JPS6128693A - Chemical fluid composition for repairing pit well - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Background of the Invention The present invention relates to a chemical fluid composition for well rehabilitation, and more specifically to suppressing the deterioration of the rheological properties of the composition under high temperatures. The present invention relates to an improved chemical fluid composition for well repair, which has the ability to smoothly transport stagnant materials in a visiting well to the surface.

In recent years, there has been remarkable progress in well drilling technology, and with the development of muddy materials and mud preparation techniques suitable for geological formations, it has become possible to maintain high specific gravity under high temperatures and suppress hydration swelling of mudstone layers. It became possible to excavate to deep strata.

After the well is completed, oil production is carried out, but if muddy water or cement slurry filtrate has entered the reservoir layer containing clay minerals, the clay minerals will swell and close the pores, causing infiltration. For sandstones where the ratio is low or the reservoir is not sufficiently consolidated.

Accompanying the production of oil or gas, sand may flow into the wellbore and become stagnant within the casing, resulting in productivity problems such as a reduction in production capacity. As a countermeasure to these productivity problems, various repair works are carried out, but in this case, formation damage (formation damage)
), well workover chemical fluids that do not contain solids, such as drilling muds such as bentonite and pallite, have recently been promoted. In other words, conventional chemical fluid compositions for well rehabilitation usually include salts and hydroxyethylcellulose, which is not easily affected by salts as a thickener, to obtain a specific gravity sufficient to control ground pressure, and as necessary [various chemicals are added to the water]. It is dissolved or suspended in

However, as the well deepens, the temperature inside the well tends to increase, and conventional chemical fluid compositions for well remediation have a tendency to deteriorate their rheological properties, especially when transporting stagnant material in the well to the surface. It has been found that the ability to clean the stagnant material cannot be fully utilized, resulting in a delay in work time or, in severe cases, the inability to completely clean the stagnant material. Therefore, only when a method of reliably and easily suppressing the deterioration of the rheological properties of conventional chemical fluid compositions for well remediation is discovered, will it be possible to fully enjoy the original functions of the compositions.

(2) Summary of the invention The present invention aims to solve the above problems, and includes a thioamide derivative.

The present invention relates to a characteristic chemical fluid composition for well repair.

As is clear from the Examples described below, the chemical fluid composition for well remediation according to the present invention is excellent in that the deterioration of its rheological properties under high temperatures is extremely small, and it is possible to fully enjoy its original functions. It becomes possible.

(3) Detailed Description of the Invention The thioamide derivatives contained in the chemical fluid composition for well rehabilitation of the present invention are thioacetamide, hydrazinecarbothioamide, and allylthiocarbamide represented by the structural formula shown below.

NH, NHCNH.

O,ooi wt% to about 0.2 wt%, preferably about 0
．． 0.05% to about 0.1% 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 the same as usual. That is, hydroxyethylcellulose has an average number of substituted moles of 1.5 or more and a viscosity of 1% by weight of 2,000c.
(Brookfield viscometer + I'h3 spindle, 30 RPM, λ, 5° C.) and the concentration in the composition is from about 0.2% to about 2% by weight. Also·
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 2.30).
, its type and concentration are determined in consideration of working temperature and crystallization temperature. The concentration of salts in the composition is about 0.
．． 01% to about 70% by weight. Furthermore, various other 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, i.e., apparent viscosity (AV), plastic viscosity (PV), and yield point (YP), are improved compared to conventional compositions. It has excellent ability to transport stagnant material within a well.

As will be explained below in Examples, since the reproducibility of actual well remediation work is poor, the chemical fluid composition for well refurbishment is cured at high temperature in a Roller Oven and then evaporated. Fann VG m
Measured with eter Model 35 (30°C).

A comparison was made between the chemical fluid composition for well repair of the present invention and a conventional chemical fluid composition for well repair.

Example 1゜Calcium chloride 35 parts by weight p average substitution mole number 2.0 1
A conventional chemical fluid composition for well workover consisting of 5 parts by weight of hydroxyethyl cellulose with a weight percent viscosity of 5,000 cp (Brookfield Viscometer, Series 4 spindle, 30 RPM, 25°C) and 65 parts by weight of water. Each of the chemical fluid compositions for well remediation of the present invention, to which 0.02 parts by weight of acetamide was added, was added to roller ozone.
After curing at 20°C for 124 hours, rheological properties were measured. The results are shown in Table-1.

Table 1 Example 2 35 parts by weight of calcium chloride and 0.4 ftit part of the same dihydroxyethyl cellulose used in Example 1.

A conventional chemical fluid composition for well remediation consisting of 65 parts by weight of water and a chemical fluid composition for well remediation of the present invention containing 0.06 part by weight of hydrazine carbothioamide were added to roller ozone at 140°C for 80 minutes. After curing for a time, the rheological properties were measured. The results are shown in Table-2.

Table 2 Example 3 Conventional chemical fluid composition for well rehabilitation consisting of 35 parts by weight of calcium chloride, 65 parts by weight of human tetraxyethyl cellulose, 6iJl, and water used in Example 1, and Each of the chemical fluid compositions for well repair of the present invention containing 0.01 part by weight of allylthiocarbamide was cured in roller ozone at 110° C. for 16 hours, and the rheological properties were measured. The results are shown in Table-3.

Table 3 Example 4 35 parts by weight of calcium chloride, 0.6 parts by weight of the same human tetraxethyl cellulose used in Example 1.

A conventional chemical fluid composition for well remediation consisting of 65 parts by weight of water and a chemical fluid composition for well remediation of the present invention containing 0.005 part by weight of thioacetamide were placed in roller ozone at 120°C for 12 hours. Time-cure and measure the rheological properties of the garden. The results are shown in Table 4.

Table 4 Example 5゜Calcium chloride 27.5 parts by weight - Calcium bromide 27.
2 parts by weight of the same human tetraxyethyl cellulose as used in Example 1 - 45.3 parts by weight of water, and to this, allylthiocarno (mido 0.4 parts by weight). 0.3 parts by weight of the chemical fluid composition for well remediation of the present invention was added to roller ozone at 130 parts by weight.
After curing at ℃ for 16 hours, the 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 repair of the present invention has superior rheological properties than the conventional chemical fluid composition for well repair.

Claims (1)

[Claims] A chemical fluid composition for well rehabilitation, characterized by containing a thioamide derivative.