EP0089986A1

EP0089986A1 - Extraction from oil fields with reinjection of separated materials.

Info

Publication number: EP0089986A1
Application number: EP82902906A
Authority: EP
Inventors: Gerard Chaudot
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-10-06
Filing date: 1982-10-05
Publication date: 1983-10-05
Also published as: NO832008L; FR2514071A1; FR2514071B1; WO1983001273A1; DE3268173D1; OA09004A; BR8207912A; EP0089986B1

Abstract

Le procédé selon l'invention consiste à récupérer les fractions légères condensables et/ou gazeuses de l'effluent et à les réinjecter dans le ou les puits et/ou le gisement. Il comprend le chauffage de l'effluent (3) provenant du puits (2), la séparation des phases gazeuses, liquides et solides de l'effluent (4), la compression, le refroidissement et la déshydratation de la phase gazeuse (5) avec récupération des condensats hydrocarbures (8) et la réinjection dans le puits (2) ou dans le gisement (1). L'invention permet de faciliter l'exploitation de gisements d'hydrocarbures.The method according to the invention consists in recovering the condensable and / or gaseous light fractions from the effluent and in reinjecting them into the well or wells and / or the deposit. It includes the heating of the effluent (3) from the well (2), the separation of the gaseous, liquid and solid phases of the effluent (4), the compression, cooling and dehydration of the gaseous phase (5) with recovery of the hydrocarbon condensates (8) and reinjection into the well (2) or into the deposit (1). The invention makes it possible to facilitate the exploitation of hydrocarbon deposits.

Description

EXTRACTION OF OIL DEPOSITS WITH REINJECTION OF SEPARATE MATERIALS

The present invention relates to a process intended to maximize the recovery of fluids from liquid hydrocarbon deposits and to facilitate their exploitation with application, in particular to heavy and / or viscous hydrocarbon deposits, and to hydrocarbon deposits having a point high freezing. In a general way. crude oils are made up of a wide variety of hydrocarbons which can range from methane to heavy parafinics sometimes mixed, in extremely variable amounts with cyclic or aromatic hydrocarbons, even even asphaltene-like solids associated with metalloid atoms, metals or others, with possible association of non-hydrocarbon chemicals.

As soon as the deposit is a little deep, the exploitation is done by well, and the recovery of the oil in place is a function more particularly, of the number of wells, their spacings, the speed of withdrawal, and the means used for maintain reservoir pressure or to move fluids in place in the deposit to the withdrawal wells.

As soon as the crude oil in place in the deposit is a little heavy and its viscosity or plasticity is high, the quantity of crude oil that we can hope to recover, compared to the quantity of petroleum in place in the deposit, is relatively weak. The means to be used to assist production being costly in equipment and in operation.

Furthermore, it often happens that the height of the crude oil column in the production well generates a pressure at the level of the deposit, close to / or greater than the pressure of the deposit. We then have to use pumps of different types to transport or assist in transporting, the crude oil to, the surface, or to have the wells produced at an acceptable rate. Another method consists in using gas which is remixed with crude oil in the well, in order to decrease the average density of the gas-oil mixture and thus cause or improve the flow rate of the well (gas lift).

In addition, as soon as the oil is too viscous, a heating fluid is injected into the deposit and sometimes, correlatively or not, fluids helping the displacement of the crude oil in the deposit.

Other methods use electrical, electrolytic or high frequency wave processes to obtain the displacement of the oil in the deposit. Finally, another way of proceeding consists in injecting air or an oxidizer in the deposit and causing the combustion of part of the oil in the deposit, and thus benefiting from the effects consecutive to this process. Depending on the type of deposit, these methods, always expensive, give results which are often questionable and sometimes random, and do not always facilitate the separation of the effluents returned to the surface.

The invention therefore aims to eliminate all or part of the disadvantages or hazards mentioned above.

To this end, the process for producing the hydrocarbon deposit, in particular with the aim of improving the recovery of the effluent, of facilitating its transportation to the treatment installations, as well as its treatment, consists in recovering the light fractions condensable and / or gaseous effluent, even if they are associated in small quantities, and to reinject them into the well (s) and / or into the deposit.

According to another characteristic of the invention, this method can also successively comprise, heating of the effluent from the well, separation of the gaseous, liquid and solid phases of the effluent, compression, cooling and possibly dehydration of the gaseous phase, with recovery of the condensates. hydrocarbons and the reinjection of condensates in the well or in the deposit.

The invention also relates to an installation for implementing the method according to the invention, this installation comprising at least one well making it possible to connect the deposit to the surface installations, at least one installation for heating the effluent, at least one separator of the gaseous, liquid and solid phases of the effluent, at least one cooling compression and possibly dehydration unit of the gaseous phase, with recovery of the hydrocarbon condensates and at least one unit for reinjecting the condensates into the well.

An embodiment of the invention will be described below, by way of nonlimiting example, with reference to the appended drawing in which:

The single figure is the block diagram of an installation for the exploitation of a hydrocarbon deposit with reinjection of the light fractions of the effluent.

In this drawing, block 1 represents the deposit from which the effluent is removed using the well. production represented by block 2. The effluent emanating from this well is reheated in at least one reheating unit 3 at a temperature favorable to the separation of the liquid and gaseous phases and to the segregation of the oil, water and possibly solid constituents in at minus a separation unit 4. In at least one compression unit 5, the gas phase is then cooled and compressed in one or more stages. In addition, the gas, during this process, is dehydrated to a pinkish point such as its water content residual will not cause difficulties in downstream processing facilities. The condensates collected at various points in the unit 5 are recovered and separated from the water associated therewith in a purifier 6 and possibly stored in an additional storage unit 7.

The residual gas recovered at the outlet of unit 5 is then refrigerated in at least one unit 8 using external refrigeration means, at a temperature making it possible to optimize the recovery of light and cold condensates.

At the outlet of the units 8, the light and cold condensates are recovered (block 9) and stored in at least one thermally insulated unit 10. At the outlet of the units 8, the residual gases are

Injected into well 2 or any other well involved in the production of the deposit, directly if their pressure is sufficient, or via at least one additional compression unit 11 if their pressure is insufficient to be reinjected at the optimum depth provided in the well (s), or directly in the deposit 1.

Depending on the type and conditions of deposit 1 envisaged, one or the other or the two units 8 and 11 will not necessarily be installed, all or part of the gases being either sold or used to meet energy or operating or detection fluid, field installations. The condensates recovered in the purifier 6 are then injected into well 2 or into any other well participating in the production of the deposit, directly if their pressure is sufficient, or via at least one pump if their pressure is insufficient to be reinjected at the optimum depth provided in the / or wells, or directly in the deposit.

Cold condensates collected by the units 9 are then injected, mixed or not mixed in whole or in part with the condensates recovered by the purifier 6, after pumping and heating (block 13), to satisfy the pressure conditions provided for the injection of the condensates recovered by the purifier 6.

Even if the hydrocarbons naturally found in the deposit have only a weak cut in gas and in parts condensable by the means described above, on condition that the installations described above do not cause any loss of substance exceeding the top-up caused by the mother production, it is created in the / όu wells 2, or in the deposit 1, a mixture of virgin hydrocarbons / recycled light hydrocarbons, whose light hydrocarbon content will increase over time.

It thus establishes a growing steering wheel of condensates and gas. As soon as the flow rate from / or wells 2 reaches the desired level, the excess light hydrocarbons can then be injected into one or more wells which can thus be put into production or which will be used to sweep the hydrocarbons in place towards / or producing wells and reinforcing the pressure of the deposits. This surplus of condensable hydrocarbons may also be remixed in variable proportions to the crude marketed in order to improve its characteristics or value, or else be marketed directly.

The start-up of the first well (s) 2 may possibly be carried out by a load of light hydrocarbons (block 1 4) condensed or not, coming from a source external to the wells. The water associated with production, and separated by units 4 and 5 can be eliminated on the surface (block 15), but if this water generates pollution or discomfort in the environment, it will be after skimming of the residual oil (block 16), reinjected into / or the deposits 1, in order to maintain the pressure of the latter within a certain measured. This residual water can be combined with adjuvants (block 17) modifying its viscosity or causing a swelling effect of the adjuvant water mixture, to move the hydrocarbons in place in the / or the deposits towards the / or producing wells.

An advantage of the process according to the invention consists in that by reinjecting into the / or the production wells σu directly into the / or the deposits of light, liquid and / or gaseous hydrocarbons, jointly or not, originating from the / or wells, with any external contribution to facilitate certain operations such as the start of production of the well (s), an effect is obtained of reducing the weight of the column of fluid in the well (s) as well as a reduction which The viscosity of the effluent can be considerable, this in order to improve the productivity of the well (s) and reduce the difficulties of separation of the phases constituting the natural effluent from the wells. The injection into the or the deposits of the excess of light hydrocarbons, gaseous or not, produced by the deposit will contribute to increase the recovery of the hydrocarbons from the deposit by washing the matrix, (reservoir rock), decrease in density, viscosity or plasticity of native hydrocarbons, without generating incompatibility problems such as those which can be created by the addition of fluids foreign to the deposit.

Even if the light hydrocarbon content of the natural effluent from the deposit is low, after a more or less long duration, a flywheel is created which allows regular flow to / from the wells to be ensured by recycling permanent.

Even if the installations described above are relatively high cost, they allow for certain conditions of isolation of fields, a significant saving, will compare the supply of foreign fluids.

Claims

CLAIMS 1.- Process for the production of hydrocarbon deposits, in particular with the aim of improving the recovery of the effluent, of facilitating its transportation to the treatment facilities as well as its treatment, characterized in that '' it consists in condensing, at least in part, leaving the production well, the condensable gases of the effluent, even if they represent only a small percentage of the flow of the effluent, and in reinjecting the condensate, liquid phase, in the above production well, or possibly the other production wells and / or the deposit.

2.- Method according to claim 1, characterized in that it successively comprises a reheating of the effluent (block 3) coming from the well, at a temperature favorable for the separation of the liquid and gaseous phases and for the segregation of the constituents oil, water and possibly solids in at least one separation unit (4), separation of the gaseous, liquid and solid phases of the effluent, compression, cooling and possibly dehydration of the gaseous phase (block 5), with recovery of hydrocarbon condensates (block 8) and reinjection of the condensates in the liquid phase, into the well (2) or into the deposit.

3. - Method according to claim 2, characterized in that it further comprises, the treatment of residual oily water from the separation of the gaseous, liquid and solid phases of the effluent (block 4) and / or dehydration of the gas phase (block 5), so as to skim off the residual oil.

4.- Method according to one of the preceding claims, characterized in that it further comprises the refrigeration of residual gases (block 8) from compression, cooling and possible dehydration of the gas phase (block 5 ), the recovery of cold condensates from this refrigeration (block 9) and injection, after possible reheating (block 13), into the well (s) (2) and / or the deposit (1).

5.- Method according to one of the preceding claims, characterized in that it further comprises, a complementary compression of the residual gases (block 11) remaining after refrigeration of the residual gases (block 8) and the injection of these gases residual in the wells (2) and / or the deposit (1).

6.- Production installation for the implementation of the method according to one of the preceding claims.