可降解纤维转向技术在川东大斜度井及水平井中的应用

Application of diversion technology using degradable fiber to highly-deviated and horizontal wells in the eastern Sichuan Basin

在四川盆地东部地区大斜度井及水平井(裸眼完井)碳酸盐岩储层改造过程中,存在着因施工井段长、储层非均质性强致使酸液合理置放难度大等问题,目前采用的机械封隔、酸液自生转向等酸液置放技术严重影响了增产效果。为解决这一问题,通过室内研究与现场试验应用,形成了一种新的适用于气井的可降解纤维暂堵转向技术。室内实验结果表明:可降解纤维的降解率高,能够满足天然气井现场施工需求。从室内实验及现场生产测井剖面来看:对两段储层而言,渗透率及流动系数差异越大,其转向效果越明显;在可降解纤维团与储层渗透率比值越小的情况下,加入可降解纤维后的过液量较之没加入可降解纤维的过液量其比值越小。可降解纤维转向技术在四川盆地东部大斜度井、水平井中应用取得了明显的增产效果,典型井的应用情况表明,该项技术增产效果明显高于采用其他酸液置放技术的井,为天然气井提供了一种全新的酸液置放技术,为长施工段、强非均质性储层酸化改造提供了新的技术方法,具有大规模推广应用价值。

In the stimulation process of carbonate gas reservoirs in the eastern Sichuan Basin, problems like the difficulty in reasonable acid placement due to long construction intervals and strong reservoir heterogeneity exist in those highlydeviated and horizontal wells （open hole completion）. Besides, the present acid placement technologies such as mechanical packers, acid selfdiversion, etc. seriously affect the stimulation result. In order to provide a solution, the laboratory research and pilot tests were conducted, and a new diversion （temporary plugging） technology using degradable fiber applicable to gas wells was developed. Based on the laboratory experiment, the degradable fiber has a high degradation rate, fully meeting the field construction requirements of natural gas wells. According to the laboratory experiment and field production log, with bigger differences of the permeability and flow coefficient between the two sections of the reservoir, the diversion effect is more obviously favorable; with lower ratios of the degradable fiber agglomerates to the reservoir permeability, the permeate flux after adding degradable fiber is smaller than the flux before adding the fiber. With the application of the degradable fiber diversion technology in highlydeviated and horizontal wells of the eastern Sichuan Basin, the production was significantly increased. The application in typical wells shows that, the production increase of wells adopting this technology is tremendously higher than other wells adopting other acid placement technologies. This technology provides a brand new acid placement solution for natural gas wells as well as a new technical approach to the acidizing frac treatment of long construction intervals and heterogeneous reservoirs, so it is of largescale popularization and application values.