SU1744245A1 - Method of formation fracturing - Google Patents

Abstract

The invention relates to the oil and gas industry. The goal is to increase the efficiency of the method due to the possibility of increasing and fixing fracture cracks. An aqueous suspension of hardener and quartz sand and a liquid sandblower are sequentially pumped into the formation. The mass of quartz sand in suspension is chosen from the expression of 0.06 Mo Mp 0.075 Mo, where Mo and Mn are, respectively, the mass of hardener and quartz sand, kg.

Description

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The invention relates to the oil industry, namely to methods for fracturing gas-bearing and oil-bearing formations.

A known method of hydraulic fracturing involves injecting a mixture of carrier fluid with a propping agent into the formation, using sodium meta silicic acid as a reducing agent.

A method of hydroacid fracturing is also known, which includes the sequential injection of hydrochloric acid solution and sand in a carrier fluid under pressure, and lime-chalk alkaline solution is used as a carrier fluid.

Closest to the present invention is a method of fracturing the formation, which consists in pumping a fluid into the formation with an abrasive material, under the action of which the formation splits.

The disadvantage of this method is the likelihood of closing cracks after pressure relief and the low quality of their development.

The aim of the invention is to increase the efficiency of the method due to the possibility of increasing and fixing fracture cracks.

SUMMARY OF THE INVENTION The essence of the invention is that an aqueous suspension of hardener - non-destructive explosive (DFR) and quartz sand is pumped into the formation before injection of the sand-carrier fluid, and the mass of quartz sand in the suspension is chosen from the following expression:

0.06 Mo Mp 0.075 Mo where Mo and Mn are, respectively, the mass of hardener (NRB) and quartz sand.

Hardener - non-explosive destructive substance is a powdery material based on free

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calcium oxide with additives in the following ratio, wt.%:

Tricalcium

silicate3,5 - 14

PRS0.07-1.4

Condensation product

naphthalenesulfonic acid

with formaldehyde so

the degree of P-2-9 (superplasticizer C-3) 0.07 -1.4

Oxides of one and a half

aluminum and iron 0.07-3.5

Free oxide

Calcium 49.7 - 65.66

NRB is a powder-colored, non-flammable, non-explosive. It has alkaline properties (pH 12.5), bulk density 1.2-1.3 g / m, water demand 27%, pressure developed up to 500 kgf / cm (50 MPa). When mixing NRB with water, a working mixture (suspension) is formed, which, when filling a closed cavity, gradually, as a result of hydration reaction of the NRB powder, hardens, increasing in volume.

The increase in volume is accompanied by the development of pressure on the walls of the containing cavity, the value of which reaches 500 kgf / cm2 (50 MPa) with time. At the same time, stresses develop in the rock system, the values of which may exceed the ultimate tensile strength, which leads to the formation of cracks in the rock and their development over time.

The essential difference of the proposed method from the prototype is that prior to injection of the sanding liquid into the formation, an aqueous suspension of the hardener — NRB and quartz sand — is injected, while the mass of quartz sand in the suspension is chosen from the following expression:

0.06 Mo Mp 0.075 Mo. where Mo and Mn are, respectively, the masses of the hardener and silica sand, kg.

The invention is as follows.

150 m3 of water, a fracturing fluid, is drawn into a special container. In the second container, a mixture of an aqueous hardener solution (HPD) and quartz sand is prepared.

volume of 4 m3, containing NRV 6.7 tons, water 1880 liters and 335 kg of quartz sand. In the third tank, a carrier fluid of silica sand in a volume of 17 m3 containing 3.4 tons of sand is prepared. When exercising

In this way, the ratio of hardener to water in the suspension should be constant and equal to 0.27.

The order of injection is as follows: a fracture fluid is injected through the deflated tubing

in a volume of 150 m ° and, without decreasing pressure, an aqueous solution of hardener (NRW) and quartz sand in a volume of 4 m3 is pumped. After injection of NTS with quartz sand, the well is maintained for 4 hours.

In each case, the holding time is different and is chosen taking into account that the resulting suspension has gained a structure for more successful crack development and pressure stabilization in the bottomhole formation zone.

reservoir.

After holding the well, a carrier fluid of quartz sand in the volume of 17 m3 is pumped.

After fracturing

the well is washed and start to develop.

Formula of the Invention A method of fracturing, which involves injection of a fracture fluid and a sand-carrying fluid into the wellbore zone, characterized in that, in order to increase the efficiency of the method due to the possibility of fracture fracture and fixation, an aqueous hardener suspension is injected into the formation and quartz sand, wherein the mass of quartz sand in suspension is chosen from the following expression 0.06 Mo Mp 0.075 Mo,

where Mo and Mn are, respectively, the mass of hardener and silica sand, kg.

Claims (1)

A method of fracturing, including injecting fracturing fluid and sand carrier fluid into the bottomhole zone, characterized in that, in order to increase the efficiency of the method due to the possibility of increasing and fixing fracture cracks, an aqueous suspension of hardener and quartz sand is injected into the reservoir before the fluid is loaded into the carrier sand. while the mass of quartz sand in suspension is selected from the following expression 0.06 Mo <Mn <0.075 Mo, where Mo and Mn are the mass of hardener and silica sand, kg, respectively.