RU2726664C1 - Method of development of oil multilayer deposit - Google Patents

Abstract

FIELD: oil, gas and coke-chemical industries.SUBSTANCE: invention relates to oil and gas industry and, in particular, to investigation and development of multi-layer deposits with pumping and extraction from several formations simultaneously and separately. Sections with two productive formations and/or interlayers in section are selected by means of the help. Deposit is drilled by vertical injection wells and production wells with formation of development elements and opening of these formations and/or interlayers. Separate injection of working reagent into each formation through injection wells and separate extraction of product of each formation and/or interlayer through production wells with measurements of oil, water and pumped liquid production. Hydrodynamic analysis is performed. Formation pressure is maintained in each formation and/or interlayer in sampling zone at the required level. Production wells are constructed vertically. In studies, gas saturation pressure in formation production is determined. Long pipe string with a packer, which is installed between the formations and a short pipe string, is lowered into each injection and production wells. It is lowered to the packer. Each pipe is equipped with pressure sensors at outlet - for injection wells, or at inlet - for production wells. Through the short and long columns of the injection wells, water is injected into the upper and lower formations until formation pressure in the nearby wells reaches at least 60 % higher than the saturation pressure. Through the short and long columns of production well pipes production is performed at pressure of not less than 30 % higher than saturation pressure. Formation pressure and sampling pressure are fixed by pressure sensors and maintained in the extraction zone at the required level.EFFECT: technical result is higher efficiency of development due to exclusion of flow stall during extraction and support of flooding front of upper and lower formations at required level.1 cl, 1 dwg

Description

The invention relates to the field of the oil and gas industry, in particular to the study and development of multilayer fields with injection and withdrawal from several layers simultaneously separately.

There is a method of simultaneous-separate research and development of multilayer deposits (patent RU No. 2371576, IPC E21B 47/10, E21B 43/14, publ. 27.10.2009 in Bull. No. 30), including lowering an underground layout into an injection well, to study hydrodynamic the connection between the formations and the targeted injection of the indicator - tracer, consisting of a pipe string, equipped above the formations and between the formations, at least with a packer, below and above which at least one well chamber with a removable element is made either in the form of a regulator - a choke with or without a check valve, for supplying a working agent, an indicator - a tracer or a chemical solution, or in the form of a blind plug for cutting off a formation, or in the form of a downhole device with or without a choke, for movement or cutting off a flow and measuring the physical parameters of the formation, injecting the flow rate of the working agent into the well and measuring its value on the surface corresponding to at least at least one measured value of the wellhead pressure, conducting a hydrodynamic and / or geophysical survey by running a downhole tool into the well, supplying at least one layer of an indicator - a tracer, recording its values at the output of production wells and determining, respectively, for each studied layer one or several physical properties - the presence of discontinuities, orientation and volumes of fractures, filtration rate, permeability, volume of unproductively injected working agent, hydrodynamic connection between reservoirs of injection and / or production wells, selection of characteristics of removable elements in the form of regulator - chokes and their installation in wells chambers at the depth of the corresponding layers, ensuring the design modes of operation for the layers of the injection well, characterized in that before pumping the tracer indicator into the injection well, temporarily stop its operation at a steady state of the reservoirs, place it using a cable technicians in all borehole chambers removable elements for cutting off the formations from the cavity of the pipe string, press the underground assembly for tightness by creating excess pressure at the wellhead inside the pipe string, and if there is its tightness to cut off and study at least one formation, they are equipped on it depth of at least one downhole chamber with a removable element in the form of a downhole tool, while a removable element in the form of a regulator - a choke or a downhole tool with a choke is installed at the depth of another or other formation for injection into at least one well chamber. however, it is left without a removable element, then the well is launched for injection at one or different wellhead and / or bottomhole pressures and, accordingly, it is recorded using a removable element in the form of a downhole tool, at least the bottomhole pressure in time for the cut-off formation, and then the removable downhole tool element from a corresponding borehole chamber ers, interpret its readings and determine the downhole pressure drop curve and, accordingly, the physical parameters of at least one cut-off formation, corresponding to both the shutdown time and the operation time of at least one of the other open formations, compare their values with each other and diagnose by the rate of change in the bottomhole pressure in the cut-off formation the absence or presence of a hydrodynamic connection between the bottomhole zones of the injection well formations, arising from the leakage of the packer or packers, or the cement bridge in the annulus, or the presence of interstratal crossflow, after that the design values of the indicator - tracer concentration are set only for formations between which there is no hydrodynamic connection, and then one or more of the formations are hermetically cut off from the cavity of the pipe string by installing a removable element in the form of a blind plug or a downhole tool in the corresponding well chamber, while leaving open alternately at least one formation by removing at least one removable element from the corresponding well chamber and / or replacing it with a regulator - choke or with a downhole tool with a choke, where it is injected once or periodically, with one or different measured wellhead and / or bottomhole pressures, a predetermined design value of the concentration of an indicator - tracer for recording it at the exit of production wells and determining the physical properties of the formations for the accuracy of designing the operating modes of the injection well.

The disadvantages of this method are the use of a one-pipe assembly for injection and withdrawal, which does not allow maintaining various simultaneous modes of water injection and withdrawal of reservoir products, and mixing of reservoir products in a production well, which can negatively affect the quality of production of one of the reservoirs due to the poor quality of the other. ...

The closest is the method of developing an oil reservoir (patent RU No. 2578090, IPC E21B 43/14, E21B 43/20, published on 03/20/2016 in Bulletin No. 8), including drilling the reservoir with vertical and horizontal multilateral wells along the technological grid with the formation of elements development, including in each injection and production wells, cyclic injection of a working reagent through injection wells and product selection through production wells, measurements of oil, water and injected fluid production, conducting hydrodynamic studies and maintaining reservoir pressure in the withdrawal zone at the initial level, characterized by that before drilling a reservoir with an areal development system, areas with two or more productive layers and / or interlayers are identified in the section, elements are formed in the areas, opening these layers and / or interlayers with vertical injection wells, in each element two multilateral wells are drilled with a horizontal end in each pl Aste and / or interlayer on two opposite sides of the element with a length equal to 80-96% of the length of the element side, in injection wells, productive formations and / or interlayers are separated by controlled packers to differentiate the injection pressure for each of the layers and / or interlayers, depending on their permeability properties, an additional production well is drilled in the elements, the horizontal sections of which are located in each of the layers and / or interlayers towards the injection wells before communicating with the corresponding injection well in the corresponding layer and / or interlayer, the section of each horizontal wellbore is provided with a blind packer, providing isolation and separating the bottomhole with the injection well at a distance of no more than 40-60 m, and the production wellhead is isolated so that the withdrawal zone is 5-24% of the length of the entire horizontal section from the entry point into the formation, while the injection wells are equipped with devices for simultaneously -separate naga no working agent flows into each of the opened formations and / or interlayers of the corresponding wells with periods and pressure that ensure maximum pressure recovery in the extraction zone during oil displacement and do not lead to premature watering of the produced product.

The disadvantages of this method are the complexity of implementation due to the construction of multilateral wells with horizontal ends, the complexity of getting into each of the ends for the installation of packers and, as a consequence, high material and time costs.

Also, the disadvantage for each of the methods is that the injection of water and the withdrawal of products from each reservoir is carried out without taking into account the gas factor (gas presence) in the product, which can lead to a disruption of the flow in the pump during the production (withdrawal) of products and difficulties in further pumping the produced gas-liquid mixture.

The technical objective of the proposed invention is to create a method for the development of an oil multilayer reservoir, which makes it possible to simply pump water from injection wells and withdraw products from production wells with a relatively low investment of time and taking into account the presence of a gas factor.

The technical problem is solved by the method of developing an oil multilayer reservoir, including the allocation of areas with two productive formations and / or interlayers in the section, drilling the deposit with vertical injection wells and production wells with the formation of development elements and opening these layers and / or interlayers, separate injection of a working reagent into each formation through injection wells and separate production of each formation and / or interlayer through production wells with measurements of oil, water and injected fluid production and conducting hydrodynamic studies, and maintaining formation pressure in each formation and / or interlayer in the production zone at the required level.

The novelty is that the production wells are built vertical, during the studies, the gas saturation pressure in the formation product is also determined, the required reservoir pressure in the withdrawal zone is maintained at a level at least 60% above the saturation level, and during withdrawal, at a level of at least 30% above saturation level.

The drawing shows a diagram of the implementation of the method.

The method of developing an oil multilayer reservoir includes the allocation of areas with upper 1 and lower 2 productive formations and / or interlayers (hereinafter referred to as formations) in the section, drilling the deposit with vertical injection 3 and production 4 wells with the formation of development elements and opening these layers 1 and 2. During Studies of wells 3 and 4 determine the gas saturation pressure of the products of each of the layers 1 and 2. Each well 3 or 4 is run a long string of pipes 5 with a packer 6 installed between the upper 1 and lower 2 layers, and a parallel anchor 7 located above the packer 6. Then a short string of pipes 8 is lowered with fixation in the anchor 7. Each string of pipes 5 and 8 is equipped with pressure sensors 9 at the outlet (for injection wells 3) or inlet (for production wells 4). In this case, each string of pipes 5 and 8 of production well 4 supplied at the inlet with a pump 10 with a filter 11. Before starting operation, a working reactor is injected through a short string of pipes 8 of an injection well 3 gent - water into the upper layer 1 until the pressure in nearby production wells 4 above the packer 6 reaches at least 60% higher than the bubble point pressure measured by the pressure sensor 9 of the short pipe string 8, the resulting pressure for injection is also recorded by the control unit (not shown) for pressure sensor 9 of the short string of pipes 8 of the injection well 3. At the same time, water is injected into the lower layer 2 through the long string of pipes 5 of the injection well 3 until the pressure in the nearby production wells 4 below the packer 6 is at least 60% higher than the saturation pressure measured by the sensor pressure 9 of the long string of pipes 5, the obtained pressure for injection is also recorded by the control unit (not shown) for the pressure sensor 9 of the long string of pipes 5 of the injection well 3. After that, the pumps 10 through the filters 11 using the short 8 and long 5 strings of pipes begin to take the product from the corresponding upper 1 and lower 2 layers, while maintaining the corresponding pressure at a level not less than 30% above the level of gas saturation, which is recorded in the production well by 4 pressure sensors 9 of a short string of pipes 8 for the upper layer 1 and a long string of pipes 5 for the lower layer 2. At the same time, the pressure in injection wells 3 is maintained at a pressure not lower than the fixed the control unit, which is fixed by the pressure sensors 9 of the short string of pipes 8 for the upper layer 1 and the long string of pipes 5 for the lower layer 2 in the injection well. During the operation of reservoirs 1 and 2, measurements are made of the volume or mass of produced oil and water (if any) from each production well 4 and injected water into each production well 3 with conducting hydrodynamic studies to maintain reservoir pressure in each reservoir 1 and 2 in the extraction zone for the required level.

The proposed method for the development of multilayer oil deposits makes it possible to simply inject water from injection wells and withdraw products from production wells with a relatively small investment of time and taking into account the presence of the gas factor, which eliminates flow disruption during withdrawal and maintains the flooding front of the upper and lower layers at the required level.

Claims (1)

A method of developing an oil multilayer reservoir, including the allocation of areas with two productive formations and / or interlayers in the section, drilling the deposit with vertical injection wells and production wells with the formation of development elements and opening these layers and / or interlayers, separate injection of a working reagent into each layer through injection wells and separate production of each formation and / or interlayer through production wells with measurements of oil, water and injected fluid production and conducting hydrodynamic studies, and maintaining formation pressure in each formation and / or interlayer in the production zone at the required level, characterized in that production wells are built vertical, during the research, the gas saturation pressure in the formation product is also determined, a long string of pipes with a packer, which is installed between the layers, and a short string of pipes, which are lowered to the packer, are lowered into each injection and production wells, at the same time, each of the pipes is equipped with pressure sensors at the outlet - for injection wells, or at the inlet - for production wells, water is injected into the upper and lower layers through a short and long string of pipes of injection wells until the formation pressure in nearby wells is at least 60% above the saturation pressure, and through the short and long strings of pipes of the production wells, products are taken at a pressure of at least 30% above the saturation pressure, moreover, the reservoir pressure and the selection pressure are recorded by pressure sensors and maintain these pressures in the extraction zone at the required level.

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