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A method for fixed-point initiation of cracking in low-permeability layers of water-flooded wells

A technology for water-flooded wells and water-flooded layers, which is used in earth-moving drilling, wellbore/well components, and production fluids, etc., can solve the problems of restricting the continuous and stable production of oil fields, immature process technology, and difficulty in oil well governance, etc. Good effect, change the dominant direction, increase the effect of water flooding sweep volume

Active Publication Date: 2021-09-28
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The invention provides a method for fixed-point initiation of cracking in low-permeability layers of water-flooded wells. It is difficult to control, and the corresponding technology is immature, which seriously restricts the problem of sustained and stable production of oilfields

Method used

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  • A method for fixed-point initiation of cracking in low-permeability layers of water-flooded wells

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0050] Please refer to figure 1 , which shows a schematic diagram of the downhole structure of a method for fixed-point initiation of cracking in a low-permeability layer of a water-flooded well provided by an embodiment of the present invention. The method for fixed-point initiation of cracking in a low-permeability layer of a water-flooded well includes:

[0051] Step 1: Inject low-molecular-weight polymer weak gel into the original perforation section of the water-flooded zone;

[0052] Step 2: Inject high-strength phenolic resin gel carrying consolidated sand into the original perforation section of the water-flooded zone;

[0053] Step 3: Inject cement sealant into the flooded layer;

[0054] Step 4: Inject replacement fluid into the water-flooded layer to replace the cement sealant to the position of the cement plug surface and close the well for solidification. The cement sealant is used to seal the original perforation section in the well, and the original perforation...

Embodiment 2

[0067] Further, in another embodiment of the method for fixed-point initiation of cracking in a low-permeability layer of a water-flooded well according to the present invention, the fracturing treatment of the low-permeability section in the step 9 is specifically:

[0068] For the low-permeability section, 1.2m 3 Injection volume / min Inject the front liquid to create a joint of 8m 3 .

[0069] In the above examples, in the low-permeability oilfield, the oil layer does not produce oil by perforation alone, and small-scale fracturing is used to open a fracture in the formation, shorten the oil flow channel, and achieve the purpose of oil production. Small-scale fracturing is mainly sand Volume (generally 5-10 cubic meters), displacement (1.0-1.4 cubic meters per minute), and liquid volume (30-40 cubic meters) are small to prevent communication from blocking water-flooded sections.

[0070] Small-scale fracturing treatment uses pre-fluid to treat low-permeability layers of wa...

Embodiment 3

[0073] Further, another embodiment of the method for fixed-point initiation of cracking in a low-permeability layer of a water-flooded well according to the present invention, in step 1, the low-molecular-weight polymer weak gel injected into the water-flooded layer is specifically:

[0074] 2.2 m to the flooded layer 3 / min displacement into the polymer microsphere solution 50m in sequence 3 and gel solution 100m 3 , the polymer microsphere solution contains 10L of 100nm polymer microspheres per cubic meter of solution, and the gel solution contains 50L of gel per cubic meter of solution.

[0075] In specific implementation, preferably, the water-flooded layer is 2.2 m 3 / min displacement into the polymer microsphere solution 50m in sequence 3 and gel solution 100m 3 , the polymer microsphere solution contains 10L of 100nm polymer microspheres per cubic meter of solution, and the gel solution contains 50L of gel per cubic meter of solution. Wherein the gel is PEG-1 gel. ...

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Abstract

The invention discloses a method for fixed-point initiation of cracking in low-permeability layers of water-flooded wells, belonging to the technical field of downhole operations in oil field exploration and development. The method of the present invention includes: step 1: using a fracturing vehicle to inject low-molecular polymer weak gel into the original perforation section of the water-flooded zone; step 2: using a fracturing vehicle to inject carrying consolidation into the original perforation section of the water-flooded zone High-strength phenolic resin gel of sand; Step 3: Use cementing to inject cement sealant into the water-flooded zone; use directional perforation to open the low-permeability zone, and run a single-up seal fracturing drilling tool to protect the blocked zone , and then use small sand volume, small displacement, and low sand ratio to press open new fractures to achieve the purpose of inhibiting the longitudinal extension of fractures and avoiding the pressure channeling with the original fractures. The affected volume is flooded, and the purpose of resuming and increasing production of water-flooded oil wells is realized. The construction process of the invention is simple, and the effect of the measures is good.

Description

technical field [0001] The invention belongs to the technical field of underground operations in oil field exploration and development, and in particular relates to a method for fixed-point initiation of cracks in low-permeability layers of water-flooded wells. Background technique [0002] After more than 40 years of oil exploration and development in the Ordos Basin, Changqing Oilfield has entered the development stage of medium-high water cut in some major blocks. In recent years, some oil well water plugging, water well profile control, water plugging and fracturing measures carried out in oil fields have an effective rate of only about 60%, and the average daily oil increase of a single well during the validity period is about 0.8t. Compared with other technologies, the water plugging pressure The fracturing technology has low efficiency and high cost, and the plugging agent material, injection process and equipment are not matched. [0003] However, the treatment of s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B33/13E21B43/26E21B43/267
CPCE21B33/13E21B43/26E21B43/267
Inventor 段鹏辉慕立俊卜向前齐银李向平康博李转红山树民刘明
Owner PETROCHINA CO LTD
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