DE1758872C - Pre-flushing liquid for acidifying calcareous petroleum and water-containing formations - Google Patents

Description

1758172

The invention relates to creating a precautionary liquid which does not entail these disadvantages

the souring of calcareous, petroleum and waaacr-containing drings. In addition, the speed of the.

Formations by means of a borehole, which are raised from an oil production from the borehole, Hydrocarbon oil and the soap of a fatty acid without the water production increasing significantly,

consists. 8 The task is solved using a

U.S. Patent No. 2,294,078, e.g. B, describes flushing fluid for acidifying calcareous, petroleum and a method for the treatment of oil and gas · water containing formations by means of a drilling · Boreholes, whereby an aqueous solution of the soap loches, which is made up of a hydrocarbon oil and the soap a fatty acid, such as ammonium palmitate, which consists of a fatty acid characterized by Drilled hole and in an adjacent salt · ίο Hate still a solvent for the soap in the alkali-bearing and oil-bearing formation containing pressed hydrocarbon oil is. The aqueous soap solution reacts with the in The pre-rinse liquid is oieophilic; by that it is Calcium and magnesium are easily dissolved in the brine, they pass through the petroleum-carrying channels of the forma salts, which lead in the brine-carrying channels to the adjoining water-carrying zones, the are to be held, with the formation of a precipitate, 15 further from the borehole, to be pressed that writes. The oil in the oil-carrying channels is there and these against the entry of the following but no precipitation with the aqueous soap solution. brought acid to block. So it becomes a big one Therefore, these channels are not blocked. The volume of oil-bearing zones of the formation is acidified. The excess of the aqueous soap solution is then removed without the water-bearing zones being removed from the oil-bearing canals in any significant amount. Alternately acidified to a significant extent, If a neutral liquid, such as oil or water, is used, it has been found that the pre-wash liquid pressed into the oil-carrying channels in order to obtain the over- this invention when it comes into contact with most Shot of aqueous soap solution further ind the Forma types of fossil water that is in petroleum reservoirs or tion and a space is found between the formations, reacts with education Soap solution and the borehole to create. Then as a precipitation product, which the water-bearing a lot of acid, e.g. B. aqueous hydrochloric acid, blocked in zones. It is not necessary that that pressed the formation. The acid is derived from the salt - fossil water or the brine calcium or Caustic channels dissolved by the magnesium salts formed therein, as a blocking Fäliungsprodukt kept away. But the acid already flows when the precipitation product meets into the oil-carrying channels and reacts with the Forma- 30 pre-rinse liquid according to the invention with water tion by dissolving part of it and opens the brine alone or with sodium. Formation so that the oil can flow more freely. The following is intended to use the invention

When the brine carrying channels are described in more detail. The technique of souring

contain the sodium salts and the like, but no CaI drilling has been known for a long time, and the basic

contains dissolved calcium or magnesium salts, 35 principles are familiar to every person skilled in the art. In a nutshell,

Phenylsulfonic acid or similar sulfonates as a liquid it will be a solution of an acid, such as hydrochloric acid, in Precipitant used instead of a soap solution. the borehole is introduced and then into the one to be acidified Such sulfonates precipitate upon conformation. The acid becomes one in the formation

tact with a sodium brine, which soap solutions leave a long enough time so that they with the

do not do. 40 formation gait reacts and parts of it

In practice, however, this procedure is difficult to solve, thereby reducing the diameter of the channels that are located pertaining to the present invention. extend through the formation largely or entirely eliminated. A difficulty and the formation fluids can flow faster into the drilling due to the oleophobic character of the hole. Calcareous formations, such as liquid precipitants, which 45 Limestone or dolomitic limestone formations, be turned. When an aqueous soap solution is in the acidification is most easily accessible. When the formation is depressed, it moves only the acid is depleted, it is out of the formation a short distance into the formation before it is withdrawn through the borehole, and the formation precipitate arises, the further solution of the inflow escapes.

steps locked. The solution is then introduced into the oil-carrying 50. The pre-wash fluid of this invention consists of Channels pushed aside. Because of its oleophobic nature, a hydrocarbon carrier and solution, the solution continues to flow into the oil-carrying agent for soap. Hydrocarbon oils, such as kerosene, Channels against great resistance, and only with diesel fuel, crude oil or refined fractions A considerable amount of force can be used to penetrate it, etc. The soap solution is reached in the oil-carrying channels. If channels carrying brine parallel to hydrogen oil by saponification of fatty acids, the irj and run adjacent to the oil-carrying channels,. the oil are brought into solution, produced, wherein if the former cannot use the oil as the reaction medium along the adjacent zone, can be blocked without the aqueous soap solution. A preferred fatty acid component is one through the adjoining oil-carrying channels through-60 purified mixture of tall oil acids, which from the going to reach the zone. Arizona Chemical Company under the product name

Another problem that came with the process according to the trademark "Acintol FA-I" on the market

of said USA. patent occurs. "Acintol FA-1" has the following identifying features

in that the aqueous soap solutions do not have the composition:

Form the desired precipitate with the brine, 65 percent by weight of fatty acids

if these no calcium or magnesium salts dissolved palmitic acid 0.5

contains. Palmitoleic acid 0.5

The object of the invention is to provide a pre-wash liquid stearic acid 2.5 Fatty acids weight percent

oleic acid, 52.5

Oleic acid. . 370

tinol pigs in the middle

Double bonds "6.0

Linolenic acid, other acids
' and unknown 1.0

Both saturated and unsaturated fatty acids and mixtures thereof can be used. Suitable saturated fatty acids are e.g. B. PaImitInic acid, stearic acid, arachical acid, behenic acid and lignoceric acid. Suitable unsaturated acids are, for example, lauroleic acid, myristoleic acid, palmitoleic acid, oleic acid, gadoleic acid, erucic acid, ricinoleic acid, linoleic acid, linolenic acid, eleostearic acid, where R is an alkyl radical with 6 to 12 C ^ ö an integer of about 2.5 DI "Jw" 3.5 who are commanded to use the For

β introduced to the pre-wash filament. Aqueous SiU * acid solutions, in particular 15- or 2 / olge, ma suitable and preferred, ^^, ^ ÄJ hydrochloric acid can also be between these values or higher or lower - others. ^ ^ΗΓ ? ^η ·.

"In general" for acidification wjJ ^ 3Sl NEN can also be used in the practice of the invention

The following ™ ^ A _n W _n ¹ Jr S illustrate the manufacture of a

is pre-wash liquid.

example 1

430 «

continue 5 min g becomes lively.

whole ^^ g ₅₅₁ and the contents of the tank

While the tank contents during de

"i and about

TKS, base used for saponification of fat - ψ ^

acids is used, aqueous ammonium is produced.

hydroxyd, namely the common solution with Ορ ^, ^^ ϊ &

26 ° trees. Other bases that are also used »Acintol ^FA ~ * ₊ r _f ^e '* 5 5i _e Mix about 5 minutes

Gaseous ammonia, sodium deposition are added, and the mixture, for example

hydroxyd potassium hydroxide, urinary stool and low -5 stirred around sickle. ^^ T

Amines, e.g. B. Ethanolamine. "Li 430 Ut The pre-wash liquid according to this invention ent- ^

holds a means of dissolving the soap in the hydrocarbon oil. Such agents are surface active substances that are soluble in the oil and one have a peptizing effect on the soap, which prevents its precipitation until the pre-rinse liquid with water or aqueous solutions, such as fossil brines, come into contact. That for the vo

Time preferred means of dissolving the soap 35 kerosene.

is a mixture of alkylphenoxy-polyethoxy- " ^l " ^ "JfJ

Ethanols. This remedy can be achieved by direct oxethy-

lation of alkylphenols «. Each

The resulting adduct has a whole molecule Number of oxyethylene groups, but the mixture that

is made contains molecules with different

Numbers of oxyethylene groups. Hence the degree

the oxethylation of the mixture as an average

not necessarily a

needs to be an integer. The preferred class

of funds are

Concentrate with 15321 Gathering

Bath

will, IaI "

Alkylphenoxy (ethyleneoxy) _{n <lurcliichn} -ethanols,

beidenen _n eineZahlvonetw _a 2, ₅ bisetwa3,5bedeutet The alkyl group may be about 6 to 12 carbon so atoms. Specific solubility agents in accordance with this invention are

JSS it is wün _{c0 m <s before} verΐ. with ammoniumhy _{if the} saponification made in s Jktiinittnk from. If this _{k the precipitated} soap in the "J ^K _v0 ""igepal CO 430" and yeast dissolved.

^^^^ proven to be effective if the ammonium hydroxide or another base is slightly smaller _{than that} for complete ^WeTS f ^m l ™ ^T J ^C "'

Nonylphenoxy (ethyleneoxy)

_bycMchn

-ethanol

and

_n -ethanol.

55

Octylphenoxy (ethyleneoxy) _{3 major}

The former is the adduct of 4 moles of ethylene oxide and nonylphenol and has the following formula:

^Ha ° ^{) 3} - ■ »<-" * ^{C f}

^ _{the base the opt} i.

^ / ^ _ίβΓ «ηα are. If more base w.rd added _{dajj can dünnflüss} ig pass into the solid gel form Vcrspülkonzentrat _e.

Example/

It is commercially available under the trademark "Igepal 430".

_{About 1900} J pre-wash liquid _{by dissolving} 118 1 oleic acid in 1682 substance. Then 55 1

Octylphenoxy- (ethyleneoxy), _through-im . -Ethanol

_dissolves . _Dana ch is oleic acid hydrolyzed by switching

O 430 «available. . _fc mix 25.71 aqueous A ™ ^o n, umhydrox

The Äthanole are used by the _{post-6 (2} 6 ° Baume) in the solution, 96 ° / ₀ for reproducing the voi-mentioned general formula: required _Standige saponification Menge- ^ P ^"0" '

A thin liquid is produced which can easily be _{pumped into aas> -O (CH 2} CH ₂ O) " _{through tc: in} CH ₈ CH ₈ OH through the ear hole and the wall of the borehole.

1 758

In Examples 1 and 2 dan reputation Depending 1OQ parts by volume VorspUinUsv / gkclt about 90 carbons Voiümteile · wassorstofföl, otwu 7 parts by volume of soap and about 3 parts by volume SolublllsierungsmlUel. Plese relationships, however, only serve to deny the invention and are not critical per se. The ratio of the constituents to one another can be varied. It has been found to be practically suitable that 3.5 to 18 parts by volume of soap and about I ₁ S to about 6 parts by volume of solidifying agent can be added to 90 parts by volume of hydrocarbon oil.

Laboratory tests

A cylindrical core 50.8 mm long and 25.4 mm in diameter was drilled from the limestone of the »5 Bedford Formation. This core was cut in half along its central axis. An auxiliary was saturated with kerosene to represent the oil-bearing part of a formation. The other Hillftc was saturated with a brine produced »o (8.5% Nucl, 2.5 ° / ₀ CNCL ₁ J and 90% water) to represent the water-carrying Tei. The two halves were put back together, separated by a thin rubber membrane. The core treated in this way and reassembled was placed in a core cylinder in which liquid can flow through the core in an axial direction.

Pre-rinse liquid according to Example 1 was pumped through the core to keep it as far as possible "Saturate Su. Then 28% aqueous hydrochloric acid was pumped through the core at low speed, to make sure the acid reacts with the limestone. After that, the core was filled with water flushed.

Then the core was taken out of the test cell and examined the two halves for their appearance. The one originally saturated with kerosene Half had been severely attacked by the acid, while half, initially saturated with brine was. showed only superficial etching at its upper end, without anything being removed from the main body was.

From this experiment it can be seen that the pre-wash treatment prevents the acid from flowing through the half of the core saturated with hydrochloric acid. All of the acid flow is directed through the oil-saturated half of the nucleus, where the acid meets the bulk reacted.

50 Attempt with the pre-rinse liquid at the storage facility

I. cleaning the mixing tanks, pumps and connections, so that they are free from water, acids and chemicals that come with the pre-wash liquid could cause soap deposits.

II. Isolating the formation so that the treatment fluid can only penetrate into this.

IH. When the borehole is filled with water, recommends it is possible to let the water run out of the isolated zone with anhydrous crude oil, in order to keep the contamination of the oil-carrying parts by water to a minimum.

IV. Pumping a few m ^{3 of} anhydrous crude oil or the like into the piping.

V. Pumping in the pre-wash liquid. It flows into and through the oil-bearing layers with the formation of a scavenger blow. If it encounters a water-bearing channel and comes into contact with water at the inlet of this channel, the soap is precipitated and fills the pores of the water-bearing channel, whereby further flow of the pre-wash liquid into this channel is stopped. VI, pumping in an intermediate buffer of a few m ^{8 of} clean anhydrous crude oil or the like in order to press the pre-wash liquid and the crude oil or the like in front of it further into the formation. Although there may be a certain tendency for the intermediate buffer to dissolve the precipitated soap at the entrances to the water-carrying canals, it will be. Volume, the pressure that could drive it into such channels, and the time that the toe buffer can be in contact with the precipitate are kept to a minimum. In practice, for example, the soap that has failed is not dissolved to any noticeable extent in the toe buffer, and the water-carrying channels remain blocked.
VII. Pumping in acid solution. Since the water-carrying channels are blocked, it penetrates into the oil-carrying channels and pushes pre-flushing fluid and pre-buffer back into the formation, where they continue to perform their function. The acid solution is preferably an aqueous solution that does not contain any significant amounts of oil, as the latter would dissolve the soap deposit in the adjacent water-bearing channels, so that the acid would penetrate into these channels and react with the formation mass, which is precisely what should be avoided. The acid is injected at a relatively slow rate to minimize the possibility of formation breaking or forcing the precipitated soap out of the aquifer.

VIII. Closing the borehole for a few hours to allow the acid to enter the formation, mainly in the oil-bearing zones, can react. IX. Extraction of the oil in the usual way, whereby one after the other the exhausted acid, the intermediate buffer, the pre-rinse liquid, the pre-buffer and then producing the formation fluid. When withdrawing the treatment solutions the toe buffer flushes the exhausted acid out of the channels from the oil-carrying channels, so that the pre-rinse liquid, which follows the intermediate buffer, does not correspond to the exhausted one Acid comes into contact and no undesired precipitate is formed in the oil-carrying channels will.

The precipitated soap is soluble in oil. Therefore, when working continuously, the soap deposit becomes in the water-carrying canals dissolved over time by the oil produced, and water comes out again out. However, the water exit velocity is not due to the previous well treatment increased significantly, but the exit velocity of the oil is generally much higher.

If in spite of the precautionary measures taken to prevent the soap from precipitating in the oil-bearing Channels have been adhered to, a little soap falls out, this is not of great damage, as the precipitation, is soluble in the formation oil, in which oil will be dissolved and carried out of the formation with it.

With
!act

the
: rch

!! en
around
ow

on
iile
Sn,
en
:'he
'P.

Si

V?

The volumes of treatment solution used depend on the type of formation, its thickness and the distance between the two to be treated Formation from the borehole. Practical trials are the best help in these cases. When dealing with Formations about 0.3 to 0.6 m in thickness are preferably used:

About 0.6 m ^s pre-buffer, about 950 to 1900 1 pre-rinse liquid, about 0.24 to 0.6 m ^a intermediate buffer and about 7570 to 37 850 1 acid.

An example of such a treatment of a bore is given below.

Example 3

An oil well in Callahan County, Texas, returned a mixture of oil and water from the Palo Pinto Reef Formation. Before the treatment, 1.67 m ^{3 of} oil and 3.348 m ^{3 of} water were pumped daily.

According to the method described above, the isolated zone was freed from water by flushing it out with clean, anhydrous crude oil. About 0.6 m ^{3 of} the crude oil was pumped into the formation as a pre-buffer. 19001 pre-flushing liquid, prepared according to Example 1, was then pumped into the formation, followed by an intermediate buffer of 0.36 m ^{3 of} clean, anhydrous crude oil. Following this, 7570 liters of 28% strength aqueous hydrochloric acid were pumped into the formation and kept in it for 3 hours

leave xo. Then the drilling was switched to production. After the well was freed from the treatment fluids, other production figures set in. The daily production was 3.457 m ^{3 of} oil and 3.348 m ^{3 of} water. So oil production had more than doubled without increasing water production.

In the table below are other cases of oil wells with details of production before and after treatment with the invention

so compiled pre-rinse liquid:

District, city and formation

Runnels, Texas, Caddo Lime

Stephens, Texas, Mississippi Lime Callahan, Texas, Palo Pinto Reef.

liter

Pre-wash liquid,

composition

according to example 1

1900 1900 1900

liter Production (m ^a / day) water after treatment water aqueous before treatment oil Hydrochloric acid oil 4.80. 6.00 7570 0 0.72 0 (28%) 0.03 28387 0.96 (15 ° / _o solution) 0.36 0.36 0.60 7570 0.84 (28 ° / _o solution) 0.24

The table shows that oil production by the Treatment was increased, the water production on the other hand little or no.

Claims (8)

Patent claims: 1. Pre-rinsing liquid for acidifying calcareous, petroleum- and water-containing formations by means of a borehole, which consists of a hydrocarbon oil and the soap of a fatty acid, characterized in that the pre-rinse liquid is still a solvent for the Contains soap in the hydrocarbon oil. 2. pre-rinse liquid according to claim 1, characterized in that the solvent is a surface-active is oil-soluble ethylene oxide adduct. 3. pre-rinse liquid according to claim 1, characterized in that the solvent is a mixture of compounds of the general formula in which R is an alkyl having 6 to 12 carbon atoms and »is a number between 2.5 and 3.5. 4. pre-rinse liquid according to claim 1, characterized in that the solvent Nonyl or octophenoxy (ethyleneoxy) _8jurihlin ethanol is. 5. pre-rinse liquid according to claim 1, characterized in that it contains a soap made by saponifying a fatty acid having 12 to 22 carbon atoms with a base selected from the group consisting of NH ₄ OH, NH ₃ , NaOH, KOH , Urea or lower amines. 6. pre-rinse liquid according to claim 1, characterized in that it consists of a liquid hydrocarbon oil, the ammonium soap of tall oil acids and Octylphenoxy (ethyleneoxy) _{3iiur (: h>} chn -ethanol consists. 7. pre-rinse liquid according to claim 6, characterized in that hydrocarbon oil, soap unc Octylphenoxy (ethyleneoxy) _3ilutchti . _lin -ethanol in a ratio of 90: 3.5 bra 18: 1.5 to 6 parts by volume are available. 8. pre-rinse liquid according to claim 6, characterized in that hydrocarbon oil, soap around Octylphenoxy (ethyleneoxy) _{3aurQht (. Hn} -ethanol in a ratio of 90: 7: 3 Vo lumbar present.