Pipe strings for existing multi-stage perforation techniques are characterized by complicated structures, low detonation efficiencies, poor reliability, high operation costs and difficulties in their application in negative-pressure perforation. Consequently, applicability of such pipe-strings in offshore oilfields is limited. In this regard, conventional single-stage perforation devices were modified to develop multi-stage perforation devices. Combined with bypassing joints, hydraulic delayed igniter, RTTS packer and other tools, the negative-pressure perforation technique with multiple igniters over super-long span was developed. Through the integral slid sleeve, the multi-stage perforation device can generate negative pressures after detonation of multiple igniters. In this way, all target intervals can be perforated in one single trip under negative pressure to satisfy demands related to perforation in multiple intervals with significant interval distances (above 500 m). The newly developed device is characterized by simplified structures, safety, reliability. The device has been successfully deployed in 6 wells in Weizhou A Oilfield in western part of South China Sea. These operating time increased by 51.3% and costs decreased by 17.68%.%现有多级射孔技术管柱结构复杂、传爆效率和可靠性较低、成本较高、难以实现负压射孔等问题限制了其在海上油田的推广应用，为此，对常规单级开孔装置进行改进，研制出了多级开孔装置，与旁通接头、液压延时点火头、RTTS 封隔器等工具配合，形成了超长跨距多点起爆负压射孔技术。多级开孔装置可通过内置滑套实现各级点火头引爆后再制造负压，具备一趟管柱负压射开所有层段的功能，满足多射孔层段、大层间距（可超过500 m）的射孔要求，并且工艺原理简单、安全可靠。该技术在南海西部涠洲 A 油田6口井进行了成功应用，与常规负压射孔作业相比，作业时效提高了51.3%，成本降低了17.68%。
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