Method for extraction of oil deposit

IPC classes for russian patent Method for extraction of oil deposit (RU 2247829):

Another patents in same IPC classes:

Oil deposit extraction method / 2247230
Method includes construction of wells and oil and gas collection system, forcing water from water-bearing level into oil deposits, flow of oil from oil deposits into secondary deposit and following extraction of oil from secondary deposit for useful implementation. Resources of deposit are separated on basis of natural energy characteristic on screened and having rigid water-forcing mode. Deposit is operated by three well types. Of the latter flow wells connect oil deposits to secondary deposit for flowing and collection of oil in upper bed under effect from gravitation. Balancing wells connect screened deposits and secondary deposit to water-forcing level for balancing of bed pressures and preventing loss of rocks stability. Extraction wells connect secondary deposit to oil and gas collection system. Selection of bed for secondary deposit is performed from number of highly penetrable beds, having maximally allowed excess over oil deposits.

Method of treating bottom zone of injecting wells / 2244113
Groups of high intake- and low intake-capacity injecting wells are chosen in a single hydrodynamic system and, for each well, oil reservoir properties and permissible degree of pollution of fluid received by high intake-capacity wells are determined. When fluid from low-permeable oil reservoir flows off through high intake-capacity wells, this fluid is cleaned to permissible degree of pollution.

Method for extraction of oil deposit / 2247829
Method includes drilling of deposit according to row-wise non-even grid of wells with distance from force to extractive rows, greater than distance between extractive rows, pumping of displacing gent into force wells, extraction of product from product wells and transferring of displacing agent pumping front to extraction area. According to invention, transferring of displacing agent pumping front to extraction area is performed by drilling side horizontal shafts in all wells of force row and directed towards extractive row by beds ad zones with most remainder oil saturation level. Then among these wells are singled out, horizontal shafts of which pass along beds and areas with lesser oil saturation level. Pumping of displacing agent is restarted, and other wells are transferred to product category. These wells are operated with face pressures lower than saturation pressure until reaching 98% water saturation level. After that pumping of displacing agent is restarted along all other wells of force row. During that, rows of extractive wells are operated in normal mode.

Oil deposit extraction method (variants) / 2254457
According to first variant of method, force and product wells are drilled, working agent is fed through force wells, oil is extracted through product wells, dome-like raised portions are marked out, which surpass absolute marks of bed, additional wells are positioned in these portions. Wells placement is planned at tops of dome-like raised portions even with breach of evenness of planned well mesh. After full drilling of wells mesh and in case of more accurate definition according to data of drilled wells of deposit of dome-like portions side shafts are drilled from adjacent wells towards more precisely defined tops of dome-like portions, controlling the deposit. In adjacent wells and side shafts, positioned on tops of dome-like raised portions , range of productive bed is opened between absolute mark of ceiling in this well and absolute mark, appropriate for ceiling in closest well. According to second variant of method practically analogical operations are realized as in first variant, except when absolute mark of ceiling of productive bed according to adjacent wells is lower than mark of sole of productive bed, whole bed is opened in side shafts.

Water-flooded reservoir development method (variants) / 2259473
Method involves withdrawing oil through production wells and ejecting working substance through ejection wells. To prevent water ingress from well bore into oil-saturated formation area formation is perforated in water-oil interface zone so that lower part of oil-saturation formation interval and upper part of water-flooded formation interval are penetrated. This provides oil relative permeability retention in oil-saturated formation area. To prevent formation mudding during initial perforation thereof drilling is performed in depression, balance and repression modes with pressure of not more than 3 MPa. As far as oil is depleted perforation interval is extended towards oil-saturated formation area.

Nonuniform oil field development method / 2259474
Method involves drilling injection and production wells; flooding oil reservoir and extracting oil out of well; defining more exactly geologic aspects on the base of drilling results; designing and drilling additional wells with horizontal bores or drilling horizontal bores from existent wells; determining location of reservoir drive zone boundaries; calculating volume of dead oil located near drive zones; drilling horizontal bores from existent wells located near drive zones and/or new wells with horizontal bores located in above zone, wherein horizontal bores are drilled in direction perpendicular to drive zone boundaries.

Method for extraction of oil deposit / 2260686
Method includes drilling vertical product and force wells, extracting oil from product wells, forcing working agent through force wells, making side horizontal shafts in force wells, forcing working agent through side horizontal shafts of force wells. Additionally, side horizontal shafts are made in extraction wells. Oil is taken through side horizontal shafts of extractive wells. With pressure in the well, decreased for 5-10% from hydrostatic pressure, all side horizontal shafts are made by washing away rock under pressure of fluid of around 15-20 mPa. Direction of all side horizontal shafts is set to be parallel to rows of wells.

Method for oil reservoir development in carbonate or terrigenous formation with developed macrocracks / 2264533
Method involves drilling production and injection wells and maintaining formation pressure; performing seismic works to determine volumetric routing of natural macrocrack system with lateral and depth routing; forming production and injection macrocracks of above system; drilling wells to corresponding macrocracks and forming producing well-macrocrack systems for oil production and injection well-macrocrack for formation flooding or production well-macrocrack for oil production and system including vertical and/or horizontal multibranch wells for formation flooding or injection well-macrocrack system for formation flooding and system including vertical and/or horizontal multibranch production wells for oil production or production well-macrocrack system, injection well-macrocrack system and system including vertical and/or horizontal multibranch production and injection wells.

Oil-bearing bed development method and equipment for group pumping station with oil deposit zone / 2265120
Method involves pumping working agent, namely water, in two stages. The first stage is performed with the use of power pumps. The second one is carried out by means of hydraulic measuring pumps, which are used to convert injection pressure created by power pumps. If it is necessary to increase pressure in water lines used to deliver water to separate injection wells pressure is regulated in accordance with necessary water volume to be injected in wells on the base of collecting properties of oil formations in bottomhole formation zones. This is performed by providing change in pump piston diameter and stroke ratios in the first and the second sections of hydraulic measuring pumps, which are selected on the base of hydraulic resistance variation depending on water flow velocity. Parameters characterizing injection system operation are simultaneously measured and efficiency of the method and equipment operation is detected from above characteristics.

Injection well operation optimization method / 2265716
Method involves flooding production bed through injection wells with the use of pump units. In the case of terrigenous porous productive bed flooding acoustical sound resonators with resonance frequency setting are installed in injection line. This eliminates amplitude of alternating low-frequency liquid pulsation sound generated by pump units. Method also involves providing constant compression mode in productive beds and frontal oil drive from productive bed.

FIELD: oil extractive industry.

SUBSTANCE: method includes drilling of deposit according to row-wise non-even grid of wells with distance from force to extractive rows, greater than distance between extractive rows, pumping of displacing gent into force wells, extraction of product from product wells and transferring of displacing agent pumping front to extraction area. According to invention, transferring of displacing agent pumping front to extraction area is performed by drilling side horizontal shafts in all wells of force row and directed towards extractive row by beds ad zones with most remainder oil saturation level. Then among these wells are singled out, horizontal shafts of which pass along beds and areas with lesser oil saturation level. Pumping of displacing agent is restarted, and other wells are transferred to product category. These wells are operated with face pressures lower than saturation pressure until reaching 98% water saturation level. After that pumping of displacing agent is restarted along all other wells of force row. During that, rows of extractive wells are operated in normal mode.

EFFECT: higher efficiency.

1 ex

The invention relates to the oil industry, in particular to methods for heterogeneous development of oil fields, and can be used for intensification of the development of heterogeneous oil fields in various stages of development, if any wells when projected development system do not maintain reservoir pressure at the project level.

There is a method of developing multilayer heterogeneous oil field [see patent RU No. 1606687 from 30.11.88 g, CL E 21 In 43/20, publ. BI No. 42 from 15.11.90,] including the placement of wells on the main reservoir, the injection of water into the primary and intermittent reservoir through injection wells and oil production through production wells primary and choppy layers with subsequent conversion of producing wells on the final stage of water injection on choppy layers, with translation by injection wells at a final stage of the exercise as they are watering their primary formation in the presence of in the context of these wells at least one discontinuous layer, and the translation of producing wells under pressure produced along the perimeter of the site with the maximum number of penetrated formations.

The advantage of this method is that the development efficiency is increased at the expense of obliczeniowa reservoir flooding.

However, a significant proportion of the recoverable reserves is not involved in the development, as the 3-layer system development zone between the injection and production series are not involved in the development.

The closest in technical essence to the present invention is a method of developing a heterogeneous oil fields, including drilling him on the uneven row of the grid with the distance from injection to extraction rows, which exceeds the distance between the extractive rows, the injection of the displacing agent in injection wells, selection of products from mining, off wells of the first rows in flooding below the maximum cost-effective and the transfer front of the injection of the displacing agent in the first series of production wells [see the book A.P. Krylov "state of theoretical work on the design development of oil fields and objectives for the improvement of these works. Sat. Experience in the development of oil fields". Costoptimized, 1957, p.116-139].

Approaching discharge to the zone selection leads to an increase in the current selection (≈8%) and reduction of development time (≈23%). The known method gives positive results in a very high degree of flooding of the first extractive series (above 98%), which occurs at a late stage of development.

However, in practice, often who the hiccups a need to strengthen the system of influence at an earlier stage of development because of the high rate of decline in reservoir pressure what worsens the technical-economic indicators of development.

In addition, part of the recoverable reserves (3-5%) is still not involved in the development due to loss of oil reserves in the zone between the injection and the first production series of wells due to incomplete washing zone at the moment of transfer of discharge.

The technical objective of the proposed method of heterogeneous development of oil fields is to increase the efficiency of development through redevelopment zone between the injection and the first production series of wells and the intensification of the extraction of oil in tightening the ranks by approaching the front of the injection zone selection without disturbing existing kinematics flows and reservoir pressure maintenance at the project level.

The problem is solved by the described method, including the drilling of a field row on an uneven grid of wells with distance from injection to extraction rows, which exceeds the distance between the extractive rows, the injection of the displacing agent in injection wells, selection of products from mining and the transfer front of the injection of the displacing agent to the area of the selection.

What's new is that the transfer front of the injection of the displacing agent to the zone selection is made by drilling a lateral horizontal wells all wells on nettling range and aimed at the extraction of a number of layers and regions with the highest residual oil saturation, then they allocate wells, horizontal stems which pass through the layers and regions with less saturation, and resume the injection of the displacing agent, and the remaining wells are transferred to the category of extracting and exploiting them at downhole pressures below the saturation pressure to achieve maximum cost-effective watering, and then resume the injection of the displacing agent for all injection wells of the row, the rows of extraction wells operate in normal mode.

The mechanism of the processes occurring in the reservoir using the proposed method, is as follows.

On the kinematics of the flow area between the injection and the first production series of wells can be divided into two parts. The first is from the bottom of injection to the end of lateral horizontal wells, where the front discharge changes its direction by 90°. The second is about the end of the lateral horizontal wells to the first extractive series. In this part of the kinematics of flows is not broken and does not disbanding zone contraction circuit of oil. Eviction will occur from the less saturated to more saturated zone, thereby eliminating the displacement of oil in the flushed zone. By approaching the front of the injection zone selection increases the speed filter is tion, consequently, increases the coverage of the displacement and the magnitude of oil extraction. When the discharge pressure set of conditions specified compensation liquid extraction by pumping water, i.e. from the condition of reservoir pressure maintenance at the project level. Further intensification of the flooding system is due to resume injection into wells, translated under the selection of products after achieving or extremely cost-effective watering.

The proposed method is effective at an early stage of development (at a relatively low level of water content), and late (when the degree of flooding of the first extractive ranks above 98%).

From available sources, the patent and scientific literature is not known to declare the set of distinctive features. Therefore, the proposed method meets the criteria of the invention "inventive level".

The method is carried out in the following sequence.

At the oil field, presents a heterogeneous reservoirs drilled row on an uneven grid of wells with distance from injection to extraction rows, which exceeds the distance between the extractive rows, if projected development system does not maintain pressure on the project level in wells supercharger is on some at any stage of the development of the Buryat lateral trunks, aimed towards producing wells. Horizontal trunks spend on areas with the greatest residual oil saturation length from 1/3 to 2/3 of the distance between injection and the first production series. Carry out the injection of the displacing agent in the lateral trunks of injection wells number with the lowest residual oil saturation, and the rest transferred to the category of extracting and exploiting them at downhole pressures below the saturation pressure to achieve maximum cost-effective watering (98%). Then these wells are again transferred to the category of discharge, renew in them the injection of the displacing agent. A series of extraction wells operate in normal mode.

An example of a specific implementation.

Oil accumulation in terrigenous sediments in the area of 9 km²with balance reserves 16728 thousand tons rasberry on three uneven grid of wells with distance from injection to extraction rows equal to 1500 m, and between the extractive rows and between the wells in row 500 meters 20 wells have been Drilled, including 12 producing wells and 8 injection wells. The borehole spacing was 45 ha/VCS.

The initial reservoir pressure on deposits is equal to 19 MPa, a temperature of 40°C, the saturation pressure of oil gas is 8.75 MPa. Oil viscosity at reservoir conditions to 3.34 MPa·s, water 1,94 MPa·C, the density of the nave and 862 kg/m ³the gas factor of 90.6 m³/so the Bottomhole pressure in the producing wells were maintained at a level of saturation pressure and was equal to 8.8 MPa, injection wells - 19.0 MPa.

When the water production of the first series of production wells above 98% injection wells stopped and drilled laterals in the direction of the zone of selection in both sides 1000m Resumed the injection of the displacing agent in the well discharge line, and the rest was transferred to the category of production and exploited them when downhole pressure P₃=0,7 P_usto achieve irrigation above 98%, and then moved them again in the category of injection and resumed the injection of the displacing agent.

Expected oil production for the whole period of development was 7260 tonnes during the recovery factor 0,434 dad (on prototype, respectively 6708 tonnes and 0,401 did).

Technical and economic efficiency of the proposed method of development of heterogeneous oil field is formed at the expense of increasing oil recovery in the zone from the injection series to the first series of production wells, as well as due to the possibility of its application at any stage of development, if any wells.

The way to develop heterogeneous oil fields, including drilling field in row neravnomern the th grid with distance from injection to extraction series, greater than the distance between the extractive rows, the injection of the displacing agent in injection wells, selection of products from production wells and the transfer front of the injection of the displacing agent to the zone selection, characterized in that the transfer front of the injection of the displacing agent to the zone selection is made by drilling a lateral horizontal wells, all injection wells range and aimed at the extraction of a number of layers and regions with the highest residual oil saturation, then allocate wells, horizontal stems which pass through the layers and regions with less saturation and resume the injection of the displacing agent, and the remaining wells are transferred to the category of production and exploit them when downhole pressures below the saturation pressure to achieve 98% water cut, and then resume the injection of the displacing agent for all injection wells of the row, the rows of extraction wells operate in normal mode.