RU2165521C1 - Process of exploitation of oil field - Google Patents

Abstract

FIELD: oil industry. SUBSTANCE: invention refers to exploitation of oil fields presented by oil pool with dam made of dense rocks and water-bearing pool and is directed for additional extraction of oil from depression zones. When oil field with oil pools having dams of dense rock and water-bearing pool is exploited pool is flooded through injection wells. Oil is extracted to surface through production wells. Inflow of water to production wells is insulated. Outlines of positions of dams of small thickness are established by geophysical investigation prior to conducting of insulation operation. Then water impermeable screens are set over entire outline through open shafts of wells in these zones to height of decrease of thickness of dams in water-bearing pools before their grouting. EFFECT: prolonged time of exploitation of wells up to their ultimate flooding by installation of water impermeable screens in constructed wells. 1 dwg

Description

 The invention relates to the field of development of oil fields, represented by oil reservoirs with a bridge of dense rocks and an aquifer.

 A known method of developing oil fields with the initial operation of production wells with bottomhole pressure below the saturation pressure and subsequent isolation of the drained sections (Reference book on oil production / Ed. Sh.K. Gimatudinova, M .: Nedra, 1974, p. 63).

 The disadvantage of this method is that the low detection efficiency and isolation of drained areas does not significantly increase oil recovery.

 The closest in technical essence to the proposed one is a method of developing oil fields with water insulation in producing wells by installing waterproof screens through wells located in the troughs of the formation (patent 2099512, 6 E 21 B 43/20, published in BI N 35, 1997 )

 The disadvantage of this method is that through wells located in the troughs of the formation, a large amount of associated water is produced due to the creation of waterproof screens only after flooding of these wells.

 The aim of the invention is to increase the life of the wells to their maximum watering by installing waterproof screens in the wells under construction to cement the casing strings in an open hole.

 This goal is achieved by the described method of developing oil fields with oil reservoirs with a jumper from dense rocks and an aquifer, including flooding the reservoir through injection wells, extracting oil to the surface through production wells and isolating the flow of water in production wells.

 What is new is that, before conducting geophysical studies, the location of the bridges with a small thickness is established, after which in these zones waterproof screens along the entire contour through the open boreholes are installed to the height of the thickness of the bridges in the aquifers before they are cemented.

 Conducted preliminary patent research on the patent fund, as well as on the fund of the technical library of the TatNIPIneft Institute showed the absence of identical or equivalent technical solutions in comparison with the claimed object. Moreover, the distinguishing features of the claimed technical solution are significant, which allows us to conclude that its criteria of "novelty" and "inventive step" are met.

 The drawing shows the layout of the wells and the installation location of waterproof screens for the proposed method.

 The claimed method is carried out in the following sequence.

 At the initial stage of development, a productive layer is opened by groups of wells, which include production and injection wells. Wells are located according to the accepted field development scheme.

 On the isometric map of the roof of the reservoir, those wells are selected that are located from the center of the structure to the circuit with a decrease in the jumper power, and through these wells waterproof screens (zones) are installed in the reservoir. Screens are installed by injection into the formation of a waterproofing material from among those that are used to isolate water inflow in production wells. For the installation of screens, insulating compositions are used, which are thickened or seized in the formation, and compositions for both permanent and temporary insulation can be used. The technology of work is similar to the work on isolation of water inflow in producing wells.

 The installation of waterproof screens in the reservoir before the casing is lowered and its cementing leads to an increase in the life of the wells to their maximum watering, as well as to a decrease in the flow rate of injected water, a significant redistribution of water flows in the reservoir, which contributes to the washing of deadlock and stagnant zones and an increase in oil recovery.

 An example of a specific implementation.

 The implementation of this method, we consider the example of a vertical well N 1, exploiting an oil reservoir in sand reservoirs, drilled in the experimental section of the field according to the adopted development technical scheme. The well is located on the structure’s contour in the place where the jumper power decreased from 3 to 1.8 m, that is, 1.2 m. According to the proposed method, a waterproof screen was installed at such a height.

Previously, near the wellhead, components of the insulating material — CaCl ₂ solution, gypsum, and cement mortar — were prepared in separate containers. A set of geophysical surveys (GK, OGK) was carried out, with the help of which it was determined that the water reservoir was located at a depth of 1768 m. The packer with a special filter at the end was lowered into 73 mm compressor pipes and installed at a depth of 1765 m. Absorption capacity of the interval reducing power jumpers 1.2 m long at a pressure of 180 kgf / cm ² is equal to 12 m ³ / h Reagents were pumped into the reservoir in the following sequence: saline water, 1.5 m ^{3 of} hypane, 3.2 m ^{3 of} cement. The injection of cement followed by hypane leads to the shutdown of the aquifer by installing a screen in the wellbore. After 24 hours, the bottom was checked and washed, the oil saturated interval was opened with a hydraulic perforator, and the pump was lowered. As a result of insulation work, anhydrous oil was obtained with a flow rate of 36 tons / day. Within 12 months after the installation of the waterproof screen, the well was not flooded.

 In the first year of operation, 1,800 tons of oil were additionally produced. At an oil price of 460 rubles per ton, the revenue will be 828,000 rubles. At the cost of producing additional oil, taking into account the costs of applying the proposed method of 300 rubles per ton, 540,000 rubles will be spent. And the economic effect will be 288,000 rubles per well per year.

 In the selected experimental section, waterproof screens were installed in 16 wells (NN 1-16) located in places where the jumper power was reduced. For the first year of operation, they gave an additional 288 thousand tons. oil. The annual economic effect will be 46080000 rubles.

Claims (1)

 A method of developing oil fields with oil reservoirs with a jumper from dense rocks and an aquifer, comprising flooding the reservoir through injection wells, extracting oil to the surface through production wells and isolating the influx of water in production wells, characterized in that contours are established before conducting geophysical studies the location of the jumpers with a small thickness, after which in these zones to the height of the decrease in the thickness of the jumpers in the aquifers set impervious screens along the entire contour through open wellbores prior to cementing.