RU2298087C1 - Method for development of oil deposits complicated with visean erosional downcuts - Google Patents

Abstract

FIELD: oil production, particularly to develop layer-uplifted Bobrikovsko-Radaevsky oil pools made of terrigenous reservoirs and Tournaisian massive oil pool including carbonate reservoirs complicated with visean erosional downcut in the case of hydrodynamic oil pools communication.

SUBSTANCE: method involves more exactly determining oil presence outlines of oil pools and determining oil-saturation thickness of Bobrikovsko-Radaevsky reservoirs in visean erosional downcut; drilling producing and injection wells in visean erosional downcut side area; extracting product and injecting working agent in formation. At least one horizontal producing well and two injection wells are drilled. Horizontal producing well bore in located within the limits of Bobrikovsko-Radaevsky pool in visean erosional downcut in parallel to visean erosional downcut side line and obliquely to displacing working agent flow from horizontal or deviating injection well located outside the visean erosional downcut of Tournaisian oil pool. Horizontal bore is drilled in parallel to downcut side line and producing horizontal well bore. The second injection well is deviating within the limits of Bobrikovsko-Radaevsky pool in visean erosional downcut according to corrected designed network.

EFFECT: increased oil recovery due to effective development of above oil pools confined to visean erosional downcut sides, decreased oil production costs due to reduced number of wells to be drilled and decreased capital oil drilling costs.

1 ex, 2 dwg

Description

The invention relates to the oil industry, and in particular to the field of development of the Bobrikov-Radaev reservoir-vaulted oil reservoir represented by terrigenous reservoirs and the Tournaisian massive oil reservoir represented by carbonate reservoirs complicated by an erosion Visean insert, if there is a hydrodynamic connection between the reservoirs.

Erosive Visean incisions have a significant impact on the distribution of oil, control the oil content of the Tournaisian carbonate stratum, as they contribute to the lateral migration of oil from adjacent carbonate reservoirs to terrigenous ones during the development of cut-in deposits.

There is a known method of developing a multilayer reservoir at a late stage, involving the development of an oil reservoir using injection of a working agent through a central injection well and taking oil through the lateral horizontal and horizontal wells surrounding the circumference (RF Patent No. 2159324 of 04.25.2000).

The disadvantage of this method is the method of developing only one oil reservoir. The authors do not provide a system for the development of two different types of deposits in the presence of erosive Visean cuts within the developed deposits, drilling and operation of horizontal injection wells.

The closest in technical essence to the proposed one is the method of developing oil deposits in the cuts, including clarifying the contours of the oil content of the deposits and determining the oil-saturated thickness of the Bobrikov-Radaev reservoirs in the erosion Visean insert, drilling production and injection wells in the instrumentation zone of the insert, production selection and injection of the working agent layer (Muslimov R.Kh. et al. Improving the system of development of deposits in cuts // Geology, geophysics and development of oil fields. - 1993. - No. 11-12. - S.11-13). In the known method, vertical injection wells are drilled in cutting rows and positioned directly near the side line of an erosive Visean insert. If there is no opportunity to meet the three-row count, with small sizes of deposits (less than 300 m ² ), there is an option to turn the injection row, where the wells are placed along or at an angle to the sideline. Production vertical wells are placed in the instrument zone perpendicularly and at an angle to the major axis of the structure. The method allows to select the main oil reserves from the deposits, increase the rate of oil extraction, reduce development time by increasing the number of production wells by 1.5-2.0 times. However, the oil-saturated instrument zone of the erosive Visean insert of the Bobrikov-Radaev and Tournaisian deposits is not sufficiently developed.

The technical task is to increase oil recovery due to the effective involvement in the development of the Tournaisian and Bobrikovka-Radaev deposits associated with the instrumentation areas of the erosion Visean cut, composed of carbonate and terrigenous reservoirs, reducing material costs for oil production by reducing the number of wells drilled and lower capital investments on them drilling.

The technical problem is solved by the method of developing oil deposits complicated by the Visean insert, including clarifying the oil profile of the deposits and determining the oil-saturated thickness of the Bobrikov-Radaev reservoirs in the erosion Visean insert, drilling production and injection wells in the instrumentation zone of the insert, production selection and injection of the working agent.

What is new is that at least one horizontal production well is drilled, two injection wells, they place the horizontal well of the production well within the erosion Visean insert on the Bobrikov-Radaev deposit, parallel to the side line of the erosion Visean insert and perpendicular to the displacing flow of the working agent from the horizontal or inclined - a directed injection well, located outside the erosion Visean insert on the Tournaisian reservoir, the horizontal trunk of which is directed parallel flax sheerline incision and extractive horizontal well bore, and a second injection well placed obliquely-directed erosion within Visean incision on Bobrikov-radaevskoy reservoir according to the corrected design grid.

A necessary condition is the correspondence of the hypsometric position of oil-saturated reservoirs that make up two oil deposits, confined to the instrumentation areas of the erosion Visean insert, composed of Bobrikov-Radaev terrigenous and carbonate Tournaisian reservoirs and having a hydrodynamic connection between each other.

The preliminary patent research on the patent fund and technical library of the TatNIPIneft Institute showed the absence of identical or equivalent technical solutions in comparison with the claimed method. This allows us to conclude that it meets the criteria of "novelty" and "inventive step".

Figure 1 presents a schematic geological profile.

Figure 2 presents the layout of horizontal (GS) and directional wells on deposits in carbonate and terrigenous reservoirs complicated by erosive Visean insert.

The method is carried out in the following sequence.

Deposits are drilled with wells on a rare grid. Based on the results of deep drilling and seismic surveys, structural maps are built on the roof of the reservoirs of the Tournaisian and Bobrikov-Radaev deposits, combine them, refine the side line of the erosion Visean insert, determine the effective oil-saturated thickness of the reservoir in the erosion Visean insert. If there is a thickness of at least three meters in the breech zone of the Bobrikovka-Radayevsky reservoir in the instrumentation zone, at least one horizontal production well No. 1 of the horizontal well is drilled, which is placed along the most permeable terrigenous reservoir parallel to the sideline of the erosion Visean incision at a distance of not more than 100 m and perpendicular to the displacing flow of the working agent from a horizontal or deviated directional injection well No. 2 GS located outside the erosion of the Visean insert into the carbonate reservoir parallel to the line side and trunk incision extractive horizontal. The second injection directional well No. 3 is drilled within the cut in the terrigenous reservoir and placed according to the adjusted design grid. Wells are drilled, mastered and put into operation. They select products and pump the working agent into the reservoir. The proposal provides an increase in oil recovery due to the effective involvement in the development of deposits confined to the instrumentation areas of the erosive Visean cut, composed of terrigenous Bobrikov-Radaev and carbonate Tournaisian reservoirs, reducing material costs for oil production by reducing the number of vertical wells drilled and lower capital investments for their drilling .

Injection directional well No. 3, drilled in terrigenous reservoirs, and horizontal horizontal injection well No. 2, drilled in a carbonate reservoir, were initially commissioned in the production wells category. When the water content of the produced products of the wells reaches 50% or more, they are transferred to injection, as a result of which the process of displacement and outflow of oil to the side of the insert towards the production well No. 1 of the hydraulic unit, which simultaneously produces oil reserves from terrigenous reservoirs and residual oil reserves from carbonate reservoirs of the instrument zone of the erosive Visean insert.

Concrete example

On the site of the field, characterized by the presence of a hydrodynamic connection between the Bobrikov-Radaev and Tournaisian deposits in the instrument zone of the erosive Visean insert, production and injection vertical and / or directional wells No. 4, 5 were drilled on a design grid of 400 × 400 m (Fig. 2) . Carried out their arrangement. On the fact of drilling, we clarified structural maps for the roof of the reservoirs taking into account the map for the reflecting horizon “U”, the side line of the erosive Visean insert, determined the thickness of the effective oil-saturated interlayers of the Bobrikov-Radaev reservoirs in the erosive Visean insert, the presence of the oil-water contact (VOC) of the oil deposits horizontal wellbore in plan and oil saturated reservoir. The width of the erosive Visean cut-in was 800-1000 m. The thickness of the collector on the cut-in board varies from 3 to 7 m. When opening two or more effective oil-saturated interlayers in the insert, a layer with a thickness of more than 3 m is selected for the horizontal trunk, in this case the lower one (Fig. .one). The absolute marks of the entry point into the reservoir and the bottom of the well bore were clarified. Placed in the cutting zone, horizontal producing wells No. 1 GS and No. 6 GS along the most permeable terrigenous reservoir parallel to the sideline of the erosion Visean insert and perpendicular to the displacing flow of the working agent from the injection wells - horizontal No. 2 GS and directional - No. 7 (Fig. 2 ) Horizontal injection well No. 2GS and directional No. 7 are placed within the cut-in side zone on the Tournaisian deposit. An inclined directional injection well No. 3 was drilled within the cut and placed according to the adjusted design grid at a distance of 400 m from the bottom points of the producing horizontal wells No. 1 GS and No. 6 GS. All injection wells are initially commissioned as production wells.

When the water content of the produced products of the wells is reached, up to 50 percent is converted to injection, resulting in a more intensive process of oil displacement and outflow to the side of the cut towards the producing wells No. 1 GS and 6 GS, which simultaneously produce oil reserves from terrigenous reservoirs and residual oil reserves from carbonate reservoirs of the instrument zone of the erosive Visean insert.

The invention allows to increase the oil production rate of a horizontal producing well by 2 times, to extend its life, to obtain additional oil production (more than 200% per year) due to overflow of production of a well through a Visean insert from the Tournaisian to the Bobrikov-Radaevskoye deposit and involvement in the development of tool sites deposits composed of terrigenous reservoirs of the Bobrikov-Radaev deposits, respectively, increase the economic effect. The intensity of fluid flows is due to the operation of injection wells in the Tournaisian deposits and the degree of hydrodynamic connection between the two deposits.

Claims (1)

A method for developing oil deposits complicated by an erosive Visean insert, including clarifying the contours of oil deposits and determining the oil-saturated thickness of the Bobrikov-Radaev reservoirs in an erosive Visean insert, drilling production and injection wells in the instrument zone of the insert, production selection and pumping of the working agent into the formation, that they drill at least one horizontal production well, two injection wells, place a horizontal production wellbore within the erosion vise cut into the Bobrikov-Radaev deposit parallel to the side line of the erosive Visean cut and perpendicular to the displacing flow of the working agent from a horizontal or directional injection well located outside the erosive Visean cut into the Tournaisian deposit, the horizontal trunk of which is directed parallel to the cut line and and the second injection well is placed directional within the erosion of the Visean cut into the Bobrikovs on-radaevskoy deposits corrected according to the design grid.

Images