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Degradable polymer for mitigating potential plugging of sand screens

IP.com Disclosure Number: IPCOM000246844D
Publication Date: 2016-Jul-06
Document File: 1 page(s) / 74K

Publishing Venue

The IP.com Prior Art Database

Abstract

Sand Screens are used for sand control as standalone or for gravel packing. There is a potential plugging of sand screen suspended in oil based muds (OBM) after completion. The difficulty of cleanout of horizontal sections before and after installing completion equipment also contributes to the sand screen plugging problem. Partial plugging of sand screens often fail prematurely because of incomplete borehole cleanout and partially plugged screens which often results in "hot spots" and converging flow. Concentrated inflow at discreet points leads to increased pressure drops, screen erosion thus increased sand production. All this ultimately leads to a decline in well productivity. Open-hole gravel pack installation methods generally require the completion of the displacement operation before installing sand screens. For gravel packing there is a practice of using separate fluids for drilling, displacing the solids-laden drilling fluid and running sand screens followed by gravel packing tool, and gravel placement. This process is both costly and time-consuming.

In this invention we are describing a coating or impregnating of sand screen with a degradable Cyanate ester polymer formulation. This degradable polymer has a glass transition (Tg) temperature of 500F and exhibits complete degradation at temperatures above 200F leaving no residues, thus providing the complete surface area of the screen for flow after the removal of polymer coating. This coating will avoid the need of thoroughly cleaning the wellbore before installing the sand screen. This invention not only saves time and money but also addresses the bore hole stability issues when swapping OBM with water based clear fluids.

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Degradable polymer for mitigating potential plugging of sand screens

Abstract of the Invention:

Sand Screens are used for sand control as standalone or for gravel packing. There is a potential plugging of sand screen suspended in oil based muds (OBM) after completion. The difficulty of cleanout of horizontal sections before and after installing completion equipment also contributes to the sand screen plugging problem. Partial plugging of sand screens often fail prematurely because of incomplete borehole cleanout and partially plugged screens which often results in “hot spots” and converging flow. Concentrated inflow at discreet points leads to increased pressure drops, screen erosion thus increased sand production. All this ultimately leads to a decline in well productivity. Open-hole gravel pack installation methods generally require the completion of the displacement operation before installing sand screens. For gravel packing there is a practice of using separate fluids for drilling, displacing the solids-laden drilling fluid and running sand screens followed by gravel packing tool, and gravel placement. This process is both costly and time-consuming.

In this invention we are describing a coating or impregnating of sand screen with a degradable Cyanate ester polymer formulation. This degradable polymer has a glass transition (Tg) temperature of 500F and exhibits complete degradation at temperatures above 200F leaving no residues, thus providing the complete surface ar...