| Popis: |
Horizontal and deviated well architectures are now quite common as they facilitate drainage of reservoir in a cost-effective manner, such architectures introduce a challenging environment for subsequent completions and bottom hole operations performed through Coiled Tubing (CT) mainly due to friction between the coiled tubing string and well casing or reservoir formation rocks. To address this, a variety of techniques have been used over the years to reduce the friction between the metallic surfaces and extend the reach of the coiled tubing string to desired depths. Several Such techniques included-but were not limited to- using a specifically designed CT string (tapered CT strings, Pipe surface smoothing treatments), using mechanical aids (downhole coiled tubing tractors, coiled tubing agitators or vibrators) and increasing lubricity of the annulus fluid through the use of lubricants, there has also been many cases in which multiple techniques have been used at the same time to further extend the CT reach.4 The use of lubricants has always been the easiest technique as it does not require investment into equipment which would increase the complexity of the operation in addition to their cost. In this study, we are evaluating the friction reduction performance of an environmentally friendly surfactant-based metal friction reducer which will be called Lubricant A, the chemistry of Lubricant A has been used before in oilfield applications, but the authors believe this is the first time this chemistry is used for lubricity enhancement. We will be assessing Lubricant A performance at room temperature and 170°F to investigate its thermal stability and we will be evaluating its compatibility with common brines used during CT operations, especially at high concentrations of salt. We will also be comparing the performance of Lubricant A to that of a Co-polymer based Lubricant -which will be labeled Lubricanr B- in terms of Coefficient of Friction (CoF) reduction at room temperature and at 170°F. A core flood test has also been performed to investigate the impact of brines containing Lubricant A on reservoir rocks permeability. Based on our lab testing, Lubricant A manages to drop the coefficient of friction (CoF) by 60-70% in most cases and shows relatively high compatibility with different brines at different salt concentrations, outperforming Lubricant B in most cases. Lubricant A has also shown insignificant reduction in permeability during core flood tests, increasing the potential for its use in operations where formation damage might be a concern. |
