【作者】 杨波；

【导师】 杨宇； 刘林；

【作者基本信息】 成都理工大学 ， 油气田开发地质， 2014， 硕士

【摘要】 水力压裂是川西地区低渗致密砂岩气藏勘探评价和开发建产的关键技术。气井压后返排效果是否理想直接关系到储层改造的增产效果，目前川西气井压后返排过程中以人为因素为主导的返排措施很大程度上导致支撑剂回流现象的发生，同时，返排制度不合理、地层伤害严重、未形成系统的返排工艺体系[1]。因此，形成一套针对不同的储层特征合加砂压裂参数的返排工艺体系就显得十分的必要。本文通过理论研究，采用压裂液滤失二维模型对川西中浅层气井压裂储层改造过程中的压裂液滤失、近缝储层的压裂液滤失量和侵入深度、储层能量场的数值计算方法进行研究；利用数值模拟的方法对开井排液过程中近缝储层的压力及含水饱和度分布情况进行计算，确定返排启动压差，并依靠剩余含水饱和度关系计算气井压裂返排的最终返排率。考虑防止支撑剂回流及克服致密气藏水锁影响下的液体启动压力的条件下，进行井口排液油嘴大小优化。另外为验证上述研究成果的准确性和可靠性，通过Eclipse软件模拟对本文模型计算结果进行验证；通过对川孝611-1井进行返排制度设计，并将设计结果与现场实际相比较。所有的验证与现场实践表明，本文建立的返排制度设计方法可行、可靠。更多还原

【Abstract】 Hydraulic fracturing is the key technology in the west area of Sichuan, whichapplied to the evaluation of explorations and developments in the low-permeabilitytight gas sandstones. Whether the flow-back efficiency is ideal or not after fractured,will influence the reservoir stimulation results directly. Currently, the flow-backmeasures, which are taken as randomly, will result in the occurrence of proppantsflowing back to large extent. There are some problems, such as the flowing backscheme is not rational, the formation is damaged severely, and the flow-back systemis not perfect. So it is necessary to form a system of proper flow-back technology,which deals with different reservoir properties and parameters of hydraulic fracturing.In the thesis, the theoretical research includes: the leak-off calculation by use ofthe2D model about fracturing fluid during the gas wells’ stimulation in the west areaof Sichuan, the leak-off volume of fracturing fluid near the fracture and thepenetration depth in the reservoir, the numerical calculation method of energy domainin the reservoir. The pressure and water saturation, which are around the fracture inthe reservoir after the well is opened and fluid is expelled, is calculated by use ofnumerical simulation method, and the start-off pressure drop is determined. Accordingto the residue water saturation relationship, the final flow-back ratio of the fracturedgas well is computed.The nozzle size for expelling fluid out of wellhead is optimized, consideringthese factors such as preventing proppants from flowing back and overcoming thestart-off pressure in the influence of water-block for tight gas reservoirs. Besides, inorder to testify the accuracy and reliability of the results, it is simulated by use ofEclipse software. The flow-back scheme about well Chuanxiao611-1is designed, andis compared with the on-site results. All of the testifications and practices on site showthat, the design method proposed in this thesis is reliable and feasible.更多还原