Flowback Emulsions Issues for Complex Crude Oil Fluid-Phases Separation Testing and Manage by Demulsification or Water Clarification

Abstract

Drilling and completion of new or mature wells are a conventional method for companies to avoid standard oil production decline. Many of these wells are drilled in existing fields to produce from zones that are considered economical. Companies initially produce fluids into a frac tank to prevent production fluids contaminated with drilling mud or completion fluids from flowing to the production facilities. However, most wells still contain enough contaminants that cause drilling fluid induced emulsions during initial production to the plant such as chemical polymers, acids, surfactants, foamer agents, and others. Some purposes of a drilling fluid or completion jobs and work over programs are to provide hydrostatic pressure to prevent formation fluids from entering the wellbore, carry the cuttings to the surface, minimize formation damage, and lubricate the drilling string and bit. Multiple chemicals and other compounds are combined to provide these functions. Traces of the filter cake and other skin damage remain in the near wellbore after the well is completed. These contaminants provide concern as they have potential to produce challenging drilling fluid induced emulsions in the production systems. Several types of drilling fluids were identified as potential candidates for drilling the new wells on this work. The several candidates consisted of water-based, brine-based, oil-based, and synthetic-based drilling muds. Multiple tests were completed to simulate the effects of the drilling mud on the production system. These fluids were added in iterations of less than one percent based on total production. Each drilling fluid iteration was treated with varying fluid separation chemicals, applying different dosages and strategies. The fluids separation test provides the least impactful drilling fluid on the production fluids. The test also highlights the optimal fluids separation chemistry to treat the new wells. This paper summarizes the best practice to identify the optimal drilling fluid and fluid separation chemistry via fluids separation testing. The paper discusses the crude oil characteristics and briefly describes the production system to provide the reader insight on the key areas when drilling induced emulsions create challenges with incumbent treatment programs.