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Acidizing method for horizontal well in carbonate rock reservoir

A technology for carbonate reservoirs and horizontal wells, which is used in earth-moving drilling, wellbore/well components, and production fluids, etc., and can solve the problems of filtration in high-permeability layers, difficulty in plugging ball setting, poor steering effect, etc. problems, to achieve the effect of preventing water expansion, reducing construction costs, and good diversion effect

Inactive Publication Date: 2019-01-29
CHINA UNIV OF PETROLEUM (BEIJING)
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] (1) The packer steering construction is complicated, time-consuming, and costly, and it is not suitable for horizontal wells with long horizontal sections;
[0005] (2) Due to the long well section and low injection displacement of the horizontal well, the plugging ball is difficult to set and seal;
[0006] (3) Foam acid temporary plugging diversion is limited in application range due to the poor temperature resistance of foam and serious fluid loss in high permeability layer (filtration characteristics of drilling fluid);
[0007] (4) The diversion of the temporary plugging agent is mainly through the formation of a low-permeability filter cake in the high-permeability layer, but acidification of carbonate rocks will produce wormholes, and the filter cake formed by bypassing the temporary plugging agent has a poor diversion effect;
[0008] (5) VES steering acid is controlled by pH value to increase viscosity, but its rheology is poor, so the effect of uniform acid distribution is limited

Method used

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  • Acidizing method for horizontal well in carbonate rock reservoir
  • Acidizing method for horizontal well in carbonate rock reservoir

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] This embodiment provides an acidizing method applied to Well X of Donghe Oilfield, Tarim Basin, which includes the following steps:

[0042] Well Donghe X is located in the Donghe No. 1 structure, with a depth of 5,700m, a reservoir thickness of 40m, and a length of 480m for the target acidizing section. The weighted average porosity of logging interpretation is 17.4%, and the oil saturation is 73%. The well was put into production naturally on February 20, 2016, with an initial daily oil production of 45.16 tons. By February 2, 2017, the daily oil production was 18 tons. Production conditions before acidification: low liquid level, insufficient liquid supply, intermittent liquid discharge. The horizontal section of the well is long, and considering uniform acid distribution, it is proposed to use fiber foam-based VES acid acidizing fracturing stimulation.

[0043] Step 1: Inject 60m of conventional acid into the horizontal well 3 (Injection flow is 1.5m 3 / m);

[0...

Embodiment 2

[0048] Based on the indoor core flow device, the core of Halfaya A well was used to carry out the core flow experiment to test the damage of fiber foam-based VES acid to the reservoir. The experimental steps are as follows:

[0049] ①Connect the equipment, check for leaks, and measure the permeability with standard brine.

[0050] ② At an injection rate lower than the minimum critical flow rate of the core, reversely inject the residual acid of fiber foam-based VES acid 3 times the pore volume of the core after gel breaking.

[0051] ③ Then use standard brine to measure the permeability of the core polluted by residual acid to determine the performance of residual acid protection reservoir.

[0052] Experimental results: Table 1 shows the experimental results of reservoir core flow after residual acid breaking.

[0053] Table 1 Evaluation results of fiber foam-based VES acid breaker damage reservoir

[0054]

[0055] From the experimental results in Table 1, it can be seen ...

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Abstract

The invention provides an acidizing method for a horizontal well in a carbonate rock reservoir. The acidizing method includes the steps that S1, acid liquor is injected into the horizontal well, the injection flow is 0.5 m<3> / m to 3 m<3> / m; S2, fiber-foam base VES acid is injected, the injection flow is 0.3 m<3> / m to 1.5 m<3> / m; and according to the length of the horizontal well, the process of the first step to the second step is circulated every 60 m to 100 m horizontal section length of the horizontal well to complete acidizing of the horizontal well in the carbonate rock reservoir. According to the acidizing method for the horizontal well in the carbonate rock reservoir, the acidizing effect of the horizontal well can be significantly improved, and no damage to the reservoir is achieved.

Description

technical field [0001] The invention relates to an acidizing method, in particular to an acidizing method for a horizontal well in a carbonate reservoir, and belongs to the technical field of petroleum exploitation. Background technique [0002] Carbonate rock acidizing refers to the method of reacting acidic fluid with carbonate rock reservoirs to decontaminate the near-wellbore area or improve the permeability of such reservoirs. During the acidification process of carbonate rocks, the acid preferentially contacts with formations with better porosity and permeability conditions or well-developed natural fractures and vugs, and further increases the permeability of such areas, and then continues to enter these formations, and the producing degree of low porosity and permeability areas is lower Low, it is difficult to achieve uniform acidification. In order to achieve uniform acidification of heterogeneous carbonate reservoirs, it is necessary to make the acid react more in...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): E21B43/27
CPCE21B43/26
Inventor 张路锋周福建张士诚王晋王月纯
Owner CHINA UNIV OF PETROLEUM (BEIJING)
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