The strengthening of near wellbore unconsolidated sand formation can play a vital role in reducing sand erosion, sand failure, formation compaction and other borehole problems. The strengthened formation is expected to tolerate higher surge and swabbing pressures leading to a reduction in trip-time failure of unconsolidated and poorly consolidated sand formations. The enhanced formation strength may allow sufficient tolerance to overbalance pressure leading to the use of higher mud weight due to the widening of the mud weight window. Adequate strengthening of the near wellbore formation may also create geo-mechanical condition for underbalance drilling. Different chemicals and polymers can be used either alone or as a part of drilling mud to invade and enhance the near wellbore formation strength characteristics. This paper describes the experimental results of a novel gel system used in improving the strength characteristics of a 16/30 sand pack representing a highly unconsolidated sand formation.

Visual observation shows that the novel gel system is capable to bind the loose sand particle together to create an integrated sand mass with good physio-mechanical consistency. Experimental results show more than 50% increase in the penetration resistance of the sandpack compared to a simulated pore fluid saturated sandpack. The gel has thermal stability up to 100 °C. Hence, its inter-particle bonding and strengthening capability will cease for formation having temperature above 100 °C. However, the gel could be potential candidate for some improvement of the near wellbore formation strength properties up to a depth having a temperature less than or equal to 100 °C. The gel is environment friendly, economically attractive and needs no cross-linking agent for bonding and networking to improve the formation strength.

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