Filtrate reducer for oil field well drilling fluid

Abstract

The invention relates to a fluid loss reducer for oil field drilling fluid, a preparation method thereof, and an application of the treatment agent in preparing a drilling fluid system. The treatment agent uses the cationic monomer dimethyl diallyl ammonium chloride to graft sodium lignin sulfonate and sulfomethyl lignite under the trigger of FeCl3 to form a new high-temperature, salt-resistant, slump-proof and dehydration-resistant agent. The synthesized product combines the advantages of lignite and lignin, that is, it combines lignite's excellent resistance to temperature drop and water loss, and lignin's excellent resistance to salt and viscosity reduction. The introduction of cations improves the anti-slump inhibition, and Fe3+ The weak bonding effect of the product further improves the temperature resistance of the product on the basis of lignite. Therefore, this product can be widely used in drilling under various complex conditions such as high-temperature deep wells, salt-gypsum formations, serious water-sensitive formations, hard and brittle formations, etc., and has broad application prospects.

Description

technical field [0001] The invention relates to an additive for oilfield drilling fluid, more specifically, to a fluid loss reducer for oilfield drilling fluid. The treatment agent has the ability to resist high temperature and salt intrusion. technical background [0002] In oil drilling operations, when the drilling fluid flows through the permeable formation under pressure, it will infiltrate, causing the liquid phase of the drilling fluid to infiltrate into the formation. This process is collectively called "water loss". If water loss cannot be well controlled, a large amount of water loss entering the formation will not only induce wellbore instability, but also cause damage to oil and gas formations. At present, the effective way to solve this problem is to add fluid loss control agent in the drilling fluid. [0003] The fluid loss control agents used in oilfield drilling fluid mainly include the following types: [0004] (1) Special ultrafine particle materials, suc...

AI Technical Summary

Problems solved by technology

However, field use shows that iron-chromium salts will lose their effectiveness at temperatures above 130°C, and irreversible degradation will occur when the temperature exceeds 177°C

Therefore the synergistic effect of sulfomethyl lignite and lignosulfonate is limited

Especially in the case of high temperature and high salt, the two will not be able to play a role due to their own shortcomings.

Images