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Method for simulating microcrack of shale by using mud cake

A micro-fracture and mud shale technology, applied in the field of core simulation, can solve the problems of high cost of natural mud shale micro-fracture simulation equipment, strong experimental repeatability, low cost, etc., achieving low cost, simple thinking and principle, and low cost. handy effect

Inactive Publication Date: 2017-05-31
SOUTHWEST PETROLEUM UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] In view of this, the present invention provides a method for simulating mud shale micro-cracks by using mud cakes to solve the problem that it is impossible to directly and simply simulate natural mud shale micro-cracks or the cost of simulation equipment is too high in the prior art. It can effectively simulate shale micro-fractures with low cost and strong experiment repeatability

Method used

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  • Method for simulating microcrack of shale by using mud cake
  • Method for simulating microcrack of shale by using mud cake
  • Method for simulating microcrack of shale by using mud cake

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] Embodiment 1 Mud cake simulation of vertical fractures

[0041] 1. Weigh 300mL of tap water at 20°C, add 12g of bentonite, 300g of ordinary barite, 150g of nanobarite, 3g of polyacrylamide, 15g of sodium polyacrylate, set the speed at 500r / min, and stir for 30min.

[0042] 2. Then pour it into a high-speed stirrer and stir for 15 minutes at a speed of 10000r / min.

[0043] 3. Pour the drilling fluid into the high-temperature and high-pressure water meter, put in the filter paper, adjust the pressure to 3.5MPa, the temperature is 35°C, and lose water for 30 minutes, then take out the mud cake and control the thickness of the mud cake to 11.25mm.

[0044] 4. Take out the mud cake, and cut the mud cake into pieces to meet subsequent needs. Afterwards, put into an electric blast drying oven and heat to 40° C. and air-dry for 2 hours, then take out the mud cake from the electric blast drying oven.

[0045] 5. After standing at room temperature for 30 minutes, use a silver n...

Embodiment 2

[0048] Bentonite selects 15g, and all the other conditions are the same as in Example 1, and the experimental results are shown in Table 1.

Embodiment 3

[0050] Bentonite selects 18g, and all the other conditions are the same as in Example 1, and the experimental results are shown in Table 1.

[0051] The properties of the vertical cracks prepared in Table 1 Example 1-3

[0052]

[0053] It can be seen from the above table 1 that when the content of bentonite is 18g (accounting for 6% of tap water), the mud cake has the lowest permeability and the thickness meets the requirements. The mud cake permeability increases after the vertical cracks are formed in the socket, but within a reasonable range, it shows that the mud cake is not destroyed and meets the experimental requirements, and the formation of vertical cracks also effectively increases the mud cake permeability.

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Abstract

The invention discloses a method for simulating a microcrack of shale by using a mud cake. The method comprises the following steps of preparing a drilling fluid; preparing the mud cake through dehydration of the drilling fluid; inserting metal wires which are 0.25-0.40mm in diameter and different in thickness from different directions; and taking out the mud cake after molding, thereby forming the microcrack. Compared with methods for simulating the microcrack of the shale by directly using a shale core and adopting existing laser simulation equipment, the method disclosed by the invention has the advantage that the microcrack simulation cost is greatly reduced.

Description

technical field [0001] The invention belongs to the field of rock core simulation methods, in particular to a method for simulating mud shale micro-cracks by using mud cakes. Background technique [0002] At present, there is no unified standard for the method of core simulation. For rock pores, laboratories can usually use direct coring or artificial cores for simulation tests. However, there is no direct and effective method for laboratory simulation of tight shale, especially tight shale with micro-fractures. In recent years, there are mainly two methods for evaluating the simulation effect of shale micro-fractures. The first is using sheet metal simulation, which uses two sheets of metal that are brought together to form a gap in the middle. The gap width simulated by this method is too large to reach the micron level. The second is Shi Bingzhong et al. (Shi Bingzhong, Hu Xuhui, Gao Shuyang, Xu Jiang, Lin Yongxue. Visual simulation test and evaluation of micro-fractu...

Claims

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Application Information

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IPC IPC(8): G01N1/28
CPCG01N1/28G01N1/286
Inventor 黄进军李学涯李文飞张潇
Owner SOUTHWEST PETROLEUM UNIV