Method for preparing fracturing fluid by utilizing seawater

Abstract

The invention discloses a method for preparing a fracturing fluid by utilizing seawater. The method comprises the following steps of: preparing a base fluid by 0.25-2.0 b (b represents unit part by weight) of antisludging agent, 0.25-1.0 b of plant gelatine powder, 0.01-1.0 b of crude oil emulsion breaker, 0.01-1.0 b of clean up additive, 0.00-1.0 b of foaming agent and 94.0-99.48 b of seawater; and preparing a cross-linking agent by 5-30 b of borax, 5-40 b of mannitol, 1-20 b of caustic soda and 10-89 b of fresh water. 100 c (c represents unit part in volume) of base fluid, cross-linking agent of which the volume is 0.1%-2.0% of the volume of the base fluid in part by volume, and gel breaker of which the volume is 0.001%-0.1% of the volume of the base fluid in part by weight are together added and mixed to prepare the fracturing fluid. According to the invention, 94.0-99.48 parts of seawater is used for preparing the base fluid, except the necessary chemical agents, all the base fluid part is prepared from seawater, so the site operation is simple and convenient, and the cost is lower; and the fracturing fluid thickener adopts natural plant gelatine powder.

Description

[0001] technical field

[0002]

[0003] The invention relates to a method for preparing a water-based fracturing fluid used in the fracturing and stimulation process of an oil well or a natural gas well, in particular to a method for preparing a fracturing fluid by using seawater.

[0004] Background technique

[0005]

[0006] Fracturing fluid is an essential working fluid for fracturing stimulation in low-permeability oil and gas fields, and water-based fracturing fluid accounts for more than 90% of the current fracturing fluid due to its convenient preparation and low cost.

[0007] In the prior art, water-based fracturing fluid mainly dissolves and swells thickeners (such as guar gum and its derivatives, modified polyacrylamide, viscoelastic surfactants, etc.) in clean water, and then adds necessary additives (such as demulsifiers, drainage aids, clay stabilizers, foaming agents, bactericides, etc.) to form thickened water with a certain viscosity. If necessary,...

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