HYDROCARBON MASS BALANCE CALCULATIONS IN PETROLEUM SYSTEMS EXPERIENCING THERMOCHEMICAL SULFATE REDUCTION (TSR)

Summary The quantitative assessment of thermochemical sulfate reduction (TSR) in petroleum systems is to date not entirely understood. Since the term TSR was first established in the 1970’s, many equations have been proposed to explain the kinetics of the reaction. Each reaction returns very often different numerical results, which reveals the degree of uncertainty. The area of study is located in SW France, in the South Aquitaine Basin where the giant sour dry gas (up to 18 vol% H2S) field of Lacq is located. The present study evaluates three TSR net equations taken from literature ( Orr, 1974 ; Goldhaber and Orr, 1995 ; Worden et al., 1995 ; Machel, 2001 ; Mougin et al., 2007 ; Liu et al., 2013 ) by applying them to mass balance calculations on the Lacq petroleum system. Objective is to compare constency of the calculated masss balance with the geological situation of the system.