Seawater-based polyamine well completion fluid and preparation method thereof

A completion fluid, seawater-based technology, applied in chemical instruments and methods, drilling compositions, etc., can solve problems such as acid-sensitive damage, achieve strong anti-swelling inhibition, less damage, and reduce oil-water interfacial tension.

Active Publication Date: 2013-06-19
CHINA NAT OFFSHORE OIL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] At present, the seawater-based completion fluid widely used in offshore drilling is stealth acid chelation completion fluid. Although it meets the above performance technical requirements, but due to the low pH, the whole system is acidic, causing acid-sensitive damage to acid-sensitive formations. In addition, the acidic environment also puts forward higher requirements for the sustained release of downhole tools

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Preparation of perforating fluid: at 25M 3 In the circulating pool with stirring, add filtered seawater (water temperature ≥ 5°C) 23M in sequence 3 , polyamine 27Kg, alkaline chelating agent 12Kg, bactericide 12Kg, fully stirred at room temperature for 60 minutes to obtain polyamine perforating fluid. After running down the perforating gun, pump the prepared perforating fluid into the perforation section in the well with a mud pump. The perforating fluid is the liquid that comes into contact with the oil layer for the first time, so the amount of polyamine is increased, which is beneficial to prevent oil layer Hydration expansion and migration of clay.

Embodiment 2

[0020] Preparation of working solution: at 40M 3 Add filtered seawater (water temperature ≥ 5°C) 38M to the circulating pool with stirring 3 , polyamine 40Kg, alkaline chelating agent 16Kg, bactericide 24Kg, fully stirred at room temperature for 60 minutes to obtain the polyamine working solution. The working fluid is used for well cleaning, perforation, filling and sand control operations, and the completion fluid used in the connection between potting and overnight operations, and is directly pumped into the well with a mud pump.

Embodiment 3

[0022] Preparation of filling liquid: at 40M 3 Add filtered seawater (water temperature ≥ 5°C) 38M to the circulating pool with stirring 3 , polyamine 40Kg, alkaline chelating agent 16Kg, bactericide 24Kg, fully stirred at room temperature for 60 minutes to obtain the polyamine filling solution. The filling fluid is used to fill the completion fluid used in sand control operations, mixed with gravel and pumped into the well through surface pumps.

[0023] Advantages of the present invention: 1. The polyamine completion fluid of the present invention is neutral or alkaline, with a pH of 7.5-8.5, which can overcome the acid sensitivity problems of some acid-sensitive reservoirs and unconsolidated sandstone formations containing clay cement; 2. The interfacial tension is low, generally lower than 1mN / m, which causes little damage to the reservoir, and the recovery value of the permeability is above 95%. 3. It has a strong chelating ability for high-valent metal cations; 4. It h...

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Abstract

The invention discloses seawater-based polyamine well completion fluid, which comprises the following components in percentage by weight: 0.1 to 10 percent of polyamine, 0.1 to 10 percent of alkali chelating agent, 0.1 to 10 percent of bactericide and the balance of aqueous solution. In addition, the invention also discloses a preparation method for the seawater-based polyamine well completion fluid. The method comprises the following steps of: adding the weighed aqueous solution, polyamine, alkali chelating agent and bactericide into a circulating pool provided with a stirring device in turn, and fully stirring and circulating the mixture to obtain the polyamine well completion fluid. The polyamine well completion fluid is neutral or alkali, and the pH is 7.5 to 8.5; and the polyamine well completion fluid has strong anti-swelling inhibition function (the anti-swelling rate is over 90 percent), strong chelating capability on high valent metal cations, low interfacial tension (generally less than 1mN / m) and little damage to reservoirs, and the permeability recovery value is over 95 percent.

Description

technical field [0001] The invention relates to a seawater-based polyamine completion fluid and a preparation method thereof. Background technique [0002] The working fluids used in oil and gas field completion operations are collectively referred to as completion fluids. The main purpose of the completion fluid is to protect the reservoir and ensure the safety of the operation, so it must have the following functions: (1) to balance the formation pressure and ensure the safety of the operation; (2) to have excellent reservoir protection capabilities and reduce damage to the reservoir; ( 3) Maintain the wellbore and casing balance and formation stability; (4) Carry and suspend solid particles to maintain the wellbore clean; (5) Have good anti-corrosion ability, which can slow down the corrosion of casing and downhole tools; (6) It maintains the stability of various performances under long-term standing conditions in the wellbore; (7) It is safe to use and harmless to the e...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/12
Inventor 范白涛张晓诚何瑞兵王健邓义成耿铁罗建生苗海龙
Owner CHINA NAT OFFSHORE OIL CORP
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