RU2386017C1 - Development method of multipay fields of carbons with heterogeneous geological conditions of bedding of producing formations and layout of downhole and control head equipment for its implementation - Google Patents

Abstract

FIELD: oil-and-gas production.

SUBSTANCE: method includes downing into well of lifting pipe string for extraction of fluid from bottom and top stratums, connected to pipe hanger and exhaust lines, installation between stratums of parting packer, using of ejector pump ensured by ejection of which stratum fluid allowing of high pressure and productivity which is active medium, involves into action passive fluid from other stratum. Development of reserve is implemented in two stages, at the first stage - with usage of jet pump up to installation of mentioned difference of bottom-hole pressures, at the second stage jet pump is excluded from layout of downhole and control head equipment, and exhaust lines are connected to pipeline for transportation of fluids mixture. For method implementation it is used layout of downhole and control head. It contains columns of lifting pipes for extraction of fluids from top and bottom stratums, installed on pipe hanger of fountain installation parallel or concentric to each other, parting packer, installed in well between stratums, jet pump, connected to surface to fountain installation exhaust lines for passing of fluids from stratums and pipeline for transporting of fluids. On exhaust lines there are installed counters of accounting of each stratum. Exhaust lines are connected to jet pump, installed on surface after counters of accounting of productivity before pipeline for transportation of fluids mixture.

EFFECT: effectiveness increase of simultaneous separate operation of two stratums by one well.

2 cl, 1 tbl, 1 dwg

Description

The invention relates to the oil and gas industry and can be used in the development of multilayer hydrocarbon deposits in the case when productive formations are characterized by various thermobaric and filtration-capacitive properties and their development during separate operation is unprofitable.

A known method of drilling and development of multilayer hydrocarbon deposits with heterogeneous geological conditions of occurrence of productive formations (patent RF2295632, ЕВВ 43/14, 7/04, 03/13/2006), including

- two-stage cluster drilling of production wells for a high-permeability lower layer selected as the main development object, over which a low-permeability layer with a higher reservoir pressure is located

- preliminary, pressure-controlled, fluid transfer from a high-pressure formation to a low-pressure formation,

- and subsequent operation of the field with well clusters,

- moreover, at the first stage, bypass wells are drilled at each wellbore with multi-lateral horizontal endings in both reservoirs, through which fluid is transferred from the upper high-pressure formation to the lower low-pressure formation;

- and above the interval of sidetracking over the upper layer, an impenetrable section is installed, for example, in the form of a cement bridge, above which a sidetrack is drilled onto the lower layer and subsequent drilling of the impenetrable section,

- at the second stage, after the reservoir pressure in the interval of opening the upper high-pressure reservoir decreases to a value exceeding the hydrostatic pressure by no more than 5-10%, production wells are drilled on each well

- and the production of fluid is carried out from the lower reservoir.

The disadvantage of this method is the additional cost of drilling bypass wells.

A known method of developing gas fields (Zakirov S.N. and others. "Design and development of gas fields", M .: Nedra, 1974, s.312), including:

- the development of two or more reservoirs operated by separate well grids with a unified land-based arrangement system

- and by combining gas flows from different layers.

The disadvantage of this method is the increased capital costs when drilling separate grids for each formation.

The well-known "Method of simultaneous separate operation of two gas reservoirs" (AS USSR No. 1406346, EV 43/00, publ. 06/30/1988, bull. No. 24) one well, including:

- separation of layers by a packer,

- gas extraction from the lower reservoir along the column of lifting pipes

- and the selection of gas from the upper reservoir in the annulus,

- moreover, to remove the accumulating fluid from the upper layer in the column of lifting pipes above the packer, an opening is made,

- through which the annular space is purged periodically by blocking the column of lifting pipes

- followed by gas bypass from the column of lifting pipes into the annulus.

A disadvantage of the known method is the low efficiency of liquid removal as the bottom formation is developed, since with a decrease in gas production from the lower layer, the upward flow velocity will not be enough to carry the liquid out. In addition, the use of annulus, i.e. of annular cross section between the outer wall of the column of lifting pipes and the inner wall of the casing, for the operation of the upper layer is not always possible, since the area of this annular section, as a rule, is much larger than the cross-sectional area inside the column of lifting pipes. Therefore, even in the initial stage of operation, when the flow rate of gas from the upper reservoir will be the largest, due to the significant annular space, the velocity of the upward gas flow may not be enough to carry the liquid out.

The well-known "Method of operation of a downhole jet installation in the operation of multilayer deposits" (RF Patent No. 2282759, EV 43/14, publ. 08/27/2006), in which:

- a jet pump fixed with packers is installed in the well,

- by means of which fluid from a reservoir having high pressure and productivity, being an active medium, involves a passive fluid from another reservoir in motion.

The joint operation of two or more productive reservoirs with one well implies the mandatory possibility of regulating fluid selection from each reservoir, conducting hydrodynamic studies in the reservoirs and accounting for fluid selection for each of the reservoirs, which is not provided by a known method. This is due to the fact that in the jet pump there is a connection and mixing of the fluids of the two layers, therefore, it is possible to determine on the surface only the total productivity of the influx of fluids, but not from each layer separately, which does not provide control of the formation production.

In addition, changing the parameters of fluid inflow (pressure, flow rate, moisture content, temperature, etc.) from each reservoir as they are used affects the performance of the jet pump, which, since it is lowered into the well, cannot be controlled. Therefore, it is possible that due to the insufficient speed of the active fluid in the working chamber of the jet pump, the necessary vacuum will not be created and, therefore, there will be no ejection effect to cause the flow of passive fluid, which makes the operation of the jet installation ineffective. To regulate the performance of the jet pump must be removed from the well, which leads to downtime and reduce gas production.

The objective of the invention is to increase the efficiency at the same time separate operation of two layers of one well.

To achieve this technical result in a known method for the development of multilayer hydrocarbon deposits with heterogeneous geological conditions of occurrence of productive formations, including:

- descent into the well of a column of lifting pipes for the selection of fluid from the lower reservoir,

- installation in the well between the layers of the separation packer,

- the use of a jet pump, due to the ejection in which the fluid from the reservoir, which has greater productivity, being an active medium, draws in the movement a passive fluid from another reservoir,

- installation of equipment layout at the wellhead including flowing fittings, pipe suspension, flow line for passing fluid from the lower reservoir and a pipeline for transporting the fluid mixture,

ACCORDING TO THE INVENTION

- an additional string of lifting pipes is lowered into the well to select fluid from the upper formation and connected to the pipe suspension and an additional flow line for the upper formation,

- the development of reserves from two layers is carried out in two stages:

- at the first stage using a jet pump to establish a predetermined difference in bottomhole pressure in the reservoirs,

- then at the second stage, the jet pump is excluded from the layout of the downhole and wellhead equipment,

- and flow lines from the reservoirs are connected to the pipeline for transporting the fluid mixture.

For the implementation of the proposed method, the known arrangement of downhole and wellhead equipment, comprising:

- a column of lifting pipes for the selection of fluid from the lower reservoir, mounted on a pipe suspension of fountain fittings,

- a separation packer installed in the well between the layers,

- jet pump

- a flow line attached to the surface of the fountain to pass fluid from the lower reservoir

- and a pipeline for transporting a mixture of fluids,

ACCORDING TO THE INVENTION

- additionally contains a column of lifting pipes for the selection of fluid from the upper reservoir, mounted on the pipe suspension of the fountain valves in parallel or concentrically to the column of lifting pipes for the selection of fluid from the lower reservoir,

- flow line for the passage of fluid from the upper reservoir, attached on the surface to the fountain

- and performance counters for each layer installed on flow lines,

- wherein the flow lines are connected to a jet pump installed on the surface after the productivity counters in front of the pipeline for transporting the fluid mixture.

The drawing shows a diagram of the implementation of the proposed method by the claimed layout of the downhole and wellhead equipment, side view.

The inventive arrangement of downhole and wellhead equipment includes a column of lifting pipes 1 for fluid selection from the lower formation 2, mounted on a pipe suspension of the fountain reinforcement 3, a column of lifting pipes 4 for selecting fluid from the upper formation 5, mounted on a pipe suspension of the fountain reinforcement 3 parallel to the column of the lifting pipes 1, a separation packer 7 installed in the well 6 between the layers 2 and 5, flow lines 8 and 9 attached to the surface to the fountain reinforcement 3 for passing fluid from each formation, connected to a common pipeline 10, counters 11 for accounting for the productivity of each layer and locking and regulating devices 12 installed on flow lines 8 and 9, and a jet pump 13 installed on the surface after the counters 11 in front of the common pipeline 10.

The inventive method is carried out in two stages as follows.

In a multilayer hydrocarbon field, represented by productive formations 2 and 5 with heterogeneous geological conditions of their occurrence and various thermobaric and filtration-capacitive properties, in the case where a low-permeable reservoir 5 with a higher reservoir pressure is located above the main development object in the form of a highly permeable low-pressure reservoir 2, development of reservoir 5 during separate operation is unprofitable, because:

a) due to the low permeability of the formation 5 and low flow rates from it, the drilling of individual wells on this formation is not economically feasible;

b) the joint operation of formations 2 and 5 by one well is impossible due to the fact that the fluid from the formation 5, characterized by a higher pressure, will prevent the drainage of fluid from the formation 2, characterized by a lower pressure;

c) the call of the inflow from the reservoir 5 due to its low permeability is possible only with significant depression, incompatible with the depression necessary for the optimal operation of the reservoir 2.

Therefore, the development of reserves from two layers by simultaneously separately operating one well is carried out in two stages using the claimed layout of the downhole and wellhead equipment.

To do this, in the interval of formation 2, a column of lifting pipes 1 with a separation packer 7 is lowered into the drilled well 6, which has opened formations 2 and 5, which is installed in the well 6 between formations 2 and 5. Then, parallel to the casing 1, the well 1 is lowered into the interval 6 of the formation 5 a column of lifting pipes 4 for the selection of fluid from the upper reservoir 5 and both columns are connected to the pipe suspension of the fountain reinforcement 3.

Next, flow lines 8 and 9 are attached to the fountain arm 3 on the surface to pass fluid from the columns of the lifting pipes 1 and 4, connected through the jet pump 13 to the common pipeline 10. Lock-control devices 12 are installed on the flow lines 8 and 9 to the jet pump 13 and counters 11 accounting for the productivity of each layer.

At the first stage, the separate operation of reservoirs 2 and 5 is simultaneously carried out using a jet pump 13, due to ejection in which the fluid from the reservoir 2, which is more productive, being an active medium, involves the passive fluid from the reservoir 5. In this case, due to its location in the well 6 individual columns of lifting pipes 1 and 4 by selecting their inner diameter and, therefore, the cross-sectional area for each of the layers 2 and 5, the most optimal upward gas flow rate is set, providing os of formation fluid, which prevents its deposition and accumulation on the bottom for the lower formation 2 and above the packer 7 for the upper formation 5, the negative consequence of which may be a decrease in the productivity of formations 2 and 5 due to reverse filtration of the liquid into the formation and its crushing. This eliminates the decrease in well productivity and the cost of its possible repair to clean the bottom hole from accumulated fluid.

The flow rate of each of the reservoirs is controlled by shut-off and control devices 12, and the productivity of each reservoir is counted by counters 11, which together provides for the regulation of fluid selection from each reservoir, conducting hydrodynamic studies in the reservoirs and accounting for fluid selection for each of the reservoirs and ultimately increases multi-layer field development efficiency.

Placing the jet pump 13 on the surface allows controlling the degree of rarefaction for fluid ejection from the low-permeability formation 5 by adjusting the cross section of the nozzles at the inlet to the mixing chamber and diffuser, which, as the parameters of the fluid inflow from formations 2 and 5 change (pressure, flow rate, moisture content, temperature, etc.) provides the most optimal value of the ejection coefficient of the jet pump, i.e. the ratio between the amount of ejected (active) and ejected (passive) fluids, which increases the efficiency of the jet pump and ultimately provides an increase in the efficiency of the development of a multi-layer field. In addition, this arrangement of the jet pump 13 reduces the time required for its maintenance and repair, since it is not necessary to lift the columns of the lifting pipes 1 and 4. At the same time, the down time of the well is also reduced, which also improves the development efficiency of a multilayer field.

As fluids are produced, bottomhole pressures in formations 2 and 5 will change and when they reach the values of the specified pressure difference, for example, no more than 2 ... 5%, they proceed to the second stage of operation. At the same time, gas production from the well is temporarily stopped, for which they shut off the shut-off and control devices 12 on flow lines 8 and 9, dismantle the jet pump 13. The flow lines 8 and 9 after meters 11 are connected to a common pipeline, after which the shut-off and control devices 12 and again simultaneously carry out separate exploitation of two layers with one well.

Example. During the exploration of one of the multi-layer hydrocarbon deposits in the Tyumen region, two gas deposits were discovered: the upper one is the Senon, confined to the Kuznetsov Formation, and the lower one is the Cenoman, confined to the Pokur Formation, which are characterized by the following parameters:

a) senon

- a depth of 770 m,

- reservoir pressure - 9.5 MPa,

- gas reserves - 200 billion m ³ ;

b) cenomanian

- depth of 920 m,

- reservoir pressure - 9.2 MPa,

- gas reserves - 600 billion m ³ .

For the implementation of the proposed method at the stage of exploration, pilot production was carried out, and for this purpose, in the southern part of the field, one of the wells that uncovered formations 2 and 5 was mounted the claimed arrangement of downhole and wellhead equipment (see drawing), including a column lifting pipes 1 for the selection of fluid from the lower reservoir 2, mounted on the pipe suspension of the fountain valves 3, a column of lifting pipes 4 for the selection of fluid from the upper formation 5, mounted on the pipe suspension of the fountain 3 mats parallel to the column of lifting pipes 1, a separation packer 7 installed in the well 6 between the layers 2 and 5, flow lines 8 and 9 attached to the surface of the fountain installation 3 for passing fluid from each formation, connected to a common pipeline 10, productivity counters 11 each layer and locking and regulating devices 12 installed on flow lines 8 and 9, and a jet pump 13 installed on the surface after the counters 11 in front of the common pipeline 10.

At the first stage, separate exploitation of formations 2 and 5 was carried out simultaneously using a jet pump 13. During the first year of operation, the following parameters were recorded (see table).

OPTIONS Layer 2 Layer 5 At the beginning of the year At the end of the year At the beginning of the year At the end of the year Flow rate (thousand m ³ / day) 100.0 95.0 25.0 20,0 Downhole pressure (MPa) 9.2 9.0 9.5 9.2

Thus, due to the use of the jet pump 13, which ensures the ejection effect and the necessary degree of depression to cause inflow from the formation 5 by using the energy of the formation 2, one well was used to simultaneously operate two layers 2 and 5, which are incompatible in their thermobaric and filtration-capacitive properties for joint development. Thus, an increase in production from one well was achieved by 21% per year and cost savings due to the absence of the need to drill a well for the operation of formation 5.

By the end of the first year of operation, the bottomhole pressure difference in the strata was 2.2%, after which the well was shut down, the jet pump 13 was removed from the wellhead equipment layout and flow lines 8 and 9 were connected to pipeline 10 to transport the fluid mixture. Due to the decrease in pressure in the formation 5, the fluid from this formation did not create counter pressure to the flow of fluid from the formation 2, which ensured the efficient production of resources of both production facilities and the total increase in production from one well by 19% per year.

Claims (2)

1. A method of developing multi-layer hydrocarbon deposits with heterogeneous geological conditions of occurrence of productive formations, including lowering into the well a column of riser pipes to select fluid from the lower formation, installing a separation packer between the layers, using a jet pump, in which the fluid from the formation is ejected, having a higher productivity, being an active medium, involves the movement of passive fluid from another reservoir, installation of equipment layout at the wellhead, including flowing fittings, pipe suspension, flow line for passing fluid from the lower reservoir and a pipeline for transporting a fluid mixture, characterized in that the column of lifting pipes is additionally lowered into the well to select fluid from the upper reservoir and connected to the pipe suspension and an additional flow line for the upper reservoir, the development of reserves from two reservoirs is carried out in two stages, at the first stage - using a jet pump until a predetermined difference in bottomhole pressure in the reservoirs is established, then at the second stage, the jet pump is excluded from the layout of the downhole and wellhead equipment, and flow lines from the reservoirs are connected to the pipeline for transporting the fluid mixture. 2. The layout of the downhole and wellhead equipment for implementing the method of developing multi-layer hydrocarbon deposits with heterogeneous geological conditions of occurrence of productive formations, containing a column of lifting pipes for selecting fluid from the lower formation, mounted on the pipe suspension of the fountain valves, an isolation packer, an jet pump installed in the well between the layers attached to the surface to the fountain fittings flow line for passing fluid from the lower reservoir and a pipeline for trans orting a fluid mixture, characterized in that it further comprises a column of lifting pipes for collecting fluid from the upper formation, mounted on a pipe suspension of flowing valves parallel or concentric to the column of lifting pipes for collecting fluid from the lower formation, a flow line for passing fluid from the upper formation, connected to surfaces to the fountain fittings, and productivity counters for each layer installed on flow lines, and flow lines connected to a jet pump mounted on erhnosti counters after accounting productivity front conduit for transporting the fluid mixture.

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