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A method for killing low-pressure oil and gas wells

A technology of oil and gas wells and methods, applied in wellbore/well components, production fluid, earthwork drilling and production, etc., can solve problems such as inability to implement effective well killing, lost circulation, low pressure coefficient, etc., and achieve low cost and less oil layer pollution , the effect of small damage

Active Publication Date: 2016-05-11
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a well killing method for low-pressure oil and gas wells to solve the problem that oil and gas wells with low formation pressure coefficient and high gas production in the oil field are prone to lost circulation and cannot be effectively killed by conventional well killing methods during the workover process. question

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] A fire flooding production well using a low pressure oil and gas well killing method

[0019] (1) Well condition of the well

[0020] The well is a newly drilled production well in the fire flooding test area, with a depth of 550 meters, 7-inch casing and 27 / 8-inch tubing. Because the casing flange and the tubing at the casing head are punctured and leaked, the casing flange and casing need to be replaced. Valves on both sides of casing.

[0021] Before the workover, the gas composition and concentration data near the wellhead were detected on site, and the results are as follows:

[0022] CO:1128ppmH 2 S: 0ppm Combustible gas: 100ppm

[0023] Casing pressure: 0.4MPa Oil pressure: 0.2MPa Gas production: 900m 3 / d

[0024] (2) Implementation of workover

[0025] The kill fluid contains about 30m of 0.02% sodium hydroxide and 0.6% guar gum 3 , The oil-soluble temporary plugging agent is about 8Kg.

[0026] Well killing method: reverse circulation killing, fluid in...

Embodiment 2

[0035] A fire flooding production test well using a low pressure oil and gas well kill method

[0036] (1) Well condition of the well

[0037] The well is an old well that has undergone steam injection production and converted to fire flooding. The well is 570 meters deep and has a 7-inch casing. It is a double-pipe (both 23 / 8-inch tubing) well for production and testing in the test area. The auxiliary pipe is run into the test cable to monitor data such as downhole temperature and pressure. Due to the failure of the test instrument, it is necessary to inspect the pump and replace the test cable for the well. Before the workover operation, the wellhead data of the well were measured: wellhead casing pressure: 3.8MPa; CO: 933ppm; H 2 S: 66ppm, gas production 3500m 3 / d

[0038] (2) Well kill implementation

[0039] Killing fluid: about 30m containing 0.05% sodium hydroxide and 0.6% guar gum 3 , oil-soluble temporary plugging agent about 40Kg (respectively particle size ...

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Abstract

Disclosed is a method for pressing a low-pressure oil and gas well. The method comprises the steps that firstly, alkaline guanidine gum liquid with the appropriate concentration and oil-soluble temporary plugging agents are prepared according to the well conditions (wellbore volume, gas production rate and the like); the oil-soluble temporary plugging agents and the guanidine gum liquid are mixed and then sufficiently and evenly stirred, and the temporary plugging agents are suspended in the guanidine gum liquid; the matched process, a ground pipeline and equipment are adopted to feed the mixture of the oil-soluble temporary plugging agents and the guanidine gum liquid into a stratum; the matched pipe column process is adopted to achieve the aims that the guanidine gum liquid with the temporary plugging agents can block and shield the stratum, leakage of well pressing liquid injected in a shaft is avoided, meanwhile, alkaline guanidine gum liquid has the better air-tight sealing performance and better safety for acid gas (hydrogen sulfide, carbon dioxide and the like), the shaft is filled with the alkaline guanidine gum liquid, the stratum gas is prevented from entering the shaft, it is ensured that well pressing succeeds, and the subsequent well repairing operation is facilitated. The method for pressing the low-pressure oil and gas well has the advantages that a near well zone nearby a shot hole is effectively blocked, the well pressing liquid is prevented from leaking, and entering the stratum, the stratum gas is prevented from entering the shaft, and it is ensured that the well repairing operation is smoothly carried out.

Description

technical field [0001] The invention relates to a well killing method in oil field workover operations, more specifically a well killing method suitable for low-pressure gas wells with low formation pressure coefficient and high gas production. Background technique [0002] The fire flooding mining technology adopted in the oil field is a method of oil recovery by injecting air through the combustion of the oil layer to generate heat, water vapor and flue gas drive. The flue gas produced from fire flooding production wells is mainly composed of nitrogen, carbon dioxide, and toxic and harmful gases such as hydrogen sulfide. Some production wells have a large gas volume (the maximum daily gas production can reach 5000m 3 above), and at the same time, the formation pressure coefficient is low (usually less than 1), the well killing operation is difficult, lost circulation is prone to occur during conventional well killing operations, the gas invasion speed is fast, and it is di...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): E21B33/13E21B43/22
Inventor 潘竟军胡承军彭辉王佳姚满仓
Owner PETROCHINA CO LTD
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