HOUSTON — A cyberattack on a shared data network forced four of the nation’s natural-gas pipeline operators to temporarily shut down computer communications with their customers over the last week.

No gas service was interrupted, the companies said, and the interruption of customer transactions was merely a precaution. It was unclear whether any customer data was stolen.

The attack highlighted the potential vulnerability of the nation’s energy system, cyberexperts say. Beyond consumer and business data — energy companies possess much proprietary information about their holdings, trading strategies and exploration and production technologies — the increasing dependence of pipeline infrastructure on digital systems makes them a particularly ripe target. Control valves, pressure monitors and other equipment connected to wireless networks are vital to daily functions of everything from refineries to oil wells.

With nearly 2.5 million miles of oil, gas and chemical pipelines crisscrossing the country, intrusions into control systems could do more than disrupt deliveries, said Andrew R. Lee, a cybersecurity expert at the law firm Jones Walker in New Orleans. The risks include “explosions, spills, or fires, which easily will threaten human life, property and the environment,” he said.