy of fracturing design philosophy and technology, the scale optimization of big-frac treatment constraint the exploratory development of this reservoir. This paper study some key theory and technology on abnormal high temperature deep reservoir, the main results are as follows:1.On the basis of analysing the formulation characteristics and performance indicators of the ultra-high temperature fracturing fluid abroad, we develop the agent of ultra-high temperature fracturing fluid, finish the experiment comprehensive evaluation, develop the low damage fracturing fluid system which is suitable for ultra-high temperature reservoir fracturing and fracturing fluid which could be used in the case of 190℃.(1) Under the conditions of 0.1 %～0.6% cross linking ratio, the cross linking speed and the viscosity will increase after the temperature of the high temperature fracturing fluid sample rising to 40～50℃. As the temperature reach 120℃, the viscosity will increase significantly and show the viscosity-temperature characteristic which is in contrast with the conventional fracturing fluid system in the medium temperature zone.(2) The result of HAAKE RS600 theological test shows that, the rage of the best cross liking ratio of the ultra-high temperature fracturing fluid is 0.2%～0.3%.(3) The result of the 180～200℃fracturing fluid viscosity-temperature experiment shows that the viscosity of the 0.55% GHPG is 164.5mPa.s and the viscosity of the 0.60%GHPG is 332.8 mPa.s when the temperature is 180℃.(4) The result of the 180～200℃fracturing fluid viscosity-time experiment shows that in the best cross linking ratio the viscosity remains at 90～100mPa.s after 120 min 180℃、170s-1 continuous shearing, the viscosity remains at 70～80mPa.s after 120 min 190℃、170s-1 continuous shearing and the viscosity remains at 60～90mPa.s after 120 min 198℃、170s-1 continuous shearing. The fluid have excellent heat-resisting property and shear performance which meet the requirements of the sand fracturing for the ultra-high temperature deep reservoir.(5) The ultra-high temperature fracturing fluid jel under the action of 180℃, 50ppm breaker, the viscosity will reduce to 20mPa.s after 50min shearing and the viscosity will reduce to 10mPa.s after 70min shearing.(6) The serface tension of breaker is 28.4mN/m, the solid residue is 587mg/L, the content of the residue is a little more than common fracturing fluid.2.The delay cross linking experiment shows that, the first inflection point of the GHPG gel viscosity is about 4 min, the system is partial cross linking and it has linear structure, strong liquidity and low friction. The second inflection point is about 8～10min, the system is reticulation and the viscoelasticity is high.3.The result of the LOOP circulation friction experiment shows that under the conditions of 80℃, 76mm operating tool string and 4～6m3/min discharge capacity, compare the friction of ultra-high temperature fracture fluid with the friction of clear water, the drag reduction rate of the former is 30%～40%.4.When the shut-in pressure is under 20.7～82.7Mpa the damage rate of breaker to fracture is less than 20%.5.Finish optimum the amount of breaker desigh for the ultra-high temperature fracturing on the basis of wellbore temperature field and fracturing temperature field calculation model.6.According to the well-log information, rock mechanics experimental parameter and actural construction data, we get longitudinal stress profile of Fengshen block, establish the breakdown pressure of ultra-deep reservoir prediction method and the surface pressure prediction model.7.Establish the proppant return mechanical model in the flowback of fracturing fluid and critical flow-back model after the closing of fracture, realize quantifying the fracturing flowback parameter and choose the best blowout choke size and present the control technique for proppant return.更多还原