RU2251565C2 - Weighting agent for treatment of drilling muds - Google Patents

Abstract

FIELD: oil-producing industry; drilling of petroleum and gas boreholes.

SUBSTANCE: the invention is dealt with the field of oil-producing industry, in particular, with drilling of petroleum and gas boreholes and may be used for preparation of weighting agents of drilling mud, including the super-heavy drilling mud intended for drilling boreholes in conditions of anomalously high seam pressures, and also at appearance of hydrogen sulfide. The technical result is improvement of the weighting agent quality at the expense of a decrease of the share of water-soluble calcium salts, a decrease of its abrasivity and an increase of weighting capacity. The weighting agent for treatment of the drilling muds containing a synthetic mix of the barytes and magnetite concentrates additionally contains sodium tripolyphosphate at the following ratio of components (in mass %): barytes concentrate - 40-60, magnetite concentrate - 40-60, sodium tripolyphosphate - no less than 0.01% over 100 % of the mix.

EFFECT: the invention ensures improvement of the weighting agent quality at decreased its abrasivity and increased weighting capacity.

3 ex, 3 tbl

Description

The invention relates to the drilling of oil and gas wells and can be used for the preparation of weighting agents for drilling fluids, including superheavy ones, intended for drilling under conditions of abnormally high reservoir pressures, as well as during the manifestation of hydrogen sulfide.

Known weighting agents for processing drilling fluids containing magnetite concentrate in various concentrations [1].

The disadvantage of these weighting agents is their high abrasiveness, which contributes to premature wear of drilling tools and equipment, resulting in a sharp decrease in the commercial speed of drilling wells.

Known weighting agent for processing drilling fluids containing magnetite concentrate and barite concentrate [2].

Its disadvantage is the reduced weighting ability, due to the presence of a high content of water-soluble calcium salts, and the difficulty of controlling the density of the drilling fluid due to the mismatch between the calculated and practical data, as well as increased abrasiveness.

The objective of the invention is to improve the quality of the weighting agent by reducing the content of water-soluble calcium salts, reduce abrasiveness and increase weighting ability.

The problem is solved in that the weighting agent for processing drilling fluids, containing an artificial mixture of barite and magnetite concentrates, additionally contains sodium tripolyphosphate in the following ratio of components, wt.%:

Barite concentrate 60-40%

Magnetite concentrate 40-60%

Sodium tripolyphosphate Not less than 0.01% in excess of 100% of the mixture.

When sodium tripolyphosphate interacts with barite concentrate in the presence of magnetite concentrate, a synergistic effect is manifested in the form of a sharp decrease in the content of water-soluble calcium salts, a decrease in air adsorption on barite particles, and a decrease in coagulation of barite particles, which increases the uniformity of the filling of the system with dispersed particles and increases the critical weight concentration due to improve the wettability of barite particles, and therefore, the technical result is achieved - increased e weighting ability of the mixture under reducing its abrasiveness due to increased screening effect of the barite particles.

The inventive weighting agent is obtained by mixing barite and magnetite concentrates and processing the mixture with a solution of sodium tripolyphosphate.

Example 1. A weighting agent is prepared by mixing 60% magnetite concentrate and 40% flotation barite with a moisture content of 10-20%. The resulting mixture is treated with an aqueous solution of sodium tripolyphosphate at the rate of 0.01 g of dry matter per 100 g of dry mix. The resulting product is dried in a muffle furnace at a temperature of 600-700 ° C for 2 minutes in accordance with the factory technology for drying weighting agents. Physico-chemical characteristics of the obtained weighting agent are given in table 1, experiment 5.

Example 2. A weighting agent is prepared by mixing 40% magnetite concentrate and 60% flotation barite with a moisture content of 10-20%. The resulting mixture is treated with an aqueous solution of sodium tripolyphosphate at the rate of 0.3 g of dry matter per 100 g of dry mix. Dry the product analogously to example 1. Physico-chemical parameters of the obtained weighting agent are given in table 1, experiment 10.

For the purpose of comparison, several weighting options are prepared, the composition and properties of which are given in Table 1, experiments 1-4, 6-9, 11, 12. Experiments 5-12 show the indicators of weighting agents prepared according to the claimed recipe. The addition of sodium tripolyphosphate in an amount of 0.01-0.3% improves the performance of the weighting agent in the content of water-soluble salts. A decrease in their content contributes to an increase in the weighting ability of the mixture (Table 3).

The abrasive properties of the weighting agent were evaluated by the wear rate of the metal rings of steel 45 in an aqueous suspension of the weighting agent with a concentration of 30%. Reducing the weight of the ring in 1 hour characterizes the abrasive wear of steel in a given environment. The test results are shown in table 2, from which it is seen that the abrasiveness of weighting agents treated with sodium tripolyphosphate is not less than 0.01% in excess of 100% of a mixture of barite and magnetite, lower than that of the initial mixture. The decrease in abrasiveness is explained by the more powerful shielding effect of barite due to a decrease in the coagulation of its particles as a result of the synergistic effect of interaction with sodium tripolyphosphate and an improvement in the conditions for filling the system with dispersed particles, i.e., their denser packing.

Example 3. In order to assess the effect of the inventive weighting agent on the basic technological properties of drilling fluids, in the sample of solutions (see table 3), such a quantity of weighting agent (φ _pre ) was introduced that is necessary to achieve the conditional ultimate viscosity value T _conv = 60 ± 5 s . T _cond conditional viscosity measured using a funnel SPV-5, the density (ρ) - using the beam balance GRP-1 structure-rheological parameters (η _mp -. Plastic viscosity τ ₀ - dynamic shear stress, CHC _1/10 - static voltage shear for 1 and 10 min) - on a VSN-3 rotational viscometer, filtration (Ф ₃₀ ) - on a VM-6 device. The results are presented in table 3, from which it can be seen that the inventive composition of the weighting agent helps to reduce the rate of filtration of drilling fluids.

Used sources

1. USSR author's certificate No. 988852, IPC S 09 K 7/02, 1982.

2. RF patent No. 1213060, IPC C 09 K 7/04, 1986.

Claims (1)

Weighting agent for processing drilling fluids containing an artificial mixture of barite and magnetite concentrates, characterized in that it additionally contains sodium tripolyphosphate in the following ratio, wt.%: Barite concentrate 40-60 Magnetite concentrate 40-60 Sodium tripolyphosphate Not less than 0.01% in excess of 100% of the mixture