New Polymer Offers Effective, Permanent Clay Stabilization Treatment

Abstract

A new clay stabilization system has been developed which prevents hydration of swellable clays without impairing permeability. The system uses a polymer that can be mixed in the HCI overflush of a typical mud acid treatment without loss of activity. Case histories proved the system to be very effective in controlling swelling clay problems.

A Collective Clay Stabilizers Review

“…Clay minerals are naturally occurring by weathering and decomposition of igneous rocks (Grim, 1968;Murray, 2007;Williams and Underdown, 1981). Clays are generally crystalline in nature, and the structure of these crystals determines their properties.…”

“…As a result, these units combine and exist as sheet structures and do not exist in isolation (Knappett and Craig, 2012). Silica sheets are formed by the combination of tetrahedral units sharing oxygen ions, and these sheets still retain a net negative charge (Knappett and Craig, 2012;Williams and Underdown, 1981). Gibbsite sheets are formed by the combination of octahedral units sharing hydroxyl ions, and unlike the silica sheets, gibbsite sheets are electrically neutral (Knappett and Craig, 2012).…”

“…Water molecules and cations occupy the space between the octahedral and tetrahedral layers, Figure 5. Furthermore, smectite are hydratable clays that can easily exchange cations such as Na ϩ and K ϩ for water, causing them to swell (Williams and Underdown, 1981). The theoretical composition of smectite is SiO 2 :66.7%, Al 2 O 3 : 28.3% and H 2 O: 5%.…”

“…Kaolinite becomes unstable with HCl at temperatures above 200°F (Coulter, IPTC-18394-MS 1999;. Kaolinite is not strongly cemented in the formation and easily dispersed by fluids during treatments such as brines or acids (Williams and Underdown, 1981).…”

Clay Mineralogy and the Colloid Chemistry of Drilling Fluids

“…However, a proprietary polyamine has recently been introduced for the purpose of stabiliz.. ing formation clays during completion and workover operations. 58 The cationic group is strongly adsorbed on the clay, reducing its negative charge, and thus inhibiting swelling and dispersion .…”