Removal of Sulfides From Brine By Aeration With Exhaust Gas From Submerged Combustion

Abstract

Abstract Proposed water flooding by Gulf Oil Corp. of the Yates formation in the North Ward-Estes field, Ward and Winkler Counties, Tex., is expected to require infection of a maximum of 150,000 BWPD. The only source in the vicinity capable of furnishing this volume of water is the Hendrick reef, which water contains approximately 500 ppm of hydrogen sulfide. Principally because of the hydrogen sulfide, the water is not compatible with the formation or the formation water, and treatment is essential. Chemical treatment alone proved to be uneconomical; however, data obtained from a scale model showed that removal of hydrogen sulfide by aeration with exhaust gases supplied by a submerged combustion unit combined with chemical treatment merited further investigation and construction of a larger treating plant. The results of the operation of a pilot plant capable of processing 7,500 B/D indicated that sulfide removal by aeration with exhaust gases from a submerged combustion unit and a flash tower was economically feasible and provided satisfactory injection water. Introduction Gulf Oil Corp. Is in the process of water flooding its holdings in the NorthWard-Estes field, Ward and Winkler Counties, Tex. This field is 16 miles long and from one to three miles wide, and approximately 730 Gulf wells that now produce from the Yates sand will ultimately be involved in the project. Water for injection is expected to reach a peak of 150,000 B/D, and a volume of this magnitude is readily available in this locality only from the Hendrick Reef formation. This formation has been oil productive in certain parts of the Permian Basin for many years; however, drill-stem test data indicated that the reef contains only sour brine in this area. In August, 1953, a well was drilled into the Hendrick Reef and completed at a total depth of 3,700 ft with a flowing capacity of 26,700 B/D at a well-head pressure of 25 psi. Chemical analyses showed that the produced water had a low concentration of chloride- and carbonates and a high concentration of sulfates and sulfides. Many difficulties in handling water with such a high sulfide concentration soon became apparent. Corrosion in the supply well was evident from a precipitate of ferrous sulfide which appeared in the well stream after a closed-in period of only a few hours. More important, iron sulfide precipitated immediately when equal volumes of source water and Yates formation water were mixed. Extensive laboratory tests revealed that significant amounts of iron compounds were present in the Yates formation and that the source water was not compatible with it or the formation water.