JPS60245687A - Chemical fluid composition for repair of well - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which can inhibit the lowering of rheological characteristics at a high temp. and enables accumulated materials in a well to be smoothly conveyed on the ground, containing 2-thioimidazolidone. CONSTITUTION:0.001-0.2wt% 2-thioimidazolidone and optionally, additives such as anti-foaming agent, corrosion inhibitor, pH adjustor, filler, suspending aid, etc. are added to a chemical fluid compsn. for repair of wells, which has a specific gravity of 1 or above and is composed of 0.2-2wt% hydroxyethylcellulose [average molar number of substitution: 1.5 or above, viscosity (1wt% soln.) of 2,000cP or above (a Brookfield viscometer, No.3 spindle, 30r.p.m., 25 deg.C], 0.01- 70wt% salts (e.g. CaCl2) and water.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chemical fluid composition for well rehabilitation, and more particularly, it suppresses deterioration of the rheological properties of the composition under high temperatures, thereby preventing stagnation in wells. It has the ability to smoothly transport objects to the ground. The present invention relates to an improved chemical fluid composition for well workover.

Conventional technology In recent years, well drilling technology has made remarkable progress, and the development of muddy materials and mud conditioning techniques suitable for geological conditions has made it possible to maintain high specific gravity under high temperatures and suppress hydration swelling of mudstone layers. ), it became possible to excavate to much deeper strata.

After completion of the well, production of m is carried out, but if muddy water or cement slurry filtrate penetrates into the reservoir layer containing clay minerals, the clay minerals will swell and close the pores, reducing the permeability rate. was decreasing. vinegar.

Or in the case of sandstone where the reservoir is not sufficiently consolidated.

Along with the production of oil and gas, sand flows into the well and stagnates inside the casing, reducing production capacity. As a countermeasure to these productivity problems, various types of repairs are being carried out. work, but in this case formation damage
), well workover chemical fluids that do not contain fixed components such as bentonite and pallite, such as drilling muds, have recently been promoted. That is, conventional well workover chemical fluid compositions typically include salts to obtain a specific gravity sufficient to control ground pressure.

Hydroxyethylcellulose, which is not easily affected by salts as a thickener, and various chemicals as necessary are dissolved or suspended in water.

Problems to be Solved by the Invention However, as the depth of the defense increases, the temperature within the wellbore tends to increase, and conventional chemical fluid compositions for defense refurbishment suffer from a decrease in their rheological properties. It was discovered that the ability to transport the stagnant material in the well to the ground could not be fully utilized, resulting in a one-hour delay or, in severe cases, the inability to completely clean out the stagnant material. Therefore, only by finding a method for reliably and easily suppressing the deterioration of the rheological properties of conventional chemical fluid compositions for well remediation will it be possible to fully enjoy the original functions of the compositions.

SUMMARY OF THE INVENTION The present invention is aimed at solving the above-mentioned problems, and relates to a chemical fluid composition for use in defense reform 46, which is characterized by containing 2-thioimidazolitone.

The chemical fluid composition for well remediation according to the present invention is superior in that the deterioration of its rheological properties under high temperatures is surprisingly small, and the original function is fully enjoyed. It becomes possible to do so.

3. Detailed Description of the Invention The concentration of 2-thioic dacylidone contained in the chemical fluid composition for defense remediation of the present invention is approximately [1 L].
001 to about α2% by weight, preferably from about CLO05 to about α1% by weight.

The above-mentioned components and their amounts contained in the conventional chemical fluid composition for well remediation, which is the object of the improvement of the present invention, are generally as follows. That is, hydroxyethylcellulose has an average number of substituted moles of 1.5 or more and a viscosity of 1% by weight λ000cp.
(Brookfield viscometer, JIFL6 spindle, 30 RPM, 25° C.), and the concentration in the composition is about α2% by weight to about 2% by weight. The salt is at least one salt selected from calcium chloride, calcium bromide, and zinc bromide, and has a required specific gravity (1.01 or more, preferably 1.16 to 2.5"0).
1. The type and concentration are determined in consideration of the working temperature and crystallization temperature. The concentration of salts in the composition is about 1
01% to about 70% by weight. Sarabutton and other various chemicals include antifoaming agents and anticorrosion agents.

These include pH adjusters, fillers, and suspension aids.

The chemical fluid composition for well remediation of the present invention has a temperature of about 80°C or higher;
After curing at elevated temperatures, preferably from about 80° C. to about 150° C., the rheological properties 2, i.e., apparent viscosity (AV), plastic viscosity (PV) and Ybertboin (YP), are compared to conventional compositions. It's expensive.

It has excellent ability to transport stagnant material in the well.

Example: Actual remediation work in wells has poor reproducibility.
Roll open chemical fluid composition for well rehabilitation
er Qven) at high temperature, and the above-mentioned rheological properties were measured using a Fann VG meter Model 55 (30°C). Make sure to compare◎
Practical Example 1 Hydroxyethyl cellulose [1% viscosity 5,000 cp (Brookfield viscometer + 44x spindle, x+] RPM, 25°C) with 35 parts of calcium chloride and 2.0 moles of average substitution. 145! Amount 1. A conventional defense refurbishment chemical fluid composition consisting of 0.04 parts by weight of magnesium ffi and 65 parts by weight of water, and 2-
Each of the chemical fluid compositions for well repair of the present invention to which 0.03 parts by weight of thioimidazolitone was added was cured in a roller open at 130° C. for 16 hours, and the rheological properties were measured. The results are shown in Table 1. Table 1 Example 2 35 selected parts of calcium chloride, Example 1. 9 parts of 5971L of 9-dihydroxyethyl cellulose used in

Magnesium oxide! A conventional chemical fluid composition for well repair consisting of 104 parts by weight of water and 65 fi:i shield part, and a chemical fluid composition for well repair of the present invention in which 2 parts by weight of 2-thioimidazolitone CLO was added to the roller. It was cured in ozone at 120°C for 16 hours and its rheological properties were measured. The results are shown in Table-2.

Table 2 Example 65 parts by weight of calcium pentachloride, Example 1. 15 parts by weight of the same hydroxyethyl cellulose α used in .

A conventional chemical fluid composition for well repair consisting of 104 parts by weight of magnesium oxide and 65 parts by weight of water, and a chemical fluid composition for well repair of the present invention in which 0.06 part by weight of 2-thioimidazolitone is added thereto. 1 each to roller ozone
After curing at 20°C for 24 hours, the rheological properties were measured. The results are shown in Table-3.

Table 3 Example: 35 parts of calcium chloride, Example 1. 145 parts by weight of dihydroxyethyl cellulose used in

A conventional chemical fluid composition for well rehabilitation consisting of 4 parts by weight of i-gnesium oxide and 65 parts by weight of water, and 2-
Each of the chemical fluid compositions for well repair of the present invention containing 0.08 parts by weight of thioimidazolitone was cured in roller ozone at 140° C. for 16 hours, and the rheological properties were measured.

The results are shown in Table 4 Table 4 Examples & Calcium chloride 275 parts by weight, calcium bromide 27.2
- parts by weight, Example 1. 58 parts by weight of the same hydroxyethyl cellulose α used in , magnesium oxide [104:
A conventional chemical fluid composition for well remediation consisting of 45.3 parts by weight of water and 45.3 parts by weight of water, and a chemical fluid composition for well remediation of the present invention in which 101 parts by weight of 2-thioimidazolitone was added thereto. Each sample was cured in low-2-ozone at 110°C for 16 hours and its fluid rheological properties were measured. The results are shown in Table-5.

Table 5 From the above examples, it is clear that the chemical fluid composition for well remediation of the present invention has better rerheological properties than the conventional chemical fluid composition for well remediation. Chemical Industry Co., Ltd.

Claims (1)

[Claims] A chemical fluid composition for well repair, comprising 2-thioimidazolitone.