Revisiting the Ideal Packing Theory with a Novel Particle Size Measurement Approach

摘要

Drilling into production zones requires the use of special fluids with minimal formation damage potential. These fluids typically include a blend of carefully designed bridging particles. The selection of these bridging particles is based on particle size distribution (PSD) and may include other attributes such as acid solubility depending on type of rock and the well completion method. One of the theories that addresses the design of these fluids is the Ideal Packing Theory (IPT). Two of the most common ways to obtain PSD are laser diffraction (LD) and sieve analysis (SA). Each method has its own bias in measurement. For instance, SA tends to emphasize the second largest dimension of a particle (Kumar et al. 2013) while LD calculates PSD based on the assumption all particles are spheres. Particles in drilling fluids are not all spherical, therefore it was deemed worthwhile to investigate PSD measured by other techniques such dynamic imaging analysis (DIA) which takes in consideration the parameter aspect ratio when generating its PSD. Sphericity of the bridging particles is a key assumption for the IPT to work. However, the use of dynamic image analysis (DIA) in the field of particle characterization in drilling fluids has led to significant findings. A key finding is that most bridging particles used are neither spherical nor uniform. This study evaluates whether there are differences in the PSD results for the same sample of bridging particles. The study then examines the effect of using the data from the various PSD techniques on the bridging algorithm thus impacting the fluid sealing ability of porous media represented by ceramic disks. This study also examines the phenomena of "packing behavior randomness" and its impact on porosity and permeability of blends of bridging particles.