Acid polymer weighted fracture fluid and preparation method thereof

Abstract

The invention discloses an acid polymer weighted fracture fluid and a preparation method thereof, wherein the acid polymer weighted fracture fluid comprises a base fluid and a crosslinked fluid, the base fluid comprises components with percentage by quality: weighting agents 20%-50%, polymer thickening agent 0.8%-1.20% and discharge aiding agent 0.2%-0.5%, and the allowance is water. The crosslinked fluid comprises an acid polymer delayed crosslinked agent and an acid polymer crosslinked agent, wherein the weight radio of the acid polymer delayed crosslinked agent and the acid polymer crosslinked agent is (1.5-2.5): (3.5-5), and the quality of the crosslinked fluid is 0.6%-0.8% of the quality of the base fluid. The acid polymer weighted fracture fluid achieves to adjust density in 1.10g/cm3-1.50g/cm3, meets the density demands for the scene, improves pressure of fluid columns in shafts, reduces construction pressure of wellheads, and is suitable to remould fracture reservoirs of deep wells, superdeep wells, abnormal high pressure wells and dense wells.

Description

technical field [0001] The invention belongs to the technical field of oil and gas field development, and in particular relates to an acidic polymer weighted fracturing fluid and a preparation method thereof. Background technique [0002] The fracturing fluid of the guar gum fracturing system currently used can better meet the needs of the fracturing process in low-permeability oilfields, but the guar gum system has a high residue content, and cross-linking in an alkaline environment can cause damage to alkali-sensitive reservoirs, etc. question. The polymer fracturing fluid system has the advantages of better viscosity-temperature characteristics, strong thickening ability, no residue, cross-linking under acidic conditions, and controllable cross-linking time. [0003] In the prior art, the publication number CN104263346A "A kind of acid weighted fracturing fluid and its preparation method and application" discloses a fracturing fluid, which is composed of the following co...

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Problems solved by technology

However, the fracturing fluid has the following disadvantages: the density range of the aggravated fracturing fluid is narrow and the maximum density value can only be adjusted to 1.42g / cm 3 ; There is only a weighted fracturing fluid formula at 150°C, so it is impossible to determine whether it is suitable for different temperature conditions; the cross-linking time of the weighted fracturing fluid cannot be adjusted

[0009] However, the above-mentioned fracturing fluids generally have the following disadvantages: 1) Guar gum is used as a thickening agent, and the molecular weight of the guar gum thickener is relatively high, and the residues after breaking the gel will cause great damage to the formation; 2) Cross-linking in an alkaline environment , has certain damage to alkali-sensitive formations; 3) The cross-linking time cannot be adjusted, so it is not suitable for fracturing reservoir stimulation in deep wells, ultra-deep wells, abnormally high pressure wells, and tight wells

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