Improved Protocol for Scale Inhibitor Evaluation: A Meaningful Step on Scale Management

Abstract

Scale occurrence can cause oil and gas production loss with high economic impacts. Currently, the use of chemicals is one of the key strategies for scale management. A laboratory tests protocol is essential to qualify and guarantee chemical effectiveness in the field. The objective of this work is to present a protocol that includes improvements in the procedures to evaluate scale inhibitors and allows wide application to several production scenarios. The protocol is an improvement based on published international technical standards and the literature. These adjustments of the experimental procedures enabled the representation of a wide range of scaling scenarios from reservoir to topside facilities. An efficient application of scale inhibitor includes the definition of the ionic composition of aqueous fluids as well as the pressure and temperature conditions of the target scenario. To perform the laboratory tests, synthetic waters are prepared to represent the water production scenario, including pH. The tests are performed using synthetic produced water, including evaluation of fluids compatibility (one or two phase experiment), thermal stability and static and dynamic performance (DSL-dynamic scale loop). The proposed test protocol allows the qualification of scale inhibitors to the production scenario considered, reducing the associated uncertainties of upscaling from laboratory to field. The availability of the company's protocols makes it possible to achieve greater accuracy in the recommendation of commercial scale inhibitors, allowing a better cost-benefit with the optimization of the effective minimum concentrations. In addition, this availability encourages the development of new generation inhibitors for challenging scenarios with high scaling potential. The improved protocol is designed to represent critical salt precipitation scenarios, similar to those found in the Brazilian Pre-salt (high salinity, high temperature, high saturation ratio, high CO2 content), and has been successfully applied in the screening and qualification of scale inhibitors.