A method of extreme cluster perforation fracturing for long horizontal wells in tight reservoirs

A technology for long horizontal wells and tight reservoirs, which is applied in the fields of earth-moving drilling, wellbore/well components, and production fluids, etc., which can solve the problem that the output of a single well cannot meet expectations, the difference is large, the operation cost and construction period increase, etc. problem, to achieve the effect of balanced crack initiation, good and effective opening, and effective opening

Active Publication Date: 2022-02-01
PETROCHINA CO LTD
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  • Abstract
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AI Technical Summary

Problems solved by technology

Affected by formation heterogeneity, conventional large-displacement general fracturing cannot achieve complete initiation and expansion of multi-cluster fractures in the interval. Tests such as step displacement analysis and downhole micro-seismic monitoring show that the effective fluid-introduced clusters under this stimulation method The number is only 50-60% of the parameter setting, which is quite different from the fracturing parameter setting, and the single well production cannot meet the expectation
At the same time, as the horizontal section continues to grow, the number of fracturing operations increases simultaneously. According to the measurement and calculation of the horizontal section length of 1500m, the parameters of a single well are set to 120-150 clusters of fractures, and each section has 4-6 clusters. It is necessary to use bridge plugs as inter-section seals. 25-30 levels of fracturing operations are carried out, and the operation cost and construction period are greatly increased, which brings great challenges to the efficient development and rapid production establishment of tight reservoirs

Method used

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  • A method of extreme cluster perforation fracturing for long horizontal wells in tight reservoirs
  • A method of extreme cluster perforation fracturing for long horizontal wells in tight reservoirs

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0058] according to figure 1 A limit cluster perforation fracturing method for long horizontal wells in tight reservoirs shown, including the following steps

[0059] Step 1: Establish comprehensive quality grading and evaluation standards for horizontal sections

[0060] According to the logging results of long horizontal wells in tight reservoirs, the numerical values ​​in the identification factors of integrated geology-engineering integration sweet spots are screened, and the comprehensive quality grading and evaluation standards for horizontal sections are established. The established comprehensive quality grading and evaluation standards for horizontal sections are divided into I, II, and III kind;

[0061] Step 2: Select the object of fracturing stimulation

[0062] According to the comprehensive quality classification result of the horizontal section in step 1, the horizontal section of category I and II is selected as the object of fracturing;

[0063] Step 3: Segm...

Embodiment 2

[0078] according to figure 1 The difference between the extreme clustered perforation and fracturing method for long horizontal wells in tight reservoirs shown in the first embodiment is that the integrated geology-engineering integration sweet spot identification factors screened in the first step include physical property indicators, Oily index, in-situ stress index and brittleness index; the physical property index adopts effective porosity, the oily index adopts oil saturation, the in-situ stress index adopts the minimum horizontal well principal stress, and the brittleness index adopts brittleness index.

[0079] Preferably, the comprehensive quality of the horizontal section established in the step 1 is divided into I, II, and III classes, and the specific grading evaluation criteria are as follows:

[0080] (1) Type I sweet spots: effective porosity ≥ 5%, oil content ≥ 70%, minimum horizontal well principal stress ≤ 30MPa, brittleness index ≥ 50%.

[0081] (2) Class II...

Embodiment 3

[0093] according to figure 1 The shown limit cluster perforation fracturing method for long horizontal wells in tight reservoirs is different from the first embodiment in that: when performing segmentation and clustering in the second step, the cluster spacing is 5-10m, The number of perforation holes in a single cluster is 2 holes / cluster, the number of fracture clusters in a single section is 8-12 clusters / section, and the length of a single section is 60-80m.

[0094] In actual use, the fracture perforation position is selected according to the reservoir logging interpretation results, and the cluster spacing is 5-10m, which greatly reduces the number of perforation holes in a single cluster, from the conventional 9-12 holes / cluster to 2 holes / cluster, and Significantly increase the number of fracture clusters in a single section, from 4-6 clusters / section to 8-12 clusters / section, and increase the length of a single section from 30-50m to 60-80m.

[0095] The technical sc...

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Abstract

The invention belongs to the technical field of oil reservoir measures to increase production in oil production engineering, and in particular relates to an extreme cluster perforation fracturing method for long horizontal wells in tight reservoirs. The invention improves the perforation opening efficiency by greatly reducing the number of holes in a single cluster, greatly improves the uniformity of fluid distribution among multiple clusters, realizes the balanced initiation and effective extension of multiple clusters, and further greatly increases the number of perforation clusters in clusters. The number increases the degree of control of single-segment fractures on the length of oil layers. The invention can better realize the effective opening of multi-cluster fractures and realize full stimulation of horizontal wells in tight reservoirs without reducing the intensity of fracturing stimulation. The present invention can effectively improve the effectiveness of multi-cluster fracturing fractures in a section, improve the control degree of single-section fractures on the length of oil layer sections, greatly reduce the number of fracturing sections, improve construction efficiency, and reduce operating costs. It has broad application prospects in improving efficiency and reducing costs.

Description

technical field [0001] The invention belongs to the technical field of oil reservoir measures to increase production in oil production engineering, and in particular relates to an extreme cluster perforation fracturing method for long horizontal wells in tight reservoirs. Background technique [0002] In recent years, segmented multi-cluster volume fracturing of long horizontal wells has gradually developed into the main technology for effective production and economical development of tight reservoirs. For tight oil reservoirs represented by a certain basin, the horizontal section length generally exceeds 1500m, and the longest is more than 3000m. Dissolvable bridge plug segmental multi-cluster volumetric fracturing technology is mainly used for transformation, the segment spacing is 20-30m, each segment is perforated with 4-6 clusters, the perforation density is 15 holes / m, and the perforation cluster is 0.6-0.8m long. The number of cluster holes is 9-12 holes, the distan...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B43/26E21B43/116
CPCE21B43/26E21B43/116
Inventor 白晓虎慕立俊赵振峰李宪文张矿生唐梅荣杜现飞马兵陈强李晓燕
Owner PETROCHINA CO LTD
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