Methodology for design and operations of field-wide and multi-well enhanced oil recovery of unconventional hydrocarbon assets

Abstract

A methodology using an interwell connectivity model for hydrocarbon management is disclosed. The interwell connectivity model may include interwell connectivity metrics indicative of fluid interconnectivity amongst pairs of wells and may be used as predictive or prescriptive for enhanced oil recovery (EOR). As predictive, the interwell connectivity model may be used to determine an effect of gas injection into the reservoir on one or more aspects of EOR, such as reservoir pressure or production rates. As prescriptive, the interwell connectivity model may be used to improve or optimize various stages of EOR, such as during drilling or construction of the extraction site, during primary depletion, or during one or more huff-and-puff cycles.

What is claimed is: 
     
         1 . A computer-implemented method for enhanced oil recovery (EOR) for a plurality of wells in one or more intervals, the method comprising:
 accessing an interwell connectivity model comprising interwell connectivity metrics indicative of fluid interconnectivity amongst at least pairs of wells in the plurality of wells, the interwell connectivity model including controllable one or more inputs for inputting gas into a reservoir and one or more outputs related to EOR; and   controlling, based on the interwell connectivity model, the one or more inputs for EOR.   
     
     
         2 . The method of  claim 1 , wherein the interwell connectivity model is used to determine pressure in a reservoir of a subsurface; and
 wherein the one or more inputs for EOR comprise one or more inputs related to injection of gas.   
     
     
         3 . The method of  claim 2 , wherein the interwell connectivity model is used to determine the pressure in the reservoir of the subsurface based on one or both of an amount of the gas injected into the reservoir or a time period of injecting the gas into the reservoir. 
     
     
         4 . The method of  claim 3 , wherein the interwell connectivity model is used to determine average pressure in the reservoir of the subsurface. 
     
     
         5 . The method of  claim 2 , wherein the interwell connectivity metrics correlate the pressure to fluid transport between two or more wells. 
     
     
         6 . The method of  claim 5 , wherein the interwell connectivity metric correlates the fluid transport to an exponential of an average pressure between the two or more wells. 
     
     
         7 . The method of  claim 2 , wherein the interwell connectivity model is used to determine, when injecting gas into the reservoir, pressure differentials between the reservoir and one or more bottomholes for EOR of hydrocarbons in the reservoir. 
     
     
         8 . The method of  claim 7 , further comprising performing at least one huff and at least one puff, the at least one huff comprises injecting the gas in the reservoir, the at least one puff comprises, after injecting the gas in the reservoir, not injecting the gas in the reservoir;
 wherein the interwell connectivity model is used to determine at least one effect from performing the at least one huff, the at least one effect comprising one or both of: (i) a change in pressure in at least a part of the reservoir, in one or more injector wells, or in one or more offset wells (ii) a change in production rates; and   wherein the interwell connectivity model is used to determine at least one effect from performing the at least one puff, the at least one effect comprising one or both of: (i) the change in pressure in the at least a part of the reservoir, in the one or more injector wells, or in the one or more offset wells; or (ii) the change in production rates.   
     
     
         9 . The method of  claim 7 , further comprising:
 performing at least one huff and at least one puff, the at least one huff comprises injecting the gas in the reservoir, the at least one puff comprises, after injecting the gas in the reservoir, not injecting the gas in the reservoir; and   performing at least one gas lift in which gas is injected into an annulus of one or more wells; and   wherein the interwell connectivity model is used to coordinate performing the at least one huff and the at least one puff with the at least one gas lift in order to create a pressure differential in order to extract hydrocarbon from the reservoir through the one or more wells.   
     
     
         10 . The method of  claim 9 , wherein the at least one huff increases the pressure differential between the reservoir and bottomholes in the one or more wells;
 wherein the at least one gas lift increases the pressure differential between the bottomholes and wellhead in the one or more wells; and   wherein the interwell connectivity model is used to coordinate the increases in the pressure differentials between the reservoir and bottomholes in the one or more wells and between the bottomholes and the wellhead in the one or more wells in order to extract the hydrocarbon through the one or more wells.   
     
     
         11 . The method of  claim 10 , wherein during the at least one huff, the gas is injected into the reservoir via one or more injector wells and the hydrocarbons are extracted via one or more offset wells; and
 wherein the interwell connectivity model is used for determining to perform the at least one gas lift on the one or more offset wells while performing the at least one huff on the one or more injector wells.   
     
     
         12 . The method of  claim 11 , wherein the interwell connectivity model is used for determining to perform the at least one gas lift on one or both of the one or more offset wells or the one or more injector wells while performing the at least one puff. 
     
     
         13 . The method of  claim 2 , wherein the fluid flow between the respective pairs of wells is dependent on the interwell connectivity metrics assigned to the respective pairs and pressures in the respective pairs of wells and inversely dependent on viscosity of fluid injected into one or more injector wells. 
     
     
         14 . The method of  claim 2 , wherein the one or more intervals includes an injector well and neighboring wells;
 wherein the neighboring wells include a first offset well and a second offset well; and   wherein the interwell connectivity model predicts bottomhole pressure (BHP) in the injector well as a function of a number and configuration of neighboring wells and as a function of a first interwell connectivity metric between the injector well and the first offset well and a second interwell connectivity metric between the injector well and the second offset well.   
     
     
         15 . The method of  claim 14 , wherein the interwell connectivity model predicts the bottomhole pressure in at least the first offset well and the second offset well. 
     
     
         16 . The method of  claim 15 , wherein the interwell connectivity model further predicts one or both of oil recovery or oil uplift based on the predicted BHP. 
     
     
         17 . The method of  claim 16 , wherein the interwell connectivity model predicts compression necessary to overwhelm well-to-well communication between the injector well and the first offset well and between the injector well and the second offset well as a function of pressure, fluid properties of injected fluid, and layout or geometry of the wells. 
     
     
         18 . The method of  claim 1 , wherein the interwell connectivity metrics are determined based on a time lag for pressure to travel from an injector well to an offset well. 
     
     
         19 . The method of  claim 18 , wherein the interwell connectivity metrics are hysteretic based on the time lag as the pressure is building up and based on the time lag as the pressure is drawing down. 
     
     
         20 . The method of  claim 19 , wherein the interwell connectivity metrics are not dependent on a magnitude or percent pressure change in a given time interval. 
     
     
         21 . The method of  claim 18 , wherein the time lag is between a change in injection rate in the injector well to when a sensed change in bottomhole pressure in the offset well; and
 wherein the interwell connectivity model is used as a fracture diagnostic technique based on the time lag.   
     
     
         22 . The method of  claim 21 , wherein the time lag is indicative of a path of least resistance between the injector well and the offset well; and
 wherein the fracture diagnostic technique eliminates one or more fracture scenarios inconsistent with interpreted interwell connectivity.   
     
     
         23 . The method of  claim 1 , wherein the interwell connectivity model enables strength of well-to-well interaction to change as a function of average bottomhole pressure and whether pressure is building up or drawing down, such that the interwell connectivity model is used to characterize the well-to-well interactions by a plurality of flow regimes. 
     
     
         24 . The method of  claim 1 , wherein the interwell connectivity model, which describes interwell connectivity as a function of pressure, estimates an amount of gas needed to build pressure as a function of injection rate.