Hydrophobic emulsion drilling fluid and the method of its preparation

(57) Abstract:

The invention relates to the drilling of oil and gas wells, in particular by emulsion drilling fluids in the mixed water and oil based with hydrophobic properties. The technical result achieved by the present invention is the development of hydrophobic emulsion mud mixed water and oil based and the method of its preparation, namely, a stable emulsion of a transitional type, characterized by minimal filtering under temperature and pressure conditions and adjustable in a wide range of values of the rheological parameters of the SNA and viscosity. Hydrophobic emulsion drilling fluid comprising a clay, a polymer, water, diesel fuel or oil, emulsifier and stabilizer, clay, polymer, water contains as polimergranita solution is water-based, and as an emulsifier and stabilizer - 20% aqueous solution carbonylsulphide pitch composition, wt. % technical lignosulfonates 15,0 - 17,0, tall peck 58,0 - 61,0, caustic soda 5,0 - 6,0, carboxymethylcellulose with a degree of polymerization of 700 and a degree of substitution 85 18,0 - 20,0, water the rest in the following ratio of ingredients, wt. %: polyterpenes the Nata 11,0 - 21,3. Polymerclay the water based mud has a density of 1180 - 1200 kg/m³and filtering 2.0 - 2.5 cm³/30 min In the preparation method of hydrophobic emulsion drilling fluid comprising a uniform flow under vigorous stirring to obtain the required values of technological parameters in diesel fuel or oil water, clay, polymer, stabilizer, emulsifier, in the preparation of the above drilling fluid flow specified solution carbonylsulphide pitch and polimergranita solution water-based exercise at the same time. 2 AD. and 1 C. p. F.-ly, 5 PL.

The invention relates to the drilling of oil and gas wells, in particular by emulsion drilling fluids in the mixed water and oil based with hydrophobic properties.

Known invert emulsion drilling fluid, consisting of an aqueous phase, a hydrocarbon environment, emulsifier, stabilizer, amendment and additional surfactant - water-repellent solid phase (USSR author's certificate No. 1058993, From 09 To 7/06, 1983).

In the specified invert emulsion drilling fluid, the amount of filtering at a temperature of +20 ° C and differential pressure on the filter surface P=1 Kho 35 kgf/cm²filtering increases to 12-14 cm³/30 minutes in Addition, emulsion solutions of this type (composition) are characterized by low values of viscosity, rheological properties and static shear stress.

Known invert emulsion drilling fluid (USSR author's certificate No. 1134594, From 09 To 7/06, 1985), containing water or mud water-based diesel fuel, tall oil pitch, saponified (OTP) sodium carbonate (soda ash), a byproduct of the production of phytosterol (PPF) and fine chalk in the following ratio of ingredients, wt.%:

water or mud

water-based 23-39

diesel fuel 40-50

tall peck, saponified

carbon dioxide sodium 10-12

a by-product

production of phytosterol 1-3

fine chalk 10-12

Preparation of invert emulsion drilling fluid is carried out on the following technology. In water or clay water based mud under stirring to dissolve the part of tall oil pitch, smilenov sodium carbonate, in an amount up to 50 wt.% from the calculation. Then injected diesel fuel dissolved in the remaining hours shall irout emulsion.

The disadvantages of this invert emulsion drilling fluid are low values of viscosity from 37 to 100 and the static shear stress: SNA over 1 min is 6 to 12 DPA, SNA for 10 minutes is 12-20 DPA.

Due to the low values of the SNA and rheological parameters: plastic viscosity of from 14 to 18 SDR, dynamic shear stress from 28 to 68 DPA no full removal of drilled cuttings particles of rocks of the sloping sections of the wellbore within the values of the Zenith angle of 60-80 degrees.

High of the actual filtering invert emulsion drilling fluid (12-14 cm³/30 min), measured under temperature and pressure conditions: temperature 93S and the pressure drop across the filter surface R=cs/cm²negatively affects the quality of the dissection of productive layers. By the time the stabilization process of filtering through 30-36 hours its value reaches 60-70 cm³. During this time, in the zone of influence of the well - filtrate penetration or emulsion is blocked part of the pore space of the reservoir.

The disadvantages of invert emulsion drilling fluid is also increased consumption of hydrocarbon liquids (diesel fuel or oil), emulate fluid to a temperature of ~80 ° C to dissolve the solid saponified tall oil pitch.

Most loved ones are hydrophobic emulsion drilling fluid comprising a clay from 0.7 to 5 kg / m³drilling fluid, the polymer is from 0.7 to 5 kg / m³mud, water, diesel fuel or oil from 30 to 95 vol.%, the emulsifier is from 1 to 7 kg / m³mud and stabilizer, and the method of preparation of the specified drilling fluid comprising water, clay, polymer, stabilizer, emulsifier into diesel fuel or oil through a uniform filing under vigorous stirring to obtain the required values of technological parameters (see, for example, U.S. patent No. 5096883, From 09 To 7/06, 17.03.1992).

The invention is directed to solving the problems of improving the quality of the opening of productive layers with decreasing filter in the permeable portion of the formation of water-in-oil emulsion or its filtrate, ensuring complete removal of sludge on sections of the wellbore with Zenith angles greater than 60 degrees, the reduced flow of the hydrocarbon fluid and an emulsifier (surfactant) for the preparation of hydrophobic emulsion drilling fluid.

The technical result achieved by the present invention is the development of hydrophobic emulsion mud mixed water-hydrocarbon oinoi filtering under temperature and pressure conditions and adjustable in a wide range of values of the rheological parameters, SNA and viscosity.

Hydrophobic emulsion drilling fluid comprising a clay, a polymer, water, diesel fuel or oil, emulsifier and stabilizer, clay, polymer, water contains as polimergranita solution is water-based, and as an emulsifier and stabilizer - 20% aqueous solution carbonylsulphide pitch composition, wt.%: technical lignosulfonates 15,0 - 17,0, tall peck 58,0 - 61,0, caustic soda 5,0 - 6,0, carboxymethylcellulose with a degree of polymerization of 700 and a degree of substitution 85 18,0 - 20,0, water the rest in the following ratio of ingredients, wt.%:

polymerclay solution

water-based 44,8-58,1

diesel fuel

or oil 30,1-40,0

this solution

carbonylsulphide 11,0-21,3

Polymerclay the water based mud has a density 1180-1200 kg/m³and filtering 2.0 - 2.5 cm³/30 minutes

In the preparation method of hydrophobic emulsion drilling fluid comprising a uniform flow under vigorous stirring to obtain the required values of technological parameters in diesel fuel or oil water, clay, polymer, stabilizer, emulsifier, in the preparation of the specified via water-based exercise at the same time.

As the polymer in the composition polimergranita mud using carboxymethyl cellulose CMC, Unifloc.

The ratio of reactants in the composition of the hydrophobic emulsion drilling fluid is selected taking into account their mutual influence on the properties of each other and achieve the highest level of stabilization of the drilling fluid that meets the requirements of qualitative opening of productive layers, ensuring complete removal of cuttings from the values of the Zenith angle of 60-80 degrees. The consumption of hydrocarbon liquid to prepare an emulsion of the solution is reduced in comparison with the known 10%, and emulsifier - 2.8-5 times per dry matter, which certainly indicates the criterion of “inventive step”.

The results of the analysis (measurement) values of the properties of the emulsion drilling fluids: the proposed and known, including filtering under temperature and pressure conditions, are presented in tables 1-3. With the aim to characterize the limits of variation of the parameters of the hydrophobic properties of emulsion mud mixed water and oil based prepared 20 different combinations with a wide range of changes concfrom 44,8 to 82.4%;

hydrocarbon liquids

(oil) from 12.4 to 40.0%;

aqueous solution LISTING

(20% concentration) from 3.2 to 24.1%

Example preparation of hydrophobic emulsion drilling fluid (item 6, PL.1). In a cylindrical glass filled 309 ml of oil, then with vigorous stirring simultaneously and evenly began to introduce an aqueous solution of LISTING (20% concentration) and the original polymerclay solution with a density of 1180 kg/m³. Was added to 110 ml of an aqueous solution of LISTING and 581 ml polimergranita solution. Since the latter was much more than solution LISTING, it continued to type with constant velocity in the emulsion after spending solution LISTING. Emulsion solution was stirred for 30 min, and then measured its technological parameters.

On the basis of the research - analysis of performance properties of the obtained hydrophobic emulsion drilling fluid was found that the optimum concentrations are:

polimergranita solution with

the density of 1180 kg/m³44,8 at 58.1%

hydrocarbon liquids

(oil) to 30.1-40.0% of

water (20%) solution

LISTING 11,0-21,3%

If this is the target, including:

density 880-980 kg/m³

viscosity 180-435

filtering 0,0 cm³/30 min

mud cake 0.1 mm

factor sticky mud cake 0,03

SNA for 1 min 66-81 DPA

for 10 min 84-165 DPA

plastic viscosity 23-36 SDR

the dynamic tension

shift 155-305 DPA

According to the table.1 the most acceptable (recommended) the following values are quantitative ratios between the original polymerphysik solution, hydrocarbon liquid and an aqueous solution of LISTING: from 2.28:1,41:1 to 5,28:2,81:1.

Fold excess amount of the original polimergranita solution with respect to hydrocarbon liquids and water (20% increase) to a solution of LISTING may be, or increase, respectively, in 2,28-5,28 times and 1.41 to 2.81 times.

Outside the field of concentrations of ingredients, limited PP 6-14 (see tab.1) when the quantity of hydrocarbon liquid will be less 30.1 per cent, of the original polimergranita solution - more at 58.1% aqueous solution of LISTING or less 11% notes: increasing the density of the hydrophobic emulsion drilling fluid from 980 to 1090 kg/m³and filter from 0.0 to 1.5 si³/30 min; the>The NS for 10 minutes - from 84 and 144 dpi to 63 and 87 DPA; plastic viscosity from 23 and 24 to 21 SDR; dynamic shear stress from 216 and 155 DPA and 135 to 149 DPA.

According to the results of comparative tests of filtering known for invert emulsion and offer a hydrophobic emulsion drilling fluids under normal conditions (t=22 ° C; P=1 kgf/cm²and in conditions close to the face (t=93C; P=35 kgf/cm²), found that (see tab. 2; 3):

filtering invert emulsion drilling fluid with increasing temperature up to 93S and differential pressure on the filter surface, ETC to 35 kgf/cm²growing from 0.0-1.0 to 12-14 cm³/30 min;

filtering hydrophobic emulsion drilling fluid with increasing temperature up to 93S, ETC to 35 kgf/cm²increased slightly from 0.0 to 2.0-2.2 cm³/30 minutes

According to the results of the analysis of values of viscosity, SNA and rheological parameters of emulsion solutions (see tab. 1 and 3) established that the known invert emulsion drilling fluid satisfies the conditions of leaching or in a vertical hole, or in wells with Zenith angle of 10-15 degrees and does not meet the requirements of drilling shallow wells because of ebouaney characterized the optimal parameter values of viscosity, SNA and rheological properties, which size is much greater than that observed in invert emulsion drilling fluid, taken as a prototype. In particular, increases:

viscosity in 4,35-4,86 times

SNA for 1 min in 6,75-11 times

SNA for 10 min at 7-8,25 times

plastic viscosity of 1.64-2 times

dynamic voltage

shift in 4,48-of 5.53 times

Industrial testing and introduction of recipes and methods of cooking hydrophobic emulsion drilling fluid produced during the drilling of 7 wells in the Urengoy gas condensate field in the interval 3100-3300 m below the shank of the production string.

Based on the actual savings from the use of hydrophobic emulsion drilling fluid when the drilling was due to: decrease the range and consumption of chemicals and materials; cost-cutting productive time for preparation and chemical treatment of drilling mud, rinse and development of the wellbore.

In the use of new technology, the consumption of reagents and materials decreased by:

According to preliminary calculations, the savings from reducing consumption chem the Oia consumption of chemical reagents and materials on 7 wells in the replacement of the invert emulsion mud of hydrophobic emulsion drilling fluid was - 1542231 rubles (without VAT and transport costs).

In the case of invert emulsion drilling mud in 7 wells was to be expected that the cost of productive time associated with mud, preparation and washing of the wells will be 958,1 hours.

The actual time when using hydrophobic emulsion drilling fluid was 308,5 hours. In the end, the time decreased to:

958,1-308,5=649,6 (hours).

At the cost of 1 day of work of the drilling team 121876 RUB savings amounted to:

121876649,6/24=3298776,9 (RUB).

The reduction of the cost of chemical reagents and materials:

3298776 + 1542231=4841007 (RUB).

1. Hydrophobic emulsion drilling fluid comprising a clay, a polymer, water, diesel fuel or oil, emulsifier and stabilizer, wherein the clay and the polymer, the water it contains in the form of polimergranita solution is water-based, and as an emulsifier and stabilizer - 20% aqueous solution carbonylsulphide pitch composition, wt.%: technical lignosulfonates 15,0 - 17,0, tall peck 58,0 - 61,0, caustic soda 5,0 - 6,0, carboxymethylcellulose with a degree of polymerization of 700 and to the East the water based mud 44,8 - 58,1

Diesel fuel or oil 30,1 - 40,0

This solution carbonylsulphide 11,0 - 21,3

2. The solution on p. 1, characterized in that polymerclay the water based mud has a density of 1180 - 1200 kg/m³and filtering 2.0 - 2.5 cm³/30 minutes

3. Method of preparation of hydrophobic emulsion drilling fluid comprising a uniform flow under vigorous stirring to obtain the required values of technological parameters in diesel fuel or oil water, clay, polymer, stabilizer, emulsifier, characterized in that in the preparation of the specified mud under item 1 supply specified solution carbonylsulphide pitch and polimergranita solution water-based exercise at the same time.