Non-crosslinking special gel leakage stopping method

Abstract

The invention relates to a non-crosslinking special gel leakage stopping method. The method is characterized in the a polishing drilling rod is feed in 20 to 30m the top part of a leaking layer; a drilling tool moves up and down; non-crosslinking special gel leakage stopping slurry is prepared through a clean slurry tank, wherein the non-crosslinking special gel leakage stopping slurry is prepared from water, a special gel ZND-2 leakage stopping agent, a gel fiber leakage stopping agent and a rigid wedging type leakage stopping agent; 0.8 to 1.6 parts by weight of special gel ZND-2 leakage stopping agent, 5 to 8 parts by weight of gel fiber leakage stopping agent and 10 to 15 parts by weight of rigid wedging type leakage stopping agent are added to 100 parts by weight of water; all components are fully agitated and mixed, and then the non-crosslinking special gel leakage stopping slurry is immediately poured into the leaking layer in a well to statically stop the leakage for 4 to 8 hours. The method is simple to construct; the bearing capacity of a plug at the special gel section can be improved; in addition, the bridge-plugged leakage stopping materials can be prevented from being diluted and flushed way by formation fluid, and therefore, the success rate of leakage stopping can be increased.

Description

technical field [0001] The invention relates to the technical field of plugging in drilling engineering, in particular to a non-crosslinked special gel plugging method. Background technique [0002] The existing special gel ZND-2 plugging agent (manufacturer: Sichuan Guangya Polymer Chemical Co., Ltd.) is a water-soluble polymer with good shear thinning performance. -1 ) or static state, can form intermolecular association and connection, viscosity up to 1×10 4 ~3×10 4 mPa·s, under high velocity gradient (about 1000s -1 ) can shear thin, but still has a high viscosity, up to 50 ~ 100mPa s. The special gel ZND-2 has strong cohesion, is difficult to mix with oil, gas and water, and is easy to stay in the leakage layer. The gel has certain strength, structure, shear force, viscosity and elasticity. When the leakage pressure difference is small, only the special gel ZND-2 is used for plugging, and the plugging effect is good. However, when the leakage pressure difference is...

AI Technical Summary

Problems solved by technology

However, when the leakage pressure difference is large, only the special gel ZND-2 is used to plug the leak. Since the starting pressure of the special gel is small (generally 2-3 MPa), the starting pressure drop gradient generated by the formed gel slug is not enough to resist The leakage pressure difference is damaged, so the plugging effect is not ideal, resulting in another leakage

The application of special gel ZND-2 back-tracking cement plugging is relatively mature, but when malignant leakage occurs in the reservoir, in order to avoid damage to the reservoir, cement plugging is generally not used, bridge plugging is often used, but due to reservoir leakage In the presence of formation fluid, the success rate of conventional bridge plugging is very low

Due to the strong cohesion of the gel plugging slurry after swelling, it is difficult to add bridge plugging materials to the ZND-2 plugging slurry, so the application of special gel ZND-2 is limited