Isolating and temporary-plugging well-repair working fluid for offshore oilfield and preparation method for isolating and temporary-plugging well-repair working fluid

A working fluid, offshore oil field technology, applied in chemical instruments and methods, drilling compositions, etc., can solve the problems of cement plugging, inability to flow back, unsatisfactory gel breaking effect, etc. Overcome the limited effect and avoid the effect of cement blocking the formation

Active Publication Date: 2016-01-13
CHINA NAT OFFSHORE OIL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Obviously, in the prior art, cement plugging cannot be used for backflow; gel plugging can meet the above requirements, but it needs t

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Example 1. Preparation and performance evaluation of working fluid for isolation temporary plugging and workover in offshore oilfields

[0027] 1. Preparation of working fluid for isolation temporary plugging and workover in offshore oilfields

[0028] The quality ratio of raw materials is as follows:

[0029] The mass ratio of clear water, sodium dodecylbenzenesulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, sodium carboxymethyl starch, sodium carboxymethylcellulose and sodium trimetaphosphate is 1000:3:2:22:4 :20.

[0030] (1) At 20°C, add sodium dodecylbenzenesulfonate and sodium fatty alcohol polyoxyethylene sulfate (its molecular formula RO(CH 2 CH 2 O)n-SO 3 In Na, n is 2, and R is an alkyl group with 12 carbon atoms);

[0031] (2) At 20°C, slowly add sodium carboxymethyl starch (relative molecular weight is 200,000) and sodium carboxymethyl cellulose (relative molecular weight is 242.16) to the system treated in step (1), and the addition proce...

Embodiment 2

[0048] Example 2. Preparation and performance evaluation of working fluid for isolation temporary plugging and workover in offshore oilfields

[0049] 1. Preparation of working fluid for isolation temporary plugging and workover in offshore oilfields

[0050] The quality ratio of raw materials is as follows:

[0051] The mass ratio of clear water, sodium dodecylbenzenesulfonate, sodium fatty alcohol polyoxyethylene ether sulfate, sodium carboxymethyl starch, sodium carboxymethylcellulose and sodium trimetaphosphate is 1000:3:3:20:3 :20.

[0052] (1) At 20°C, add sodium dodecylbenzenesulfonate and sodium fatty alcohol polyoxyethylene sulfate (its molecular formula RO(CH 2 CH 2 O)n-SO 3 In Na, n is 3, and R is an alkyl group with 15 carbon atoms);

[0053] (2) At 20°C, slowly add sodium carboxymethyl starch (relative molecular weight is 300,000) and sodium carboxymethyl cellulose (relative molecular weight is 242.16) to the system treated in step (1), and the addition proce...

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Abstract

The invention discloses an isolating and temporary-plugging well-repair working fluid for an offshore oilfield and a preparation method for the isolating and temporary-plugging well-repair working fluid. The working fluid consists of water, sodium dodecyl benzene sulfonate, fatty alcohol polyoxyethylene ether sodium sulphate, sodium carboxymethyl starch, sodium carboxymethyl cellulose and sodium trimetaphosphate. A mass part ratio of the water to the sodium dodecyl benzene sulfonate to the fatty alcohol polyoxyethylene ether sodium sulphate to the sodium carboxymethyl starch to the sodium carboxymethyl cellulose to the sodium trimetaphosphate is 1000 to (2-4) to (2-4) to (20-25) to (3-5) to (15-25). The isolating and temporary-plugging well-repair working fluid for the offshore oilfield provided by the invention has the characteristics of great viscosity, a high dynamic plastic ratio, good stability of a well-repair liquid system, moderate formation plugging capacity, easy flow-back and the like, so that the problem that the formation is plugged by cement is avoided, and the defect that gel flow-back needs gel breaking and is limited in effect is overcome. In use, the isolating and temporary-plugging well-repair working fluid for the offshore oilfield has the advantages of small dosage, simple site construction, small reservoir damages, and the like.

Description

technical field [0001] The invention relates to an isolation temporary plugging workover working fluid for offshore oil fields and a preparation method thereof, belonging to the field of well workover in petroleum engineering. Background technique [0002] In the process of oil reservoir exploitation, in order to eliminate faults, improve wellbore conditions, and resume normal production of oil and gas reservoirs, workover operations are usually carried out. Workover operation is an important measure to increase recovery, increase single well production, and prolong production cycle. It is also an important means to tap the potential of old wells, discover new layers, and expand exploration results. [0003] However, due to the drop in formation pressure in the later stage of the reservoir, the workover fluid is easy to leak, which in turn affects the normal workover operations. [0004] One solution is to inject a plugging fluid for direct plugging. For mild leakage, ultr...

Claims

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Application Information

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IPC IPC(8): C09K8/10C09K8/514C09K8/40
CPCC09K8/10C09K8/40C09K8/514
Inventor 刘书杰周建良曹砚锋王珊周文胜周定照耿站立南小宁刘尧
Owner CHINA NAT OFFSHORE OIL CORP
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