Plugging agent for oil-base drilling fluid and preparation method

Abstract

The invention provides a plugging agent for an oil-base drilling fluid with high crack matching ability. The plugging agent is composed of elastic sponge, regenerated fiber, adsorbent, calcium carbonate superfine powder and flexible graphite. Specifically, the components in parts by weight added into 100 parts of oil-base drilling fluid are as follows: 0.1-0.8 part of elastic sponge, 0.1-1.5 partsof regenerated fiber, 3-8 parts of adsorbent, 5-10 parts of calcium carbonate superfine powder and 3-8 parts of flexible graphite. The plugging agent for the oil-base drilling fluid provided by the invention can easily enter into cracks and form bridges in the cracks; high-temperature resisting materials and high-temperature resisting inert materials are high in dispersity in the oil-base drilling fluid, so that the success rate of plugging can be effectively increased and the happening of re-leakage can be avoided; the plugging construction process is simplified by adopting the plugging agent; the plugging material has excellent temperature resistance, does not lose efficacy under high temperature and has an excellent plugging effect for fracture-cavity type leakage.

Description

technical field [0001] The invention relates to the field of chemical materials for oil drilling, in particular to a plugging agent for oil-based drilling fluid loss. Background technique [0002] Lost circulation is the phenomenon that various working fluids leak into the formation under the action of pressure difference during various downhole operations such as drilling, cementing and completion, testing or workover. Once lost circulation occurs, it will not only delay drilling time, lose drilling fluid, damage oil and gas layers, interfere with geological logging work, increase drilling costs, but also easily cause a series of complicated situations such as pipe sticking, blowout, and well collapse, and even lead to the scrapping of the wellbore. cause huge economic losses. At present, the commonly used plugging materials in the plugging construction are mostly permanent bridging plugging materials and chemical gel plugging materials. Chemical plugging mainly plays a p...

AI Technical Summary

Problems solved by technology

Chemical plugging has a good plugging effect on malignant leakage, but the chemical plugging reaction is more intense, the construction is complicated, and the risk is higher

The bridging plugging material has a simple construction process and low cost, and is the most commonly used in the field, but some materials have poor temperature resistance and are prone to decomposition and failure at high temperatures, resulting in repeated leakage of the leaky layer

At the same time, these materials have problems such as sealing the door and not being able to soak for a long time, and the plugging effect is sometimes not ideal