Horizontal well staged fracturing method

Abstract

The invention provides a horizontal well staged fracturing method. The horizontal well staged fracturing method comprises the step that N sand-carrying fluid injection stages are sequentially carriedout, wherein the volume density of a supporting agent used in the N sand-carrying fluid injection stage is smaller than the volume densities of supporting agents used in the (N-1) sand-carrying fluid injection stages before, and N is a natural number larger than one. Furthermore, fracturing fluid with the energy-storing modulus and the energy-consuming modulus being (2.0-5.0):1 is selected andused for the N sand-carrying fluid injection stage. According to the horizontal well staged fracturing method, by improving the suspension performance of the supporting agents and / or the fracturing fluid, the even replacement effect of each cluster of cracks is ensured, even fluid inlet and sand inlet of each cluster of cracks are ensured, thus synchronous gel-breaking back-displacement of the fracturing fluid in all the clusters of cracks is achieved, the replacement phenomenon occurring in the horizontal well staged fracturing process is reduced accordingly, the effect after fracturingis improved, and maximization of the stable production period is achieved.

Description

technical field [0001] The invention relates to the technical field of horizontal well staged fracturing, in particular to a horizontal well staged fracturing method for reducing over-displacement, and in particular to the field of low-permeability and tight sandstone, carbonate rock, shale and coal rock horizontal well fracturing A method of staged fracturing in horizontal wells to reduce overdisplacement. Background technique [0002] At present, the horizontal well staged fracturing technology has become the main development technology of low permeability and tight sandstone, carbonate rock, shale and even coal rock, and has played a huge economic and social benefit in production practice. During the construction of this technology, high-viscosity fluid must be used for displacement. However, unlike vertical well fracturing, the horizontal well staged fracturing technology has the phenomenon of over-displacement, and the amount of over-displacement in some cases can reach...

AI Technical Summary

Problems solved by technology

[0004] The adverse effects of over-displacement on the fracturing effect mainly include: 1) severe reduction of the conductivity of near-wellbore fractures at the initial stage after fracturing, resulting in complete loss of the conductivity of near-wellbore fractures, resulting in the so-called "dumpling-making" effect; 2) if The synchronous gel breaking control is not good, the fracturing fluid in the first fracturing stage hydrates and breaks the gel in advance, and the large filtration loss causes the fracture to close prematurely, which has a fatal impact on the remedial measures of the fracture conductivity near the wellbore; The method of uniform perforation for each cluster leads to different over-displacement effects of fractures in different clusters during fracturing in the same section. The closer to the wellbore, the more over-displacement volume, and the contribution of each cluster of perforations to production is not balanced.