Non-acidic Multi-Functional Iron Sulfide Scale Dissolver for High Temperature Sour Wells

摘要

A non-acidic multifunctional iron sulfide scale dissolver has been developed as one of the efficient and cost-effective alternatives for removing iron sulfide dominated scale deposited both in the downhole tubular and near wellbore region. Compared with three typical conventional iron sulfide scale dissolvers (THPS, pH neutralized chelate and traditional chelate), this newly developed iron sulfide dissolver showed significantly better performance on pyrrhotite, calcite and field iron sulfide scales, and much less corrosive at high temperature. Different with the traditional HCl acid based iron sulfide scale dissolver, this new dissolver is non-corrosive, no H_2S generation and iron sulfide re-precipitation problems, which is significantly improve the efficient and safe operations. In addition, the new developed iron sulfide dissolver showed multifunctional characteristic of well stimulation, addressed and confirmed by dynamic coreflood evaluation and CT scan technique. This paper introduces a new developed non-acid iron sulfide scale dissolver with multi-function of well stimulation, and gives a guideline of selection criteria and procedure for iron sulfide dissolver for high temperature application. It can be applied to iron sulfide dissolution in both sour oil and gas wells.