Fluid Flow and Particle Transport Analyses Show Minimal Effect of Annulus Between Horizontal Wellbore and Expandable Screen

Abstract

Proposal Expandable screens are becoming increasingly more important in sand-control completions because of their exceptional capabilities for providing wellbore support and optimized wellbore geometry. This is particularly important for offshore horizontal wells. Currently, two types of screen expansion technologies exist; i.e., the constant-diameter (fixed-cone) expansion technology and the variable expansion technology. Each approach has its own advantages and disadvantages in terms of deployment, wellbore support, and inflow performance characteristics. With fixed-cone expansion technology, the industry has had the concern that annular flows between the open hole and screen can lead to transport of formation sands. This phenomenon can lead to localized screen erosion due to partial screen blockage, concentrated flow in unblocked portions of the screen, and finally, failure of the filtration layers. This paper discusses a method that can determine the probability of the above concerns with a model that analyzes fluid flow and particle transport. The forces acting on individual sand particles are modeled to ascertain the particle transport within the annulus and determine annular flow problems. Based on a given production profile that takes into account the frictional pressure losses of fluid in the annulus and in the base pipe, this model can predict if there is any possibility that particles in the annulus will be transported. Using this method, the wellbore (annulus) section in which no particles would be transported can be predicted. Computational Fluid Dynamic (CFD) simulations were carried out to study the flow distribution in the horizontal wellbore. At a given wellbore location, the percentages of fluid flowing inside the basepipe and in the annulus were calculated. The simulations typically showed that the average fluid velocity in the annulus is an order of magnitude less than the fluid velocity inside the base pipe. The study also showed that if designed properly, a screen with fixed-cone expansion can be used successfully without concern of particle transport and with very limited flow in the annulus.