Aluminum-based anti-collapse agent for drilling fluid

Abstract

The invention relates to an aluminum-based anti-collapse agent for drilling fluid. The efficient aluminum-based anti-collapse agent is synthesized through reaction of organic acids with aluminum-containing compounds under an acid condition at 25-105 DEG C, wherein the organic acids are gallotannic acid, citric acid, humic acid and oxalic acid; the aluminum-containing compounds are aluminum hydroxide, aluminum chloride, aluminum sulfate and aluminum nitrate. Aiming at a mudstone stratum, the aluminum-based anti-collapse agent can inhibit hydration expansion of clay and shale by virtue of the unique chemical property of organic acid-aluminum, pressure conduction in shale can be retarded, and the semipermeable membrane property of shale can be improved. By adopting the aluminum-based anti-collapse agent, the linear expansion rate of shale within 8 hours is less than or equal to 15%, a high / low water content shale sample can be effectively stabilized, the pore pressure transfer in mudstone can be reduced by more than 12 times, the induction osmotic pressure can be increased by greater than 50%, and the aluminum-based anti-collapse agent is excellent in anti-collapse property and beneficial for well wall stabilization.

Description

technical field [0001] The invention relates to a plugging and anti-collapse agent for drilling fluid in the process of petroleum drilling, which is used in drilling fluid construction and belongs to the field of petroleum drilling. technical background [0002] Wellbore instability is a common and often encountered complex problem in oil and gas drilling. Downhole complex accidents caused by well wall instability are extremely harmful to drilling and completion, and have always been a prominent problem in the petroleum engineering circles at home and abroad. During drilling operations, once the wellbore instability occurs, it will not only delay the drilling time, damage oil and gas layers, interfere with geological logging, etc., but also lead to a series of downhole complex situations and accidents such as well collapse and drill sticking. It may even cause the wellbore to be scrapped, resulting in significant economic losses. [0003] During drilling, more than 75% of ...

AI Technical Summary

Problems solved by technology

With the development of drilling fluid technology at the present stage, many plugging agents with different forms and characteristics have been developed, mainly including silicate-based sealing agents and polymeric alcohol-based sealing agents, which are widely used. It has also received good results, but there are also shortcomings that are difficult to overcome

For example, polymeric alcohol plugging agents are expensive and difficult to use on a large scale, while the biggest weakness of silicates is that rheology is difficult to control

At present, the aluminum-based anti-slump agent used in China has a great influence on the rheology and fluid loss of drilling fluid, and the dosage is not easy to control, which cannot meet the environmental protection requirements in current drilling projects.

Images