Multi-Well Interference Testing and In-Situ Reservoir Behavior Characterization

Abstract

Using multi-well testing, operators can characterize a reservoir and its in-situ behavior using direct measurements of reservoir pressures. One or more impulses are generated in an impulse well or location using production, injections, or the like. Downhole pressure tools directly measure pressure responses at various observations wells in the reservoir. Based on the magnitudes of the responses, the distances between the wells, the time lag between responses, and other variables, operators can characterize the pressure distribution of the reservoir and various features, such as the connectivity and extent of the reservoir, barriers, faults, obstructions, pools, communication paths, layer contacts, and well spacing efficiency.

1 . A reservoir characterization method, comprising:
 deploying a plurality of downhole pressure devices in a plurality of wells penetrating a reservoir;   initiating at least one pressure impulse at at least one impulse time in at least one of the wells penetrating the reservoir;   obtaining pressure responses at response times with the downhole pressure devices in the wells;   communicating the at least one impulse time, the pressure responses, and the response times to a central unit;   processing the pressure responses and the response times with the central unit; and   characterizing the reservoir based on the processing.   
     
     
         2 . The method of  claim 1 , wherein deploying the downhole pressure devices comprises coupling tools in the wells for measuring pressure of formations surrounding the wells. 
     
     
         3 . The method of  claim 1 , further comprising:
 obtaining reference pressure measurements with the downhole pressure devices in the absence of the at least one impulse; and   scaling the pressure responses with the reference pressure measurements.   
     
     
         4 . The method of  claim 3 , further comprising determining if magnitudes of pressure responses of the downhole pressure devices fall within a limit by performing reservoir simulation. 
     
     
         5 . The method of  claim 1 , wherein initiating the at least one pressure impulse comprises performing one or more of:
 producing a pressure drop in the at least one well;   performing production from the at least one well   producing a pressure spike in the at least one well;   drilling in the at least one well with drilling fluid;   injecting treatment fluid in the at least one well; and   performing a test in the at least one well.   
     
     
         6 . The method of  claim 1 , wherein communicating the pressure responses and the response times to the central unit comprises recording the pressure responses and the response times in memory of the downhole pressure devices. 
     
     
         7 . The method of  claim 1 , wherein communicating the pressure responses and the response times to the central unit comprises transmitting the pressure responses and the response times in real time from the downhole pressure devices to the central unit. 
     
     
         8 . The method of  claim 1 , wherein communicating the at least one impulse time, the pressure responses, and the response times to the central unit comprises transmitting one or more of the at least one impulse time, the pressure responses, and the response times in real-time to the central unit, or transferring one or more of the at least one impulse time, the pressure responses, and the response times from memory to the central unit. 
     
     
         9 . The method of  claim 1 , wherein processing the pressure responses and the response times with the central unit comprises one or more of:
 comparing magnitudes of the pressure responses;   determining speeds of pressure wave propagation based on the response times and based on distances between the at least one impulse and the downhole pressure devices;   determining connectivity of the reservoir between the wells;   determining a path length of the reservoir;   determining an extent of the reservoir;   determining a fluid type of the reservoir; and   determining distribution of pressure in the reservoir.   
     
     
         10 . The method of  claim 1 , wherein processing comprises combining the response pressures and the response times with one or more of: depths of the downhole pressure devices, seismic data of the reservoir, information from formation cores of the wells, locations of the wells having the downhole pressure devices, known fluid types in the wells, previous production data of the wells, previous logging data of the wells, and reservoir simulations. 
     
     
         11 . The method of  claim 1 , further comprising:
 initiating at least one pressure impulse at at least one impulse time in another one of the wells penetrating the reservoir; and   repeating the acts of obtaining, communicating, processing, and characterizing the reservoir.   
     
     
         12 . The method of  claim 1 , wherein characterizing the reservoir comprises characterizing one or more of a barrier, a fault, a pool, a permeable zone, a communication path, an extent, a fluid contact, and an obstruction of the reservoir. 
     
     
         13 . The method of  claim 1 , wherein characterizing the reservoir comprises:
 determining that at least one of the downhole pressure devices has failed to obtain at least one of the pressure responses; and   characterizing an obstruction in the reservoir between the at least one well and the at least one downhole pressure device.   
     
     
         14 . The method of  claim 1 , wherein characterizing the reservoir comprises:
 determining that at least a first of the downhole pressure devices in a first of the wells has obtained at least one of the pressure responses;   determining that at least a second of the downhole pressure devices in a second of the wells has failed to obtain one of the pressure responses; and   characterizing the reservoir as having a first pool associated with the first well and having a second pool associated with the second well.   
     
     
         15 . The method of  claim 1 , wherein characterizing the reservoir comprises:
 determining that at least one of the downhole pressure devices in a first of the wells has obtained a first magnitude of the pressure responses within a first time interval;   determining that the at least one downhole pressure device in the first well has obtained a second magnitude of the pressure responses within a second time interval; and   characterizing the reservoir as having a first communication path for the first time interval and a second communication path for the second time interval.   
     
     
         16 . The method of  claim 15 , wherein the second magnitude is less than the first magnitude. 
     
     
         17 . The method of  claim 1 , wherein deploying the downhole pressure devices in the wells of the reservoir comprises deploying at least two of the downhole pressure devices at different depths than the at least one pressure impulse. 
     
     
         18 . The method of  claim 17 , wherein processing comprises calculating speeds of pressure wave propagation for the pressure responses of the at least two downhole pressure devices. 
     
     
         19 . The method of  claim 18 , wherein characterizing the reservoir comprises determining a characteristic of one or more layers in the reservoir based on the calculated speeds of pressure wave propagation. 
     
     
         20 . The method of  claim 17 , wherein one of the at least two downhole pressure devices is deployed in a same well as the one in which the at least one pressure impulse is initiated. 
     
     
         21 . The method of  claim 17 , wherein one of the at least two downhole pressure devices is deployed in a different well from the one in which the at least one pressure impulse is initiated. 
     
     
         22 . A reservoir characterization system, comprising:
 a plurality of downhole pressure devices deploying in a plurality of wells penetrating a reservoir, the downhole pressure devices each obtaining pressure responses at response times in response to at least one pressure impulse initiated at at least one impulse time in at least one of the wells penetrating the reservoir;   communication equipment communicating the at least one impulse time, the pressure responses, and the response times of the downhole pressure devices; and   processing equipment communicatively coupled to the communication equipment and receiving the at least one impulse time, the pressure responses, and the response times, the processing equipment processing the pressure responses and the response times and characterizing the reservoir based on the processing.