An improved workflow for handling an excess of Hydrogen Sulfide (H2S) in treatment facilities is presented. The objective is for the selection of wells to decrease H2S production by reduction of choke sizes with the lowest possible impact on oil production.
During operational restrictions in a gas treatment plant, it is necessary to reduce the H2S quantity received at the facility. To perform this operation, an approach is to limit the production from wells with the biggest rate production of H2S (volume); another solution is to restrict the wells with the highest concentration of H2S (% molar - composition); However, both scenarios have an impact on oil production. KOC - KwIDF Jurassic, has developed a procedure that considers the derivative of the produced H2S curve as a function of produced Oil to find the optimal scenario.
The proposed method was evaluated using the results from a sequence of monthly allocations that include characteristics such as: facility, number of wells, and fluid compositions. The data was analyzed applying three methodologies that have different objective functions, such as H2S volume, H2S concentration, and a new criterion called H2SOR. As a result, there were three different way to rank the wells to reduce H2S production. A monthly plot of Cumulative H2S Production vs Cumulative Oil Production was prepared to calculate the derivative of the curve, finding the optimal solution at different levels of H2S treatment restriction. Finally, the economic analysis for each method was also calculated.
H2SOR methodology guarantees the best alternative to ensure the restriction of sour gas rates with the lowest impact on oil production. It also proves to be the best solution from the economical point of view.