Connection gas

{
  "id": "MLC-T-OAG-000816",
  "term": "Connection gas",
  "field": "Oil and gas",
  "definition": "A small slug of formation gas that enters the well while a connection is made, because stopping the pumps removes the annular friction pressure and pipe movement can swab, so bottomhole pressure briefly dips below pore pressure. It appears as a gas peak on the mud logging unit one lag time after the connection. Its presence signals that the mud weight is close to balance with formation pressure.",
  "subject": "Drilling",
  "url": "https://mlchart.com/terminology/oil-and-gas/connection-gas/"
}