Paper: Increase Production By Using A Silt-Suspending Acid Additive

In the reaction of formation rock with acid, as in a matrix acidizing treatment, varying quantities of insoluble fines are released or otherwise dislocated by the flow. Also, normal reservoir flow can break or dislodge fragile clays and minerals present on the pore linings. If allowed to settle and accumulate, these fines have the capability of plugging pore throats when disturbed in mass upon the return flow of the treatment and formation fluids. The addition of a silt suspending additive to the acid used for treatment will prevent this accumulation by keeping the fines distributed in this fluid, thus preventing plugging while removing them from the formation. A silt-suspending system that uses an electrostatic repulsion approach to fine suspension is discussed. Laboratory work describes the system's properties in relation to oil reservoirs and field data shows the system's usefulness. This treatment has been successfully used in well workovers to remove existing clays, fines, and precipitated solids. Production data on this aspect is presented.