JPS6085190A - Boring finish fluid composition - 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 The present invention relates to a finishing fluid composition for poling in underground drilling for oil wells.

(1) Remove the cutting debris generated as the drill bit scrapes the strata from the wellbore, and cool the drill bit.

(2) Provides lubrication to the drill stem.

The active drilling fluid flows downward through the drill pipe and is injected from the nozzle in the dolphit. Then, after passing through the annulus section, it returns to the earth's surface.

Most drilling fluids, commonly referred to as muds, contain dispersed hydrated and swollen clay particles.

Clay-based fluids have the ability to cool drill bits and transport debris, as well as prevent gas eruptions in high-pressure formations.

This is because the various functions of the clay-based drilling fluid are greatly improved by the colloidal properties such as gel strength and specific gravity of the drilling fluid containing dispersed clay.

To increase the specific gravity, weighting agents such as pallite are added.

When the dolphit excavates the production layer during excavation operations, insoluble materials such as clay and pallite in the muddy water create a filter cake on the surface of the formation.

Until it reaches the production layer, this filter cake is very important in terms of preventing well collapse, but once it reaches the production layer, the surface of the production layer is blocked with filter cake, and as a result, it can be said to be permanent. It is a big problem that it causes a decrease in the penetration rate of the productive layer.

The clay and pallite particles that make up these filter cakes can sometimes be removed by a process called acid treatment, but even this costly acid process often does not reverse wellbore damage.

This is because clay and pallite solids have low solubility in acids.

Therefore, to prevent damage to permeability, it is necessary to use clean drilling fluids with sufficient specific gravity to suppress formation pressure. This is called the finishing fluid. For example, since the permeable production layer will be in contact with the workover fluid, it is preferable to use a fluid that does not cause high density formation damage.

Commonly used are high specific gravity salt solutions, such as saturated aqueous GaCl2 solutions, which do not cause formation damage.

The highest specific gravity of GaCl2 aqueous solution is 1.38 g/C1,
1 (=11.5 pounds per gallon)
and is not satisfactory for all well treatment operations.

1.81g/a for a mixed solution of GaBr2 and CaG12
j(15,j pour+ds per gallon
). In addition, CaG12 solution and other high specific gravity solutions (e.g., NaNO3, Ga(NO3) 2, Zn
Mixing f:l 2 ) has also been proposed to obtain high density fluids.

The addition of water-insoluble substances such as CaC03 further increases the density of the salt solution and also increases the gun-performance.
ation (drilling work), especially in permeable strata and
1nva of finishing fluid for ture (crack)
It is added to minimize ion (osmosis).

It is often used because it is readily soluble in acids and available in a variety of particle sizes.

It is necessary to add polymers to such finishing fluids as thickeners, water loss reducers, and transport enhancers. This polymer also acts as a dispersant for CaC03.

Conventionally, polymers that provide the above functions include (1) HEC (hydroxyethyl cellulose) (2)
CHC (carboxymethyl cellulose) (3) polyacrylonitrile (4) xanthan gum (5) guar gum, etc. are known, and in particular (1) HEG has been mainly used.

However, (1) HEC generates bubbles due to stirring and dissolution; (2)
CMC and (3) polyacrylonitrile are not soluble in alcohol; (4) xanthan gum is only 50% soluble in acid;
Furthermore, (4) xanthan gum and (5) guar gum have various problems such as being degraded by enzymes. In particular, the generation of foam is not only caused by corrosion caused by enzymes, but also by lowering the apparent specific gravity of the liquid, and furthermore, the foam is so large that it cannot be eliminated even by adding an antifoaming agent, so the cost of adding an antifoaming agent is ignored. No.

Depending on the type of inorganic cations in the finishing fluid, changes in pH such as acid treatment and the addition of pH modifiers to minimize the corrosion rate of finishing fluids can cause very large viscosity reductions. There are various problems like this.

It is an object of the present invention to provide a finishing fluid for polling containing at least one of a -valent group or a polyvalent salt, excellent thickening ability, water loss reduction ability, transport ability, dispersion ability, stable over a wide range of pH, and almost no toxicity. An object of the present invention is to provide a finishing fluid composition that does not cause formation damage.

The amount of polymer added is generally 0.3 to 0.5% by weight based on the finished fluid volume.

In view of the above-mentioned current situation, the present inventors have conducted extensive research to obtain an aqueous solution polymer that is stable against finishing fluids for poling containing at least one of -valent salts or polyvalent salts.
This has led to the present invention. That is, the poling finishing fluid containing at least one of -valent groups or polyvalent-salts has a degree of substitution in the range of 0.50 to 2.50,
and 1% ρ weight) aqueous solution viscosity 5 to 5.000 (cp) (hereinafter SE
It is called C. ) as an essential component.

Next, the structural formula of the repeating unit of SEC (however, the degree of substitution
1.0).

n is an integer, and is an alkali metal salt. ) The degree of substitution is the average number of substitutions per unit of glucose, which must be sufficient to make the molecule water-soluble. In order to have sufficient water solubility, the SEC degree of substitution must be 0.5 or more.

When the degree of substitution is less than 0.5, solubility is poor and the effects of the present invention cannot be fully exhibited.

The reason why the degree of substitution is set to be 2.5 or less is because if the degree of substitution is higher than that, it is difficult to manufacture industrially and it is not economical.

The viscosity of SEC is not particularly limited, but as long as the viscosity of the 1% aqueous solution is 5 to 5.000 (cp), the object of the present invention can be fully achieved. Normally, thickening properties are required, so the bottom of a 1% aqueous solution is 10
It is particularly preferable that it is 0 (cp) or more.

Inorganic salts contained in the finishing fluid include NaCl, K
CI, CaCl2, and CaBr2 are commonly used, but other salts may be preferable depending on economical conditions and required density.

However, it is necessary to pay attention to the specific gravity and crystallization temperature.

Other salts include, for example, LiCl, NH4Cl, N)+
4NO3, (NH4) 2 SO4, -Na2 CO3
, NaCr2O2・2H20, NaBO2, NaN0a
, NaBO3, Na2SO4, Na2 S03 +17
H20, Na2S 2[13*! It) I2o, N
a2HP04 ・12H20, K 4Fe(CN)6e
3H20, Ca5O'4, Ca(C2H302), C
a(CHO2) 2, Ga(NO3) 2, Ca
(CH20H(CHOH)4Coo)2, MgCl2
, MgSO4, Mg(G2H'302), Mg(C
HO2) 2, Mg (NOa) 2', Mg
(C1120H(CHOH)4 C00)2, B
aCl2, Ba(OH)2, Ba5(14, ZnCl2
．． Zn (NO3), Zn(O)I)2, ZnS
O4, AlC1a・6H20, AI(OH)a, A
l2(SO4) 3. AI(CH3CO2) 3.
FeCIa ・CH20, Fe(OR)a, Fe2(
So'4) a, Fe(NO3) a, Cr
(NOa), 1.0r(OH3GO)3, CT
B D3, Or Cl3, Cr(OH) (
NOa)2, Cr(OH)2(NOa),
Examples include SnCl2, AgNO3, FeCl2, etc., but are not particularly limited to these.

These salts are not limited by their solubility and may be included as solids in the finishing fluid if measures are taken to minimize formation damage.

The biggest feature of SEC is that even if monovalent or trivalent soluble cations are present in the system, the pH is 1 to 13.
Even within this range, the viscosity increasing property, water loss reducing ability, and clay dispersing ability are not impaired in any case, and it is stable.

Another characteristic is that HEC (hydroxyethyl cellulose), which has conventionally been generally used, has extremely high foaming properties. In this respect as well, SEC used in the present invention has no foaming property, so in the present invention use where the specific gravity is high,
It can be said that it has excellent properties.

Furthermore, SEC is harmless to the human body and should be handled with care.
It is easy and there is no need to worry about environmental pollution. It is also easier to transport than HEC. The effects achieved by the present invention are summarized as follows.

(1) It exhibits very good thickening properties without forming any insolubles even in highly concentrated (10,000 ppm to saturated) finishing fluids containing at least one type of -valent group or multivalent group.

(2) The system described in (1,) shows an extremely excellent ability to reduce water loss.

(3) Acts as an excellent dispersant in the system described in (1).

(4) The system described in (1) is completely free of foaming and is very advantageous in terms of operation (liquid management). There is no need for antifoaming agents or corrosion inhibitors.

(5) The system described in (1) has a wide range of pH range (pH
= 1 to 13), the decrease in viscosity is small and therefore the pH resistance is excellent.

(e) In the system described in (1), SEC is not degraded by enzymes, unlike xanthan gum and guar gum.

Although an embodiment of the invention is shown below, the invention is not limited thereto.

(However, % and parts are based on weight.) Example 1 Na11, KGI, CaCl2. AlCl3,A
Make 2% by weight and 10% by weight aqueous solutions of l2(SO4)3, and make the polymer concentration (anhydride basis) 1%.
It was added and dissolved in each solution, and the viscosity was measured using a B-type viscometer. The results are shown in Figure 1.

The degree of substitution (DS) of the sodium salt of sulfoethyl cellulose (N a -SE C) in the present invention is 0.90.
．． The bottom of a 1% aqueous solution is 149 (cp).

As a control, the sodium salt of cellulose sulfate (Na-C3) DSt-10,87,]2 has a bottomness of 142 (CP).

In addition, as a control, highly substituted carboxymethyl cellulose, which is conventionally used as a salt-resistant material, is used as a control material.
(Ha-CMC) DS=1.07.1z The bottom of the aqueous solution is 1!1 (cp).

As is clear from Fig. 1, Na-CMC almost completely dissolves in the presence of monovalent cations such as Ha+, and the viscosity decreases as the salt concentration increases from 2wt to 10wt$. Although not significant, in the presence of Ca2+ or A13+, it combines with these cations and becomes an insoluble substance. Therefore, the decrease in viscosity is significant, and Na-C9 also exhibits a significant decrease in viscosity (due to the formation of insoluble matter) in any aqueous solution system.

On the other hand, the Na-8EC of the present invention does not form any insoluble matter even in the presence of divalent or trivalent cations and exhibits good solubility. This shows that the SEC of the present invention has excellent salt resistance and is also excellent as a thickener.

Example 2 Although the solution in Example 1 shows durability up to a salt concentration of 10%, in this example, various inorganic salts were used to prepare several aqueous solutions with concentrations ranging from 5z to saturation. The compatibility of this with an aqueous solution of 1z polymer (Na=SEG, HEC, carboxymethylhydroxyethyl cellulose C) was observed.

The experimental method was to take each of the above salt concentration aqueous solutions 10 - into test tubes, add 1 d of lz polymer aqueous solutions thereto, and check for the presence or absence of insoluble matter formation after stirring. The results are shown in Table-1.

The DS of Na-SEC in the present invention is 2.45, and the bottom of the 1z aqueous solution is 12 cp.

Control HEC (degree of molar substitution of ethylene oxide 2,
The 1z aqueous solution of 0) is lOcpte.

Ha-CMHEC (degree of molar substitution of ethylene oxide 2
, 0) degree of substitution of carboxymethyl group = 0.30, 1z
The aqueous solution is 15 cp.

As is clear from Table 1, NEC is the polymer most often added to finishing fluids, but depending on the type and concentration of inorganic salts, it creates insoluble matter, limiting its use.

The same applies to Na-GMHEC. On the other hand, the Na-
9EC is at least the inorganic salt (-valent cation or
(trivalent cations) do not form any insoluble matter. In addition, the fact that the solubility is excellent even in inorganic salts indicates the superiority of #salt performance of the present invention.

Example 3 1z polymer (Na-5EC, Na-CMC, Na-
Using H2So4i or NaOH for 0S), the decrease in viscosity was observed when the pH was variously changed.

A B-type viscometer was used to measure the viscosity, 25.0±0.5°
Measured at C. The results are shown in Figure 2.

The present invention provides such a polymer Na-3EC has a DS of 0.5
The 5.1% aqueous solution viscosity is l, 130 cp.

The control Na-C5(7)DS has a 0.53.1% aqueous solution viscosity of 1.1]5 cp, and the control Na-CMC D
S is 0.55.1z aqueous solution liquid bottom is 1.080cp.

As is clear from Figure 2, pH = 6 for Na-CMC.
．． 0-11.0, P for Ha-O3)(=4.5-1
In the range of 0.0(7), the viscosity is stable, in other words, no decrease in viscosity occurs, but outside this range there is a significant decrease.

On the other hand, in the pH range of 1 to 13, the cy)Na-3EC of the present invention exhibits almost no decrease in viscosity and has a wide range of #
It can be confirmed that it has pH properties.

However, 5E with a low degree of substitution is outside the scope of the present invention.
For example, with C2 of about 0.35, there is no decrease in viscosity due to p)1 change, but the solution contains a lot of insoluble matter (free fibers), which causes formation damage, so it cannot be used as a finishing fluid. Undesirable.

Example 4 3$Ga1LOa (solid matter) containing 10.20.40
．． Polymer (N
a-9EC, HEC, Na-CMHEG, Na-08
0) ci degree is 2 ppb (pounds per ba
It was added and dissolved so that the amount (rrel) = 0.57% was obtained, and a filtration test was conducted.

The results are shown in Figure 3.

The filtration test followed the API (American Petroleum Institute) method.

The DS of Na-5EC according to the present invention is 1.05.1χ The aqueous solution surface is 3,900 cp.

The molar substitution degree of ethylene oxide in the control HEC is 2.0.
．． The viscosity of 1% aqueous solution is Otsu, 500 cp, and Na-CMH
The molar substitution degree of ethylene oxide in EC is 2.0, the substitution degree of carboxymethyl group is 0.60, and the viscosity of lz aqueous solution is
4,0OOcp, DS of Na-CNC is 1.00.1
% aqueous solution viscosity is 4,200 cpt.

As is clear from FIG. 3, in a wide range of salt concentrations, Ha-3EC according to the present invention is different from control HEC, N
It can be confirmed that it has an excellent ability to reduce water loss when compared with a-CMHECl and Na-CMC.

The smaller the water loss (WL), the better.

Example 5 4.15.30.6oz and saturated Peladnw(C
aC12 industrial grade, manufactured by Dow Chemical Company (same below)
In each of the aqueous solution and ZnBr2 aqueous solution, 350-
Three types of polymers, a-3EC, HEC, and Na-CMHEC, were added individually to a concentration of 4 ppb = 1.14%, and stirred at 10.00 rpm for 30 minutes with a multimixer (manufactured by Balloid, USA). The volume increase due to residual bubbles was measured after the sample was allowed to stand overnight. The results are shown in Table-2.

The DS of Na-3EC of the present invention is 0.50.1z aqueous solution bottom is 3.000 cp, and the control (D Ha-CMHE
The molar substitution degree of ethylene oxide in C is 1.7, the substitution degree of carboxymethyl group is 0.50, and the tX aqueous solution viscosity is 3.
．． The molar substitution degree of ethylene oxide in HEG is 2.0, and the viscosity of lz aqueous solution is 2.900c.
It is p.

Volume after stirring If the value shown in Table 2 is 1 (=) the volume before stirring, it means that no bubbles are generated at all, or even if bubbles are generated, they disappear quickly.

The larger the value, the more difficult the stirring operation during polymer dissolution becomes, which is undesirable.

As is clear from Table 2, Na-CMHEC and H
Although EC has relatively good solubility even in the presence of Peladow or ZnBr2, it generates a large amount of bubbles during dissolution and stirring, which do not disappear easily.

Therefore, a large amount of atmospheric oxygen enters the finishing fluid,
This results in difficulties such as oxygen corrosion of the equipment and completion (decreased density of the fluid, thereby increasing the risk of wellbore collapse).

On the other hand, the Na-9EC of the present invention is similar to Peladow and ZnB.
There is little foaming over a wide concentration range of r 2 , and therefore it has advantages such as no need for antifoaming agents in the operation of adding and dissolving it into finishing fluids.

[Brief explanation of drawings]

Figure 1 shows NaCl, KCI, CaC in Example 1.
l2. AlCl5, A12 (SO4) 3 of 2
wt%, 10wt%, aqueous solutions were prepared, added and dissolved in each solution so that the polymer concentration was 1z, and the viscosity was measured with a B-type viscometer. Figure 2 is a graph showing the results of 1z in Example 3. Polymer (Ha-8EC1Na-CM
G, Na-C5) H2SO'4 or NaO in aqueous solution
Figure 3 is a graph showing the decrease in viscosity when the pH is variously changed using H. (Na-5EC, HEG, Na-
This is a graph showing the results of a filtration test after addition and dissolution of CMHEC:, Na-CMC) to a concentration of 2 ppb. Patent applicant Daiichi Kogyo Seiyaku Co., Ltd. KCI NaCl CaCl2 AlCl3 A12 (
SO4]s No. 217 2 4 6 8 10. 12 pH Procedural corrective power■, Indication of the case 1982 Patent Application No. 193210 2, Name of the invention Finishing fluid composition for polling 3, Relationship with the person making the amendment Patent applicant 4, 11th request for amendment order Amendment 5, Number of inventions increased by amendment 6, Detailed description of invention column 7 of subject specification of supplementary IF, Contents of amendment The present application is amended as follows based on the original specification. 1) At the bottom of the first page of the specification, in the 7th line, "φ for ru oil valve..." is corrected to "Ru. for oil valve...". 2) In the first line from the bottom of the first page of the same page, the phrase "Fighting for the future work..." is corrected to "These works are φ...φ." 3) On page 2, line 8, correct the text ``...gas ejection...J'' to r...gas ejection...''. 4) On the 5th line from the bottom of the 2nd page, the phrase ``During the excavation operation...'' is corrected to ``During the excavation operation.'' 5) On the 4th line of the 3rd page, ``Permanently It can be said that "it can be said to be permanent..." is corrected to "It can be said that it is permanent...". 6) On the 4th line from the bottom of the 3rd page of the same page, the phrase ``There is. For example,...dispute...'' should be corrected to ``There is. Similarly,...j.'' 7) On the 4th line from the bottom of the 3rd page of the same page. ``... (drilling work), especially...''
−...(during the hole work), correct it to...''. 8) It is easily soluble in Ir acid in the 4th line from the bottom of the 3rd page, and...j is 1rCaC0.
3 is easily soluble in acids, and is corrected to J. 9) 2nd line from the bottom of page 6, "...Φ・, generally 0.3 to 0.5% by weight・eφj" is replaced with "..., generally 0.3 to 1.5% by weight... Corrected to "Conflict". io) Page 9, line 4 ['NaCr2O2''' ” ”j F N
a Cr 207...". 11) On page 9, line 13, "..., Z n (N O3)..." is corrected to [' in..., ZnNO3・number・ri. 12) Page 9, lines 17 to 18 1' * * * e *, cr(cH3co)3,
...-j is lj a e * * *, Cr (C,'H3Co
2) Corrected to 3.me conflict. 13) On page 11, lines 3 to 2 from the bottom, it says "f-φ...fewer, therefore...". Correct it to "-fist s * less than 5, full stand...J" 14) Same. Page 12, lines 1 to 2, "゛... There is no deterioration of the jar. It says j. W... There is little deterioration. Correct to j. 15) Page 133, line 2, the table of contents reads as follows: 1'Na-C5 was used as a control for SEC and J of the present invention.
This is because A'j is structurally similar, so it was expected that it would be equivalent to SEC in terms of performance. ” 16) Same page 16 “In Table 1j, a) f for inorganic
Concentration (wt), 1.
wt%) Corrected to J. mouth) (A] 2 (SO4)2 .1 1r
AI2 (S04) 3 Correct to j. C) As a polymer, Na=CMHEC1 As an inorganic In, AI 2 (SO4) 3 The "x" in the column is corrected to "x (saturated) j. 17) Same as above, page 177, line 8, the present invention applies to such polymers. -..." is corrected to "Polymer fist according to the present invention -.phi." 18) Same page 23 "In Table 2j, a) Pe1adOW (CaC12) as an inorganic salt, its concentration is 30 wt%,
As for the polymer, 1rlj is written in the NaCMHEC (7) column. Correct it to ``1.2j.'' In the case of (a) above, Fl, 2 are written in the polymer HEC column.
j Correct it to [11,3j. c) ZnBr2. as an inorganic salt. The concentration is 4 wt%, and the column for Na-CMHEC as a polymer is corrected as 1rlj to ll'1.2j. 2. Title of the invention: Fluid composition for polling 3. Person making the amendment Relationship to the case Patent applicant 4. Date of amendment order 1982 IJ] 118 Sacrilege [1 January 1980 311+) 7. List of attached documents (1) Supplementary section

Claims (1)

[Claims] The poling finishing fluid containing at least one type of monovalent salt or polyvalent salt has a degree of substitution (DS) in the range of 0.5 to 2.5, and a 1% (by weight) aqueous solution viscosity of 5 to 5,000.
A finishing fluid composition for poling, characterized in that it contains a sulfoethyl cellulose alkali metal salt (CP) as an essential component.