RU2501948C1 - Method for hydrodynamic tomography of formation permeability - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: method involves creation of steady-state abnormal pressure in the chosen source well at the productive formation interval, fan-type recording of interval time of propagation of steady-state pressure mode in the same formation to wells of receivers distributed along the network on the deposit surface area, subsequent repetition of fan-type recording of interval time of propagation of steady-state pressure using the largest number of wells as the abnormal pressure source, which participate in fan-type recording with further processing of the obtained two-index data of interval time as to tomographic modification of methods of integral geometry that is adapted to kinematic equations of movement of flow of fluids in non-homogeneous medium using optimised principles.

EFFECT: receiving reliable information on spatial distribution of alternating effective permeability having the nature of carrying capacity of formation fluids under action of steady-state pressure along the surface area.

Description

The present invention relates to the oil and gas industry in the field of monitoring the development of oil and gas fields and can be used to monitor changes in the spatial characteristics of the throughput of the reservoir.

In the process of field exploitation, the throughput of formations significantly changes due to physicochemical processes of interaction between the components of the fluid fluids (asphalt) of the reservoir, both initial and injected into the reservoir during the implementation of measures to maintain reservoir pressure, as well as due to the formation of compacted low-permeability zones formed due to the intense effect on non-Neotonic fluids, including oil, up to the formation of stagnant sections and Foot edema formation throughput capacity and output of the effective operation of significant portions of the deposit.

Currently, the monitoring of the dynamics of the permeability of the reservoir is carried out by hydrodynamic control methods, in particular hydraulic listening [A. Chodri. Hydrodynamic studies of oil wells / Premium Engineering LLC, 2011, 730 C.] by pressure injection and subsequent analysis of the nature of its recovery in the local vicinity of the formation, followed by interpolation of the result of such a study for all wells into the interwell space. In the process of interpolation, geological and geophysical information is additionally used [Paynt RF No. 2092691, Е21В 47/00 published in BI N 28, 1997] or a multiphase filtering process is simulated using a complex of geological and geophysical data [RF Patent No. 2166630, Е21В 49/00 , 43/16 published in Bul. No. 13, 2001]. A known method of finding non-conductive elements of an oil reservoir [RF Patent No. 2229020, MKI Е21В 43/00, 2002.] based on the analysis of the correlation matrix between the data of water injection volumes and oil and water production rates, as well as its development [RF Patent No. 2298647, Е21В 47/10 (2006.01)], which consists in downloading the indicator into the injection well, followed by analysis of the trajectory of the indicator and estimating the time of its movement. This path and its analogues do not allow revealing local spatial disturbances of the permeability of the formation in the interwell region, since the initial data used by the authors do not contain information about the nature of permeability in the inner, interwell zone of the reservoir within the field, sufficient to unambiguously find the spatial distribution of the permeability coefficient. The question of the uniqueness of finding permeability is ignored by the authors, and the results of calculations in this regard are of the nature of obtaining a private, subjective model.

At the same time, obtaining such previously inaccessible information about the spatial distribution of the heterogeneous reservoir capacity is extremely important for increasing the oil recovery coefficient, since it allows you to determine the areas and areas of technological work for the decoupling of stagnant zones, and to ensure the inclusion of previously inaccessible sections for product recovery.

A full-fledged prototype of our invention is absent, since the statement of the problem of a spatial study of heterogeneous conductivity relative to the movement of formation fluids within the entire field was considered unsolvable [K.S. Basniev N.M. Dmitriev, R.D. Kanevskaya, V.M. Maksimov Underground Hydromechanics. Moscow - Izhevsk, 2006, 487 S.] and is such from the point of view of classical statements of boundary value problems for equations of fluid motion.

The possibility of studying a spatial image of an inhomogeneous (containing local minima and maxima) distribution of formation permeability within a drilled section of a field during its operation exists and is based on a specialized method for studying the interval times of steady-state pressure propagation between pairs of wells and modern tomographic-type information technologies. The use of a set of interval time intervals of steady state motion in all pairs of wells acceptable for measuring with the subsequent technology for constructing a spatial image of formation permeability was not found in the patent literature.

The objective of the invention is to provide reliable information on the spatial distribution of the variable effective permeability having the character of the flow capacity of the formation fluids under the influence of stationary pressure over the area, in order to information support technological measures to increase the flow rate of deposits by eliminating the found zones of reduced conductivity or complete relief of permeability, taking fragments of the field out of operation.

This set of actions and means will be called the “Method of hydrodynamic tomography of a permeable formation”, as tomography based on measurements of intervals of time of a hydrodynamic reaction in wells of receivers for hydrodynamic excitation in wells of sources in the interval of the studied permeable formation.

The method of hydrodynamic tomography of a permeable formation is aimed at finding a tomographic image of the permeability of the formation, based on specialized formation of a tomographic data set for fluid distribution in the formation and subsequent imaging using tomographic modification of integral geometry methods adapted to kinematic equations of motion of a steady flow of fluids in an inhomogeneous medium using optimization principles.

The main elements of the tomographic modification of the methods of integral geometry, adapted to the kinematic equations of motion of a steady fluid flow in an inhomogeneous medium using optimization principles, are:

1. The formation of a kinematic model of the motion of a steady fluid flow in the form of a finite element model for a function of the flow velocity [Marchuk G.I. Methods of Computational Mathematics. Moscow, Science, Head. Ed. Fiz - Mat. Literature, 1980, 534 S.];

2. modeling of the interval time of the steady-state fluid motion along all pairs of wells source-receiver of the field based on optimization principles [Boltyanskiy V.G. Mathematical methods of optimal control. Moscow. The science. The main editorial board - mat. lit. 1969, S. 408.];

3. calculation of the discrepancy between the actually measured and simulated interval times;

4. solving the inverse problem of integral geometry [Invalid problems of mathematical physics and analysis / M.М. Lavrentiev et al. - M .: Nauka, 1980. - 286 p.] For the calculated discrepancy and finding the correction to the original model;

5. control of the accuracy of the resulting model and, in the case of large errors, return to step 2.

The method of hydrodynamic tomography of a permeable formation includes the following steps:

1) the creation of a stationary abnormal (positive or negative depending on the operating conditions of the field) pressure in the borehole source of abnormal pressure in the interval of the reservoir;

2) recording the propagation times of the steady-state pressure regime in the same reservoir from the source well to all receiver wells distributed over the network on the field’s area forming the correct observation system;

3) sequential repetition of the correct registration of the interval time of propagation of the steady-state pressure using as wells the source of abnormal pressure of all the wells participating in the fan registration;

4) processing the obtained two-index interval time data by tomographic modification of integral geometry methods adapted to the kinematic equations of motion of a steady fluid flow in an inhomogeneous medium using optimization principles.

Claims (1)

A method of hydrodynamic tomography of a permeable formation, which allows determining the spatial distribution of effective throughput in the inter-well area within the productive formation of an oil and gas field according to the interval time for establishing the stationary pressure regime, including the creation of a stationary abnormal pressure in the selected well source in the reservoir interval, fan registration interval propagation time of the steady state pressure in in the reservoir to the receiver wells distributed over the network over the field’s area, sequentially fan repeating recording the interval time of steady-state pressure propagation using as anomalous pressure source wells the maximum number of wells participating in the fan recording, followed by tomographic processing of the obtained two-index interval time data modifications of integral geometry methods adapted to kinematic equations of motion are established curled flow of fluids in a heterogeneous medium with optimization principles.