Lessons and Experiences Learned from Hybrid Inflow Control Device Practices in Strong Aquifer Reservoirs with Loose-Sandstone—A Case Study of Offshore Heavy Oilfield
Authors: He Yifan , Shi Hongfu , Zhou Yanbin , Zhang Jilei , Shang Baobing 
Published: October 2020

Inflow Control Device(ICD) is considered to be an effective water control technology, especially in offshore reservoirs with strong bottom water, which is more conducive to slowing water breakthrough, increasing recovery factor during low water cut period, reducing produced water treatment costs and improving development effect.

The H oil field in Bohai Bay, China is a target oil field where horizontal wells are widely used by traditional ICDs. The characteristics of the H field are heavy oil (average viscosity of 260 mPa·s under reservoir conditions), excellent reservoir quality (up to 30% porosity and 3D permeability), loose sand, heterogeneity and strong aquifer.

In the process of water control in horizontal wells, the sand channeling and annulus channeling outside the sand control screen were the main factors that caused the water control failure by early ICDs. In the later design and application, the ideas and methods were improved. Based on the review of the conventional ICD application, a new work-flow was proposed to design and to optimize the ICD to improve the opportunities for success and to prolong the effective water control period.

Compared with the previous design ideas, more attention was paid to the segmentation and environmental control isolation methods:

In the case of reservoir heterogeneity uncertainty, increasing the number of segments and uniform segmentation is more conducive to accurate plugging and release potential. The most ideal condition is continuous step-less isolation. A new type of lightweight, high-strength, and easy-to-carry particles were used to fill the environmental control with high strength, which results in a step-less continuous horizontal sealing effect while preventing sand production. The particle filling volume and particle radius can be adjusted. The size of the particle radius determines the additional pressure drop of the loop control zone, and the filling volume determines whether the loop control channeling is completely avoided.

The improved ICD completion device had been successfully applied in 4 production wells in the oil field. The water cut of the well dropped by 10%, and the initial daily oil production increased by 145 barrels. This result greatly inspired our confidence. In the future plan, we are willing to adopt the plan to control water in 12 wells in two batches. And due to the improvement and quality control of key links in the design and process, implementation time have been significantly saved which is extremely important for offshore platforms to obtained good economy returns.

This article proposes a detailed, complete, and smooth work-flow, including actual oil field information, target well selection, segmentation method, fill volume estimation and implementation effect evaluation. This work-flow has great reference value for industry peers to improve the efficiency and quality control of hybrid ICD projects.