Encana Corp. wants to ensure the shale-oil boom keeps booming. The Canadian producer is among a growing number of companies that are restricting initial output — a process known as choking back — in basins from North Dakota to Texas. They’re conceding huge up-front gushers of crude in exchange for smaller production declines over time so that the wells ultimately generate more oil. The strategy sacrifices one of the biggest benefits from shale. The early gushers paid back investments fast, allowing companies to pour capital into new projects. Instead, Encana and others envision a future with a more stable flow from wells, so that they don’t always have to keep drilling simply to maintain output. “You’re losing a barrel today to get two or three barrels tomorrow,” said Allen Gilmer, chief executive officer of consultant Drilling Info Inc. in Austin. “It’s not a zero-sum game.” Red Queen Curbing initial […]