Alternating Liquid Gas Fracturing for Enhanced Oil Recovery of Well

Abstract

A fracturing operation stimulate a region of a well by alternating between pumping liquid intervals and injecting gas intervals to the region. A given liquid interval can include slick water with or without proppant. The gas interval can include produced gas, and a given interval can be injected at pressures above or below fracture initiation pressures. In a depleted region, the stimulation can energize an existing fracture and can carry the proppant into the energized fracture. In an under-developed region, the stimulation can create a new fracture and can carry proppant into the new fracture. The liquid delivers the proppant, and turbulence from the injected gas at the fracture can help further carry the proppant therein. A diverter then temporarily seals the energized or new fracture so the injected gas temporarily sealed therein can interface with residual formation fluid therein, providing for enhanced oil recovery.

1 . A method of fracturing a well having at least one region including one or more existing fractures formed therein, the method comprising:
 stimulating the at least one region by alternating between pumping one or more first liquid intervals and injecting one or more first gas intervals to the at least one region;   energizing at least one of the one or more existing fractures of the at least one region with the stimulation;   carrying proppant into the at least one energized fracture with the stimulation fluid;   temporarily sealing the at least one energized fracture with a diverter in the well; and   interfacing the injected gas temporarily sealed in the at least one energized fracture with residual formation fluid therein.   
     
     
         2 . The method of  claim 1 , wherein liquid for the one or more first liquid intervals comprises at least one of a water-based fluid, an oil-based fluid, a polymer-based fluid, a foam, slick water, a synthetic fluid with low viscosity fluid and a high proppant carrying capacity, a linear gel, a cross-linked gel, and a liquefied gas; wherein gas for the one or more first gas intervals comprises at least one of produced gas, produced lean gas, carbon dioxide, ethane-dominated gas, and rich hydrocarbon gas; and wherein the diverter comprises at least one of a mechanical tool, a plug, a sliding sleeve, a particular diverter, a chemical diverter, a polyactic acid (PLA), and a ployglycolic acid (PGA). 
     
     
         3 . The method of  claim 1 , wherein pumping the one or more first liquid intervals to the at least one region comprises delivering the proppant with at least one of the one or more first liquid intervals. 
     
     
         4 . The method of  claim 3 , wherein pumping the at least one first liquid interval delivering the proppant comprise suspending the proppant in pumped liquid of the at least one first liquid interval; and delivering the pumped liquid comprising the suspended proppant into the existing fractures. 
     
     
         5 . The method of  claim 1 , wherein injecting the one or more first gas intervals in the well comprises injecting at least one of the one or more first gas intervals at a pressure at least at or above a fracture initiation pressure of the at least one region. 
     
     
         6 . The method of  claim 1 , wherein injecting the one or more first gas intervals in the well comprises injecting at least one of the one or more first gas intervals at a pressure at or above reservoir pressure of the at least one region. 
     
     
         7 . The method of  claim 1 , wherein stimulating the at least one region comprises configuring one or more characteristics of at least one of the proppant, the one or more first liquid intervals, and the one or more second gas intervals for the at least one region. 
     
     
         8 . The method of  claim 1 , wherein to energize the at least one existing fracture, the method comprises determining an amount of pressure in the one or more first liquid intervals sufficient to reopen the at least one existing fracture. 
     
     
         9 . The method of  claim 1 , wherein energizing the at least one existing fracture comprises:
 entering gas from the one or more first gas intervals into the at least one existing fracture in the at least one region; and   interfacing the entered gas with the residual formation fluid in a vicinity of the at least one existing fracture.   
     
     
         10 . The method of  claim 1 , wherein energizing at least one of the one or more existing fractures of the at least one region with the stimulation further comprises extending at least one of the one or more existing fractures of the at least one region with the stimulation and carrying the proppant into the extension of the at least one extended fracture of the at least one region with the stimulation. 
     
     
         11 . The method of  claim 10 , wherein to extend the at least one existing fracture, the method comprises determining an amount of pressure and fluid volume sufficient to induce additional fracture length of the at least one existing fracture. 
     
     
         12 . The method of  claim 1 , wherein carrying the proppant into the at least one energized fracture with the stimulation comprises:
 carrying the proppant into the at least one energized fracture with at least one of the one or more liquid intervals; and   moving the proppant further with turbulence created by interaction of at least one of the one or more gas intervals with the one or more liquid intervals.   
     
     
         13 . The method of  claim 1 , wherein temporarily sealing the at least one energized fracture with the diverter in the well comprises at least one of: operating a mechanical tool as the diverter, installing a plug as the diverter, closing a sliding sleeve as the diverter, pumping a particular diverter as the diverter, and pumping a chemical diverter as the diverter adjacent the at least one energized fracture. 
     
     
         14 . The method of  claim 1 , wherein interfacing the injected gas temporarily sealed in the at least one energized fracture with the residual formation fluid therein comprises using at least one of a vaporization, swelling, and miscibility mechanism. 
     
     
         15 . The method of  claim 1 , further comprising producing fluid from the at least one region upon completion of the re-fracturing. 
     
     
         16 . The method of  claim 1 , further comprising:
 stimulating the at least one region by alternating between pumping one or more second liquid intervals and injecting one or more second gas intervals in the well to the at least one region;   energizing at least one other of the one or more existing fractures of the at least one region with the stimulation; and   carrying the proppant into the at least one other energized fracture with the stimulation.   
     
     
         17 . The method of  claim 1 , further comprising:
 stimulating the at least one region by alternating between pumping one or more second liquid intervals and injecting one or more second gas intervals to the at least one region; and   creating at least one new fracture in the at least one region with the stimulation; and   carrying proppant into the at least one new fracture with the stimulation.   
     
     
         18 . The method of  claim 17 , wherein alternating between pumping the one or more second liquid intervals and injecting the one or more second gas intervals in the well to the at least one region comprises:
 pumping a first of the one or more second liquid intervals to create the at least one new fracture;   pumping, thereafter, a second of the one or more second liquid intervals with the proppant to carry the proppant into the at least one new fracture; and   injecting, thereafter, a first of the one or more second gas intervals to the at least one new fracture to further carry the pumped proppant into the at least one new fracture and to interface the injected gas with the residual formation fluid in a vicinity of the at least one new fracture.   
     
     
         19 . The method of  claim 17 , wherein alternating between pumping the liquid and injecting the gas in the well to the at least one region comprises:
 pumping a first of the one or more second liquid intervals to create the at least one new fracture;   pumping, thereafter, a second of the one or more second liquid intervals with the proppant to carry the proppant into the at least one new fracture;   injecting, thereafter, a first of the one or more second gas intervals to the at least one new fracture; and   pumping, thereafter, a third of the one or more second liquid intervals to compress the injected gas in the at least one fracture.   
     
     
         20 . A method of fracturing a well, the method comprising:
 stimulating at least one region of the well by alternating between pumping one or more first liquid intervals and injecting one or more first gas intervals to the at least one region of the well;   creating at least one fracture in the at least one region with the stimulation;   carrying proppant into the at least one fracture with the stimulation;   temporarily sealing the at least one fracture with a diverter in the well; and   interfacing the injected gas temporarily sealed in the at least one fracture with formation fluid therein.   
     
     
         21 . The method of  claim 20 , wherein alternating between pumping the one or more first liquid intervals and injecting the one or more first gas intervals in the well to the at least one region comprises:
 injecting a first of the one or more first gas intervals at least above a fracture initiation pressure to create the at least one fracture;   pumping, thereafter, a first of the one or more first liquid intervals with the proppant to carry the proppant into the at least one fracture; and   injecting, thereafter, a second of the one or more first gas intervals to the at least one fracture to further carry the pumped proppant into the at least one fracture and to interface the injected gas with the residual formation fluid in a vicinity of the at least one fracture.   
     
     
         22 . The method of  claim 20 , wherein injecting the first of the one or more first gas intervals at least above the fracture initiation pressure to create the at least one fracture further comprises filling the at least one fracture with the injected gas. 
     
     
         23 . The method of  claim 20 , wherein pumping the first of the one or more first liquid intervals further comprises extending the at least one fracture. 
     
     
         24 . The method of  claim 20 , wherein alternating between pumping the one or more first liquid intervals and injecting the one or more first gas intervals in the well to the at least one region and creating the at least one fracture comprises:
 pumping a first of the one or more first liquid intervals to create the at least one new fracture;   pumping, thereafter, a second of the one or more first liquid intervals with the proppant to carry the proppant into the at least one new fracture; and   injecting, thereafter, a first of the one or more first gas intervals to the at least one fracture to further carry the pumped proppant into the at least one fracture and to interface the injected gas with the residual formation fluid in a vicinity of the at least one fracture.   
     
     
         25 . The method of  claim 24 , further comprising pumping, thereafter, a third of the one or more first liquid intervals to compress the injected gas in the at least one fracture. 
     
     
         26 . The method of  claim 24 , wherein alternating between pumping the one or more first liquid intervals and injecting the one or more first gas intervals in the well to the at least one region comprises pumping an initial one of the one or more first gas intervals in the well before first pumping the first liquid interval. 
     
     
         27 . A system for fracturing a well, the system comprising:
 pumping equipment in fluid communication with the well and configured to pump one or more of liquid intervals into the well at pressure;   delivery equipment in fluid communication with the pumping equipment and configured to deliver one or more of proppant and diverter to at least one of the one or more of the pumped liquid intervals; and   gas injection equipment in fluid communication with the well and configured to inject one or more gas intervals into the well;   the system using the pumping, delivery, and gas injection equipment and being configured to:
 alternate between pumping the one or more liquid intervals and injecting the one or more gas intervals to the region to stimulate at least one region of the well; 
 energize at least one fracture of the at least one region with the stimulation; 
 carry the proppant into the at least one energized fracture with the stimulation; 
 temporarily seal the at least one energized fracture with the diverter; and 
 interface the injected gas temporarily sealed in the at least one energized fracture with residual formation fluid therein. 
   
     
     
         28 . The system of  claim 27 , wherein to energize the at least one fracture of the at least one region with the stimulation, the system is configured to at least one of:
 energize the at least one fracture from one or more existing fractures of the region with the stimulation; and   create the at least one fracture in the at least one region with the stimulation.   
     
     
         29 . The system of  claim 27 , wherein the gas injection equipment comprises one or more compressors compressing gas for the one or more gas intervals. 
     
     
         30 . A method of hydraulically fracturing and enhanced oil recovering a hydrocarbon-producing subterranean formation, the method comprising:
 ranking candidates of the subterranean formation;   performing numerical analysis to quantify a proppant-carrying capacity of selected fracturing fluid and enhanced oil recovery efficiency of injected gas on the ranked candidates;   selecting operational parameters of the selected fracturing fluid and the injected gas based on the numerical analysis;   delivering the fracturing fluid, the injected gas, and a proppant to the ranked candidates of the subterranean formation at the selected operational parameters;   temporarily sealing at least one energized fracture of the ranked candidates with diverter; and   interfacing the injected gas temporarily sealed in the at least one energized fracture with residual formation fluid therein.   
     
     
         31 - 41 . (canceled)