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Blockage-removing method for polymer flooding blocking wells

A polymer and mortar technology, which is applied in drilling compositions, chemical instruments and methods, and earth-moving drilling and mining, etc., can solve the problem of short plugging validity period, decreased production, and no consideration of the plugging characteristics of polymer injection wells near the wellbore, etc. problem, to achieve the effect of improving oil recovery, reducing impact, and high conductivity

Active Publication Date: 2017-07-18
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] In the existing technology, the plugging removal of polymer injection wells focuses on the selection of plugging removal materials, and does not take into account the plugging characteristics of the near wellbore zone of the polymer injection well, resulting in a short period of validity for plugging removal, and a decline in production after a short period of time

Method used

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  • Blockage-removing method for polymer flooding blocking wells
  • Blockage-removing method for polymer flooding blocking wells
  • Blockage-removing method for polymer flooding blocking wells

Examples

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Embodiment 1

[0054] The plugging removal method of the polymer flooding plugged well of the present embodiment may further comprise the steps:

[0055] 1) The cumulative injection volume of polymer in Well T4-212 is 2.1×10 4 m 3 , the formation temperature is 50°C, and the PV number is 0.2; the depth of the oil layer is 1200m, and the oil production drops to 1.8 tons / day; the cementing quality of the production well is qualified and the upper and lower adjacent layers of the oil layer are all dry layers;

[0056] 2) Carry out fracturing construction on the oil layer blocked by polymer injection, and control the length of the artificial fracture to be 40m-60m, and the height to be below 20m; the fracturing construction includes the following steps:

[0057] a) Adjust a 700-type pump truck to the second gear, with a distance of 1.2m 3 / min displacement will be 10m 3 The formation treatment fluid is injected into the formation to pretreat the formation under the condition of lower than the...

Embodiment 2

[0075] The plugging removal method of the polymer flooding plugged well of the present embodiment may further comprise the steps:

[0076] 1) There are two oil layers in Well T470, and the cumulative polymer injection in the first oil layer A is 2.9×10 4 m 3 , the formation temperature of the first layer is 79°C, the PV number is 0.35, and the cumulative polymer injection volume in the second oil layer B is 3.0×10 4 m 3 , the formation temperature of the second layer is 80°C, and the PV number is 0.4; the depths of the first and second oil layers are 1800m and 1821m respectively, and the oil production of this well drops to 1.0 tons / day; the cementing quality of this oil production well Qualified, 1791m above the first oil layer is a water layer, and the adjacent layer at 1832m below the second oil layer is a water layer;

[0077] 2) Carry out fracturing construction on the oil layer blocked by polymer injection, and control the length of the artificial fracture to be 40m t...

Embodiment 3

[0086] The plugging removal method of the polymer flooding plugged well of the present embodiment may further comprise the steps:

[0087] 1) The cumulative injection volume of polymer in the first oil layer of Well T478 is 6.1×10 4 m 3 , the formation temperature is 110°C, and the PV number is 0.46; the cumulative injection volume of polymer in the second oil layer is 8.1×10 4 m 3 , the formation temperature is 120°C, the PV number is 0.58; the depths of the first and second oil layers are 2300m and 2400m respectively, and the oil production drops to 0.5 tons / day; the cementing quality of the production well is qualified and the upper, The lower adjacent layers are all dry layers;

[0088] 2) Carry out fracturing construction on the oil layer blocked by polymer injection, and control the length of the artificial fracture to 40m-60m, and the height to be below 20m; the fracturing construction parameters are shown in Table 2, and other uninvolved processes are the same as in...

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Abstract

The invention relates to a blockage-removing method for polymer flooding blocking wells, and belongs to the field of fracturing reformation of oil wells. The blockage-removing method includes the steps of conducting fracturing construction to an blocked oil layer caused by polymer injection and controlling the length of an artificial fracture to 40-60 m, and the height to no more than 20 m, specifically, the fracturing construction is small-scale fracturing construction by sequentially injecting stratum treating fluid with a volume of 10-35 m3, injecting ahead fluid with a volume of 10-30m3, injecting particle loaded fluid with a volume of 40-60 m3, and injecting displacing fluid with a volume of 8-16m3. By reasonable selection of the polymer flooding to block wells, the pertinency and effectiveness of subsequent fracturing measure reformation are improved; by control of the length and the height of the artificial fracture, not only the permeability of a polymer blocked oil layer in near bore zones and effectiveness of the measures are improved, but also wastes of materials and labor cost caused by an excessive large construction scale are avoided, the validity of fracturing blockage-removing measures is increasingly prolonged, and the reservoir recovery is improved.

Description

technical field [0001] The invention belongs to the field of fracturing reconstruction of polymer injection wells, and in particular relates to a plugging removal method for polymer flooding plugged wells. Background technique [0002] In the process of oilfield water flooding development, the heterogeneity of reservoir and unfavorable mobility ratio lead to low sweep efficiency of water flooding. Polymer flooding is a commonly used technology to increase recovery in the process of secondary oil recovery in oilfields. The polymer used in polymer flooding is mostly high-molecular-weight polyacrylamide (molecular weight is about 15 million). The polymer solution first enters the high-permeability layer, and the subsequent injected water changes the flow direction around the polymer and enters the low-permeability layer, thereby increasing the sweep coefficient and achieving the purpose of enhancing oil recovery. [0003] However, polymer injection wells often get blocked. Th...

Claims

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Application Information

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IPC IPC(8): E21B43/27E21B43/26C09K8/524
CPCC09K8/524E21B43/25E21B43/26
Inventor 李梦楠冯兴武蒋尔梁黄家骥刘欣张燕利董建立
Owner CHINA PETROLEUM & CHEM CORP
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