RU2100400C1 - Hydrocarbon-based drilling fluid - Google Patents

Abstract

FIELD: oil and gas production; drilling fluids. SUBSTANCE: invention focuses on drilling fluid used when advancing through unstable clays, mudstones, salts as well as through zones with abnormally high formation pressures containing carbon oxides and hydrogen sulfide. Increased barite-capacity (density) of solution, decreased viscosity and strength of structure and reduced filtration loss are caused by that hydrocarbon-based drilling fluid contains diesel fuel or kerosene fraction, or petroleum, and also caustic lime, water, high-oxidation bitumen, sulfonol, an oil-containing sulfonate additive, and barite modified by sodium tripolyphosphate. Owing to sulfonate additive, barite-capacity of solution increases from 39.18 to 50 vol.% and thence density increases from 2200 to 2520 kg/cu.m, Engler viscosity decreased by a factor of 1.5 (52 and 35 s), static shear stress by a factor of 25 (303 and 12 dPa), and filtration loss is 5.2 times reduced. EFFECT: improved performance characteristics of fluid. 4 tbl

Description

 The invention relates to exploration, oil and gas industry, in particular to hydrocarbon-based flushing solutions used in drilling oil, gas and exploration wells.

The invention can be used in the sinking of unstable clays, mudstones, salts, as well as in sinking in areas of abnormally high reservoir pressure (AAP) containing CO, CO ₂ and H ₂ S.

A well-known hydrocarbon-based drilling fluid containing oil or its distillates, a filtration regulator, a builder, a weighting agent, water, a gyrofobizator and a viscosity regulator surfactant [1]
analogue.

 The disadvantage of this solution is the low barite capacity, high filtration losses, as well as a strong thickening of the solution with increasing density.

 Closest to the claimed composition is a drilling fluid (IBR-2) containing diesel fuel, highly oxidized bitumen, quicklime, water, sulfonol, flotation barite, bentonite, SMAD-1, emulsifier and neutralizer and hydrogen sulfide ZhS-7 [2] prototype .

 The disadvantage of this solution is also low barite capacity, high viscosity, high structural strength and large filtration losses. As the density increases, the solution thickens significantly and does not pump through the well due to large hydraulic resistances exceeding the hydraulic power of the mud pumps. The solution does not allow the use of barite as a weighting material having a hydrophobic surface (barite modified with sodium tripolyphosphate).

 The aim of the invention is to increase the barite capacity (density), reducing the viscosity and strength of the drilling fluid based on hydrocarbon, as well as reducing its filtration losses.

 This goal is achieved in that the hydrocarbon-based drilling fluid, including diesel fuel, highly oxidized bitumen, quicklime, water, sulfone, flotation barite, bentonite, SMAD-1, emultal and ZhS-7, additionally contains an oil-containing additive SKG-2, which replaces in the prototype, bentonite, SMAD-1 and emultal, which allows to increase the barite intensity of the solution, reduce the viscosity, structure strength and its filtration losses, and the components are taken in the following proportions, wt.

Highly oxidized bitumen 1.23 12.29
Quicklime 1.35 26.22
Water 0.02 1.04
Sulfonol NP-3 0.18 0.25
Oil-containing additive SKG-2 0.3 0.37
Barite modified with sodium tripolyphosphate 0.01 83.3
Diesel fuel or a mixture of diesel fuel with a kerosene oil fraction or oil
The introduction of the SKG-2 additive makes it possible to use not only flotation barite, but also barite modified with sodium tripolyphosphate to weight the solution. As a dispersion medium in the inventive solution can be used oil with a pour point not lower than -20 ^o C or a mixture of diesel fuel and kerosene oil fractions (K-20 KO-30).

 In the table. 1 shows the chemical composition of the additive SKG-2.

Comparative analysis with the prototype allows us to conclude that this solution is different from the known introduction of new components, namely additives SKG-2 and barite modified with sodium tripolyphosphate. As a result of the introduction of the SKG-2 additive, the barite capacity of the solution increases from 39.18 to 50 vol. as a result, its density rises from 2200 to 2520 kg / m ³ , conditional viscosity decreases by 1.5 times (52 and 35 s), static shear stress decreases by 25 times (303 and 12 dPa), filtration losses at 80 ^o C are reduced 5.2 times (31 and 5.9) (Tables 2 and 3).

Thus, the claimed technical solution is new. Analysis of known compositions of hydrocarbon-based drilling fluids and emulsions [2
5] used in drilling wells, showed that the introduction of additives SKG-2 in the composition of the solution is unknown.

 Thus, this composition of the components gives the hydrocarbon-based drilling fluid new properties, which allows us to conclude that there is an inventive step.

 The solution is prepared as follows.

 In a hydrocarbon-based diesel fuel or oil, calcium oxide is quenched by entering the calculated amount of water. After lime is extinguished, sulfonol and highly oxidized bitumen are introduced into the solution. After mixing the mixture for one hour, SKG-2 additive and barite modified with sodium tripolyphosphate are added to its composition. According to the electoral plan, hydrophobic barite can be used (Table 2, experiments 14–16). After an hour of mixing, the solution is ready for use.

 Example. In a hydrocarbon base (17.4 wt.), Calcium oxide (5.72 wt.) Is quenched by introducing water (0.27 wt.) Into the mixture. After lime is extinguished, sulfonol (0.62 wt.) And highly oxidized bitumen (2.68 wt.) Are added to the mixture. After dissolution of bitumen, the solution is weighted with barite (73.34 wt.) And processed with SKG-2 additive (0.32 wt.). In the table. 4 shows the composition of solutions depending on their density.

In this way, nineteen solutions were prepared (Tables 2, 3) with different (wt.) Content of SKG-2 additive. The density of the prepared samples varied from 1020 to 2520 kg / m ³ . In the table. 2 shows the physical properties of the solutions, in table 3 the barite capacity of the solutions.

From the above data it follows: the barite capacity of the solution increased 1.3 times (39.18 and 50 vol.), As a result of which its density increased from 2200 to 2520 kg / m ³ ; conditional viscosity decreased by 1.5 times (52 and 35 s); static shear stress (CHC ₁ ) decreased by 25 times (303 and 12 dPa); filtration losses at 80 ^o C decreased by 5.2 times (31 and 5.9 ml).

 Description of the ingredients of the solution.

Highly oxidized bitumen is a solid consistency product obtained by oxidizing the residue from the distillation of oil (tar containing alkali) at a temperature of 130 160 ^o C. The composition of BV includes asphaltenes (≥ 25 wt.), Resins (≅ 24 wt.) And oil (≥ 51 wt.).

 Quicklime calcined carbonate rock product ground by mechanical crushers. Composition: the content of active CaO and MgO is not less than 70 - 90%; the content of non-extinguished particles is not more than 7 12%;

 Sulfonol NP-3 (alkylbenzenesulfonate) synthetic surfactant, a mixture of sodium salts of alkylbenzenesulfonic acids 80 84 wt. unsulfonated compounds 1.7 3.0 wt. sulfate and sodium sulfite 12 15 wt. moisture 2.5 wt.

 Oil-containing additive SKG-2 is a colloidal solution of calcium sulfate, carbonate and hydroxide stabilized with calcium sulfonate (M 450 600) in mineral oil diluted with a highly aromatic hydrocarbon solvent containing acid tar.

 Barite modified with sodium tripolyphosphate is anhydrous barium sulfate modified with sodium tripolyphosphate to suppress flotation reagents. The content of barium sulfate is not less than 90 94 wt.

Diesel fuel oil distillate with a boiling point of 255 - 360 ^o C.

Kerosene distillates direct oil race with a boiling point of 200 - 300 ^o C.

 Water is a chemical substance consisting of 11.19 wt. hydrogen and 88.81 wt. oxygen. The molecular weight of 18.015.

Sources of information
1. Rogers F. Composition and properties of flushing liquids. M. Nedra, 1976, p. 489,500.

 2. Kaspersky B.V. et al. Lime-bitumen solution with improved rheological properties (IBR-2). Oil industry 1985, N 1, p. 9.

 3. Copyright certificate. USSR N 1198090, class C 09 K 7/06, 1984

 4. Ornyak M. V. Rudi V. P. et al. Emulsion drilling fluids stabilized by cationic surfactants. Physico-chemical mechanics of washing and grouting dispersions, Kiev, 1979, p. 10.

 5. Bulatov A.I. et al. Well flushing technology. M. Nedra, 1981 p. 124.

Claims (1)

A hydrocarbon-based drilling fluid containing quicklime, water, highly oxidized bitumen, NP-3 sulfonol and a weighting agent, characterized in that the solution additionally contains SKG-2 oil-containing sulfonate additive, and barite modified with sodium tripolyphosphate is used as a weighting agent, and hydrocarbon as a weighting agent the basis of diesel fuel, or oil, or kerosene in the following ratio of components in solution, wt:
Highly oxidized bitumen 1.23 12.29
Quicklime 1.35 26.22
Water 0.02 1.04
Sulfonyl NP-3 0.18 0.25
Oil-containing additive SKG-2 0.30 0.37
Barite modified with sodium tripolyphosphate 0.01 83.3
or
Oil rest

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