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A mud cake simulating low permeability of shale formation and preparation method thereof

A low-permeability and permeability technology, which is used in the preparation of test samples, permeability/surface area analysis, suspension and porous material analysis, etc.

Active Publication Date: 2020-11-03
SOUTHWEST PETROLEUM UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

So far, there is no set of methods for the preparation of mud cakes that simulate low-permeability physical environments

Method used

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  • A mud cake simulating low permeability of shale formation and preparation method thereof
  • A mud cake simulating low permeability of shale formation and preparation method thereof
  • A mud cake simulating low permeability of shale formation and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] A mud cake simulating the low permeability of shale formations, prepared from the following raw materials in parts by weight, each part is 1 gram: calcium bentonite 16g, barite 150g, nanobarite 100g, 1250 mesh calcium carbonate 40g, 2200 mesh calcium carbonate 10g, polyacrylamide 2g, sodium polyacrylate 10g and water 200g.

[0044] Among them, the barite density is 4.15g / cm 3 , the nanobarite is 4.4g / cm 3 .

[0045]Preparation method, first measure 200g of tap water into the instrument, add 16g of calcium bentonite under the condition of stirring with an electric low-speed stirrer at a speed of 600r / min, and stir for 2 hours to fully disperse the calcium bentonite in the water; then add 150g of recrystallized clay in order stone, stirred under a high-speed stirrer at 8000r / min for 30min, then added 100g of nanobarite, and stirred at a constant speed for 30min; then added 40g of 1250 mesh calcium carbonate and 10g of 2200 mesh calcium carbonate, and Stir at a high spe...

Embodiment 2

[0047] A mud cake simulating the low permeability of shale formations, prepared from the following raw materials in parts by weight: calcium bentonite 13g, barite 170g, nanobarite 90g, 1250 mesh calcium carbonate 50g, 2200 mesh calcium carbonate 15g, polyacrylamide 1g, sodium polyacrylate 15g and water 180g.

[0048] The preparation method is the same as in Example 1.

Embodiment 3

[0050] A mud cake simulating the low permeability of shale formations, prepared from the following raw materials in parts by weight: calcium bentonite 19g, barite 120g, nanobarite 115g, 1250 mesh calcium carbonate 30g, 2200 mesh calcium carbonate 15g, polyacrylamide 4g, sodium polyacrylate 5g and water 220g.

[0051] The preparation method is the same as in Example 1.

[0052] For the mud cake prepared in Examples 1-3, a GGS42-2A high-temperature and high-pressure fluid loss tester was used to evaluate the effect of the prepared low-permeability mud cake.

[0053] Table 2 Experimental results of mud cake permeability prepared by multiple groups of clean water

[0054]

[0055] Note: The results in the table are the average value of data from three experiments.

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Abstract

The invention relates to a preparation method of a novel low-permeability mud cake. The mud cake is prepared from tap water, calcium bentonite, barite, millimicro barite, 1250-mesh calcium carbonate,2200-mesh calcium carbonate, polyacrylamide and sodium polyacrylate. The preparation method comprises the steps of firstly adding the tap water into an instrument, slowly adding the calcium bentoniteunder the condition of stirring at low speed, stirring until uniformly dispersing, then adding the barite and stirring at high speed, and then adding the millimicro barite and stirring at high speed;adding the 1250-mesh calcium carbonate and the 2200-mesh calcium carbonate, and stirring for 30 minutes at high speed; then slowly adding the polyacrylamide and the sodium polyacrylate, stirring for 1hour at high speed, pouring prepared mud into a high temperature and high pressure filtration instrument, and filtering for 30 minutes at the pressure being 3.5Mpa and the normal temperature. The mudcake prepared through the method can achieve a low-permeability effect, meanwhile, the used materials are less in type and dosage and wide in source, the process is simple, convenient and high-efficient, and the preparation method is easy to popularize.

Description

technical field [0001] The invention relates to a preparation method for simulating the physical environment of low permeability of shale formations by using mud cakes. According to the preparation method, thin, tough and compact materials can be obtained, and at the same time, the permeability of mud cakes can reach the order of magnitude of shale formations, which can be The optimization and evaluation of shale formation plugging agents provide data and environmental support, as well as conditions for shale formation microfracture simulation. Background technique [0002] Nowadays, the development of shale gas has become the key to my country's energy development. However, due to the development of micro-cracks and micro-pores in shale formations and strong water sensitivity, wellbore instability is prone to occur in long horizontal sections. The key to solving this problem It is to improve the plugging performance of drilling fluid. From the perspective of plugging perform...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N1/38G01N15/08
CPCG01N1/38G01N15/0826
Inventor 黄进军田月昕李文飞李学涯李春霞郭星波沈景原
Owner SOUTHWEST PETROLEUM UNIV