Scale Prediction and Inhibition for Oil and Gas Production at High Temperature/High Pressure

Abstract

With the advance of new exploration and production technologies, oil and gas production has gone to deeper and tighter formations than ever before. These developments have also brought challenges in scale prediction and inhibition, such as the prevention of scale formation at high temperatures (150-200 C), pressures (1,000-1,500 bar), and total dissolved solids (TDS) (>300,000 mg/L) commonly experienced at these depths. This paper will discuss (1) the challenges of scale prediction at high temperatures, pressures, and TDS; (2) an efficient method to study the nucleation kinetics of scale formation and inhibition at these conditions; and (3) the kinetics of barite-crystal nucleation and precipitation in the presence of various scale inhibitors and the effectiveness of those inhibitors. In this study, nine scale inhibitors have been evaluated at 70-200 C to determine if they can successfully prevent barite precipitation. The results show that only a few inhibitors can effectively inhibit barite formation at 200 C. Although it is commonly believed that phosphonate scale inhibitors may not work for high-temperature inhibition applications, the results from this study suggest that barite-scale inhibition by phosphonate inhibitors was not impaired at 200 C under strictly anoxic condition in NaCl brine. However, phosphonate inhibitors can precipitate with Ca 2þ at high temperatures and, hence, can reduce efficiency. In addition, the relationships of scale inhibition to types of inhibitors and temperature are explored in this study. This paper addresses the limits of the current predition of mineral solubility at high-temperature/high-pressure (HT/HP) conditions and sheds light on inhibitior selection for HT/HP application. The findings from this paper can be used as guidelines for applications in an HT/HP oilfield environment.

Improvement of Thermodynamic Modeling of Calcium Carbonate and Calcium Sulfates at High Temperature and High Pressure in Mixed Electrolytes

“…As an important sector of global energy support, deep water oil and gas production are getting more attention today (Miller and Newman 2011;Fan et al 2012;Kan and Tomson 2012). Increasing water depth in the oil and gas production process not only indicates increasing financial rewards due to the larger amounts of oil and gas reserves, but also means increasing risks due to extreme operation conditions with high temperature (150 to 200 o C, or 302 to 392 o F), high pressure (1,000 to 1,500 bar, about 14,500 to 22000 psi), and high concentration of total dissolved solids (TDS more than 300,000 mg/L) (Chawathe et al 2009;Kan and Tomson 2012).…”

Laboratory investigation of a new scale inhibitor for preventing calcium carbonate precipitation in oil reservoirs and production equipment

“…Huge amounts of water are injected into reservoirs to maintain the reservoir pressure at the required level, whereby salt deposition occurs as a result of water combination (Fan et al 2012). As the reservoirs continue to deplete and more and more wells are experiencing increasing high water cut, the scaling problem is aggravated.…”

An experimental and modeling study of barite deposition in one-dimensional tubes

“…In the meantime, conventional fossil fuels are rapidly being depleted (Fan et al 2010). This had led to increased research into techniques to improve the secondary recovery of oil and gas.…”