System and method for optimized production of hydrocarbons from reservoirs via cyclic injection

Abstract

Method for enabling the optimized production of hydrocarbons from reservoirs via cyclic injection to reservoir pressures that exceed the formation fracture pressure to achieve an improved and optimal recovery of oil. The method determines and optimizes the composition of injected fluids to be injected, the rate, pressure and duration of injection, the production rate and pressure of produced fluids; determines and utilizes the optimum number of injection and production cycles; and the amount of soaking time; and determines the equipment design and operating characteristics to provide for the optimized injection of injection fluids, and the separation of produced fluids for both reinjection and delivery to sales or storage.

1 . A method for increasing recovery of hydrocarbons from a reservoir utilizing a cyclic injection wherein the cyclic injection process (1) comprises a plurality of injection periods and a plurality of production periods, and (2) cycles alternatively between an injection period in the plurality of injection periods and a production period in the plurality of production periods, wherein the method comprises the steps of:
 (a) determining a composition of a hydrocarbon-containing composition for injection, wherein the hydrocarbon-containing composition is in a liquid state at surface injection conditions;   (b) determining a fracture pressure of the reservoir at which the hydrocarbon-containing composition can cause the reservoir to fracture;   (c) determining a maximum injection rate and a maximum injection pressure in a well to be utilized during the injection period, wherein the maximum injection pressure results in a near wellbore reservoir pressure that is at least the fracture pressure;   (d) injecting the hydrocarbon-containing composition into the reservoir during the injection period so as to create fractures and displace a portion of the hydrocarbon-containing composition into the created fractures, wherein the injection period comprises a period of time during which the near wellbore reservoir pressure of the well reaches at least the fracture pressure, and, while continuing injecting of the hydrocarbon-containing composition, the near wellbore reservoir pressure is maintained at or above the fracture pressure for a pre-determined period of time of the injection period;   (e) determining a maximum production rate of gases and liquids from the well and the minimum production pressure at the well to be utilized during the production period;   (f) producing the well to obtain hydrocarbon fluids during the production period in the plurality of production periods for a period of time such that the pressure at the well reaches the determined minimum production pressure;   (g) during the production period, assessing the composition of the hydrocarbon fluids;   (h) utilizing a compositional reservoir simulation model and/or a geomechanics model to determine one or more formation characteristics of the reservoir;   (i) determining a composition of an adjusted hydrocarbon-containing composition for injection based upon the one or more formation characteristics determined in step (h);   (j) adjusting the composition of the hydrocarbon-containing injection fluids to the composition of the adjusted hydrocarbon-containing composition for injection;   (k) repeating steps (b) through (j) utilizing the adjusted hydrocarbon-containing composition as the hydrocarbon-containing composition.   
     
     
         2 . The method of  claim 1 , wherein the injection and method does not comprise a shut-in or soaking step between the step of injection in step (d) and the step of producing in step (f). 
     
     
         3 . The method of  claim 1 , wherein the method comprises a shut-in or soaking step between the step of injection in step (d) and the step of producing in step (f). 
     
     
         4 . The method of  claim 1 , wherein the hydrocarbon-containing composition comprises a fluid selected from a group consisting of ethane, propane, butane, heptane, hexane, and combinations thereof. 
     
     
         5 . The method of  claim 4 , wherein the hydrocarbon-containing composition further comprises a gaseous substance selected from a group selected from carbon dioxide, carbon monoxide, and combinations thereof. 
     
     
         6 . The method of  claim 1 , wherein the hydrocarbon-containing composition comprises a material selected from a group consisting of liquid surfactants, nano-surfactants, nanoparticles, and combinations thereof. 
     
     
         7 . The method of  claim 1 , wherein the step of utilizing the compositional reservoir simulation model comprises utilizing the compositional reservoir simulation model to to increase recovery of residual crude oil. 
     
     
         8 . The method of  claim 1 , wherein the step of determining the maximum injection rate and maximum injection pressure during the injection period is based upon at least one of surface facilities capacities, reservoir conditions, wellbore conditions, and operation constraints. 
     
     
         9 . The method of  claim 1 , wherein the step of determining the maximum production rate and minimum production pressure during the production period is based upon at least one of surface facilities capacities, reservoir conditions, wellbore conditions, and operation constraints. 
     
     
         10 . The method of  claim 1 , wherein the hydrocarbon-containing composition is injected at a temperature of at most 50° F. 
     
     
         11 . The method of claim claim  16 , wherein the hydrocarbon processing apparatus further comprises hydrogen sulfide removal equipment, carbon dioxide removal equipment, or both. 
     
     
         12 . The method of  claim 1 , wherein the method further comprises determining or estimating the extent of formation fracturing and location of the formation fracturing. 
     
     
         13 . The method of  claim 1 , wherein a proppant material is injected with the hydrocarbon-containing composition, wherein the proppant comprises a solid selected from a group consisting of sand, ceramic, bauxite, petcoke, polymer, and combinations thereof. 
     
     
         14 . The method of  claim 12 , wherein the determining or estimating the extent of formation fracturing and the location of the formation fracturing is performed during the injecting of the hydrocarbon-containing composition in step (d). 
     
     
         15 . The method of  claim 12 , wherein the step of determination or estimated the extent of formation fractioning is performed utilizing equipment selected from a group consisting of microseismic measurement equipment, formation resistivity measurement equipment, surface deformation equipment, and combinations thereof. 
     
     
         16 . The method of  claim 1 , wherein
 (a) the method further comprises utilizing a hydrocarbon processing apparatus to recover a portion of the hydrocarbon containing composition from the produced hydrocarbon fluids, and   (b) the hydrocarbon processing apparatus comprises equipment selected from a group consisting of stage separators, compressors, refrigeration units, joule-thompson units, fractionation and stabilization units; chemical additives storage and injection pumps; gauges, sensors, controls, SCADA equipment, heat exchangers, coolers, vessels, and combinations thereof.   
     
     
         17 . The method of  claim 14 , wherein the method further comprises processing the produced hydrocarbon fluids above ground with the hydrocarbon processing apparatus to remove (a) methane and ethane gases, (b) hydrocarbons containing hexanes, and (c) hydrocarbons having a molecular weight greater than hexane. 
     
     
         18 . The method of  claim 15 , wherein the adjusting step of step (j) comprises adjusting the portion of the hydrocarbon-containing composition recovered utilizing the hydrocarbon processing apparatus to the composition of the adjusted hydrocarbon-containing composition and thereby forming the adjusted hydrocarbon-containing composition. 
     
     
         19 . The method of  claim 1 , wherein the one or more formation characteristics determined in step (h) is a formation characteristic selected from the group consisting of composition of the residual hydrocarbons in the reservoir, formation stresses, permeability, porosity, fluid conductivity of the hydrocarbon-containing composition, Young's modulus, Poisson's ratio, Biot coefficient, density, tensile strength, and compressive strength. 
     
     
         20 . The method of  claim 1 , wherein the one or more formation characteristics determined in step (h) comprises composition of the residual hydrocarbons in the reservoir. 
     
     
         21 . The method of  claim 1 , wherein the determining the maximum injection rate and the maximum injection pressure is performed utilizing the compositional reservoir simulation model. 
     
     
         22 . The method of  claim 1 , wherein the determining the one or more formation characteristics is performed utilizing the compositional reservoir simulation model. 
     
     
         23 . The method of  claim 1 , wherein the determining the one or more formation characteristics is performed utilizing the geomechanics model. 
     
     
         24 . The method of  claim 1 , wherein the determining the one or more formation characteristics is performed utilizing the compositional reservoir simulation model and the geomechanics model. 
     
     
         25 . The method of  claim 1 , wherein the hydrocarbon-containing composition comprises a fluid that is an aliphatic hydrocarbon compound.