Gas-drilling industry, opponents gathering in Phila.

Brace yourself, Philadelphia. The city is about to have a firsthand experience with natural gas.

The Marcellus Shale Coalition, a natural gas industry trade group, on Wednesday will open a two-day conference called Shale Gas Insight at the Convention Center. Gov. Corbett and former Govs. Ed Rendell and Tom Ridge are scheduled to speak.

Anti-drilling activists are gearing up to welcome the event with street protests and a counter-conference, called Shale Gas Outrage.

Thousands of visitors are expected. The industry says its event is sold out - 1,600 participants are registered, and 150 exhibitors have signed up. And protesters hope to attract hundreds more for a rally and a march Wednesday.

While gas drilling is more visible in northern and Western Pennsylvania, the coalition said it deliberately sited its first conference in Philadelphia, where the industry has a low profile and has come under political attack because of Harrisburg's opposition to approving a production tax on shale gas.

"Southeastern Pennsylvania has so much to gain and certainly has a major role to play in this economic success story," said coalition president Kathryn Z. Klaber.

The industry will use the conference to promote converting gasoline and diesel vehicles to natural gas to help the region meet air-quality goals.

Robert C. Wonderling, president of the Greater Philadelphia Chamber of Commerce, said the region had much to gain from shale gas. Professional businesses - such as engineering firms, environmental service providers, legal firms, and financial advisers - are already getting work from the Marcellus industry.

Wonderling also said the environmental challenges of shale drilling also represent a research opportunity for universities and institutions such as the Academy of Natural Sciences to "reduce the negative environmental consequences" of gas development.

Klaber, the shale coalition president, said she believed the industry's message of economic growth, jobs, and energy security would resonate more strongly with Americans.

The protest organizers, who have called the industry event a "brazen expression of its political muscle," will present a competing vision of gas drilling, portraying the economic benefits as meager compared with the environmental and health risks.

Josh Fox, director of the Oscar-nominated film Gasland, is scheduled to be the headline speaker at a noon rally on Arch Street near Broad Street.

For more on the industry conference: http://shalegasinsight.com.

For more on the protests: http://shalegasoutrage.org.