SU829871A1 - Method of isolating formations - Google Patents

Description

 54J METHOD OF INSULATING A PLATE of permeable cores are impregnated with seams of calcium chloride-type water with a total mineralization of 280 g / l, and the least permeable core is oil. Each core is enclosed in a metal pipe with a diameter of 15 mm. First, a hydrofluoric acid of 40% concentration (TU02-14-18-75) is injected into the model of the reservoir at a pressure of 0.1 kgf /. Then an insulating material - latex-oil emulsion containing 50% latex is pumped into the same model under the same pressure. volume oil, 48% volume, and emulsate, 2% volume. Then, a solution of hydrofluoric acid is injected into the model again.With each injection of acid, acid and insulating material, pressure and filtration rate are measured in each zone of the formation model fr. e. in each core). After the injection of reagents, the formation model is left in a quiescent state for an hour to wait for the coagula of the insulating material. After that, the permeability of the outer zone (of each core) is determined. For this, reverse filtration is carried out at a pressure of 0.1 kgf / cm of saline water through water-rich cores and reverse filtration of oil through an oil-saturated core. The rate of flow of fluids through each zone is controlled. - To obtain comparative data, the permeability of cores processed according to the well-known method of isolating plates is additionally determined. Taking into account that, according to a known method, granular magnesium and hydrochloric acid are injected only for the purpose of obtaining an electrolyte solution in the reservoir, to simplify the experiment, both watered cores are immediately mixed with electrolyte solution containing saline water containing magnesium ions. After the injection of reagents according to the known method, the reservoir model remains in a quiescent state to wait for coagulation already for 24 hours. h, and not for one hour, as in the proposed method. The results of the tests obtained according to the proposal of 14 aeMOMy and the known methods are presented in Table. 1 and 2. The test results show that when the proposed method is used, after injection of hydrofluoric acid into the reservoir model, the permeability of the highly permeable watered zone (core C decreases to the average permeable watered zone (core 2); Both of the water-saturated zones of Stern 2 and 3 are sharply reduced (iO-18 times), although channels for supplying water still remain, since with a permeability of 0.087 D (core 2) and 0.049 DUn 3) filtering is possible water to a greater extent than oil filtration with a permeability of 0.131 D (core 1 with the same pressure gradient. And during subsequent injection of acid injected after the insulating material, both water-impressed zones of the model are almost completely isolated, while the permeability of the oil-saturated zone (core, D), on the contrary, even increases by 25.2%, which, under field conditions, allows an increase in well production. In the known method, a rather high degree of isolation is provided only in the highly permeable and intruded zone (core 6). ate layer. The less saturated watered zone (core 5} after injection of insulating material reduces permeability by only 3.2%, and the permeability of oil-saturated zone (core 4) remains unchanged. At the same time, the proposed method reduces the permeability of both aquifers. zones (cores 2 and 3) up to 99.7 and 99.9% within one hour after completion of the insulation works, i.e. within an hour, the Gshasta aquifers are almost completely isolated from the Bodopritok. reduction t lko very high permeability formation zone (the core b). The proposed method allows to isolate both high and less permeable zones of the formation in a nonuniform permeability, whereas the known method only allows to isolate the high-permeability portion

582987

flat, leaving uninsulated areas with less permeability. In addition to improving the quality of the insulation work, the proposed method, as compared with the known method, simultaneously reduces the coagulation time of poly-. measured insulating material no less than 20-40. and more times, which reduces the total time of insulation work on the well by 2-3 times, liter 2-3 days, instead of 5-7 days.

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The economic effect of using the proposed method consists of an increase in additional oil production, a reduction in the amount of added water, a reduction in the time of simple wells and crews of capital repair for the duration of the insulation works.

When isolating a reservoir, saving on one well is no less than 10 thousand rubles. in year.

Table 1

1 Neftenasy0, 151 0.151 0.1510.189 schenny

0.863 0.860 0.0870.003

1.637 0.882 0.049 0.002

Oil saturated

Formula of Invention The method of isolating a formation by pumping an insulating material based on a polymer into it, which differs by 25.2

99.7

99.9

table 2

0.187

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so that, in order to improve the efficiency of the isolation of a reservoir that is not uniform in permeability, before injection into the formation of insulating material 78298 and after it is injected into the formation, hydrofluoric acid is pumped. Sources of information taken into account during the examination 71 USSR № 492645, cl. E 21 B 33/13, 1973. 2. USSR author's certificate No. 413292, cl. E 21 V 33/13, 1971 (prototype).

Claims (1)

Claim A method of isolating a formation by injecting polymer-based insulating material into it, characterized in that in order to increase the insulation efficiency of a heterogeneous permeability of the formation, hydrofluoric acid is injected into the formation and after it is injected into the formation.