Segmented multi-cluster flow-limiting fracturing method for horizontal well with perforation sub-clusters

Abstract

The invention provides a segmented multi-cluster flow-limiting fracturing method for a horizontal well with perforation sub-clusters. The method specifically comprises the steps that (1) the quantityof perforation clusters in a fracturing segment and the position of each of the perforation clusters are determined; (2) multiple perforation sub-clusters are disposed at the position of each of the perforation clusters, and the interval between the perforation sub-clusters is not less than 2m and not larger than 8m; (3) a perforation tool is put at a preset position inside the horizontal well segment for perforation, so a perforation cluster with the perforation sub-clusters is formed; and (4) fracturing construction is carried out, the multiple sub-clusters of the perforation cluster can getfractured and tend to extend along different directions of two sides of a wall shaft, and nearly uniform and symmetric hydraulic cracks can be formed at the perforation cluster positions in the segment and on two sides of the well shaft. The method provided by the invention has the beneficial effects that through flow limiting effects of perforation holes, the cracks get fractured from the perforation sub-clusters and extend towards two sides of the horizontal well shaft respectively, so the nearly uniform and symmetric hydraulic cracks can be formed at each of the perforation cluster positions on two sides of the well shaft. In this way, generation of invalid perforation clusters can be reduced; and a reservoir reformation degree can be increased.

Description

technical field [0001] The invention relates to a segmented multi-cluster flow-limiting fracturing method for a horizontal well with perforation sub-clusters, and belongs to the field of oil gas and geothermal reservoir reconstruction. Background technique [0002] Horizontal well staged multi-cluster fracturing is currently the main means of developing tight oil and gas resources and hot dry rock geothermal resources. In this method, the horizontal wellbore is segmented by running bridge plugs first, and perforating guns are used to perforate multiple positions on the casing in the segment, which is called multi-cluster. Usually, each fracturing stage has 3-12 clusters of perforations, the cluster spacing is between 10-30 m, and the length of each perforation cluster on the casing is between 0.2-2 m. Then pump fracturing fluid into the section with a large displacement and a large amount of fluid, in order to realize the simultaneous initiation and expansion of hydraulic f...

AI Technical Summary

Problems solved by technology

[0005] In order to overcome the problem in the prior art that multiple fractures will expand outward alternately on one side of the wellbore, the present invention provides a segmented multi-cluster current-limiting fracturing method for horizontal wells with perforation sub-clusters. Perforate at a predetermined position in the section to form a perforation cluster with perforation sub-clusters for fracturing. During the fracturing process, the construction displacement is increased step by step. Affected by the heterogeneity of reservoir rocks and within the perforation limit Under the action of the flow effect, multiple sub-clusters of the perforation cluster will crack and tend to extend in different directions on both sides of the wellbore, forming nearly uniform and symmetrical hydraulic fractures on both sides of the wellbore at the position of the perforation cluster in the section, thereby improving the storage capacity. Layer Transformation Degree Purpose

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