超高孔密等孔径射孔技术在南海西部深水气田中的应用

Application of Ultra-high Density and Equal Aperture Perforation Technology in Deep Water Gas Field in Western South China Sea

南海西部深水气田属高孔高渗透储层,射孔完井后需要进行砾石充填防砂。常规高孔密、大孔径射孔时,由于射孔枪在套管内无法保持居中状态,枪管与套管之间的间隙不一致,导致射孔孔径大小不一,造成不同孔径处砾石填充不均匀。文章提出一种高孔密等孔径的射孔方法,使得射孔孔径相对均一,配合砾石充填,以提高高孔高渗透储层气田的产能。对三种不同结构的药型罩进行射流数值仿真分析,得到最有利于等孔径射孔的药型罩结构,进而对该药型罩进行不同枪管与靶体之间间隙的钢靶有限元仿真分析,得到间隙分别为5 mm、15 mm、25 mm时靶体开口处的直径相对标准偏差仅为9.2%。对178型60孔/m射孔枪进行模拟井下整枪穿套管抗爆性能测试,结果符合国标GB/T 20489-2006的要求。混凝土靶偏心射孔试验结果表明等孔径射孔弹孔径偏差仅为9.8%,与数值仿真结果较为吻合,远小于常规大孔径射孔弹孔径偏差,且穿深性能与常规大孔径射孔弹一致。超高孔密等孔径射孔技术成功应用于南海西部X-2深水气田并获得高产,对国内其他高孔高渗储层的开发具有借鉴意义。

The deep water gas fields in western South China Sea belong to high porosity and high permeability reservoir and the sand control of gravel pack is required after perforation completion.In conventional high-density and large-aperture perforation,the perforating gun cannot be kept in the center state in the casing,and the gap between the gun and the casing is inconsistent,resulting in different perforating diameters and uneven gravel packing of different diameters.In this paper,a set of perforation methods with high density and equal aperture are put forward to make the perforation aperture relatively uniform and improve the productivity of gas fields with high porosity and high permeability.The numerical simulation analyses of jets of three liners with different structures are carried out and the most favorable liner structure for equal aperture perforation is obtained.The finite element simulation analyses of the steel target with different gaps between the barrel and the target are conducted,and the relative standard deviation of diameter of the target opening is only 9.2%when the gaps were 5 mm,15 mm and 25 mm,respectively.The simulative anti-explosion performance across casing of 178 perforating gun with 60-hole/m was tested,and the results were in line with GB/T 20489-2006.The results of eccentric perforating test of concrete target show that the aperture deviation of the equal aperture charge is only 9.8%,which is consistent with the numerical simulation results,and much smaller than the conventional large-aperture charge,and the penetration performance of the two is consistent.The perforation technology with ultra-high density and equal aperture has been successfully applied to X-2 deep water gas field in the west of South China Sea and high production is achieved.It has reference significance for the development of other high porosity and high permeability reservoirs in China.