Plugging agent suitable for large leakage, its preparation method and leaking stopping technology

Abstract

The invention relates to a plugging agent suitable for large leakage, its preparation method and a leaking stopping technology. The invention is suitable for repeatable large leakage, belonging to the field of petroleum drilling. The plugging agent comprises the following ingredients by the following weight ratio: clear water: HSD (HHH): HD-1: HD-2: LD-102: DF-A: barite = 100: 12-15: 4-5: 7-8: 4-5: 30. According to the invention, by reinforcing the interaction among ingredients, maximizing the structural strength of the plugging agent entering a leak layer, maintaining the trend that the leak layer is gradually enhanced with time after injecting the plugging agent in the leak layer, and further increasing the pressure bearing capacity of the leak layer, the leakage problem of a repeatable return-lost large-scale absorption well can be solved, the problem of leaking stopping existing in the prior art can be overcome, and the one-time leak stopping success rate is increased.

Description

technical field [0001] The invention relates to a plugging agent suitable for large-scale leakage, a preparation method thereof and a plugging process, which are suitable for repetitive large-scale leakage and belong to the field of petroleum drilling. Background technique [0002] In the existing drilling construction process, permeability loss occurs frequently. Commonly used are "bridge plug plugging, bridge plug + cement slurry plugging, stone + bridge plug + cement slurry plugging, gel plugging, gel + cement slurry, stone + gel + cement slurry plugging", etc. Mainly conventional leak prevention and plugging technology, and played a very important role in the practice of plugging. However, the conventional plugging process has a low one-time plugging success rate, and multiple comprehensive pluggings are required to achieve successful plugging. The main factors leading to the low plugging success rate are as follows: [0003] 1. Some have regional permeability lea...

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Problems solved by technology

[0005] 3. The internal structure of several gel plugging systems currently used is loose and lacks a unified structural integrity, which leads to a serious shortage of compressive strength of the material itself, no cementation with the leaking layer, and is easy to follow along with the erosion of the mud. The leakage channel is lost, resulting in a low plugging success rate

[0006] 4. Once the conventional plugging system is formed, the system structure will not change, and will change with time, and its overall compressive strength will decline in the middle and late stages of the formation; as the drilling fluid is repeatedly washed out during the later drilling process, the probability of lost circulation will increase , a great loss of plugging time and plugging costs

[0007] 5. When encountering a large section of mudstone, a larger space for density increase is required. When the density is increased, many wells have permeability loss. Because of the protection of the production layer, cement injection can not be used for plugging, and conventional bridge plugging cannot meet the requirements , prone to repeated leaks

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