RU2535723C1 - Invert emulsion solution based on mineral oil for exposure of productive beds - Google Patents

Abstract

FIELD: oil-and-gas industry.

SUBSTANCE: proposed invert solution comprises the following components in wt %: "ВМГ3" hydraulic mineral oil as solvent - 32.0-63.0; organophilic bentonite for creation of solution structure - 0.8-3.2; microtiff - 3.9-8.0; Rhodopol 23 for adjustment of rheological and filtration properties - 0.2-0.8; emulsifier "ЭКС-ЭМ" - 2.3; 10% water solution of calcium chloride as emulsion stabiliser and inhibitor of shape hydration - 15.3-16.0; quicklime - 1.7, foam killer "МАСС-200" - 0.5-0.8, and heavy spar - 7.5-40.0.

EFFECT: high heat resistance at low chemical aggression against ambient medium and, in fact, almost zero filtration of water phase.

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Description

The invention relates to the oil and gas industry, in particular to hydrocarbon-based drilling fluids for opening productive formations, in particular drilling open areas with abnormally high reservoir pressure (AAP).

A carbon-based emulsion solution is known that contains diesel fuel, organophilic bentonite, an MR emulsifier, ADB water repellent, a water phase mineralized with potassium, sodium or calcium chloride, a mineral filler — chalk or barite, a 20% polyisobutylene solution with a molecular weight of 20,000 in industrial oil I-20A and calcium oxide / RU 2424269 C1, IPC C09K 8/02 (2006.01), C09K 8/467 (2006.01), publ. 07/20/2011 /.

Known emulsion drilling fluid containing bentonite clay powder, KMTs-700 as a regulator of rheological, thixotropic and filtering properties, washed taly pitch as an emulsifier, tal oil as a solvent, microcalcite as an inert filler, sodium tripolyphosphate as a stabilizer, MAC-200 antifoam and water (Technological regulations of TyumenNIIgiprogaz LLC, Gazprom OJSC “Use of lightweight drilling fluid for opening productive formations at the Yamburg and Urengoy gas condensate fields”, RD-00158758-251-2000, Tyumen, 2000, pp. 8-9).

However, when drilling wells terrigenous with layers of carbonate rocks, this solution is unsatisfactorily cleaned of cuttings, which leads to rapid abrasive wear of both bottomhole and drilling equipment on the surface, there is also no stability in the high temperature range, the solution freezes in the range of perennial frozen rocks with prolonged shutdowns of wells.

The objective of the invention is to preserve the natural filtration and capacitive properties of reservoir reservoirs, to prevent decompression of the rock mass, as sandstone, limestone, and shale, the possibility of its use for prolonged shutdowns at low temperatures.

The technical result is to provide high flocculating and inhibitory properties of the solution for removing sludge during cleaning, ensuring high drilling speeds, ensuring high heat resistance of the drilling fluid with low chemical aggression to the environment when opening the pressure drop and almost zero filtration of the aqueous phase.

The specified technical result is achieved by the fact that the invert emulsion drilling fluid for opening productive formations contains VMGZ mineral oil, organophilic bentonite to create a solution structure, microcalcite, xanthan gum for regulating rheological and filtration properties, emulsifier EX-EM, 10 as a solvent % aqueous solution of calcium chloride as emulsion stabilizer and clay shale hydration inhibitor, quicklime, antifoam MASS-200, barite, the next the ratio of components, wt.%: hydraulic mineral oil VMGZ - 32.0-63.0, organophilic bentonite - 0.8-3.2, microcalcite - 3.9-8.0, xanthan gum - 0.2-0, 8, emulsifier EX-EM - 2.3, 10% aqueous solution of calcium chloride - 15.3-16.0, quicklime - 1.7, antifoam MASS-200 - 0.5-0.8, barite - 7, 5-40.0.

The causal relationship between the essential features and the technical result achieved is as follows: calcium chloride is used as a stabilizing reagent, xanthan gum gives the solution the necessary rheological properties and regulates water loss, and with the addition of organophilic bentonite and emulsifiers these properties can change, therefore, the concentration of xanthan gum 1 -2% can be considered optimal. With an increase in the concentration of calcium chloride and mineral oil, the thixotropic properties are enhanced and the resulting solution is better cleaned of cuttings. In turn, mineral oil in combination with calcium chloride, used as a stabilizer for a barite-weighted solution, increases the effect of inhibition of shale, however, the maximum effect exists only at the stated concentrations and combinations.

VMGZ hydraulic mineral oil is known as low viscosity oil for any of the most common hydraulic systems: crane, road-building and other equipment, it is produced according to TU 38.101479-00, mass fraction up to 80%, water mass fraction 0.66%.

Organophilic bentonite, which is a product of the interaction of bentonite clay with ammonium salt, and barite are widely used in well construction (manufacturer of OJSC "Bentonites of the Urals").

Microcalcite, a fine dry powder of bright white color; crystalline calcium carbonate - 98 ... 99%; TU 5716-003-40705684-2001; production of Everest LLC.

Xanthan gum is a biopolymer used as a thickener and weighing agent for water-based drilling fluids, produced in accordance with TU 2458-002-50635131-2003.

Emulsifier EKS-EM / TU 2413-035-53501222-2003 / is a complex reagent, including an emulsifier and an additive that reduces the pour point and increases the stability of the emulsion, manufactured by Polyex CJSC.

Technical calcium chloride is produced by PO Khimprom LLC in accordance with GOST 450-77, introduced into the inventive solution as an emulsion stabilizer and shale inhibitor up to 10% in an aqueous solution. The solution is prepared as follows.

For the required volume of invert emulsion drilling fluid (IER-1M) to open productive formations of oil and gas reservoirs, VMGZ mineral oil is collected, an EX-EM emulsifier and quicklime are introduced through a hydraulic disperser, then the required amount of organophilic bentonite is added, after the formation of a uniform structure the aqueous phase of the emulsion, consisting of a 10% aqueous solution of calcium chloride, to prevent the foaming process is introduced antifoam MASS-200 (manufacturer Kazanorgsintez), rheological The properties and filtering efficiency are controlled by the introduction of xanton gum, after which an inert filler, microcalcite, is introduced. Barite is weighed upon reaching a density of 1600 kg / m ³ .

During preparation, standard solution parameters are measured: density, conditional viscosity, dynamic shear stress (CSN), plastic viscosity, static shear stress, fluid loss, medium pH, filter cake thickness, stickiness, and also one of the important indicators of emulsion stability - breakdown voltage by current - electrical stability, etc.

The table shows the compositions and a number of parameters of drilling fluids. The tests performed show that changing the quantitative content of the components down (composition No. 1) does not provide the necessary technological parameters, and upward (composition No. 5) is not economically profitable, since organophilic bentonite with a concentration higher than that stated reaches saturation and increased the consumption of reagents does not correspond to the expected result.

Claims (1)

Invert emulsion drilling fluid for opening productive formations containing VMGZ mineral oil, organophilic bentonite to create a solution structure, microcalcite, xanthan gum for regulating rheological and filtration properties, emulsifier EX-EM, aqueous solution of calcium chloride 10% as an emulsion stabilizer and an inhibitor of hydration of shale, quicklime, antifoam MASS-200, barite, in the following ratio of components, wt.%:
mineral oil hydraulic VMGZ 32.0-63.0 organophilic bentonite 0.8-3.2 microcalcite 3.9-8.0 xanthan gum 0.2-0.8 emulsifier EX-EM 2,3 aqueous solution of calcium chloride 10% 15.3-16.0 quicklime 1.7 antifoam MASS-200 0.5-0.8 barite 7.5-40.0