裂缝性储层压裂液滤失计算模型研究

MODAL OF FRACTURING FLUID LEAK-OFF FOR FRACTURED RESERVOIRS

裂缝储层压裂与普通均质储层压裂存在明显的差异,最主要的差别就是流体的滤失。现有的压裂液滤失模型是针对均质储层而建立的,不能用于裂缝性储层压裂液的滤失计算。文章建立了裂缝性储层压裂液滤失计算的数学模型,采用正交变换法给出了模型的精确解,并讨论了其收敛性,对于裂缝性储层压裂设计和压裂压力分析具有重要的意义。实例计算表明,裂缝性储层压裂液滤失速度计算不能采用滤失速度与滤失时间的平方根成反比的经典滤失理论。

As gas-boosting technology develops, gas injection with high pressure is used wider and wider in oil/ gas fields. To meet the working conditions of gas injection with high pressure, it is very necessary to make proper design and safety check for gas injection string. Aiming to a well of some offshore oil field where gas injection with high pressure will be conducted, the method of design and safety check is proposed for the gas injection string. Based on the force analysis of the gas injection string, integrating the real drilling trajectory and operation situation, the 3-D stress strength check is conducted while the influence of the axial force, outside and inside crush pressure on the strength of the gas injection string is considered sufficiently. When gas pressure is calculated, the pressure produced by gas when packer installing and under the gas injection conditions should be considered. The method of design and check for gas injection string has been applied in the fields.