ABSTRACT
There are a number of new developments and trends in the oil and gas industry that impact how mineral scales are formed and prevented, namely, (a) the production of oil and gas (and water) from deepwater and ultra deepwater, especially from subsea satellite elds that are tiebacks to a main production platform or a oating production, storage, and of oading (FPSO) vessel; (b) production from high-pressure, high-temperature (HPHT) reservoirs, some of which contain high-salinity (HS) formation brines; (c) production from long-reach horizontal wells and complex wells in complex reservoir formations; (d) the minimization of environmental impact from chemical products to meet more stringent regulatory requirements; and (e) gas hydrate formation and the use of hydrate inhibitors. In response to these operational and environmental challenges, signi cant technological advances have recently been made in oil eld scale control. This chapter therefore intends to review and discuss some of these major developments and advances in the last few years, namely, (a) the use of viscosi ed uids to improve chemical placement into targeted formation zones in horizontal wells, complex wells, and complex formations; (b) the use of nonaqueous inhibitor solutions and treatment packages to minimize potential formation damages resulting from scale inhibitor squeeze treatments; (c) the development and selection of chemical inhibitors that are more environmentally acceptable or that are with enhanced functionality or improved secondary properties; (d) alternative
8.1 Introduction .......................................................................................................................... 129 8.2 Viscosi ed Fluids for Improvement of Scale Inhibitor Placement ....................................... 130 8.3 Nonaqueous Scale Inhibitors for Squeeze Treatments ......................................................... 131 8.4 Development and Use of New Chemical Inhibitors ............................................................. 132
8.4.1 Environmentally Acceptable Inhibitors .................................................................... 132 8.4.2 Inhibitors with Enhanced Functionality ................................................................... 133
8.5 Sulfate Removal from Injection Seawater ............................................................................ 133 8.6 Brine Mixing, Ion Exchange, and Scale Precipitation Inside Oil Reservoirs ...................... 136 8.7 Impact of Hydrate Inhibitors ................................................................................................ 137 8.8 Fundamental Studies on Scale Formation, Inhibition, and Inhibitor-Rock Interactions ..... 140
8.8.1 Scale Formation, Precipitation, and Deposition ....................................................... 141 8.8.2 Scale Inhibition ......................................................................................................... 143 8.8.3 Scale Inhibitor Interactions and Reactions with Rock Substrates ............................ 146
8.9 Miscellaneous Developments ............................................................................................... 148 8.10 Summary .............................................................................................................................. 148 Acknowledgments .......................................................................................................................... 149 References ...................................................................................................................................... 149
approaches to scale inhibition by reducing/removing sulfate ions in the injection seawater; (e) the mapping of ions and scale precipitation throughout oil reservoirs; and (f) the impact of gas hydrate inhibitors on scale formation and inhibition. Furthermore, this chapter attempts to review some of the recent fundamental studies on scale formation, inhibition, and inhibitor-rock interactions, and transport. Instead of attempting to critique the soundness and validity of the referenced studies, this chapter intends to keep readers abreast of the recent major developments in oil eld scale and the resulting key ndings, and serve as a source of literature references for further reading.
