In the face of population shifts, dwindling Mass attendance, and thinning clerical ranks, the Archdiocese of Philadelphia will soon call on half of its 266 parishes to begin talking among themselves about their needs - and survival.

In an announcement to be made Wednesday, the archdiocese will say it has reached "no decisions" about the fates of the churches in the 22 "parish planning areas" involved. It is not ruling out parish closings as a result of the process.

Each congregation will be asked to begin a "prayerful and participative" discussion to identity its mission and goals, and "determine if it has the resources required for sustained operation," the announcement reads.

It also notes there are many instances in which a "high density of parishes [serves] a relatively small geographic area."

That situation has led to financial stresses and underused facilities, which have "impacted the quality of parish life," according to the statement.

Robert Miller, director of the archdiocese's Office for Planning, said Tuesday that it had not yet identified which 22 of the 44 pastoral planning areas will be involved in the first round of study, which could take three years.

All parishes eventually go through the process, he said.

Although newly installed Archbishop Charles J. Chaput issued a pastoral letter Sunday warning his 1.5 million-member flock that 2012 would likely be a year of "painful" changes, Miller noted that the parish self-study process was initiated more than a year ago by Chaput's predecessor, Cardinal Justin Rigali.

A "blue-ribbon panel" appointed by Rigali a year ago to study the needs of the archdiocesan school system is to issue its report in January. Chaput said in his letter that "some, and perhaps many, schools must close or combine."

Miller said that while the current "parish pastoral planning initiative" has echoes of the "cluster planning" process Cardinal Anthony J. Bevilacqua launched in the late 1990s, decisions about mergers and closings will probably be more "top-down" than they were 15 years ago - but still collaborative.

He said many of the lay people involved in cluster planning were reluctant to recommend closings, and opted to "twin" underused parishes.

As a result, the pastors serving those twinned parishes were obliged to maintain dual parish and finance councils and two sets of records, and perform sacramental duties at two sites.

"There's a feeling now among many of the priests that the archdiocese needs to assert itself more in how long it can go along with these arrangements," said Miller, who helped coordinate the cluster planning process in the 1990s.

He also noted that 15 years ago, the cluster leadership in Manayunk voted to keep all five parishes in that neighborhood open, though the churches were just blocks from one another.

Said Miller: "It might be legitimate for the archdiocese now to say, 'We think five is too much.' "

Contact staff writer David O'Reilly at 215-854-5723 or doreilly@phillynews.com.