Drillable gel plug for underbalanced drilling and preparation method thereof

Abstract

The invention discloses a drillable gel plug for underbalanced drilling. The drillable gel plug for the underbalanced drilling comprises the following components in percentage by mass: 4 to 15 percent of main monomers, 0.1 to 0.25 percent of cross-linking monomers, 0.05 to 0.2 percent of an initiator, 1 to 2 percent of kerosene, 0.05 to 0.2 percent of an emulsifying agent, 0.02 to 0.07 percent of a cross-linking time regulator, 3 to 7 percent of a gel brittleness regulator, 0.1 to 1.0 percent of a suspending agent, 5 to 15 percent of a weighting agent, and the balance of water. The product is obtained by mixing and stirring the components. The drillable gel pug can pack a well shaft safely under a high temperature; the gel is convenient to break; a well liquid is prevented from being polluted.

Description

technical field [0001] The invention belongs to the field of petrochemical industry, and in particular relates to a drillable gel plug for underbalanced drilling and a preparation method thereof. Background technique [0002] Underbalanced drilling has developed rapidly due to its advantages such as high rate of penetration, prevention of differential pressure sticking, reduction of wellbore circulation loss, reduction of formation damage, and improvement of oil and gas reservoir display levels. At present, the main factor affecting the effect of underbalanced drilling is that it is often necessary to balance the formation pressure by killing the well before or during the drilling process. But killing wells can partially or completely negate the benefits of underbalanced drilling, and may even cause more damage to the formation. Therefore, the snubbing operation is the key point to realize the underbalanced technology. At present, there are mainly two types of technology t...

AI Technical Summary

Problems solved by technology

This patent mainly has two disadvantages: first, only relying on the initiator to control the polymerization time, uncontrollable detonation will occur when the temperature exceeds 100°C during deep well drilling, causing the drilling tool to be stuck and unable to be lifted, causing downhole ACCIDENT

Second, the cross-linking agent only provides chemical cross-linking. When the amount is small, the gel slug is too elastic, the drillability is insufficient, and it is difficult to break the gel; Not tight, prone to gas channeling