Drilling fluids in offshore areas must be handled so as to avoid water pollution. To accomplish this, it has pollution. To accomplish this, it has been necessary to improve operating practices and mud handling facilities. practices and mud handling facilities. These improvements have been made and have led not only to a cleaner, nonpolluting operation but also have tended to minimize mud losses and treating costs. Both water base and oil mud systems are being utilized in sustained drilling operations without polluting the water. polluting the water. Water base mud systems, some containing small amounts of emulsified oil, have been used pollution-free offshore without difficulty. In most cases the drill cuttings are disposed directly into the water, although a precautionary seawater wash is used in precautionary seawater wash is used in the Santa Barbara channel.
Oil muds are being used in clean offshore drilling operations with a combination of good housekeeping practices and cuttings disposal methods. practices and cuttings disposal methods. The oil drill cuttings are being handled by collecting and transporting them to shore for disposal, and by washing the oil from the cuttings and then disposing of the cleaned cuttings into the water. Both methods have proven workable. proven workable. A cuttings collection system, designed to facilitate handling, storage, and transportation for onshore disposal, has proven very successful with oil mud. The system also includes a cuttings conveyor unit but so far the containers have been adapted to the rig shaker discharge with no conveyance needed.
Two basic methods have been tried in an effort to clean the oil from drill cuttings. These are by heating and washing. The heating method has not been successful. Solvent washing of the cuttings to remove oil has proven workable. Diesel oil has proven a good solvent.
