Method for oil deposit development based on system address action. RU patent 2513787.

FIELD: oil and gas industry.

SUBSTANCE: invention is related to oil and gas industry and can be used for development of oil deposits at late stage characterised by heterogeneous reservoirs of different origin and, in particular, by zonal heterogeneous reservoirs with formations having different permeability or fractured-porous type reservoirs. The concept of the invention is as follows: the method includes cyclic instable injection of the agent through injection wells, extraction of fluids through producing wells, additional targeted impact by chemical reagents to the formations through the total number of injection and producing wells with identification of sections having different geological and physical properties, current state of development and degree of reserves recovery. According to the method a testing field is selected for which its average permeability is determined with use of core material and weighted average values of flow capacity, piezoconductivity are calculated for the formation at this testing field; penetration test is made with determination of oil displacement, stimulating or isolating properties for used chemical reagents. Duration of the agent injection within borders of the testing field is determined with use of analytic expression considering a distance from the injection front up to fluid extraction point; average piezoconductivity of the formation, its permeability, porosity and elastic ratio for the rock and fluid are also determined. Targeted duration of the agent injection is determined for each area and algorithm for further development of the selected areas is defined on the basis of laboratory feasibility study and results of hydrodynamic simulation of impact technologies for specific selected areas. Then system-address action is carried out at each area.

EFFECT: increasing reservoir recovery and reducing volume of associated water, reducing costs for implementation of the method, improving efficiency of the development as a whole and intensification of the development process.

1 ex, 2 tbl, 3 dwg

The invention relates to the oil and gas industry and may be used in the development of oil deposits at a later stage, characterized by heterogeneous reservoirs of different nature, in particular zonal inhomogeneous reservoir, a reservoir that has layers of different permeability, or fractured porous reservoirs.

There is a method of development of oil deposits on the basis of system-address impacts, including cyclic change pumping regimes displacing agent, the analysis of geological and production data for the operation of a well targeted regulation system development in selected areas. The first cycle in the ranks of injection wells pumped displacing agent, and the average number of production wells produce forced selection with the volume of 10-15% higher volume than in the selection in the other series. By results of the analysis of geological and production data from production wells, quantity, rate and irrigation and/or aeration of oil decide the transition to the second cycle with change of the areas of development, perpendicular and similar to the original areas, while the pumping regimes displacing agent in injection wells and oil extraction from wells choose similar to the first cycle, by results of the analysis to make decisions about the transition to the first cycle, after which cycles alternated [EN 2418155, 10.05.2011].

The disadvantage of this method is the lack of measures to address change of filtration flows and alignment profile pick, selection of optimal technologies of exposure to specific geological and physical conditions of formation and current state of development.

Known the way of the development of oil deposits on the basis of system-address the impacts, including the injection of displacing agent through one or more of injection wells, extraction of oil through one or more production wells, the analysis of geological and field data on the work of each of the wells, taking into account the entire history of the development of this Deposit, the allocation from the history of development of spontaneous unplanned changes in the hydrodynamic regime of all boreholes and response deposits to these spontaneous changes in the hydrodynamic regime changes of parameters of work of producing wells, the allocation of the response deposits zones of residual oil reserves, determination of residual oil reserves on the parameters of the received response and targeted regulation system development in selected areas of the response to the findings of the response. In selected zones carry out the drilling of additional injection and/or production wells, and in selected areas and identify primary preferential direction of filtration flows displacing agent in the field, then filtration flows specify new directions [EN 2209947, 10.08.2003].

The disadvantages of this method are:

- first, high the cost of its implementation, due to the fact that in selected areas produce drilling of additional injection and/or production wells;

- secondly, the low efficiency of the method due to the complexity of its implementation;

- thirdly, the lack address alignment profiles pickup.

The technical result of the invention is to increase the efficiency of the method by increasing oil recovery, reduction of volumes of produced water, reduction of expenses for realization of the way and ensure the intensification of the development process.

The necessary technical result is achieved that the way of the development of oil deposits on the basis of system-address to its impact on the reservoir includes cyclic - stationary discharge agent through injection wells, fluid through production wells, additional address the impact of chemicals on reservoirs through all set injection and production wells, for which the object of development emit characteristic sites with different geological and physical properties, the current state of development and the degree of development of the reserves, there are the experimental plot on which with the use of core material define its average permeability and calculate the weighted average of hydroconductivity, piezoconductivity of the reservoir within this area, carry out filtration test, oil-driving, stimulating or insulating properties of the chemicals used, and the length of the discharge agent (the duration of poluchila nonstationary effects) in the limits of this section is determined by the formula:

T=L 2 /2X,

where T is the duration of discharge agent, day;

L - distance from the front of forcing the agent to the field of fluid, m;

X - average piezo-conductivity of the layer, m 2 /s;

X=k/µCm,

where k is the average permeability of the reservoir, 2 microns ;

mu - medium viscosity of the reservoir, MPa·sec;

m - average porosity reservoir, the share of units;

C - coefficient of elasticity rocks and fluids, PA -1 ,

address define duration of discharge agent on each sector, and an algorithm for further development selected plots on the basis of laboratory studies and the results of hydrodynamic modeling of the impact of technology for the specific conditions of the selected sites, then carry out a systematic address the impact at each site.

Summary of the invention

At present in the country for more than 90% of oil production carried out on objects by the method of flooding. At the expense of oil recovery in comparison with the regime of exhaustion increased on average more than 2 times. However, the effectiveness of this method of development is largely dependent on the geological structure of the manifold. With the good geo-physical conditions in the flooding of final oil recovery does not exceed 50-60% of the initial oil reserves, and under adverse conditions - 30-40%. Along with the large water consumption for the production of oil flooding gives poor results at high heterogeneity of formations and high viscosity oil.

In a strongly inhomogeneous reservoir of the pumped water breaks to producing wells in highly permeable strata and regions, leaving nevelesanas oil in low permeability layers areas, zones, etc. This leads to the fact that the areas of oil fields at the front of flooding are unsystematic alternating flooding of high permeability and net pay, less permeable layers and areas.

In inhomogeneous layers deposition oil-saturated areas and layers may not be covered by water flooding by 20-50% and more. Low percentage of extraction of oil is mainly due to the low coverage of the formation flooding. Due to the primary production of highly productive high-permeability reservoirs increasing number of remaining reserves passes into the category of hard to recover. In such conditions existing stationary field development systems become ineffective.

Cyclic (non-stationary) method flooding based on periodic regime change impact on oil fields of the complex structure, which in productive deposits artificially created non-stationary distribution of reservoir pressure and movement of reservoir fluids.

Non-stationary field pressure in the reservoir created by the periodic changes of the volume pumped displacing agent and extracted from the reservoir fluid (in the case of artificial reservoir flooding) or circular selection of a liquid (in the case of natural water regime). The effectiveness of unsteady flooding in the later stages of development of small and is expressed in 1-3% increase of oil recovery factor - KIN.

The proposed system-address flooding and the well is that all activities for use as processing technologies well bore zone formation and methods of enhanced oil recovery in General should be implemented with the use of specially developed compositions of chemicals and technologies for the specific conditions of the Deposit taking into account the existing problems and current state of development. Thus engineering of treatment of wells should be carried out taking into account their interaction with the surrounding wells and unified development of the productive formation in General.

This approach is carried out on the basis of certain principles of implementation with the use of chemicals and compositions technologies developed for the specific conditions of the reservoir, will allow to raise efficiency of oil field development, which is especially important for deposits with it is difficult recoverable reserves are either on the later stages of development.

Principles of realization of the address of the impact:

1. Production and realization of all complex of works on the basis of a detailed analysis of geological and physical characteristics of the specific object of development.

2. Identification of priority areas for targeted methods of influence on results of analysis of the current state of development of formation, formation of system of development and distribution of the residual oil saturation.

3. Rationale method of address impacts taking into account the identified reasons for the decrease in the efficiency and capacity of system development.

4. Development of chemical compositions and methods address the impacts on the basis of experimental studies using natural core material and formation fluids in conditions close to the reservoir.

5. Selection of the programs and settings of targeted exposure for experimental site-specific geological and physical characteristics, the technical condition of wells and environmental infrastructure.

6. Improvement and industrial introduction of the most efficient technologies on the basis of the commercial results of their application in analogichnym geo-physical conditions.

The algorithm of realization of system address the impact on the reservoir and well presented on figure 1.

Production and realization of all complex of works on application of technology of system address the impact on the reservoir and well starts with a comprehensive analysis of geological and physical characteristics of the specific object of development and peculiarities of the current state of development. At this stage are considered physical-lithologic features of the structure of the reservoir, its filtration-capacitive characteristics, size of a reservoir pressure and the pressure of saturation, reservoir temperature and the precipitation of paraffin, properties of reservoir fluids, etc. Then analyzed the current state of development, based on its identifies the main reasons of increase of efficiency of process of oil extraction and ways of solution of the revealed problems.

The next step is the identification of priority areas of impact given the uneven distribution residual oil saturation, specific geological and physical characteristics of individual parts deposits, zonal and layered heterogeneity, the current state of development and system well placement. Such plots can be separate units between the rows of injection wells or oil-bearing contour, sections, separated from other neutral currents lines, screens, areas of seepage, etc. the Number of wells in these areas can vary from 2-3 up to 100 and more.

Further analysis geological and physical characteristics of the chosen site, available results of research of wells and formation fluids, the capacity of the wells, hydrodynamic couplings, is the construction of geological profiles, permeability, initial and current watering, identifies features of the development process specifically chosen site.

In addition, the evaluation of the suitability of the system development and water injection for targeted stimulation, since in the absence of, for example, the formed system of reservoir pressure maintenance - TTD or the presence of the low number of injection wells at the selected site, makes impossible the implementation of unsteady flooding. Thus, the rationale of the method address the impact of taking into account the identified problems reduce the efficiency and capacity of the system development is one of the key stages.

As the impact of technology in this case, there are variants of realization wells treatments based on the principles of system technology and technologies of enhanced oil recovery (complex technology, including non-stationary flooding with the treatment of wells). In principle can be used with any technology enhanced oil recovery and development efficiency, suitable for implementation in specific conditions of the chosen site.

In case of implementation of the treatment of wells (system technologies stimulation) at the beginning, based on the identified causes of declining productivity of wells, justified requirements songs chemicals. Taking into account these requirements for specific geological and physical conditions of the selected pilot area on the basis of complex physical-chemical and rheological methods are developed of optimal composition of the chemicals for processing of wells. Further research to identify changes of filtration in porous media are carried out using natural core material and formation fluids in conditions close to the reservoir. Filtration test is performed to determine the oil-driving, stimulating or insulating properties of the developed compositions of chemicals and are the basis for developing recommendations and instructions for use sound composition (technology) real field conditions.

According to the results of physical-chemical research and conducted filtration experiments prepared statement on the application of the developed compositions of chemicals for processing of wells. In the Statement provides information about the mechanism and conditions of use, the selection of wells, the recommended volumes injection, are the main types of wells before and after treatments, etc. as Applied to all the selected area is composed address the work Programme, in which the basis of the principles of system technology specifies a list and sequence treated wells, provides information about the treatment technologies and methods of determining technological efficiency.

Next are systemically address processing wells on pilot plot, and the basis of the obtained results is determined by the volume of additionally produced oil, refined injected amount, the sequence of operations, justified optimal parameters of realization of technologies of processing of wells for further expansion of work and industrial implementation of the most optimal technologies.

When implementing complex technology (see figure 1) list of works has gone through some changes, but in General remain the same principles site selection effects.

figure 2 - test-section seam BV Aganskoye field;

figure 3 Dynamics of oil production (per month) and the water content of the experimental area Aganskoye field.

The method is as follows (example).

As an example, consider implementing a system-address the impact at the experimental site of a layer BV Aganskoye field.

The main objects of development Aganskoye oil deposits, which determine the production of oil at the field are layers BV 8 and BV 9 , containing 73% of all reserves of oil.

Collectors are sandstones gray, brownish-gray at the expense of the reservoirs, coarse, medium, fine-grained and coarse-grained silts, cemented clay cement, areas with interlayers and lenses of various forms of calcareous Sandstone, homogeneous or layered.

The total thickness of the layer in the middle of 22.3 m, the average effective thickness is 13.3 meters Coefficient equal ones 0,69, ruggedness - 6,0. Permeability of the formation BV is 342,1 2 microns , open porosity of 22.8. Initial saturation by reservoir averages 71,2%.

Object BV 8 project documents was provided by line development system. Five cutting series has divided the Deposit area for 6 blocks. In the 2nd, 4th, 5th units approved five development system to the grid 500 x 700 m in area of operation and the remoteness of the first rows from the discharge line at 600 M. Selected one (3) three-row block with net producing wells 700 x 700 m and the distance between the first, producing and injection rows of 850 m

The development Project provides for a phased transition from the linear to block square and the electoral system impact. To generate stocks of the object BV 8 approved 621 well the main Fund (including 487 mining and 134 injection) and 30 wells reserve Fund. Project borehole spacing - 36 ha/SLE.

For the implementation of unsteady flooding was selected pilot plot, located within 1-th block, which is less exposed to changes in system development, taking into account the fact that currently the development system for reservoir BV undergoing changes, namely the transition from a linear to a block-square and electoral systems impact, as well as the transfer line discharge in some blocks. Within the experimental site is located 26 injection and 47 wells (figure 2).

Since the efficiency of unsteady flooding depends on proper timing cycles of exposure, based on the definition of average permeability of experimental plot in accordance with the available geological and commercial information, including data GDI and research cores. Based on the obtained data were calculated weighted average of hydroconductivity and piezoconductivity of the reservoir within the pilot area (table. 1).

To pron., mkm 2

To long did

Viscosity, MPa·sec

Water permeability, mkm 2 ·cm/MPa·sec

To pies., cm 2 /s

Duration of discharge agent on each section (i.e. the duration of poluchila nonstationary effects) is determined by the formula:

T=L 2 /2X,

where T is the duration of discharge agent, day;

L - distance from the front of forcing the agent to the field of fluid, m;

X - average piezo-conductivity of the layer, m 2 /s;

X=k/µCm,

where k is the average permeability of the reservoir, 2 microns ;

mu - medium viscosity of the reservoir, MPa·sec;

m - average porosity reservoir, the share of units;

C - coefficient of elasticity of the breed and liquid, PA -1 .

On the basis of information about the reaction of producing wells to the changing volumes of water injection, the results of research on injection of indicators and technical capabilities of reservoir pressure maintenance system were calculated by definition of poluchila nonstationary effects, taking into account the viscosity of the reservoir oil, porosity, permeability of the reservoir, which is characteristic for the given object. As a result of calculations obtained that the duration of poluchila of the experimental area of the reservoir BV 8 is 3,5 months or 107 days (table 2).

The results of determining duration of cycles on the plot formation BV Aganskoye field

L 2 , 10 4 m 2

To pies., cm 2 /s

T cycle, days

T cycle, month

T p/t, days

T p/t, months

Analysis of the technological parameters of injection of the experimental area in accordance with distribution of wells The CND and evaluation of the maximum level injection in the period prior to the implementation of the technology showed that the total upload all wells on the NCS during the cyclic flooding in period 1 and period 2-nd half-cycles will not exceed average monthly injection in the period of stationary flooding and, moreover, the design capacity of the CND.

On the basis of the performed analysis of the development of a pilot site of a layer BV 8 Aganskoye field and on the basis of the results of calculation of parameters of realization of unsteady flooding was compiled schedule (starts-stops) injection wells in accordance with the calculated duration of the cycles.

To increase the efficiency of the process of unsteady flooding on wells of the reservoir pressure maintenance system was planned works on the redistribution of filtration flows (TFG) and on the intensification pickup taking into account the available geological and commercial information, including GIS data control.

Figure 3 shows the dynamics of oil production in the month of the experimental area, which also shows an increase in oil production. Assessment of additionally produced oil linear trend of monthly dynamics of oil production shows that the application of the system of address the impact of additionally produced 10191 tons of oil, thus reduction of produced water was 68,9 thousand m 3 , and unproductive water injection is reduced by 73 thousand m 3 . Thus, the total electricity savings from the reduction of water extraction and limitations unproductive injection is 2,027 million kW/hour.

The way of the development of oil deposits on the basis of system-address effect on its layers, including cyclic - stationary discharge agent through injection wells, fluid through production wells, additional address the impact of the chemicals at the seams through all set of injection and production wells, for which the object of development emit characteristic sites with different geological and physical properties, the current state of development and the degree of reserves depletion, allocate experienced a plot that using core material determine its average permeability and calculate the weighted average of hydroconductivity, piezoconductivity of the reservoir within this area, carry out filtration test, oil-driving, stimulating or insulating properties of used chemicals, and the duration of forcing agent in the limits of this section is determined by the formula: T=L 2 /2X, where T is the duration of discharge agent that day; L is the distance from the front of forcing the agent to the field of fluid, m; X - average piezo-conductivity of the layer, m 2 /s; X=k/µCm, where k is the average permeability of the layer, mm 2. - the average viscosity of the reservoir, MPa·sec; m - medium porosity reservoir, the share of units; C is the coefficient of elasticity rocks and fluids, PA -1 , address define duration of discharge agent on each sector and an algorithm for the further development of the selected plots on the basis of laboratory studies and the results of hydrodynamic modeling of the impact of technology for the specific conditions of the selected sites, then carry out a systematic address the impact at each site.