An Experimental Investigation on use of Nanoparticles as Fluid Loss Additives in a Surfactant – Polymer Based Drilling Fluid

摘要

As we approach an age of deeper discoveries in hostile environments, we need to either improve on existing drilling fluids or design new ones in order to meet the technological demands for success. The filtrate invasion is the most critical parameter that may cause a wellbore failure if not properly controlled. Also, the filtrate induced formation damage and problems with filter cake removal adversely affect the well productivity or injectivity. The literature survey reveals the advantages of polymer, surfactant and Nanoparticles systems independently and also combination of two of these. A study is necessary to see the effect and advantages of combining all three systems together i.e. a Polymer-Surfactant-Nanoparticles system and to measure the rheological and fluid loss characteristics of the complex combined drilling fluid system. An attempt to study the same has been made in paper. Therefore, in this paper the authors present the results of testing the rheological properties and the API filtrate loss of a Bio-Polymer and Surfactant blend system with addition of Nanoparticles and compare the fluid loss reduction by using Nanoparticles as fluid loss additive with an industry standard polymer-based fluid loss additive The objective of this research was to study the effectiveness of a Bio Polymer - Surfactant fluid blends, containing Nanoparticles as fluid loss additives in reducing the filtrate losses to the formation by forming a thin, non-erodible filter cake. Laboratory experiments were carried out for the different combination of polymer and surfactant with varying concentrations to find the optimum of fluid performance. The laboratory measurements included measuring mud weight, pH, viscosity, gel strength, standard API filter test and High Temperature High Pressure (HTHP) test using Permeability Plugging Apparatus. Presented results show that sized silica nanoparticles can be used instead of sized calcium carbonates which are a very effective inorganic bridging agent, however, difficult to maintain. The polymer - surfactant blend is better in rheological properties as well fluid loss properties than a Bio-Polymer based fluid or Surfactant based fluid. It captures the merits of both fluid systems. The nanoparticles play an important role in reducing the fluid loss of the individual fluid systems. Also, the nanoparticles based Polymer-Surfactant blend is a good solution for solids free reservoir drill in fluids for horizontal shale drilling applications. The nanoparticles is most effective for shale drilling application as it can penetrate the pores of the shale and act as a bridging material and causing wellbore strengthening.