Separation of fractures and cavities in carbonate reservoirs in the Tahe Oil Field

Most of the fractures and cavities that remain in carbonate reservoirs are water flooded in the Tahe Oil Field.This complex distribution of oil and water makes successful exploration and production more difficult.A new concept and some methods for separating fractures and cavities in carbonate reservoirs are proposed based on petroleum geology cocepts.Separation models were classified into three types and seven sub-types as follows: separation by river channels or pipes (separation by branch channels, fillings, or U pipes), separation by faults (separation by internal faults, intersecting faults or parallel faults), and separation by karst channels.This method was applied to some old oil fields, and was proved effective in deploying a denser coverage of new wells.The traditional well spacing limit of at least 500 m was broken.The potential of fracture and cavity reservoirs is proposed, and the risk of water flooding in the dense deployment of new wells was reduced.