Well Completion Experiences With Autonomous Inflow Control Devices in Latin America
Authors: Porturas Francisco 
Published: June 2014

Well completions in Latin American oil and gas fields are characterized by numerous challenging conditions, including reservoir traps with high structural and sedimentological complexity, diverse hydrocarbon reservoir fluids and rock properties, and fluid PVT properties and wettability characteristics that vary regionally within a reservoir. Furthermore, production units on land, offshore and particularly in deep water environments have limited gas and or water treatment capabilities. Therefore the objective of many assets is to produce at the lowest possible gas-oil ratio (GOR) and water cut (WCUT).

Horizontal wells are often completed with conventional slotted liners. Historical production data confirmed by several production logs indicate that a vast number of wells are under-performing due to non-uniform reservoir influx along the wellbore. This results in early water or gas coning and un-even reservoir drainage that leaves valuable by-passed oil in the ground. To compound the issue, the rapid production increase of highly mobile fluids such as water or gas generates high operational costs for fluid treatment, re-injection, and disposal.

The fluidic diode type Autonomous Inflow Control Devices (AICD) is a new completion component designed with innovative fluid dynamic principles. Its geometry is designed to produce oil while restricting unwanted water and gas. There are a few variations of the fluidic diode type AICD which have been classified as Ranges according to the oil viscosity range to which it is suited. Four designs cover a wide range of oil viscosities from 0.6 to 1000+ cP. Previous publications have explained AICD principles and design while this paper describes examples of successful AICD installations in oil well producers in Latin America. AICDs have shown robustness and production performance, reducing high water production at a well, group or field level, extending production life and reducing production costs by minimizing the risk of handling unwanted fluids at surface.

Introduction

Today, heavy oil constitutes some of the largest hydrocarbon reserves from several countries in Latin America. Figure 1 shows more than 100 sedimentary basins containing hydrocarbons spread along the entire continent and offshore.

Several countries in Latin America have been exploiting heavy oil hydrocarbons for the past few decades. Initially, the heavy oil production wells were drilled vertically, with well designs progressing to deviated or slant trajectories, then to short reach horizontal sections, leading to the longer horizontal wellbores of today. Drilling technology advances have necessitated the evolution of completion hardware design and its development to enhance production from the wells. Recently, the drilling and completion technical advances have unlocked more complex reservoirs, particularly narrower oil-bearing formations, by maximizing contact with the pay zone. To add to the challenge, infill drilling is often targeted in partially depleted or mature fields, densely populated with existing wells completed with conventional completions. (Figure 2)

Heavy oil production has unique challenges compared to light oil production such as high contrast in fluid mobility, lower API gravity and very high in-situ fluid viscosity. The high contrast between water and heavy oil mobility often results in early water breakthrough into sections of horizontal or highly deviated production wells at the expense of oil production from the remainder of the wellbore. AICD hardware can be installed to delay premature breakthrough of unwanted effluents, like a conventional passive ICD, and to restrict the production of unwanted fluids once they break through to the wellbore.