Optimisation of Acid Fracture Design for the Basement Formation in the White Tiger Field

Abstract

Abstract After the period of exploitation at the basement formation of the White Tiger field, the production rates of producer wells had been declining due to near-wellbore formation damaged from drilled cutting and lost circulation materials of drilling activity, leading to natural permeability of the basement reservoir to be decreased. In fact, the effective permeability of the basement was varied between 0.004D 10 464D, with an average permeability of 135mD, the reservoir temperature was ranged between 1300C and 135°C and reservoir pressure was varied 200atm to 320atm. There were a wide variety of stimulating technologies methods applied to the near-wellbore treatment basement formation such as acid salt, mud acid, oil acid emulsion, Gas-Oil-Acid emulsion, and explosion treatment. However, these methods had been brought a low successful stimulation after treatment when the production rates were rapidly decreased after a short time because the near-wellbore basement was re-damaged of producer wells. To eliminate the above problems, this study has presented the optimal acid fracture treatment design with an acid HCl concentration of 15%. The program of acid fracture treatment comprises a fracture propagation model, the acid volume 50400gals, the acid fracture length 119ft, etched acid width 0.344in, and acid fracture conductivity 3350mD.ft, and NODAL tubing evaluation production rate and bottom hole flowing pressure of 3500psi, and comparison between production the rate at pre-treatment and post-acid fracture treatment. The result showing the oil productivity index has been increased with folds of 2.6.