Solid free scale-preventing workover fluid suitable for sodium bicarbonate formation water

A sodium bicarbonate and workover fluid technology, applied in the direction of drilling compositions, chemical instruments and methods, can solve the problems of high preparation cost and high density, and achieve the effects of good fluidity, low corrosion and low cost

Inactive Publication Date: 2014-07-16
CNPC BOHAI DRILLING ENG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to overcome the defects of high density and high preparation cost in the scale-inhibiting solid-free workover fluid in the prior art, and provide a solid-free scale-inhibiting fluid suitable for sodium bicarbonate-type formation water. Workover fluid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Embodiment 1 (the following percentages are mass percentages)

[0039] Raw materials (both are commercially available products): 56% of liquid calcium, 2% of glacial acetic acid, 2% of quaternized imidazoline, and the balance is fresh water. The above raw materials are uniformly mixed to prepare a solid-phase scale-inhibiting type workover fluid. The workover fluid is a pale yellow free-flowing liquid with extremely low dynamic viscosity, within 10mPa.s, pH value of about 4, and a density of 1.20g / cm measured by a Pomerol density meter. 3 . Take 200mL of the workover fluid, put it in a 400mL Erlenmeyer flask with a stopper, and place two consecutively under the conditions of normal temperature and pressure, medium temperature (90°C) normal pressure and high temperature and high pressure (190-195°C, 16-17MPa) respectively. In one month, the liquid in the bottle has no precipitation and is as clear as ever. It shows that the compatibility of the workover fluid system i...

Embodiment 2

[0041] Raw materials (both are commercially available products): liquid calcium 97%, glacial acetic acid 1.4%, quaternized imidazoline 1.6%, no fresh water added. The above raw materials are uniformly mixed to prepare a solid-phase scale-inhibiting type workover fluid. The workover fluid is a light yellow free-flowing liquid with extremely low dynamic viscosity, within 10mPa.s, pH value of about 6, and a density of 1.40g / cm measured by a Pomerol density meter. 3 . Take 200mL of the workover fluid, put it in a 400mL Erlenmeyer flask with a stopper, and place two consecutively under the conditions of normal temperature and pressure, medium temperature (90°C) normal pressure and high temperature and high pressure (190-195°C, 16-17MPa) respectively. In one month, the liquid in the bottle has no precipitation and is as clear as ever. It shows that the compatibility of the workover fluid system is good. The workover fluid was mixed evenly with the formation water of Ban 5-3 well ...

Embodiment 3

[0043] Raw materials (both are commercially available products): 85% liquid calcium, 12% zinc chloride, 1.2% glacial acetic acid, 1.8% quaternized imidazoline, without adding fresh water. The above raw materials are uniformly mixed to prepare a solid-phase scale-inhibiting type workover fluid. The workover fluid is a light yellow free-flowing liquid with extremely low dynamic viscosity within 10mPa.s and a pH value of about 5. The density measured by Pomerol density meter is 1.55g / cm 3. Take 200mL of the workover fluid, put it in a 400mL Erlenmeyer flask with a stopper, and place two consecutively under the conditions of normal temperature and pressure, medium temperature (90°C) normal pressure and high temperature and high pressure (190-195°C, 16-17MPa) respectively. In one month, the liquid in the bottle has no precipitation and is as clear as ever. It shows that the compatibility of the workover fluid system is good. The workover fluid was mixed evenly with the formation...

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Abstract

The invention discloses a solid free scale-preventing workover fluid suitable for sodium bicarbonate formation water. The fluid comprises the following components in percentage by weight: 56-97% of basic liquid, 0-12% of a weighting agent, 1.2-10% of a scale-preventing agent, 1.6-10% of a corrosion inhibitor and the balance of fresh water, wherein the density of the workover fluid is 1.20-1.55g/<cm3>; the basic liquid is an industrial calcium chloride solution with the saturated density of 1.40g/<cm3>; the weighting agent is zinc chloride; the scale-preventing agent is one of glacial acetic acid and formic acid; the corrosion inhibitor is imidazoline of quaternary ammonium salt. The density of the workover liquid disclosed by the invention can be randomly adjusted in a range from 1.20g/<cm3> to 1.55g/<cm3>. The workover fluid is particularly remarkable in scale preventing effect to sodium bicarbonate formation water, low in corrosivity to a sleeve of an oil pipe, good in compatibility with formation water, low in cost, low in damage, pollution-free, solid-free and good in mobility, and can meet the field construction demand.

Description

technical field [0001] The invention relates to an oilfield downhole workover fluid, in particular to a solid-phase scale-inhibiting workover fluid suitable for sodium bicarbonate formation water. Background technique [0002] In the stage of oilfield exploration and development, oil, gas and water wells need to carry out oil testing and workover operations. Workover hydraulic wells are often used to carry out operations in the wellbore. Generally, it is necessary to inject workover fluid into the wellbore to ensure that the hydrostatic column pressure in the wellbore is greater than or equal to the formation pressure, avoid well kick and blowout accidents, and ensure the safety of workover construction operations. [0003] According to the oil exploration and development data compilation (analysis and testing part) of Dagang Oilfield in 20 years, 1462 wells and 5824 levels of oil testing and oil production statistics, sodium bicarbonate formation water accounted for 87.036%...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09K8/06
CPCC09K8/06
Inventor 何风华邹鹏刘德正李文杰何静藏春雷
Owner CNPC BOHAI DRILLING ENG
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