METHOD OF REMEDIATING WELL BORE DRILLING CUTTINGS

摘要

The present invention relates to the field of well bore drilling for access to subterranean stores of resources such as petroleum oil and natural gas. In one aspect the invention seeks to provide a method of treating drill cuttings and spoils which renders them suitable for safe disposal or suitable for use as a fertilizer in agriculture. According to one aspect of the present invention there is provided a method of treating drill cuttings comprising drilling fluid and spoil, which drilling fluid comprises water, silicate ions, hydroxide ions, potassium ions and an optional activity control agent and an optional density modifier, the method comprising treating the cuttings with a precipitation agent which causes the silicate anions to from a substantially insoluble solid silicate which precipitates out of solution in the drilling fluid. The precipitation agent may comprise a calcium salt which reacts to form an insoluble or substantially insoluble calcium silicate which precipitates from the solution. The calcium salt preferably comprises an anion which is suitable for use in forming a fertilizer, such as calcium nitrate or calcium ammonium nitrate. The activity control agent preferably includes anions of carbonate acetate (and any other appropriate organic anions), or sulphate. The method makes is possible to avoid the presence of harmful amounts of chloride and sodium in the treated drill cuttings.