FR2473054A1 - DRILLING FLUID CONTAINING ALWAYS AGENT - Google Patents

Abstract

DRILLING FLUID CONTAINING HEAVY-DUTY AGENT. THE DRILLING FLUID CONTAINS A WEIGHTENING AGENT CHOSEN FROM THE GROUP OF NON-HYDRATED MINERALS HAVING A HARDNESS OF AT LEAST 4.5 MOHS SCALE AND A SPECIFIC MASS AT LEAST EQUAL TO 4.4, SUCH WEIGHING AGENT HAVING A GRANULOMETRY AS WATER LESS 85 IN WEIGHT OF THE PARTICLES PASS THROUGH A SIEVE OF 0.044MM OF MESH OPENING AND APPROXIMATELY 98 IN WEIGHT OF THE SAID PARTICLES THROUGH A SIEVE OF 0.074MM OF MESH OPENING, THIS WEIGHTING AGENT IS PRESENT IN ENOUGH ENOUGH QUANTITY PROVIDED FOR DENSITY OF THE DRILLING FLUID AND A WATER-DISPERSABLE ANTI-WEARING AGENT IN SUFFICIENT DRILLING FLUID IN SUFFICIENT QUANTITY TO SIGNIFICANTLY REDUCE THE ABRASION CAPACITY OF THE DRILLING FLUID. APPLICATION IN THE BORING OF OIL WELLS.

Description

The present invention relates to improved compositions and methods

  for drill holes such as

  oil wells, gas wells or the like. More particularly

  In particular, the invention relates to high density drilling fluids which contain abrasive weighting agents. Drilling fluids used for the drilling of oil wells, gas wells and similar holes in soil are commonly composed of

  water containing clays or other

  as well as certain additives that are used in

  depending on the drilling conditions. The fluid or mud of

  rage acts primarily as an agent to

  carry the debris produced by the drill bit up

  the soil surface. In addition, the drilling fluid serves to

  It drills the drill bit and the drill pipe and prevents the penetration of field fluids, such as oil, gas and salt water, into the hole during drilling. The drilling fluid performs other functions and has other features that do not need to be described in detail since they are well

  known and have been defined in many pu-

  publications, such as Walter F. Roger's book "Composition and Properties of Oil Well Drilling Fluids", 3rd edition, Houston, Texas, 1963; Kirk-Othmer's book, "Encyclopedia of Chemical Technology", 2nd Edition, New York,

1965, Volume 7, pages 287-307.

  As stated above, one of the functions of a fluid

  drilling is to maintain in the fluid column is

  sufficient hydrostatic pressure to prevent the entry of fluids from the ground into the

  and, in extreme circumstances, to prevent a

  flowing well. Depending on the drilling conditions encountered

  In this case, sufficient hydrostatic pressure can be obtained almost with the bottom water. However, under normal circumstances, and usually as a safety precaution, it is necessary, in order to achieve the desired hydrostatic pressure, to charge the sludge with an appropriate weighting agent to increase its density. These weighting agents are generally in the form of finely divided solids which consist of a material having a high intrinsic density. The most commonly used weighting agent is finely milled barite, although in other cases it has been used

  iron oxides, celestine, galena and

  very materials. Barite, because of its relative density

  The high level of insolubility, chemical inertness and good availability to date has been a weightless agent of choice. However, because

  baryta availability is decreasing, we are in the process of

other heavy agents.

  Apart from the fact that baryta sources are becoming depleted, and are almost non-existent in some areas of the world where drilling activity is high, barite is a relatively soft material,

  whose hardness is between 2.5 and 3.5 Scale / Mhos.

  This relative softness of the barite affects the rheological properties of the drilling mud after barite has been

  placed in circulation in the hole during the drilling operation.

  In the drilling operation, the entire system circulates

  It behaves a little like a fluid mill

  because the softer mineral particles are subject to

  to attrition and decrease in size. This decrease

  particle size and the increase in their total number have a direct influence on the increase in

the viscosity of the drilling mud.

  It has been proposed to use other heavy materials

  baryte to overcome the disadvantages described

  above with regard to weight-bearing

  latively soft as barite, which are subject to a gradual disintegration. GB patent 1,495,874 describes the use of ilmenite and / or hematite as a material

  weighting agent for drilling fluids. In addition,

  Colombian vet 9,396 describes the use of specular hematite

  micaceous as a weighting agent in drilling fluids.

  Specular hematite is a natural ore found in large quantities on earth, in different forms and in different purities. For example, the micaceous specular hematite described as a weighting agent for

  drilling fluid in Colombian Patent 9,396 is a mine-

  micaceous ray, laminated, relatively soft and having a characteristic laminated structure. This form of micaceous specular hematite tends, at grinding, to form very thin flat scales and, when using this material in a drilling fluid, these scales tend to

  to break down easily into very small

  which causes an increase in the viscosity of the drilling fluid. This micaceous specular hematite is essentially non-abrasive under the existing conditions

in a borehole.

  The specular hematite which concerns the present invention

  is an unhydrated mineral which, although having

  seems a laminated structure, is hard and forms, at the

  grinding, particles with abrasive and uneven edges

  liers. This specular hematite has a relatively high intrinsic density, i.e. a density greater than

  about 4.3 and has a hardness of about 5 to 6

  the / Mnhs When using it as a weighting agent

  in a drilling fluid, the specular hematite according to

  vention does not tend to fall apart in small parts

  which would significantly modify the rheo-

  logic of the drilling fluid. However, because of its intrinsic hardness, the specular hematite according to the invention is quite

  abrasive and can cause excessive wear on the equipment.

  drilling equipment, in particular the drill pipe and the

  pan. Because the search for oil and gas results in the drilling of deeper and deeper wells, excessive wear or erosion of the drill pipe and bit creates

  more and more important difficulties.

  The object of the present invention is to provide an improved drilling fluid; an improved drilling fluid that can use abrasive and relatively hard weighting agents;

  an improved method of drilling a hole in use

  reading a drilling fluid that contains a relatively hard weighting agent. According to one embodiment, the invention relates to

  a water-based drilling fluid which contains a feed agent

  forming agent of non-hydrated specular hematite and an anti-wear agent which is dispersible in water and which is present

  in sufficient quantities in the drilling fluid to re-

  substantially reduce the abrasion capacity of the drilling fluid.

  The particle size of the weighting agent used in the drilling fluid shall be such that at least 85% by weight of the

  agent passes through a sieve with a mesh size of 0.044 mm.

  The amount of weighting agent present in the drilling fluid varies depending on the drilling conditions encountered

  but in general this agent is present in sufficient quantities

  to substantially increase the density of the drilling fluid.

  According to another embodiment, the invention

  The invention relates to a method of field drilling, characterized in that

  the drilling fluid defined above is circulated

  in the hole during the drilling operation.

  Other advantages and characteristics of the invention

  will be highlighted in the following description, given

  by way of non-limiting example, with reference to the drawings

  nexes in which: 1 is a graph giving the weight loss of abrasive which is obtained with different compositions of the drilling fluid; in this figure the abscissa scale

  indicates the stirring time in hours (h), while the

  y-axis indicates weight loss by abrasion in%. 2 is a graph showing the abrasion wear characteristics of different drilling fluid compositions; in this figure the abscissa scale indicates

  the pair in cm.kg while the ordinate scale indi-

  than the wear rate in grams / hour (g / h).

  The weighting agents useful in the fluids of

  according to the invention are hard and non-hy-

  have a specific mass of about 4.3 or more,

  as for example specular hematite. Specular hematite

  The iron ore is a commonly available ore which is chemically ferric oxide (Fe 2 O 3). It is described, for example, in the book of Ivan Kostov "Mineralogy" (Oliver

  & Boyd, Edinburg and London), 1st English edition (1968).

  Typically, the specular hematite contains 69.94% iron and 30.06% oxygen. There may be some titanium content. Specular hematite is often mixed with

  hydrated iron oxides, iron carbonate and magnesium

  as well as iron silicates. However, non-hydrated specular hematite deposits are available and then

  it is not necessary to remove the water of hydration.

  The weighting agents useful in the present invention

  they have a density of at least 4.3, preferably at least 4.5. If necessary, the quality of the weighting agent can be improved by known metallurgical processes, for example by flotation, in order to achieve the desired minimum density. The weighting agent has a hardness of at least 4.3 scale / ng. Many grades of specular hematite have a hardness of 5 to 6. For their use in the present invention, the weighting agents have

  particle size such that at least 85% by weight of the particles

  These cells pass through a sieve with a mesh size of 0.044 mm and at least 98% pass through a 0.074 mm sieve.

  mesh opening. More advantageously, the granulometer

  should be such that between 90% and 92% of the particles

  pour a sieve of 0.044 mm mesh size. The desired particle size for the weighting agent can be obtained

  by well known grinding processes.

  The amount of weighting material in the drilling fluid can vary within wide limits.

  depending on the desired density of the drilling mud. This den-

  sity is obviously a function of the drilling conditions encountered

  or estimated. In any case, the amount of barite needed to achieve the desired density of sludge is well known and tables indicating this relationship can be conveniently obtained. From the point of view of comparing the intrinsic density of the weighting agents with that of the baryte, these tables can be used to determine the amount of weighting agent necessary to obtain sludge or drilling fluids having the desired density. As indicated above, the weighting agents according to the invention are materials that are relatively hard and therefore less prone to disintegration.

  progressive. As a result, the weighting agents

  have relatively high abrasion characteristics which can cause excessive erosion of drilling equipment such as pumps, drill pipes and drill bits during the drilling operation. We have now found

  that, if appropriate anti-wear agents are

  in the water to the drilling fluids made with the agents

  relatively hardeners according to the invention, it is possible to

  to reduce the abrasion capacity of the drilling fluid to a degree

  such that no more wear is registered than that which is

  duit with drilling fluids having a similar density

  and using softer barite as a weighting agent.

  The anti-wear agent used in the drilling fluid according to the invention must be dispersible in water to such a degree that it forms a colloid, emulsion or other such heterogeneous system in which the anti-wear agent is wear is generally uniformly dispersed or distributed in the aqueous phase. The anti-wear agent must be of a type which makes it possible to obtain the desired rheological properties of the fluid of

  drilling. Preferably, the anti-wear agent must be a

  which, when present in sufficient quantities, produces a useful drilling fluid which contains the hard-weighting agents in accordance with the

  characteristics of wear and / or abrasion generally

  or substantially identical to those obtained with a drilling fluid having substantially the same density or

  same weight and containing barite as a weighting agent.

  It has been found that particularly effective antiwear agents

  In the present invention, the freshwater-based drilling fluids are those containing fatty acids such as oleic acid, stearic acid, linoleic acid, palmitic acid and the like. These fatty acids are commonly found in vegetable oils such as cottonseed oil, soybean oil, corn oil, castor oil, flax seed oil, and the like. The fatty acids, either in pure form or in the form of the vegetable oils mentioned above, are mixed with small amounts of surfactants or other agents for the purpose of preparing them.

  make it dispersible in water. These surfactants can

  These include, for example, long chain alcohols, alkanolamines, sulfonated vegetable oil derivatives such as sulfonated castor oil, and the like. A particularly effective anti-wear agent is a mixture of

  of soybean oil, long-chain alcohols and rye oil

  cinsulfonée. This composition and similar materials give excellent anti-wear agents since it is sufficient to add them in relatively small amounts to the fluid.

  drilling to reduce abrasion capacity to an acceptable level

  table. Moreover, since it is sufficient to add relatively small quantities, only alterations occur.

  negligible theological properties.

  The amount of anti-wear agent in the fluid of

  rabies can vary widely but is generally

  typically between about 0.1 and 5% by weight. How-

  In general, the anti-wear agent does not need to be

  in quantities which produce a substantial reduction

  the abrasion capacity of the drilling fluid.

  Preferably, the drilling fluid contains agents

  thickeners. These thickening agents can be

  killed by formations containing clay, such as shale or clay sands that are encountered in the operation of

  drilling and which are driven by the fluid or drilling mud.

  Alternatively or additionally, it is possible to add

  clays in the mud. As typical and not limita-

  Very colloidal clays include smectites, particularly bentonite, attapulgite and sepiolite, with bentonite being the preferred clay. A wide variety of other water-dispersible materials are available.

  particularly organic colloids, can serve as

  thickeners, especially starch derivatives, cellulose derivatives, synthetic polymers such as sodium polyacrylate, natural gums such as

  guar gum, kiraya gum,

  such as those made by certain Xanthomonas species, and others. Where appropriate,

  mixtures of these suitable thickeners. Techno-

  The use of such thickeners in drilling muds is well known to those skilled in the art. The

  different thickening agents have a wide range of

  weight in terms of their effectiveness, expressed in number of kilograms, which must be incorporated into a barrel (0.159 m3) of fluid

  or drilling mud of a given type to achieve a

desired degree.

  In addition to the thickening agents, the drilling mud may optionally contain fluid loss control agents, viscosity control agents, antifoam additives, freezing point depressants,

and the like.

  It is important to note that in the implementation

  of the process according to the invention where the fluids are

  of drilling defined above, it is possible to add, during the drilling of the hole, additional quantities of the weighting agent and / or the anti-wear agent to maintain or modify the density and the abrasion capacity of the hole. drilling mud.

  The examples below illustrate, in a non-limitative

tif, the present invention.

  The specular hematites used in these examples were provided by U.S. Steel Corporation, these hematites being unhydrated and having a specific gravity.

between 4.9 and 5.1.

Example 1

  A basic drilling fluid or slurry was prepared by stirring with stirring 25 grams of AQUAGEL (commercial designation of a bentonite clay sold by NL Baroid, Houston, Texas) and 50 grams of Glen Rose shale.

  in 350 ml of water for 20 minutes using a

  high speed dispersion. - Then we added to the

  mud 5 grams of Q-BROXIN (commercial designation of a ligno

  sulfonate sold by NL Baroid, Houston, Texas), 5 grams of

  CARBONOX (commercial designation of an organic humic acid

  sold by NL Baroid, Houston, Texas), 1.5 grams of caustic soda and 4 grams of AKTAFLO S (commercial designation of a drilling fluid surfactant sold by NL

  Baroid, Houston, Texas), while providing

  10 minutes in the dispersion device. We left

  rest the mud thus prepared overnight.

Example 2

  Using the basic slurry prepared in the example

  1, various drilled drilling muds have been prepared using

  BAROID Baritone (commercial product name)

  sold by NL Baroid, Houston, Texas) and specimen hematite

  lar. Test results of the heavy drilling muds thus produced are obtained for a sludge at 1.56 kg / l (Table I), a sludge at 1.92 kg / l (Table II) and a sludge.

at 2.16 kg / l (Table III).

  Sample designation Base mud BAROID, kg Specular hematite, kg

TABLE I

A B

0.159 0.159 C

A B

), 159 0.159

Agitation (multi-

  mixer), min. Roll at 66 ° C, h Aging at 149 ° C, h o Viscosity plastiquemPa.s 54 Pour point, kg / m1 0.48 gel.10.S, .kg / m2 0.19 gel. l0 mninkg / m 182 pH 184 API filtrate, ml / 30 min 3.0 Filtrat, 149 C, 35 kg / cm2, ml

Shear strength-

  kg / m2 o 0.70 0.42 18; g2 0.3 0.1x 0.2 O

4 0.29

4 0.14

4 0.19

3.5

20

16 16

O O

  1.18 0.24 0.24 4.5 12.4 1.05 0.29 0.29, 0 16.4

4.8 4.8

  A 0.159 B 0.159 A 0.159 B 0.159 1.25 0.19 0.24 9.0 3.5 1.25 0.24 0.24 9.0 4.0 oH o fN o c M CD

TABLE II

  Sample designation Base mud, in m BAROID, kg Specular hematite, kg

A B

0,159

A B A B

0.159 0.159

0.159 0.159 0.159

A B

  0.159 0.159 Agitation (multi-exchanger), min15 Rolling at 66 C, h 0 Aging at 149 C, h 0 Plastic viscosity mPa.s Flow point, kg / m2 gel.10 s, kg / m2 gel 10.min. , kg / m2 pH Filtrat API, ml / 30 min Filtrate, 149 C, 35 kg / cm2 ml

Shear strength-

  kg / m2 Dose of heavy material H = large MOD = - moderate 0.77 0, 24 0.38 8.8 2.5 O

15 20 20 25

16 16 16 16 16

O O O O 16

  0.09 0.19 0.24 8.7 2.5 0.63 0.29 0.38 0.24 0.09 0.09 0.34 0.24 0.48 8.4 2, 5, 0 0.38 0.14 0.19 8.5 3.0, 0 0.14 0.42 1.68 8.6, 0 19.2 H Fi Fi 0.14 0, 09 0.09 8; , 0 7.7 MOD N wcw Sample designation Base mud, m3 BAROIDkg Specular hematite, kg A 0.159

TABLE III

B A

0.159. 0,159

  299. Agitation (multinmixer), min. Rolling at 66 ° C, aging at 149 ° C. Plastic viscosity mPa.s pour point, kg / m2 gel.lO s, kg / m2 gel 10 mn, kg / m2 pH Filtrat API, ml / 30 min. Filtrate, 149 C, 35 kg / cm2, ml Shear strength kg / m2 O o o 0.048 9.9, 0 15

16 16

0 O

0.19 0.14 0.19, 1, 0

43 18

0.34 0.14

* 0.09 0.09

0.24 0.19

  o0 0.14 0.14 0.19 9.0 6.0O 64.0 o 0.58 0.09 0.14 9.5, 5 '118.0

25

16 16

16 16

H, 76, 95, 0.58 0.29 1.74 8.4

48 19.2

H = .grand o ul B 0.159 to 0.159 B

0,15.9

  A 0.159 B 0.159 As shown by a comparison of the results of the

  Tables I, II and III above, the drilling fluids pre-

  Resin with specular hematite compares favorably with conventional drilling mud prepared using barite as a weighting agent.

Example 3

  To control comparative attrition rates under

  a strong shearing effect of the different heavy agents

  in drilling muds, we used sludge

  The results of Table IV below show that the attrition rate of specular hematite is considerably lower than that of Example 1 and 2.

  barite in comparable drilling muds. This re

* attrition resistance is advantageous because it ensures that the Theological properties of the drilling fluid are not as susceptible to change during

  drilling operations where the sludge is put into circulation

aunt in the borehole.

TABLE IV

Sieve analysis in% Absolu

  wet pathway% penetration of health a sieve of 0.044 mm fineness of mesh opening Initial mud Final mud Finale minus (15 minutes) (8 hours) initial

BAROID 93.2 97.0 3.8

Specular hematite 92.0 93.0 1.0

Example 4

  A water-based drilling mud was prepared using

  15 grams of AQUAGEL and 60 grams of "Glen Rose" shale hydrated in 350 ml of water, then 300 grams of the particular weighting agent to be evaluated were added. Slurries containing specular hematite were diluted with 0.27 g / l of

  BARAFOS (commercial designation of a polyphosphate compound

  phate sold by NL Baroid, Houston, Texas). To control

  the abrasion or wear characteristics of the sludge

  picks, ie the influence of the addition of anti-

  wear, two methods were used. One method, referred to as A, has been to consider the phenomenon of wear caused by the movement of particles of a fluid against a metal surface. In this method, the

  overall weight loss over the entire surface.

  Method A. Hamilton Beach Model 936 Mixer was used,

  rotating at 15,000 tr / muLn to produce, with simulation in

  boratory, abrasion and particle breaking effects.

  For each drilling mud, a new blade was used in the mixer and weighed to define a reference for the abrasive activity. Periodically, the slide was examined for weight loss after different periods

  stirring. The sludge was immersed in a cooling bath.

  during the mixing phase to avoid overheating and evaporation. We have minimized the thickening of

  heavy sludge being stirred by adding BARAFOS.

  The results of the wear rate tests are indicated in

Table V below.

  Sample designation Base mud, m3 BAROID, kg. Specular hematite, kg A-310.92.6% sieve 0.044mm A-314.93.1% sieve 0.044mm BARAFOS, g / l 0.39 Anti-wear additive, g / 1 Properties: Initial plastic viscosity2, mPa. s18 Pour point, kg / m 0,14 gel.10 s. kg / m2 0.14 gel.lO mir kg / m2 0.58 pH 8.2 Properties: 4 hrs. plastic viscosity, mPa.s Pour point kg / m2 gel.lO s.kg/m22 gel.lO minikg / m pH 2.51 2.73 6.24 8.4 A 0.159

TABLE V

B C

0.159 0.159

  0.39 O 0.048 0.53 8.2 1.72 2.11 64 8.3 O 0.19 9.0 0.34 0.14 1.056 9.0 D 0.159 E 0.159 F 0.109 1.45 0 65 1 1 0.96 0.42 1.16 9.1 0.67 0.82 2.85 9.8 0.09 0.09 0.58 9.6 0.09 0.048 0.58 9.6 7.34 6.58 12.44 9.5 1.29 0.62 2, 11 8.9 -4 w Ue CD Lq Sample designation Properties: 8 h plastic viscosity, mPla.s Pour point kg / m2 gel .10 s kg / m2 gel.lOmin, kg / m2 pH Abrasion wear, blade weight, g Blade weight loss,% after 1 hour 2 hours 4 hours 8 hours TABLE V (continued)

A B

  2.34 2.64, 04 8.2, 17 0.24 0.47 0.94 1.52 1.87 2.35, 23 8.2, 15 0.50 0.98 1.93 3.23

C D

  3.88 2.98 9.17 9.6, 21 3.92 8.00 14.10, 18 2.85, 42, 20 14.33 F, 19 E, 21 1.47 2.50 4.67 0% 2.64 4.86 8.56 ww A second method of wear testing was used

  or abrasion, designated B, this method taking into consideration

  the surface movement of metal surfaces against each other while being exposed to a fluid flow. In Method B, the objective was to measure

  weight loss on the area exposed to loads.

  Method B The test block used for the measurement of extreme pressures (EP) was machined to expose a constant wear surface to the element to be tested during the tests. Ring speed of 432 rpm has been selected since this is approximately equivalent to a 130 rpm drill pipe rotational speed, which is quite common in well drilling processes. Torques of different values were applied to the ring and block at this rate for 15 minute intervals. The initial weight and final weight of the test block were measured and for each sludge a loss was determined. weight of the block considered. The wear rate was then determined and calculated for one hour. The results are indicated

  in Tables VI to VIII below.

  As the results of Tables V show

  to VIII below, the specular hematite presents, by comparison

  Its baritone has much greater abrasion capacity.

  With reference to Table V, it can be seen that the addition of

  anti-wear agent greatly reduces abrasion wear

  a drilling mud weighed down with specular hematite.

  The results are highlighted graphically in the figure

  A drilling mud weighed down with specular haematite and not containing anti-wear agent (curve A) is compared with a sludge similarly weighed down and containing about 10.8 g / l of anti-wear agent (curve B) and a conventional drilling mud weighed down with barite

(curve C).

  Referring to Tables VI to VIII and Figure 2, it can also be seen that the sludge wear rate containing specular hematite is much greater than

  that of a classic mud weighed down with baryta.

  However, as shown by the curves in Figure 2,

  the addition of relatively small amounts of an anti-

  wear dramatically reduces wear rates. It should be noted, for example, that the wear rate of a sludge weighed down with specular hematite (curve A) which is quite abrasive without

  addition of an anti-wear agent, has an abra-

  when combined with about 21.6 g / l of an anti-wear agent (curve D)) similar or substantially identical to that of conventional heavy-duty drilling mud

  with barite (curve C). Even for relatively large quantities

  low anti-wear agent, ie 10.8 g / l

  (curve B), the abrasion capacity is greatly reduced.

  It can thus be seen that very improved drilling muds with excellent rheological properties can be prepared with hard or relatively hard weighting agents without causing wear and abrasion.

  excessively, when the drilling mud contains additional

  an anti-wear agent as described above.

  Naturally, the invention is not limited to the embodiments described above and described from which we can provide other modes and other embodiments, without departing from the scope of the invention.

TABLE VI

  Thickening agent Load, cm.kg Ring speed, rpm Ring speed m / s Wear period, min

112.5 \ ',

0.78 112.5 0.78

BAROID

225,225

432,432

0.78 0.78

15

0.78

338,450

432,432

0.78 0.78

15

  Initial block weight, g final block weight, g weight loss, g wear rate g / h

9.8453

9.8401

0.0052

0.0208

Average wear rate g / h

9.8401

9.8357

0.0044

0.0176

9.8183

9.8100

0.0083

0.0332

0.0192

9.8100

8.8026

0.0074

0.0296

0.0314

9.7690.9.7562 9.7143 9.7005

9.7562 9.7423 9.7005 9.6852

0.0128 0.0139 0.0138 0.0153

O, 0512 0.0556 09ES2 0.0612

0.0534

0.0582

0.78% 0 w

TABLE VII

  Thickening agent Load, cm.kg Ring speed, rpm Ring speed m / s Wear period, min Initial block weight, g Final block weight, g Weight loss, g Wear rate g / h

SPECULAR HEMATITIS

56, 0.78

9.4625

9.4523

0.0102

0.0408

56.1 0.78

9.4523

9.4445

0.0078

0.0312

112.5 0.78

9.4443

9i4199

0.0246

0.0984

112.5 0.78

9.4199

9.3950

0.0249

.0996

0.78 0.78

9,3950 9,3082

9.3082 9.2116

0.0868 0.0966

0.3472 0.3864

Average wear rate g / h

0.0360

.0990

.3668

r4 UI> w * 4 ui

TABLE VIII

  Weighting agent SPECIFIC HEMATITE Anti-wear agent, g / l 0.192 0.192 0, 384 0.384 Load, cm.kg 338 225 338 225 Ring speed, rpm 432 432 432 432 Ring speed m / s 0.78 0.78 0 , 78 0.78 Wearing period, min 15 15 15 15 Initial block weight, g 8.4698 8.4483 8.4318 8.4178 Final block weight, g 8, 4483 8.4318 8.4178 8.4087 Weight loss, g 0.0215 0.0165 0.0140 0.0091 Wear rate g / h 0.0860 0.0660 0.0560 0.0364 Average wear rate, g / h - "I w. tO

Claims (5)

  1. A water-based drilling fluid, characterized in that it contains a weighting agent selected from the group of non-hydrated ores having a hardness of at least 4.5 scale / qs 1 and a specific mass at least equal to 4 , 4, said weighting agent having a particle size such that at least 85% by weight of the particles pass through a sieve of 0.044 mm mesh size and about 98% by weight of said particles pass through a sieve of 0.074 mm aperture   of mesh, said weighting agent being present in quantitative   sufficient to substantially increase the density of the drilling fluid and a dispersible antiwear agent in   the water present in said drilling fluid in sufficient quantity   to significantly reduce the abrasion capacity of the drilling fluid.   2. Drilling fluid according to claim 1, characterized   characterized in that the dispersible anti-wear agent in water   is present at about 0.1 to 5% by weight.   3. Drilling fluid according to one of the claims   1 or 2, characterized in that the weighting agent is specular hematite.   4. Drilling fluid according to claim 1, characterized   in that it includes an additional burdensome   chosen from baryte, celestine, galena and mixtures of said substances.   5. Drilling fluid according to claim 1, characterized in that it contains additives chosen from thickening agents, fluid loss control agents, additional weighting agents,   dilution and mixtures of said agents.