Temporary plugging agent for pH-sensitive drilling fluid, and preparation method and using method thereof

A technology of drilling fluid and temporary plugging agent, applied in the field of temporary plugging agent, can solve the problems of poor temperature resistance, the temporary plugging agent does not have pH responsiveness, etc., achieves strong temperature resistance, restores reservoir permeability, and improves single well production Effect

Active Publication Date: 2021-12-17
CHINA PETROCHEMICAL CORP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The object of the present invention is to provide a temporary plugging agent for pH-sensitive drilling fluid based on PEOx-DMMA modified nano silicon dioxide and its preparation method and use method , to solve the problem that the existing temporary plugging agent does not have pH responsiveness and poor temperature resistance

Method used

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  • Temporary plugging agent for pH-sensitive drilling fluid, and preparation method and using method thereof
  • Temporary plugging agent for pH-sensitive drilling fluid, and preparation method and using method thereof
  • Temporary plugging agent for pH-sensitive drilling fluid, and preparation method and using method thereof

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preparation example Construction

[0047] In the present invention, the preparation method of PEOx-DMMA modified nano silicon dioxide powder comprises the following steps: a) adding nano silicon dioxide particles into the reactor, slowly adding acetone, then adding a dispersant, stirring, standing and aging; b) add silane coupling agent and NaOH successively, heat up for the first time, increase the stirring speed, and make the silane coupling agent hydrolyze and condense with the silicon hydroxyl groups on the surface of nano-silica particles; c) add 2-methyl-2 -Oxazoline monomer, cool down, add initiator 1, make 2-methyl-2-oxazoline monomer ring-opening polymerization; d) make the system anoxic, add methacrylic acid N,N-dimethylaminoethyl ester, and initiator 2, reduce the stirring speed, and raise the temperature for the second time, so that N,N-dimethylaminoethyl methacrylate undergoes graft copolymerization; Pressure distillation and drying to obtain PEOx-DMMA modified nano silicon dioxide powder.

[0048...

Embodiment 1

[0083] Preparation of PEOx-DMMA modified nano silica:

[0084] a) Add 1000g of SP15 nano-silica particles into the high-pressure homogenizer, slowly add 2000mL of acetone, then add 30g of sodium dioctyl sulfosuccinate, stir at 10000rpm for 2h, and let stand for 2h;

[0085] b) Add 10g of silane coupling agent KH151 into the above reactor, then add 5g of NaOH, raise the temperature of the system to 80°C, increase the stirring speed to 20000rpm, and continue the reaction for 6h;

[0086] c) Add 30g of 2-methyl-2-oxazoline monomer (PEOx) into the above reactor, lower the system temperature to 50°C, add 3g of azobisisobutyronitrile, and react for 2h;

[0087]d) Pass high-purity nitrogen gas into the above reactor to remove oxygen for 3 hours, add 60g of N,N-dimethylaminoethyl methacrylate, add 6g of tert-butyl hydroperoxide, reduce the stirring speed to 5000rpm, and the temperature of the system rises Up to 70°C, continue to react for 8 hours;

[0088] e) After the reaction, was...

Embodiment 2

[0096] Preparation of PEOx-DMMA modified nano silica:

[0097] a) Add 1200g SP30T nano-silica particles into the high-pressure homogenizer, slowly add 2000mL acetone, then add 40g monoglyceride stearate, stir at 10000rpm for 2h, and let it stand for 2h;

[0098] b) Add 20g of silane coupling agent KH171 into the above reactor, then add 7g of NaOH, raise the temperature of the system to 90°C, increase the stirring speed to 20000rpm, and continue the reaction for 7h;

[0099] c) Add 40g of 2-methyl-2-oxazoline monomer (PEOx) into the above reactor, lower the system temperature to 55°C, add 4g of azobisisoheptanonitrile, and react for 2.5h;

[0100] d) Pass high-purity nitrogen gas into the above reactor to remove oxygen for 3 hours, add 70g of N,N-dimethylaminoethyl methacrylate, add 7g of tert-butyl peroxybenzoate, reduce the stirring speed to 5000rpm, and the system temperature Raise to 75°C and continue to react for 9 hours;

[0101] e) After the reaction, wash with acetone...

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Abstract

The invention relates to a PEOx-DMMA modified nano silicon dioxide-based temporary plugging agent for a pH sensitive drilling fluid. The temporary plugging agent is prepared from PEOx-DMMA modified nano silicon dioxide, a cationic surface active agent, superfine calcium carbonate and micron fibers. PEOx and DMMA are introduced into the temporary plugging agent to jointly stabilize nano silicon dioxide, the PEOx, DMMA, superfine calcium carbonate and micron fibers have a synergistic effect, the new hydrophobic temporary plugging agent is formed, hydrophobic temporary plugging under the high-temperature condition is achieved, and the hydrophilicity and lipophilicity of a temporary plugging layer can be controlled by adjusting the pH value of drilling fluid, so recovery of the permeability of a pickling-free self-plugging-removal reservoir under the high-temperature condition is achieved.

Description

technical field [0001] The invention relates to the technical field of oil and gas reservoir drilling, in particular to a temporary plugging agent added to drilling fluid during oil and gas reservoir drilling. Background technique [0002] At present, during the development of oil and gas reservoirs, the formations encountered are becoming more and more complex, and the reservoir types are also becoming more and more complex. During the contact with foreign fluids, the properties of the formations will change, such as the expansion and migration of clay minerals in the formations. , The solid phase particles of the drilling fluid enter the pores of the formation, and the liquid phase reacts with the formation minerals, etc., resulting in a decrease in the formation permeability, resulting in the inability to effectively extract the oil and gas from the reservoir to the ground during the later stage of oil recovery. Therefore, generally in the well completion stage, earth aci...

Claims

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Application Information

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IPC IPC(8): C09K8/514C09K8/508C09K8/504C09K8/84C09K8/88C09K8/90C08F292/00C08F220/34E21B33/13D01F2/00
CPCC09K8/514C09K8/5083C09K8/5045C09K8/882C09K8/845C09K8/905C08F292/00E21B33/13D01F2/00C09K2208/10C09K2208/08C08F220/34Y02P20/141
Inventor 王家航李基伟姜韡张天炬田壮壮何阳子熊振宇姚远高东亮杜帅
Owner CHINA PETROCHEMICAL CORP
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