High-temperature and High-Salt resisting gel water packing-off method

A high-temperature-resistant, gel-based technology, which is applied in earthwork drilling, wellbore/well components, sealing/isolation, etc., can solve problems such as oil plugging but not water blocking, low strength, and lack of selective plugging ability. To achieve the effect of improving the success rate and thermal stability

Inactive Publication Date: 2007-01-03
PETROCHINA CO LTD
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Problems solved by technology

When the existing chemical water plugging technology is used in the reservoir of >90℃, the thermal stability of the chemical agent will appear, and it will not have the selective plugging ability and the gel strength cannot reach the strength required for long-term high-pressure flushing when it is generally injected. There are problems such as blocking
The reasons may be: the pressure of the water layer of the oil well is higher than the pressure of the oil layer, and the plugging agent is easy to enter the oil layer when it is directly injected, resulting in oil plugging but not water blocking; the polymer plugging agent cannot form a stable gel when the temperature is higher than 120 °C; The plugging agent is easy to reverse; the cement plugging agent is difficult to inject in large doses. After solidification in the oil sand, there are still gaps between the cemen

Method used

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  • High-temperature and High-Salt resisting gel water packing-off method
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  • High-temperature and High-Salt resisting gel water packing-off method

Examples

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Example Embodiment

[0024] Example 1: Indoor core plugging test

[0025] At 125℃, the modified tannin extract plugging agent main agent was used to plug the cemented quartz sand non-cracked cylindrical core and the cemented quartz sand cracked square core. The results are shown in Table 1 and Figure 4 .

[0026] The water permeability of the core without cracks (K w ) Is 1870.95×10 -3 μm 2 , The plugging agent formula is: 10% GKJ + 3% HMTA + 1% NaOH. The sol injection balance pressure is 0.011MPa, and the resistance coefficient (F r ) Is 25. At a constant temperature of 125°C for 5 days, the core was displaced with formation water at a Darcy velocity of 0.879m / d, the breakthrough pressure was measured to be 0.44MPa / cm, and the residual resistance coefficient (F rr1 ) Is 24000, the core is almost completely blocked, and the permeability drops to 0.08×10 -3 μm 2 . Continue constant temperature aging, the residual resistance coefficient after 28d (F rr2 ) Is 20000, indicating that the thermal stability...

Example Embodiment

[0030] Example 2 Shixi Oilfield Carboniferous deep well bottom water plugging field test

[0031] On October 27, 2001, the Shixi Oilfield Carboniferous deep well bottom water plugging was carried out on site. The basic data of SH1104 well are shown in Table 2. As the production has been stable for nearly 3 years, the amount of underground movable oil may not be much. In view of the serious flooding of the well and the high water pressure that may cause the main agent of the plugging agent to not easily enter the water layer, a special plugging method of temporary plugging agent-modified tannin extract plugging agent main slug-cement sealing slug is adopted. Among them, the temporary plugging agent formula is: 0.6% polyacrylamide + 0.1% sodium dichromate + 0.3% anhydrous sodium sulfite; the modified tannin extract plugging agent formula is: 10% GKJ + 3% HMTA + 1% NaOH; sealing section The plug is: 20% cement + 4% soil removal + 0.15% sodium borate. It is hoped that the water flow c...

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Abstract

The present invention relates to a high-temperature-resistant and high-salt-resistant gel water-plugging method for raising petroleum recovery efficiency. Said invention adopts three-slug injection water-plugging method, and provides the concrete steps of said three-slug injection water-plugging method. These steps are as follows: first slug, adding temporary blocking agent, its added quantity is 10-20% of total injection amount, after the temporary blocking agent is injection for 0.5-1.5 hr, closing well, the temporary blocking agent can be formed into gel, can be used for temporarily blocking the oil layer; then making second slug, injecting low-viscosity gel which is easily injected and can be formed into gel with high viscoelasticity under the condition of stratigraphic temperature, its injected quantity is 70-80% of total injection amount; and third slug, injecting cement as sealing agent, its injected quantity is 10-20% of total injection amount.

Description

technical field [0001] The invention belongs to the technique of enhancing oil recovery rate developed in oil fields, and specifically relates to a high-temperature and high-salt gel water plugging method. Background technique [0002] Indoor research work on high temperature plugging agents has been reported [1~3] , Navratil et al. from Canada mixed black wattle extract and sulfonated extract with formaldehyde and phenol to prepare a gel that can be used in high-temperature formation plugging [1，2] . Liu Chengjie and others made a blocking agent that can be used at high temperature by using rubber extract [3] . However, no successful field test of water plugging and profile control has been reported. When the existing chemical water plugging technology is used in the reservoir of >90℃, the thermal stability of the chemical agent will appear, and it will not have the selective plugging ability and the gel strength cannot reach the strength required for long-term high-...

Claims

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Application Information

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IPC IPC(8): E21B33/13
Inventor 朱怀江刘玉章熊春明
Owner PETROCHINA CO LTD
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