CN101418680A

CN101418680A - Gas lift unblocking technology by chemical method

Info

Publication number: CN101418680A
Application number: CNA2007101134395A
Authority: CN
Inventors: 王长俊; 王长杰; 陈莉; 仲崇利; 韩炜
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-10-23
Filing date: 2007-10-23
Publication date: 2009-04-29
Anticipated expiration: 2027-10-23
Also published as: CN101418680B

Abstract

The invention relates to a chemical method gaslift plug removal technology for oil and water well, which is characterized in that acid and carbonate are adopted to react in the oil and water well pipe to generate gas so as to cause gaslift function, and stronger negative pressure will generate at the region near the well, and the plug removal technology for removing the plug of oil and water well by acid dipping is performed in the oil and water well. The operation technology is that: acid solution and carbonate solution which can generate CO2 are prepared; a single pump pumps the prepared acid solution from the well head to the upper part of the oil reservior to dip the oil reservior; then two pumps pump other acid solution and all the carbonate solution into the well; the well is closed to guarantee that the acid solution and the carbonate solution can fully disperse, contact and react with each other; and finally the well is cleaned to guarantee maximum gaslift effect. The invention can be adapted to plug removal for various oil reservoirs, has better plug removal effect for low permeability and very low permeability oil reservoirs, has low cost and good safety and environment protection performance, and can regulate the gaslift effect by changing the mount of reactants, and thereby is simple in regulation and is in favor of popularization.

Description

Gas lift unblocking technology by chemical method

Technical field

The present invention relates to plug removal in oil and water well technology, particularly adopt chemical method to cause the gas lift unblocking technology by chemical method of " gaslift effect " de-plugging.

Background technology

At present, the de-plugging process of each oilfield oil well mainly is divided into three major types: chemical plugging removal, physics de-plugging, physics---chemical plugging removal.Chemical plugging removal, physics---chemical plugging removal is of a great variety, but ubiquity is to the injury of the secondary of oil reservoir, and constructor's labour intensity is big simultaneously, and bigger to health of human body harm.In addition, two kinds of de-plugging process are owing to being long-time high pressure squeeze note, so danger coefficient is big more than.Under the particular case, some formation physical property extreme difference belongs to special low permeability reservoir, and squeeze pressure is more than 35MPa, and the execute-in-place difficulty is very big.Physics de-plugging principle is: physical means changes borehole and near wellbore zone permeability or obstruction is fluffed and looses into nano sized particles, thereby reaches the de-plugging purpose by contamination and plugging regional migration to depths, stratum in subsequent production.The greatest drawback of this technology is: obstruction does not still exist to be eliminated, and it is discharged by the stratum, has very big potential injury.Though more than a few class technologies effective, many shortcomings such as have that construction cost height, environment pollution are big, labour intensity and danger coefficient are big.

Summary of the invention

The purpose of this invention is to provide a kind of utilization acid and can produce CO with carbonate reaction ₂Gas is angry in the profit well casing, causes " gas lift ", at the stronger negative pressure of nearly oil-water well area generation, the gas lift unblocking technology by chemical method of effectively removing the oil-water well obstruction fast that carries out acidleach simultaneously in oil-water well.Operating procedure of the present invention is:

A, preparation can be reacted and be produced CO ₂The acid solution of gas and carbonate solution;

B, the single pump of elder generation are replaced into the top of the acid solution for preparing to oil reservoir by well head, are used for soaking oil reservoir;

C, again double pump replace simultaneously into, 1 pump replaces into all the other acid solutions, in addition 1 pump replaces into whole carbonate solutions.

D, closing well, 10～40 minutes closed-in times guaranteed that acid solution and carbonate solution fully spread and contact and react completely.

E, well-flushing, backwash discharge capacity want big, and well head pressure testing in advance guarantees sealing, and outlet must connect the traditional thread binding spray apparatus that subtracts of hard system steel pipe, with guy wire, earth anchorage, guarantee maximum gaslift effect.

Acid solution recited above is to add clear water to be mixed with concentration be 5～25% HCI solution, add the polyethers acidification corrosion inhibitor simultaneously, the mass percent concentration that the polyethers acidification corrosion inhibitor is accounted in joining solution is 1～2%, and HCI solution total amount is 2 to 8 cubes.Described carbonate solution is that the concentration that adds hot water preparation is 15～50% NaHCO ₃Solution, NaHCO ₃The solution total amount is 3 to 10 cubes.Be that the single pump of elder generation replaces the HCI solution into 1-2 side when replacing into acid solution and carbonate solution, double pump replaces respectively simultaneously into HCI solution and NaHCO then ₃Solution, replace into HCI solution with replace into NaHCO ₃The pumpage ratio of solution is: 7:10

The present invention has the following advantages:

1, can be used for the de-plugging of all kinds of oil reservoirs, better to hypotonic, special LOW PERMEABILITY RESERVOIR plugging removal effect,

2, compare cost with traditional de-plugging process and significantly reduce, be beneficial to popularization.

3, Safety and Environmental Protection is good, can therefore not be restricted in the application.

4, on-the-spot workable, the scene there is not specific (special) requirements, be easy to realize.

5, the stratum there is not injury.

6, can how much regulate " gaslift effect " size by what change reaction volume, therefore regulate very easy.

The specific embodiment

For further disclosing technical scheme of the present invention, existing applicable cases with certain 509-3 well technical application checking is as described below:

Certain 509-3 well belongs to summer 502 wells.This piece reservoir properties average pore 13.7%, mean permeability 4.2 * 10-3um2, carbonate content average out to 9.1%.3 sand group degree of porosity 13.1% wherein, permeability 3.5 * 10-3um2, carbonate content 9.1%, 4 sand group degree of porosity 14.6%, permeability 7.6 * 10-3um2, carbonate content 6.8%.Above data declaration, the husky three times reservoir properties extreme differences of this piece are low hole, special low permeability reservoir.The slight fouling of former well casing post, estimation has the foulant of 500Kg approximately, and main component is a carbonate, is to guarantee to remove all foulant, consumes whole carbonate and produces CO as much as possible ₂Gas, 4 cubes of on-the-spot complex salt acid solutions and concentration are 15%, and is higher because of the carbonate content of tubing string inwall dirt, can produce considerable CO ₂Gas is not for safety prepared carbonate solution in addition again.Replace into 4 cubes of tops of the hydrochloric acid acid solution for preparing by well head, be used for soaking oil reservoir, utilize carbonate scale and 4 cubes of hydrochloric acid acid solution reactions on the former well casing column wall to produce a large amount of CO simultaneously to oil reservoir ₂Gas.Suppress fast in the construction to 35MPa, put pressure more fast, so the exciting borehole of repeatable operation is 5 times, and closing well guaranteed the dirty fully contact of acid in 20 minutes and complete reaction.Last big discharge capacity anti-flushing well, reaction generate a large amount of gas moment the well head of gushing out fast, form " gaslift effect ", continue to produce stronger negative pressure at borehole and near wellbore zone, produced about 120 cubes of CO through measuring and calculating ₂Gas, about negative pressure 1.7MPa, thereby the foul that spues is returned on the stratum, and well-flushing water is taken to ground.Water filling is good behind this well construction, and initial stage oil pressure 25MPa day annotates 49m ³See the following form:

Certain 509-3 water injection well daily paper

Sequence number	Date	Dry-pressing	Oil pressure	Day joins	Day annotates	Remarks
Sequence number	Date	Dry-pressing	Oil pressure	Day joins	Day annotates	Remarks	1	2007-06-17	26	25.8	50	52	ZKJ: well-flushing 45 sides: 9:-11:: open notes: 16:
2	2007-06-18	27	25	50	49		1	2007-06-17	26	25.8	50	52	ZKJ: well-flushing 45 sides: 9:-11:: open notes: 16:

The effective water filling in construction back 81 days, accumulative total water filling 1892 sides.

Claims

1. gas lift unblocking technology by chemical method, it is characterized in that utilizing acid and carbonate reaction angry in the profit pipe, cause " gas lift ", produce stronger negative pressure in the near wellbore zone, carry out simultaneously the gas lift unblocking technology by chemical method of effectively removing the oil-water well obstruction fast of acidleach in oil-water well, its operating procedure is:

E, well-flushing, backwash discharge capacity want big, and well head pressure testing in advance guarantees sealing, and outlet must connect the traditional thread binding spray apparatus that subtracts of hard system steel pipe, with guy wire, earth anchorage, guarantee maximum " gaslift effect ".

2, according to the said gas lift unblocking technology by chemical method of claim 1, it is characterized in that described acid solution is to add clear water to be mixed with concentration be 5～25% HCI solution, add the polyethers acidification corrosion inhibitor simultaneously, the mass percent concentration that the polyethers acidification corrosion inhibitor is accounted in joining solution is 1～2%, HCI solution total amount is 2 to 8 cubes, and described carbonate solution is that the concentration that adds hot water preparation is 15～50% NaHCO ₃Solution, NaHCO ₃The solution total amount is 3 to 10 cubes.

3, according to the said gas lift unblocking technology by chemical method of claim 1, be that the single pump of elder generation replaces the HCI solution into 1-2 cube when it is characterized in that replacing into acid solution and carbonate solution, double pump replaces respectively simultaneously into HCI solution and NaHCO then ₃Solution, replace into HCI solution with replace into NaHCO ₃The pumpage ratio of solution is: 7:10