Halliburton DPU® helps operator improve safety, logistics and costs

Overview 

Before tubing can be replaced or pulled during workovers, it must be perforated to equalize pressure inside and out. A large Middle East operator used explosives to do that until recently. The explosives created risks and costs they wanted to mitigate. Logistical delays for permitting, transporting and storing the explosives – as well as bringing in an e-line crew to trigger them – all increased costs. Transporting and handling the explosives created additional risks. With no reliable mechanical perforating alternatives in the market, in 2006, the operator approached Halliburton about developing a better solution. The DPU Actuated Tubing Perforator was the answer. After more than a year of development and testing, the operator used it in more than 300 wells with a success rate greater than 99 percent. The tool has reduced costs, simplified logistics and improved safety.

Challenge 

As long as operators have been doing workovers, there has been a need to perforate tubing. Perforation allows pressure from fluids inside and outside of the tubing to equalize. Explosives create a reliable perforation. But they also tend to create holes quickly. And if there is a large amount of fluid between the tubing and the casing, the sudden, radical pressure change can blow fluids up the tubing, creating a safety risk. Moreover, many countries highly regulate the use of explosives. The operator’s home country requires permitting, special transportation and secure warehousing, all of which can be difficult to arrange in many locations. Offshore rigs could be idled for days while the operator worked out logistical issues. So the company had long sought an alternative to using explosives. However, there simply were no good mechanical alternatives in the marketplace.

Solution

To improve safety, costs and logistics, in 2006, the operator asked Halliburton to develop a better mechanical alternative. At Halliburton’s Carrollton, Texas facilities, a handpicked crew of engineers began the search for solutions. Their efforts focused on adapting Halliburton’s field-proven DPU® (downhole power unit) tool to the task. As a screw inside the DPU tool moves downward, it forces the tip of the blade – which rotates on a fulcrum – against the wall of the tubing. Eventually the tubing begins to perforate. Starting with a pinhole, the blade gradually enlarges the perforation to about one half-inch across. As the DPU tool continues to apply pressure against the blade, the blade flips over and retracts back into the tool so that the tool can be removed from the hole. The tool produces a puncture in the tubing within minutes. More than a year’s worth of design went into this collaborative effort which tested different variables in multiple grades of tubing. Eventually, Halliburton engineers determined the right combination of properties to work in J55, P110 and 13-chrome. 

Result

To date, the operator has deployed the DPU Actuated Tubing Perforator in more than 300 workovers for this operator. Their success rate exceeded 99 percent. The client has recognized significant cost savings by eliminating issues associated with provisioning, transporting and using explosives (including special crews needed to handle them) in this volatile part of the world. The DPU Actuated Tubing Perforator saves the expense of mobilizing a second crew. One of the biggest time and money saving features is that it can be used on any slickline, e-line or coiled tubing unit at the rig site – whether it’s Halliburton’s or a competitor’s.