【作者】 潘永强；

【导师】 孙玉学； 杨智光；

【作者基本信息】 大庆石油学院 ， 石油与天然气工程， 2009， 硕士

【摘要】 本文设计并加工的造缝装置,能够满足用天然砂岩、凝灰岩、安山岩、玄武岩基质制备裂缝性岩心样品的要求;形成的人造裂缝能够较好地模拟天然裂缝的裂缝表面形态。应力敏感性研究表明,大庆裂缝性储层具有很强的应力敏感性。随着有效压力增加,裂缝的渗透率和缝宽下降;初始裂缝宽度越大,应力敏感越严重。综合损害机理实验研究结果表明,对于裂缝宽度在1.8～2.6μm的裂缝性储层,钻井液的主要损害方式为滤液侵入引起的液相损害;对于裂缝宽度在16.5～19μm和50～70μm的裂缝性储层,钻井液的主要损害方式为固相损害。对于裂缝宽度小于50μm的裂缝性储气层,不必考虑钻井过程中储层的保护问题。考虑了裂缝表面特征和裂缝内流动特性,通过采用流体力学和渗流力学及裂缝的分形维数,建立裂缝的有效流动宽度的数学模型,有机地和裂缝性岩心的渗透率联系在一起,更适合钻井液对裂缝性储层的损害评价。粒度分析和暂堵实验证明了有效流动宽度的实用性和准确性。利用1/2～2/3倍裂缝宽度的架桥理论进行模拟损害实验结果表明,针对裂缝宽度在70～110μm的裂缝性岩心,普通的两性复合离子钻井液中加入D50值为47μm的刚性架桥粒子,加量在5%时,基本能够满足实现快速形成桥堵进而大幅度降低钻井液的固相侵入深度的要求;该理论对裂缝性储气层的暂堵是适用的。对裂缝性储气层,在欠平衡钻进过程中不会受到钻井液损害。在条件允许的情况下,采用欠平衡钻井工艺打开深部裂缝性储气层,可以同时有效地保护在地层所处压力状态下的所有宽度范围的裂缝性储层,是保护裂缝性储气层的最佳途径。更多还原

【Abstract】 The joint, designed and processed in this paper, can satisfy the request of samples made with natural sandstone, tuff, and esite, basalt matrix; the artificial crack formation can simulate the crack surface morphology of natural fractures. The results showed that the stress sensitivity of fractured reservoir at east of daqing changyuan is strong. The permeability and width of crack dicrease with the increasing of the effective pressure; the larger is the initial crack width, the more serious is the stress sensitivity. The results of comprehensive experimental show that the major damage is the liquid-phase damage caused by the invasion of filtrate for the fractured reservoir in 1.8 ~ 2.60μm; while the major damage way is solid-phase damage for fractured reservoirs in16.5 ~ 19μm and 50 ~ 70μm. It need not consider drilling process of reservoir protection problems when the width of crack is less than 50μm.Considering the crack surface characteristics and the inner flow characteristics of crack, and adopting hydromechanics, percolation mechanics and the fractal dimension of crack, the mathematical model of the effective width of crack is established, wihich is more suitable for studying the damage assessment of the drilling liquid through linking the permeability of fracture core. Grain size analyses and temporary plugging experiments have proved that the effective flow width is practical and accuracy. The results of the simulation experiment by using the bridge theory with 1/2 ~ 2/3 times of crack width showed that: for the fractured core in 70-110μm crack width, when 5.0% rigid bridge particles with D50 value was added into the common amphiphilic drilling liquid D50 value, it can meet the needs of the rapid forming bridge and the reduction of the wall drilling depth by the solid-phase invasion. The theory is applicable for the temporary plugging of the gas reservoir. The fractured gas reservoir can not be damaged by the drilling in the underbalance drilling process. Under the considerable condition, the fractured gas reservoir can be opened by the underbalanced drilling technology, which can effectively protect the fractured gas reservoir under pressure for all the width of the fractured reservoirs, and the method is the optimal way for protecting the fractured gas reservoir.更多还原