RU2652240C1 - Method of developing two objects of different stratigraphic accessories - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas production industry, namely to development of a multi-object deposit. Method of developing an oil field includes drilling of obliquely directed production and injection wells, selection from production wells and injection of a displacing agent into injection wells. Before drilling wells, zones of overlapping in plan two oil-bearing objects of different stratigraphic affiliation with a vertical distance of 100 to 400 m are determined, isolate zones of oil-bearing objects with a thickness of 0.5 to 50 m. At a thickness of oil-bearing objects from 0.5 to 4 m, at least one vertical well is drilled and oil-bearing objects are simultaneously developed in a separate way. At a thickness of oil-bearing objects from 4 to 50 m, horizontal wells (HW) are drilled. First, the HW is drilled to the lower oil-bearing facility. Entry points to the oil-bearing objects according to the HW are in plan separated from each other by half the distance of the grid along the drilling path. Drilling is performed with a zenith angle of 68–80° on the roof of the upper oil-bearing object. After the fall of the zenith angle, the zenith angle is again set to 74–83° on the roof of the lower oil-bearing object and enter the oil-bearing object 12 m below the roof along the trunk. Then, geophysical surveys of wells (GSW) are carried out, the roof hypsometry is clarified and the casing string is lowered. After isolating the cavernous space, GSW is carried out to determine the tightness of the cavernous space. After drilling a horizontal trunk with a smaller diameter along the length equal to the grid distance, with an outlet in an oil-bearing facility at 89–91° depending on the structural features of the topography of the roof of the lower oil-bearing object in the direction to the slaughter in plan, and in the zones with plantar water the trunk is located above the oil-water contact (OWC) by 10–45 m, and in zones without plantar water – above the dense underlying rocks by 2–46 m. Horizontal trunk is filled with a hydro-emulsion solution. Then, the upper horizontal trunk is drilled in the upper oil-bearing object from a removable wedge-deflector. Horizontal barrel is cut over the roof or within the oil bearing object and the drilled with a smaller diameter and the same azimuth as the lower trunk, with an acceptable divergence from 0 to 7° and with an exit in the facility at 89–91° depending on the fall or rise of the relief of the roof of the oil-bearing object in the direction of slaughter in plan. Moreover, the trunk is located above the OWC at 10–45 m in zones with plantar water, and in zones without plantar water it is higher than dense underlying rocks by 2–46 m. Trunk is left open or planted with a filter, depending on the petrophysical characteristics of the oil-bearing rocks. Well is equipped with equipment for simultaneous-separate operation and is put into operation.

EFFECT: proposed method allows to increase oil recovery factor, and also to shorten development term due to development of reserves of two objects with a single well grid.

1 cl, 2 dwg, 1 ex

Description

The invention relates to the oil industry and may find application in the development of a multi-field field.

A known method for the development of deposits (patent RU No. 2282023, IPC ЕВВ 43/20, publ. 08/20/2006, bull. No. 23), including drilling a producing formation in at least one conditionally horizontal well with an angle of inclination of 75-85 ° to the vertical along the downward profile, ensuring the placement of the bottom of the well near the oil-water contact (VOC) outside the region of high pressure gradients not exceeding 0.25 MPa / m, casing of the well with the descent of the production string to the bottom of the well, opening 30-70% of the reservoir, starting from the roof, while dneniya dovyrabotku oil wells is carried out by drilling a second angle and / or horizontal stems above first strand fiberglass with a hole in the column.

The disadvantage of this method is that the reserves of the upper part of the reservoir before drilling the second trunk are in long-term conservation. The application of the known method does not allow to achieve high technological indicators, the full coverage of the section by drainage and high oil recovery rates in the development of oil-bearing objects of different stratigraphic affiliations.

Closest to the proposed invention in technical essence is a method of developing a massive type of oil deposit (patent RU No. 2447272, IPC EV 43/20, publ. 04/10/2012, bull. No. 10), including drilling the main horizontal shaft in a thickness of from the roof not more than 30% of the total oil-saturated thickness, drilling a second lower horizontal or subhorizontal shaft under the first with an azimuth deviation of not more than 10 °, with an anti-aircraft angle of at least 60 ° and a distance from the first shaft of at least 3 m with one or more square a dock for equipment of a controlled filter with a length of at least 15 m, ensuring the absence of fluid flows between the zones of the formation before and after the site, equip the well and put it into operation, measure the flow rate of liquid, oil, determine its productivity and the degree of water cut of the product; when the water content of the product is 85% or more, the controlled filter is lowered to the installed site and its lower shutter is closed, cutting off the lower part of the well, and the upper part of the well with low water content of the product is continued to operate.

The disadvantage of this method is the low efficiency of the development of several objects of different stratigraphic affiliation in the field as a result of the fact that horizontal wellbores are drilled in the same reservoir along the section, while the reserves of other oil-bearing objects are in conservation, the influence of the oil-and-gas industry is not taken into account, which reduces oil recovery, and also allows you to develop simultaneously and separately several objects of different stratigraphic affiliations.

The technical objectives of the method of developing two oil-bearing objects of different stratigraphic affiliations are to achieve the maximum oil recovery coefficient with maximum coverage by drainage of the field by area and section with maximum savings in capital investments.

Technical problems are solved by the method of developing two oil-bearing objects of different stratigraphic affiliations, including the drilling of directional production and injection wells, selection from production wells and injection of the displacing agent into injection wells.

The new one is that before drilling wells, zones of combination in terms of two oil-bearing objects of different stratigraphic affiliation with a vertical distance between them from 100 to 400 m are determined, zones of oil-bearing objects with a thickness of 0.5 to 50 m are distinguished, with a thickness of oil-bearing objects from 0 , 5 to 4 m drill at least one vertical well and develop oil objects simultaneously and separately, with a thickness of oil objects from 4 to 50 m horizontal wells are drilled - horizontal wells first to the lower oil-bearing operation object, and entry points to oil-bearing facilities along the horizontal well are half as far from each other as the design grid in the direction of drilling, and the zenith angle on the roof of the upper oil-bearing facility is 68-80 °, then drilling is performed with the zenith angle falling onto the roof of the lower oil-bearing facility again make a zenith angle set to 74-83 °, go into an oil-bearing facility 12 m below the roof along the trunk, conduct well geophysical surveys - well logging, refine roof hypsometry and lower the pipe casing, isolate annulus , a well logging is carried out to determine the tightness of the annulus, a horizontal well is drilled with a smaller diameter along the length equal to the grid distance, with an exit in the oil-bearing facility at 89-91 ° depending on the structural features of the topography of the oil-bearing object in the direction toward the bottom in the plan, and in the zones with the bottom water, the trunk is located 10-45 m above the oil-water contact - the oil-water contact, and 2-46 m above the dense underlying rocks in the zones without bottom water; the horizontal trunk is filled with a hydroemulsion solution, then drilled a horizontal horizontal borehole in the upper oil-bearing facility from a removable deflecting wedge, is cut above the roof or within the oil-bearing facility and a horizontal borehole is drilled with a smaller diameter in the same azimuth as the lower bore, with a permissible difference from 0 to 7 ° and exit in the object 89-91 ° depending on the fall or elevation of the topography of the oil-bearing object in the direction towards the bottom in the plan, moreover, by 10-45 m above the oil drainage zone in zones with plantar water, and in areas without plantar water, by 2-46 higher than dense underlying rocks m, the trunk is left open thawed or cased with a filter depending on the petrophysical characteristics of oil-bearing rocks, equip the well with equipment for simultaneous and separate operation and put it into operation.

In FIG. 1 shows the layout of wells at oil-bearing facilities (top view).

In FIG. 2 shows the layout of wells in the context of oil-bearing objects of different stratigraphic affiliations.

The method is carried out in the following sequence.

A minimum of exploratory wells are drilled at the field, well logging and hydrodynamic studies of wells are carried out before bottomhole, the presence and number of oil objects in the context of different stratigraphic affiliations are determined, the presence and position of oil and gas facilities in each oil object, geological modeling is carried out, structural maps are constructed, oil-bearing contours are drawn from the oil oil-saturated thicknesses, the degree of coincidence of objects in the plan are determined for objects selected in the section according to structural structures. Based on the GIS results, the hypsometric marks of the roof and the sole of the upper and lower oil-bearing objects, their collection properties, saturation, the position of the OWC or the hypsometric position of the bottom of the oil-saturated layer in each are specified.

The zones of full or partial combination of 1 in terms of two oil-bearing objects of different stratigraphic affiliation with a vertical distance between them from 100 to 400 m are determined, zones of oil-saturated thicknesses from 0.5 to 50 m are distinguished.

In the selected zones for oil-saturated thicknesses from 0.5 to 4 m, at least one vertical well is drilled for two oil-bearing objects or one grid of vertical wells with a distance between them equal to the design grid of line 2 or area 3 development systems (Fig. 1), and they are developed simultaneously-separately, without leaving the reserves of the second oil-bearing facility in long-term preservation, and during operation during flooding of well products from 85 to 98% they are transferred for injection.

In the selected areas for oil-saturated thicknesses from 4 to 50 m, GS 4 is drilled first at the lower oil-bearing operation site, and the entry points to oil-bearing objects along the horizontal well are halfway apart from each other by half of the design grid in the direction of drilling, and the zenith angle is 5 on the roof the upper oil-bearing facility 6 is 68-80 °. Then, drilling is performed with the zenith angle falling and the zenith angle 8 is again set on the roof of the lower oil-bearing object 7 to 74-83 °. They enter the oil-bearing object 12 m below the roof along the trunk, perform well logging, clarify roof hypsometry and lower the column, isolate annular space, conduct well logging to determine the tightness of annular space. A horizontal trunk is drilled with a smaller diameter of 9 along the length equal to the distance of the grid, with an exit in the oil-bearing facility at 89-91 ° depending on the structural features of the topography of the oil-bearing object in the direction toward the bottom in the plan, and in areas with plantar water the trunk is located higher than the oil-well cutting 10 by 10-45 m, and in areas without bottom water, by 2-46 m above the dense underlying rocks. A horizontal well is filled with a hydroemulsion solution to preserve reservoir properties. The upper horizontal barrel 11 in the upper oil-bearing facility is cut above the roof or within the oil-bearing facility from a removable deflecting wedge and the horizontal shaft is drilled with a smaller diameter and in the same azimuth as the lower shaft with a permissible difference from 0 to 7 ° and exit in the object 89-91 ° depending on the fall or elevation of the topography of the oil-bearing object in the direction to the bottom in the plan, moreover, by 10-45 m above the oil-water supply in zones with bottom water or in areas without bottom water above dense underlying rocks 12 by 2-46 m. Barrel leaving open or cased with a filter depending on the petrophysical features of oil-bearing rocks. They equip a well with equipment for simultaneous and separate operation and put it into operation, measure the flow rates of liquid and oil, carry out modeling, determine the productivity and degree of watering of the product for each oil-bearing facility. When watering products more than 85%, GIS is performed to determine the interval of water inflow. A packer is lowered into the water inflow interval, it is installed before and after the waterlogged interval, the waterlogged interval or the well as a whole is isolated, the well with a low water cut is continued to operate.

Case Studies

Four vertical exploratory wells were drilled in the north, south, east and west of the field. Two oil-bearing objects in the Bashkir and Tournaisian stages with an average occurrence depth of 900 and 1250 m, respectively, completely coinciding in plan, the distance between which along the section was 290 m, were identified in the section of the field according to the results of well logging. We determined the position of the oil and gas complex in each oil-bearing object at absolute elevations minus 670 and minus 975 m, respectively, performed geological modeling. The deposit of the lower oil-bearing object is underlain by plantar waters, the upper - by dense rocks. Structural maps were constructed, oil contours were drawn along objects according to structural constructions, oil saturated thicknesses were determined. The combination in terms of zones with oil-saturated thicknesses of 0-50 m was determined.

Vertical wells were placed in the selected zones for thicknesses from 0.5 to 4 m. Design wells for oil facilities were placed on one grid 300 × 300 m so that the entry points to the oil objects were 300 m apart from each other in plan.

We drilled producing vertical wells before bottomhole at the lower oil-bearing object of the Tournaisian stage sediment and performed well logging, clarified the hypsometric elevation of the roof of the upper oil-bearing object minus 645 m and its reservoir properties: porosity - 17%, permeability - 475 mD, oil saturation - 78%, determined the oil-and-gas concentration for hypsometric elevation minus 670 m, oil saturated thickness 25 m; the roof of the lower oil-bearing object was found at a hypsometric elevation of minus 940 m, the reservoir properties of the host rocks are heterogeneous and average: porosity - 13%, permeability - 315 mD, oil saturation - 80%. VNK for the deposits was determined at the hypsometric elevation minus 975 m, i.e. the oil-saturated thickness of the Tournaisian object in the drilling area is 35 m.

They equipped the well with equipment for simultaneous and separate operation and commissioned it, produced stratum products, measured the flow rate of liquid and oil, determined its productivity and the degree of watering of products for each of the facilities.

When drilling for each oil-bearing facility according to different independent grids, the flow rate of 2 vertical wells was 10 tons / day, the development period of the area was 2 times higher than the term of the proposed method, 44.9 thousand tons of oil and 140.9 thousand m ^{3 of} liquid were produced.

The balance reserves per well estimated by the volumetric method amounted to 112.5 thousand tons. According to the known method, when drilling two vertical wells, one for each of the objects with different stratigraphic affiliations, the final oil recovery coefficient is 0.2 units, according to the proposed 0.26 d. 6% more.

In FIG. 1 shows the layout of wells in plan on a map of oil-saturated thicknesses. As a result of drilling wells according to the proposed method, an additional 13.6 thousand tons of oil were produced. At a cost of oil production of 9.9 thousand rubles. per ton and price of oil 12.4 thousand rubles per ton, the savings amounted to:

E = (C - C) ⋅ ΔQn = 2.5 thousand rubles. × 13.6 = 34 million rubles.,

where ΔQн - additional oil production, thousand tons;

C is the price of oil, thousand rubles / t;

C - the cost of production of one ton of oil, thousand rubles / t,

those. According to the proposed method, an average of 0.97 thousand tons of additional oil was produced per year and the savings for 1 year amounted to 2.43 million rubles.

In the selected zones, horizontal wells were placed at thicknesses of 4 to 50 m. Designed wells for oil-bearing facilities were placed along a grid of 300 × 300 m so that the wellbores were in the same plane, and the entry points to the oil-bearing facilities in the plan were spaced from each other from 150 to 400 m.

Mining wells are drilled at the lower oil-bearing exploitation site - deposits of the Tournaisian stage. Upon reaching the roof of the Bashkir tier with a zenith angle of 68-80 ° to the roof, they reached the base of the oil-bearing facility and performed well logging, specified the hypsometric elevation of the roof of the upper oil-bearing facility minus 645 m, its reservoir properties were: porosity - 17%, permeability - 475 mD, oil saturation - 78%, determined the OWC at the hypsometric mark minus 670 m, the value of the oil-saturated thickness is 25 m.

Then, drilling continued with the zenith angle falling, and the Tournaisian deposits deposited the zenith angle again to the roof of the lower oil-bearing object up to 74-83 °, entered the oil-bearing object 12 m below the roof along the trunk, and performed well logging. According to the GIS results, the roof of the lower oil-bearing object was found at a hypsometric elevation of minus 940 m. The structural map was clarified. We lowered the column with a diameter of 168 mm, carried out grouting work to isolate the annular space, conducted a well logging test to determine the tightness of the column. Drilling from under the shoe of the column was continued with a smaller bit diameter of 144 mm, followed by access to the zenith angle of 89-91 ° to the bottom at the hypsometric mark of minus 965 m. We drilled the trunk 300 meters long, performed well logging before the bottom. According to the results of well logging, the reservoir properties of the host rocks along the wellbore are heterogeneous and average: porosity - 13%, permeability - 315 mD, oil saturation - 80%.

The trunk of the hydraulic system was left open, it was filled with a hydroemulsion solution to preserve reservoir properties. VNK for the deposits was determined at the hypsometric elevation minus 975 m, i.e. the oil-saturated thickness of the Tournaisian object in the drilling area is 35 m.

The second horizontal trunk in the Bashkir oil-bearing facility was drawn within the oil-saturated thickness of the object 10 m below the roof of the Bashkir layer along the trunk from a removable deflector wedge with a bit diameter of 144 mm in the same plane with the first trunk, with access to the zenith angle of 89-91 ° and the hypsometric downhole mark minus 660 m with a barrel length of 300 m. The trunk was left open. They equipped the well with equipment for simultaneous and separate operation and commissioned it, produced stratum products through production wells and pumped a displacing agent through injection wells, measured the flow rate of liquid and oil, determined its productivity and the degree of water cut in each of the facilities.

When drilling for each oil-bearing facility using different independent grids, the flow rate of 4 vertical wells amounted to 20 tons / day, the development period of the area was almost doubled and 66.8 thousand tons of oil and 210.6 thousand m ^{3 of} fluid were produced.

The balance reserves for the well, estimated by the volumetric method, amounted to 83.5 thousand tons. According to the known method, the final oil recovery coefficient is 0.20 units, according to the proposed method, 0.31 units, i.e. 11% more.

In FIG. 1 shows the layout of wells in plan on a map of oil-saturated thicknesses. In FIG. 2 shows a well with two horizontal shafts in the context of the reservoir. As a result of drilling the wells according to the proposed method additionally produced 43.6 thousand tons of oil. At a cost of oil production of 9.9 thousand rubles. per ton and price of oil 12.4 thousand rubles per ton, the savings amounted to:

E = (C - C) ⋅ ΔQn = 2.5 thousand rubles. × 43.6 = 109 million rubles.,

where ΔQн - additional oil production, thousand tons;

C is the price of oil, thousand rubles / t;

C - the cost of production of one ton of oil, thousand rubles / t,

those. According to the proposed method, an average of 3.1 thousand tons of additional oil was produced per year and the savings for 1 year amounted to 7.8 million rubles.

The application of the proposed method for the development of two oil-bearing objects of different stratigraphic affiliation allows to increase the oil recovery coefficient for oil fields with large oil-saturated thicknesses by increasing the coverage of drainage by area and section with fewer wells drilled, and reducing the development time as a result of the development of reserves of two objects by one well network.

Claims (1)

A method of developing an oil field, including drilling of directional production and injection wells, selection from production wells and injection of a displacing agent into injection wells, characterized in that before drilling the zones of alignment in terms of two oil-bearing objects of different stratigraphic affiliation with a vertical distance between them are determined from 100 to 400 m, zones of oil-bearing objects with a thickness of 0.5 to 50 m are distinguished, with a thickness of oil-bearing objects from 0.5 to 4 m, at least one vertical is drilled the first well and oil-bearing facilities are being developed simultaneously and separately, with oil-bearing facilities from 4 to 50 m thick, horizontal wells are drilled - horizontal wells - first to the lower oil-bearing operation object, and the entry points to the oil-bearing objects along the horizontal well are halfway apart from the design grid in the direction of drilling, and the zenith angle on the roof of the upper oil-bearing facility is 68-80 °, then drilling is performed with the zenith angle falling and the zenith angle is again set to the roof of the lower oil-bearing object to 74- 83 °, enter the oil-bearing object 12 m below the roof along the trunk, conduct geophysical surveys of wells - well logging, check roof hypsometry and lower the casing, isolate annulus, conduct well logging to determine the tightness of annulus, drill a horizontal trunk of smaller diameter along the length equal to the distance of the grid, with an exit in the oil-bearing facility at 89-91 ° depending on the structural features of the relief of the roof of the oil-bearing object in the direction to the bottom in the plan, and in areas with plantar water the trunk is positioned 10-45 m above the oil-water contact — OWC, and 2–46 m above the dense underlying rocks in zones without bottom water; the horizontal well is filled with a hydroemulsion solution, and then the upper horizontal well is drilled in the upper oil-bearing object from a removable deflecting wedge , cut over the roof or within the oil-bearing object and drill a horizontal trunk with a smaller diameter in the same azimuth as the lower trunk, with an acceptable difference from 0 to 7 ° and with an exit in the object by 89-91 ° depending on the fall or rise of of the roof of the oil-bearing object in the direction toward the bottom in the plan, with 10–45 m higher in the zones with bottom water and 2–46 m higher in the areas without bottom water, the trunk is left open or cased with a filter, depending on petrophysical features of oil-bearing rocks, equip the well with equipment for simultaneous and separate operation and put it into operation.

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