RU2346148C1 - Method of developing oil or oil-gas condensate minefields at late stage - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to oil industry, and can be used when developing oil or oil-gas condensate minefield having wide production history or being at the late stage of development. According to the method, product is taken through production wells, operating agent is injected through pressure wells, logging surveys of wells are performed, formation fluids and core are analysed, data on operation of production and pressure wells is analysed, a geological hydrodynamic model of productive fields is built, areas with residual saturation of productive fields are defined, actions regarding additional extraction of deposits and prognosis of product extraction product indices on geological hydrodynamic model is prepared, and further development of the field according to geological hydrodynamic model data is performed. In addition, there carried out are seismic investigations of the minefield and logging surveys of wells in operation, covering 20-25% of existing well stock, and actual values of porosity, permeability, oil-water contact position, oil-gas contact position, and residual oil-gas condensate saturation of layers are determined. New wells are bored or surface holes are drilled for wells with recovery of core in amount of 0.5 -1.5% of existing well stock, and properties of productive layers are determined as per the core. Downhole fluid samples are taken in amount of 3-5% of the existing well stock, and complex analysis thereof is made. Thermal hydrodynamic surveys of wells of not less than 60% of existing well stock are carried out. At the late stage of formation development there prepared is a database according to current parameters and there built is geological hydrodynamic model of the field development status, which considers technogenic object changes with its monthly adaptation according to parameters of wells' operation for the last 1-3 years. There defined is a state, volumes and distribution of technogenically changed hydrocarbon reserves of the minefield. There predicted are different versions of development with regard to present thermal hydrodynamic conditions, characteristics of formations and saturating fluids, and the most effective version is implemented on the minefield.

EFFECT: improving oil-gas condensate production rate of the minefield having wide production history at the late stage.

1 ex, 9 tbl

Description

The invention relates to the oil industry and can find application in the development of an oil or oil and gas condensate field with a long history of exploitation or at a late stage of development.

A known method of developing a complex oil reservoir, including pumping a displacing agent through injection wells and selecting reservoir fluids through production wells, mapping geological and technological parameters, selecting the most effective methods of stimulating the formation and using them on a real reservoir, characterized in that they create a geological hydrodynamic model of the reservoir, including a series of geological maps and development maps showing the coordinates of the well, geological parameters of the reservoir To the reduced intervals, data of reservoir and bottomhole pressures from the beginning of development, the coordinates of the pinch lines, internal and external oil contours, the model is structured according to each indicator by adding and then normalizing the parameter values, for which maps are constructed: structural, effective oil-saturated layer thickness, initial oil saturation of reservoirs, their sandiness and ruggedness, initial balance reserves of oil and accumulated oil, water, liquid and water injection , as well as maps of the current oil saturation and isobars for different dates from the beginning of development, while taking into account the areas of development of geological parameters above and below the conditional values, the selection of which is carried out according to additive maps constructed by variant calculations separately for each group of reservoir stimulation methods (RF Patent No. 2123582, published. 1998.12.20).

The known method does not allow constructing an adequate geological and hydrodynamic model for a field with a long history of operation or at a late stage, taking into account technogenic changes over a long period of field operation, excludes the possibility of satisfactory adaptation according to history and, therefore, does not allow substantiating effective forecast options for the future with achievement of high oil recovery.

Closest to the proposed invention in technical essence is a method that includes conducting geophysical research of wells (GIS), geological and field studies of wells and laboratory studies of the properties of reservoir fluids and porous media, interpretation of GIS materials, construction of a detailed volumetric geological and hydrodynamic model of a layered heterogeneous formation by section breakdown and correlation according to well logging data, determination of cumulative oil production volumes for producing wells and injection volumes for pumping non-producing wells and issuing recommendations for geological and technical measures. Additionally, a complex of well logging studies is carried out and local geological and statistical sections are constructed using a complex of logging curves. To divide and correlate sections, an adaptive approach is used, which consists in the accumulation of knowledge about the features of the geological structure of the formation by sequentially moving from identifying global patterns of change in geological and geophysical characteristics to identifying and taking into account local structural features. Based on this, a detailed volumetric geological and hydrodynamic model of a layered heterogeneous formation is built and the hydrodynamic relationship of the correlated layers of neighboring wells is further confirmed by comparing the volumes and dynamics of injection and perforation intervals of injection wells and the dynamics of oil and water extraction, perforation intervals, production wells and / or by conducting additional research using geophysical methods (RF Patent No. 2135766, published. 1999.08.27 - prototype).

The known method does not allow constructing a geological and hydrodynamic model that is adequate to the current state of the field, which would reflect the technogenic changes in the reservoirs and the fluids saturating them, which occurred in connection with changes in the thermobaric conditions and the interaction of reservoir and injected fluids. In some cases, the technogenic changes in reservoirs and fluids that have taken place are irreversible. In addition, the information base for the entire history of the development of a field for production and injection of a working agent for wells and reservoirs, as well as for reservoir and bottomhole pressures, is either absent or not created on the basis of direct measurements and does not reflect the actual filtration processes in the reservoirs for the previous period of operation . These factors will virtually exclude the creation of a geological and hydrodynamic model that adequately reflects the current state of the field in terms of filtration-capacitive properties (FES) and the nature of fluid saturation and their properties, creates insurmountable problems in its adaptation and reduces the degree of validity of the recommended measures for field development and the accuracy of production forecasts prospective products.

The proposed method solves the problem of increasing oil and gas condensate recovery fields with a long history of operation at a late stage.

The problem is solved in that in a late stage method of developing an oil or gas condensate field, including product selection through production wells, injection of a working agent through injection wells, well logging, core and formation fluid analyzes, analysis of production and injection well operation data, construction geological and hydrodynamic model of the development of productive deposits, identifying areas with residual saturation of productive deposits, drawing up measures about their recovery and the forecast of production indicators on the geological and hydrodynamic model, the subsequent development of the field in accordance with the data of the geological and hydrodynamic model, according to the invention, seismic studies of the field are additionally carried out, well logging is carried out on existing wells covering 20-25% of the existing well stock, determine the current values of porosity, permeability, the position of the oil-water contact, gas-oil contact and the residual oil and gas condensate reservoirs, new wells are drilled or sidetracks are drilled with core sampling in the amount of 0.5-1.5% of the existing well stock, and the properties of productive reservoirs are determined by core, depth fluid samples are taken for 3-5% of the active well stock and their complex analysis, conduct thermohydrodynamic studies of wells with coverage of at least 60% of the existing fund, create a database of current parameters at a late stage of reservoir development and build a geological and hydrodynamic model of the current state of field development Taking into account the technogenic changes of the object taking place with its monthly adaptation according to the indicators of well operation with high reliability over the last 1-3 years, they establish the state, volumes and distribution of technologically changed hydrocarbon reserves of the field, calculate various development options for the forecast taking into account the prevailing hydrothermodynamic conditions and physical -chemical characteristics of formations and saturating fluids and realize the most effective of them in terms of technical and economic Atelier.

The essence of the invention in the known technical solutions, the construction and adaptation of the geological and hydrodynamic model of an oil or oil and gas condensate field, which is at a late stage of development, is carried out using seismic and well logging studies of wells and produced fluids, as well as performance indicators of production and injection wells. The model constructed in this way takes into account too much useless data accumulated over the entire history of field development. These data distort the current picture of the development status and the geological state of the reservoirs. At the same time, this approach superficially takes into account the changes that have occurred in reservoirs and reservoir saturating fluids in the very last years of development, which is most important for creating an adequate development model. Against the background of a huge amount of data, this information becomes insignificant or insignificant. These factors exclude the possibility of creating an adequate geological and hydrodynamic model for the conditions prevailing in the field, reduce the effectiveness of its application to solve problems of increasing oil and gas condensate recovery of objects, which leads to a decrease in the efficiency of development and oil and gas condensate recovery of the field. The proposed method solves the problem of increasing the efficiency of development and oil and gas condensate recovery of the field. The problem is solved as follows.

When developing an oil or oil and gas condensate field at a late stage, products are selected through production wells, and a working agent is injected through injection wells. Conduct seismic studies of the field, conduct well logs in existing wells covering 20-25% of the existing well stock, determine the current values of porosity, permeability, water-oil contact position, gas-oil contact and residual oil and gas condensate saturation of the reservoirs, 0.5– 1.5% of the existing well stock, coring during drilling and determining the properties of the productive formations according to the core, conduct depth sampling of the fluid by 3-5% wells and their complex analysis, conduct thermohydrodynamic studies of wells with coverage of at least 60% of the existing fund, create a database of current parameters at a late stage of reservoir development and build a geological and hydrodynamic model of the current state of development of the field, taking into account the technogenic changes of the object with its monthly adaptation according to the indicators of well operation with high reliability over the last 1-3 years, establish the condition, volumes and distribution of technogenic changes The accumulated reserves of hydrocarbons in the field, various development options are calculated for the forecast, taking into account the prevailing hydrothermodynamic conditions and the physicochemical characteristics of the reservoirs and saturating fluids and realize the most effective of them in terms of technical and economic indicators.

To compile a geological and hydrodynamic model of field development, data from the last 1-3 years are used. They analyze the development status of the oil or gas condensate field and establish the features and problems of the situation at the development site, determine the location and numbers of wells and perform a complex of geophysical studies, including nuclear-physical and wave methods (for example, KNK - compensation neutron logging; INK - pulsed neutron neutron logging; INGC - pulsed neutron gamma-ray logging; SGK - spectrometric gamma-ray logging; INGKS - spectrometric pulsed throne gamma-ray logging (C / O-logging); MAK - multi-probe acoustic logging) covering 20-25% of the well stock, thermohydrodynamic studies covering at least 60%, taking deep fluid samples - 3-5%, drilling new wells or horizontal lateral trunks with coring - 0.5-1.5% of the current fund. Studies of control, piezometric and other categories of wells are also carried out. Processing the research results, information is obtained on the technologically altered parameters of reservoirs and reservoir fluids, which is used as a new database in the area of the studied wells. Conduct modern seismic surveys (3D - 3-dimensional (areal) seismic research; 3D / 3C - 3-dimensional (areal) seismic research with 3-component recording; 4D - 4-dimensional (4-dimensional time) seismic survey), in interpreting the results of which use the speed characteristics of technologically altered objects according to the data of the completed well logging complex and determine the parameters of the reservoirs and the nature of their saturation in the inter-well areas of the field, supplementing the new base data. A geohydrodynamic model of the development object is built using a database reflecting its technologically altered state, a monthly adaptation of the model is carried out for the last 1-3 years of field operation, creating during this period a reliable information base on the performance of production and injection wells, as well as materials of their thermohydrodynamic and geophysical surveys in order to control the development process for this period of time. Establish the condition, volumes and distribution of technologically altered hydrocarbon reserves in the deposits. A set of technological measures is being developed in order to increase the level of current production and the final recovery coefficient, perform predictive calculations according to the options on the created geological and hydrodynamic model that adequately describes the current technologically altered state of the object, select the best option according to technical and economic indicators and implement it at the field.

Concrete example

The oil and gas condensate field had the following initial characteristics: depth - 2800 m; pressure - 57.0 MPa; temperature - 110 ° С; effective oil saturated thickness - 44 m; gas condensate - 110 m; gas condensate up to 600 g / m ³ ; condensation start pressure - 56.0 MPa; oil saturation with gas - 37.0 MPa; initial gas factor - 520 m ³ / t; the field has been actively developed for about 20 years; it began with the extraction of oil and gas, but the injection of water and dry gas to maintain pressure was delayed. Over 250 wells for various purposes have been drilled at the field. The reservoir pressure rapidly decreased and amounted to 12.0-13.0 MPa. Significant changes have occurred in the position of the oil-water and gas-oil contacts, oil degassing, condensation from the gas, and, obviously, the reservoir-filter characteristics of the collector have deteriorated due to deformation phenomena. There is a technologically altered field, information about this in the materials of initial seismic studies and logging of drilled wells, of course, is not contained.

An analysis of the development of the field is carried out and zones of strong rise in oil-water contact and a decrease in gas-oil contact are established, wells or lateral horizontal trunks are sampled and drilled, and geophysical studies are carried out through the column and the current values of the reservoir parameters are determined. Conduct thermohydrodynamic studies and determine the operating intervals, perform seismic studies determine the nature of the saturation and porosity of the formation in the interwell sections.

The deep fluid samples are taken and analyzed: the condensate content in the gas is about 100 g / m ³ ; the gas factor decreased to 360 m ³ / t, reservoir temperature on average decreased to 107.5 ° C.

The data are summarized in tables 1-4. Below is the procedure for entering information when building a geological model in the Petrel software package.

1. Wellhead well coordinates.

Well number X Y

2. Inclinometry.

Depth Azimuth Bias Declination angle dx dy

3. Altitude, formation indices.

4. LAS files.

Depth Porosity Permeability

5. Trending surfaces (seismic, CPS product - two-dimensional reservoir models or digitized structural maps).

6. Well logging conclusions.

Information transfer to the Eclipse software package. After constructing the geological model, files (numerical arrays) are formed, where the keys indicate: a) grid coordinates, b) reservoir properties (porosity, permeability, oil saturation at the grid nodes). A file with well trajectories and their grid coordinates is also generated.

To generate a Schedule file (development history), the following tables are required.

Table 1 day month year Well number Sign of perforation Formation index Perforation Depth Perforation End Depth Skin factor

Table 2 Well number date of Oil selection Water withdrawal Gas sampling Water injection Gas injection Bottomhole pressure

Table 3 Well number Group name

Table 4 Formation index Grid Number Vertical

Well trajectory file and model geometry.

At the end of the Schedule option, a Schedule file is generated for import into Eclipse.

Using the obtained database (Tables 1-4), a geohydrodynamic model of the technologically altered field is built using software tools recognized in this field, for example, Petrel, Eclipse. To adapt the model, actual monthly well performance indicators for the last 1-3 years are used (tables 5-9), including the results of thermohydrodynamic studies.

An analysis of the state of development of the field according to an adequate current technogenic changed state of the adapted model shows areas with high residual oil and gas condensate saturation, thermodynamic anomalies, and specified water and gas contacts. Measures to improve the development and increase the oil and gas condensate recovery coefficient include optimizing the system and the intensity of water and dry gas injection in certain areas, drilling additional wells and lateral horizontal shafts into formations and zones with high residual oil and gas condensate saturation, disaggregating production facilities, pumping flow-rejecting reagents, etc. according to options . Calculate the predicted production / injection indicators according to the options on the geological and hydrodynamic model adequate to the current state of the field and implement the most effective of them according to technical and economic indicators and the ultimate oil and gas condensate recovery.

When implementing the proposed development method, the absolute growth of extraction coefficients relative to those achieved during the implementation of the current project is not less than:

for oil - 2.5-3.0%;

condensate - 2.0-2.5%;

for gas - 1.5-2.0%.

The application of the proposed method will increase the oil and gas condensate recovery of the field.

Claims (1)

A method of developing oil or oil and gas condensate fields at a late stage, which includes taking products through production wells, injecting a working agent through injection wells, well logging, core analysis and formation fluids, analyzing production data from production and injection wells, building a geological and hydrodynamic model for developing productive deposits, identifying areas with residual saturation of productive deposits, drawing up measures for their additional recovery and forecast providers of production on a geological and hydrodynamic model, the subsequent development of the field in accordance with the data of the geological and hydrodynamic model, characterized in that they additionally carry out seismic studies of the field, logging is carried out on existing wells covering 20-25% of the existing well stock, current values are determined porosity, permeability, water-oil contact position, gas-oil contact and residual oil and gas condensate saturation of formations, new wells are being drilled or they drill sidetracks with core sampling in the amount of 0.5-1.5% of the existing well stock and determine the properties of the productive formations by core, take depth fluid samples for 3-5% of the active well stock and analyze them comprehensively, conduct thermohydrodynamic well surveys with coverage of at least 60% of the existing fund, create a database of current parameters at a late stage of reservoir development and build a geological and hydrodynamic model of the current state of field development, taking into account technogenic and changes in the facility with its monthly adaptation in terms of well operation over the last 1-3 years, establish the condition, volumes and distribution of technologically changed hydrocarbon reserves of the field, calculate various development options for the forecast taking into account the prevailing hydrothermodynamic conditions, characteristics of the reservoirs and saturating fluids and implement them on the field the most effective of them.