Reservoir treatment

Abstract

A method of treatment of a subterranean hydrocarbon-bearing reservoir, the reservoir comprising at least one porous and permeable rock formation, the reservoir being penetrated by a plurality of injection wells and one or more production wells, the injection wells sharing a common injection header for delivering an aqueous injection fluid to the injection wells, the method comprising: a. identifying a group of injection wells selected from the injection wells sharing the common injection header; b. determining a cumulative volume of the treatment stream that is to be supplied contemporaneously to all of the injection wells within the identified group; c. simultaneously transmitting the treatment stream only to the identified group of injection wells so as to inject the treatment stream into the reservoir, thereby treating the reservoir to improve the sweep efficiency of subsequently injected fluid.

1 - 14 . (canceled) 
     
     
         15 . A method of treatment of a subterranean hydrocarbon-bearing reservoir, the reservoir comprising at least one porous and permeable rock formation, the reservoir being penetrated by a plurality of injection wells and one or more production wells, the injection wells sharing a common injection header for delivering an aqueous injection fluid to the injection wells, the method comprising:
 a. identifying a group of injection wells selected from the injection wells sharing the common injection header and specifying for each of the injection wells of the identified group a predetermined volume of a treatment stream wherein the treatment stream comprises an aqueous dispersion of thermally activated treatment particles, the thermally activated treatment particles being present in the treatment stream at a predetermined concentration;   b. determining a cumulative volume of the treatment stream that is to be supplied contemporaneously to all of the injection wells within the identified group;   c. providing the cumulative volume of the treatment stream by dosing a concentrated aqueous surfactant solution and a concentrated dispersion of thermally activated treatment particles into the aqueous injection fluid stream that is flowing through the common injection header over a predetermined period of time;   d. simultaneously transmitting the treatment stream only to the identified group of injection wells so as to inject the treatment stream into the reservoir wherein the rate of injection of the treatment stream into each of the identified group of injection wells is controlled such that the predetermined volume of treatment fluid is delivered to each injection well of the identified group, thereby treating the reservoir to improve the sweep efficiency of subsequently injected fluid.   
     
     
         16 . A method according to  claim 15  in which the specified predetermined volume of a treatment stream is determined based on at least one of: the injection pattern size, the treatment zone thickness, the porosity of the formation, and the percentage of the injection pattern volume accounted for by a region of higher permeability than the remainder of the formation in the injection pattern volume. 
     
     
         17 . A method according to  claim 15  in which the specified predetermined volume of a treatment stream is determined based on at least one of: the volume of the dispersion of the thermally activated treatment particles and the volume of the concentrated surfactant solution that are dosed into the aqueous injection fluid over the predetermined time period of the treatment. 
     
     
         18 . A method according to  claim 15  in which the volume of the dispersion of the thermally activated treatment particles is selected based on the volume of a thief zone that is to be treated, wherein a thief zone comprises a region of higher permeability than the remainder of the formation in the injection pattern volume. 
     
     
         19 . A method according to  claim 17  in which the volume of the dispersion of the thermally activated treatment particles is selected based on the volume of a thief zone that is to be treated, wherein a thief zone comprises a region of higher permeability than the remainder of the formation in the injection pattern volume. 
     
     
         20 . A method according to  claim 15 , wherein transmission of the treatment stream is initiated for every one of the identified group of injection wells at the same time. 
     
     
         21 . A method according to  claim 15 , wherein the transmission of the treatment stream is stopped for every one of the identified group of injection wells at the same time. 
     
     
         22 . A method according to  claim 20 , wherein the transmission of the treatment stream is stopped for every one of the identified group of injection wells at the same time. 
     
     
         23 . A method according to  claim 15 , wherein the thermally activated treatment particles are polymeric. 
     
     
         24 . A method according to  claim 15 , wherein the surfactant solution is dosed into the injection fluid stream at a point upstream of the point at which the dispersion of thermally activated treatment particles is dosed into the injection fluid stream. 
     
     
         25 . A method according to  claim 15 , wherein the dispersion of thermally activated treatment particles comprises 35% (w/w) of thermally activated treatment particles. 
     
     
         26 . A method according to  claim 15 , wherein the surfactant solution and the dispersion of thermally activated treatment particles are present in the treatment stream at a ratio by volume of from 1:1 to 1:5 
     
     
         27 . A method according to  claim 15 , wherein the surfactant solution comprises ethoxylated alkyl sulphate. 
     
     
         28 . A method according to  claim 15 , wherein dosing of the surfactant solution to the common injection header begins prior to dosing of the dispersion of thermally activated treatment particles thereby forming a pre-flush stream 
     
     
         29 . A system for carrying out a treatment of a subterranean hydrocarbon-bearing reservoir, the reservoir comprising at least one porous and permeable rock formation, the reservoir being penetrated by a plurality of injection wells and one or more production wells, comprising:
 a common injection header for delivering an aqueous injection fluid to the injection wells;   a first fixed storage tank for storing a surfactant solution for use in the treatment; and   a second fixed storage tank for storing a dispersion of thermally activated particles for use in the treatment;   wherein the first fixed storage tank is connected to the common injection header at a first tie-in point and the second fixed storage tank is connected to the common injection header at a second tie-in point, the second tie-in point being located downstream of the first tie-in point such that, in use, the surfactant solution and the dispersion of thermally activated treatment particles can be added to an injection fluid stream in the common injection header to provide a treatment stream.   
     
     
         30 . A system according to  claim 29 , wherein the system comprises more than one common injection header.