Application of Reverse Demulsifiers in Treating Produced Water at 1/2/4 Block Oil Fields in Sudan

The oil output in 1/2/4 block oil fields in Sudan run by the Company named is started in 1999 and a gradual change to electric submersible pumps in oil production is finished in 2004.In that year the following data are characteristic: increase in fluids production by 7.5 times,in water cut from 8.7% to 82% and in volume of water produced by 38 times;reduction in residence time of fluids in oil/water separators from 1.82 to 0.57 hrs and of waste water in production water settling tanks(PWSTs) from 69 to 3.6 hrs;and increase in oil content in waste water from 50 to 4100 mg/L,an xtra-high value in comparison with the standard norm of 100 mg/L.The produced fluids treatments include zonal oil/water separation(O/WS) in FPFs and central electric dehydration (ED) in CPF;the demulsifier is introduced into the facilities at the wellhead and before ED;the reverse demulsifier(RD) is introduced at three spots: before and after O/WS and after ED.In a field test in Heglig zone it is ascertained that at an equal total dosage of RD the lowest oil content in waste water determined turbidimetrically in PWSTs is observed with RD of dosage 106,60,and 54 L/d introduced at the three spots above mentioned,respectively.In a fast laboratory waste water treatment experiment at room temperature in 20 min with 5 KS-60 series RDs of Sino King Shing Chemical Co Ltd,KS-60-22 is chosen as the most effective one.In a field trial performed at 6 zonal FPFs and CPF Nov 2—27,2004,the oil content of waste water in PWSTs is decreased down to 50 mg/L when KS-60-22 is introduced at dosage 5.7—17.8 mg/L.