Cementing and blocking type wall fixing agent for water-based drilling fluid as well as preparation method and application of cementing and blocking type wall fixing agent

Abstract

The invention relates to the technical field of well drilling, and discloses a cementing plugging type wall fixing agent as well as a preparation method and application thereof. The method comprises the following steps: (1) preparing a dispersion system A from nano silicon dioxide, preparing a dispersion system B from gamma-(methacryloyloxy) propyltrimethoxysilane, mixing the dispersion system A and the dispersion system B, adjusting the pH value to 8-9, adding phenothiazine for reaction, filtering after the reaction is finished, and washing and drying a product; (2) mixing the modified silicon dioxide prepared in the step (1), acrylamide, acrylic acid, sodium p-styrenesulfonate, dimethyl diallyl ammonium chloride, 1-ethyl-(3-dimethylaminopropyl) carbodiimide, dopamine hydrochloride and water, introducing protective gas to remove oxygen, and adding an initiator to react; and (3) washing, drying and crushing the product obtained in the step (2) to obtain the wall fixing agent. The wall fixing agent disclosed by the invention is beneficial to maintaining and even enhancing rock strength, so that an effect of stabilizing a fractured formation well wall is achieved.

Description

technical field [0001] The invention relates to the technical field of drilling, in particular to a cementing and plugging-type wall solidifying agent for water-based drilling fluids and a preparation method and application thereof. Background technique [0002] Micro-fractures and fractures are developed in the fractured formation. During the drilling process, the water-based drilling fluid is easy to enter the deep formation along the pores and fractures, causing serious accidents such as wellbore collapse and pipe sticking, resulting in a long drilling cycle and high drilling and completion costs. No less. The existing treatment technology is mainly to add a plugging agent to plug the fractured formation pores and fractures: the asphalt plugging agent requires its softening point to match the formation temperature, and the plugging strength is insufficient; the calcium carbonate plugging agent has high plugging strength, However, its shape and size are difficult to accur...

AI Technical Summary

Problems solved by technology

[0002] Micro-fractures and fractures are developed in destructive formations. During drilling, water-based drilling fluid easily enters deep formations along the pores and fractures, causing serious wellbore collapse and pipe sticking accidents, resulting in longer drilling cycle and high drilling and completion costs

The existing treatment technology is mainly to add plugging agent to plug the fractured formation pores and fractures: asphalt type plugging agent requires its softening point to match the formation temperature, and the plugging strength is insufficient; calcium carbonate type plugging agent has high plugging strength, However, its shape and size are difficult to accurately match the formation pores and fractures, and cannot be effectively plugged; polymer microsphere plugging agents can effectively match the formation pores and fractures shape and size, but the plugging strength is not high

[0003] In recent years, chemical cementing wall-solidifying agents have gradually become a research hotspot for stabilizing fractured formation well walls. Carboxymethyl shells grafted with dopamine groups on the main chain Polysaccharides (CN104177517A, CN106634878A), polymers grafted with dopamine groups on the main chain (CN109679598A, CN108456286 A) can cement formation pores, but their temperature resistance and plugging strength are insufficient; epoxy resins (CN107502322A) It can effectively cement formation pores and fractures, but its compatibility with drilling fluid is poor

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