简介：油井产量的成功，取决于完美的射孔效果。目前，一种新型的7英寸射孔枪，也是第一个能达到额定30000 psi的射孔枪，可以应用在市场不断扩大的海洋超深水开采领域，进行世界上最深井的射孔作业，并减少相应风险。

Deep drilling is risky business in any environment. With lower prices for oil and increased day rates for drilling equipment, the specter of failure looms large over an operator seeking to do things right the first time.

A crucial part of any drilling project is where and how to place the perfect perforation. Many times, crews only have one chance to get it right. Mitigation solutions are available for badly placed perforations, but these often add days ? and excessive costs ? to projects located in deepwater or ultra-deepwater environments. Wells can still be brought to production in time, but they are never as “sweet” as they could have been.

The 7-in. perf gun is not new to the industry. However, Halliburton has just released the world’s first 7-in. gun rated to 30,000 psi. What are the implications? Challenging and complex wells are now viable candidates for strategically placed, timely completions with a perforating tool capable of withstanding high pressures associated with deep reservoir targets and difficult ultra-deepwater projects.

The new gun is designed for conveyance by tubing, wireline, or slickline, and can meet the requirements of 95⁄8-in., 97⁄8-in., and 101⁄8-in. casing projects. The ultra-high pressure gun uses bi-directional boosters, non-lead azide charges, and a high-velocity/low-shrink detonating cord to meet safety and reliability assurances.

For ultra-deepwater projects, operators can enter deep well bores with more confidence. The gun is designed to maintain the integrity of the well and perforating system at extreme depths while providing greater function windows for downhole, pressure-operated tools.

The tool’s time-delay firer (TDF) also adds to the advantage of the high-pressure gun. It allows underbalanced or overbalanced perforating through the use of a pressure-actuated firing head with a time-delay fuse that burns for a predetermined time (between five and seven minutes depending on bottomhole temperature).

The TDF uses a predetermined number of shear pins for specific downhole conditions. As the tubing is slowly pressured to the maximum actuating pressure, the pins are sheared, allowing the firing piston to be forced into the primer. The delayed system allows independent perforating of selected zones and the maximum use of overbalanced or underbalanced pressure. It can be run in heavy mud systems, and it can be used with full-opening or non-full-opening tools. The ability to run multiple guns ? running TDFs on the top and bottom of gun assemblies ? without spacers helps to reduce costs.

In addition, the ultra-high pressure (30,000 psi), fully programmable electronic firing head may soon give operators an advantage when working to complete ultra-deepwater projects. The perforating technology is also capable of low-pressure cycle operation.

The high-pressure firing head enables safe, adaptable perforating to be done with increased precision. The instrument can initiate a gun system through a preset sequence of events. The programming flexibility ranges from minutes to up to 30 days, and it can be tailored to work under most completion sequences.

Overall, with a new capacity for placing the new 7-in. gun in high-pressure environments, operators may experience some relief from the inherent risks involved with completing ultra-deepwater projects in areas like Tupi offshore Brazil or in the Lower Tertiary in the Gulf of Mexico. “Junk-in-hole” scenarios created by imploded perf guns or misplaced perforations resulting from early ignition brought on by extreme pressure may soon be a thing of the past in these ultra-deepwater plays.