By Osama Abazeed, Area Manager – GCC

Published in Oil & Gas Vision, October 2018

The Middle East boasts more than 60% of the world’s conventional oil reserves and approximately 70% of that oil is held in carbonate reservoirs.

These highly complex reservoirs have varying flow mechanisms and fluid properties in its often-fractured formations. Such diverse porosity and permeability means it is difficult to understand the position and shape of the natural fractures, and even more complicated to get an accurate measurement of the reservoir structure. This, and other factors, will create a complex path for fluid and affect the well productivity over time.

Another fundamental characteristic is the wettability of the rocks in the carbonate reservoir. The heterogeneous nature of the rock means that it starts to become more oil-wet in aging carbonate rocks. This ultimately makes it more technically challenging and risky to improve the recovery factor, particularly in fields that are undergoing water flooding.

First AICD installation in a carbonate reservoir

Over three years, Tendeka carried out reservoir modelling assignments with several oil companies in the Middle East to fully understand these challenges and therefore, devise sustainable solutions to increase oil recovery in those fields. Earlier this year, the company installed its first Autonomous Inflow Control Device (AICD) completion in a carbonate reservoir.

AICDs are designed to automatically react to the properties of the fluid flowing through them. The device, which comprises of three components: valve body, nozzle, and disk, restricts the flow of less viscous fluids, such as water and gas, this allows more viscous fluids, such as heavy oil, to pass through with minimum pressure drop. When used in horizontal wells that have been compartmentalised using swell packers, AICDs restrict the flow of water in high water cut zones. This allows greater drawdown of the reservoir in high oil saturation zones, thereby reducing water cut and improving oil recovery across the entire well over time.

Deployed as part of the lower completion using zonal isolation packers to divide the reservoir into compartments, the AICD can be integrated with sand control screens for soft formations.

Middle East ambitions

Many other installations of the device have since followed in carbonate reservoirs in the Middle East. While still in the evaluation period, the initial results over many months show very promising prospects.

The Autonomous ICD, FloSure, was also utilised in sandstone reservoirs in the region, with the objective of reducing water cut and improving oil recovery.

This and other topics and technologies will form three presentations by Tendeka at this year’s ADIPEC.