Well stimulation apparatus and a method of use thereof

Abstract

The present disclosure relates to a well-stimulation apparatus with one or more elongated tie rods, at least one sealing assembly coupled to the one or more tie rods, and a stimulation material for generating a pressure event. The pressure event can stimulate a targeted portion of a geological formation that is positioned about an isolated portion of the wellbore. The pair of sealing assemblies are actuatable between a dormant condition for moving the well-stimulation apparatus in a wellbore and an active condition for defining the isolated portion of the wellbore.

1 . A well-stimulation apparatus comprising:
 a tie rod with a first end and a second end;   a stimulant-material container that is configured to be secured about the tie rod; and   a sealing assembly that is couplable to the first end of the tie rod, the sealing assembly being actuatable between a dormant condition and an active condition for isolating a portion of a wellbore.   
     
     
         2 . The well-stimulation apparatus of  claim 1 , further comprising a second sealing assembly that is couplable to the second end of the tie rod. 
     
     
         3 . The well-stimulation apparatus of  claim 1 , further comprising a fastener for coupling the first sealing assembly and the second sealing assembly to the first end and the second ends respectively of the tie rod. 
     
     
         4 . The well-stimulation apparatus of either  claim 1 , wherein the stimulant-material container comprises one or more sleeves that are configured to receive stimulant material therein. 
     
     
         5 . The well-stimulation apparatus of  claim 4  wherein the stimulant material is deflagratable for generating a pressure event. 
     
     
         6 . The well-stimulation apparatus of  claim 5 , wherein the tie rod is configured to bear a tensile load that is generated by the pressure event. 
     
     
         7 . The well-stimulation apparatus of  claim 5 , wherein when the sealing assemblies are in the active condition, the pressure event is directed in a radial outward direction from the well-stimulation apparatus. 
     
     
         8 . The well-stimulation apparatus of  claim 5 , wherein the pressure event has a peak pressure of between about 10, 000 pounds per square inch (psi) and 50, 000 psi. 
     
     
         9 . The well-stimulation apparatus of  claim 1 , further comprising at least one stimulation-activation device for igniting the stimulant material. 
     
     
         10 . The well-stimulation apparatus  claim 1 , wherein each of the first sealing assembly and the second sealing assembly comprises:
 a mandrel;   a plurality of sealing elements positioned about the mandrel, each of the plurality of sealing elements comprises an outer edge that is configured to engage an inner wall of a wellbore or a tubular therein; and   an actuation body for actuating the plurality of sealing elements to move from the dormant condition to the active condition.   
     
     
         11 . The well-stimulation apparatus of  claim 10 , wherein the actuation body is at least one of: an actuation gas-generator, a hydraulic-pressure driven mechanism, a pneumatic-pressure driven mechanism, a mechanical mechanism such as a spring, an electric motor, an electric solenoid, and combinations thereof. 
     
     
         12 . The well-stimulation apparatus of  claim 10 , wherein the plurality of sealing elements are stacked about the mandrel at an acute angle with respect to a longitudinal direction of the well-stimulation apparatus. 
     
     
         13 . The well-stimulation apparatus of  claim 10 , wherein the plurality of sealing elements are swingable between an angle of repose α in the dormant condition and an angle of attack β>α in the active condition. 
     
     
         14 . The well-stimulation apparatus of  claim 13  wherein the angle of repose α is between about 0° and about 75°. 
     
     
         15 . The well-stimulation apparatus of  claim 13 , wherein the angle of attack β is between about 10° and about 80°. 
     
     
         16 . The well-stimulation apparatus of any  claim 1 , further comprising a knuckle that is couplable to one end of the well-stimulation apparatus, and the knuckle comprises:
 a central portion rotatably coupled to well-stimulation apparatus via a first joint; and   a coupling portion rotatably coupled to the central portion via a second joint.   
     
     
         17 . A sealing assembly for isolating a portion of a wellbore, the sealing assembly comprising:
 a plurality of sealing elements that are actuatable between a dormant condition and an active condition; and   an actuation gas-generator for generating a gas flow for actuating the plurality of sealing elements from the dormant condition to the active condition.   
     
     
         18 . A knuckle connector for coupling a first downhole apparatus to a second downhole apparatus, the knuckle connector comprising:
 a central portion rotatably coupled to a first joint and a second joint;   a first coupling portion rotatably coupled to the central portion via the first joint; and   a second coupling portion rotatably coupled to the central portion via the second joint.   
     
     
         19 . A knuckle connector for coupling a first downhole apparatus to a line from surface, the knuckle connector comprising:
 a central portion rotatably coupled to having a first joint and a second joint;   a first coupling portion rotatably coupled to the central portion via the first joint; and   a second coupling portion rotatably coupled to the central portion via the second joint.   
     
     
         20 . A well-stimulation system comprising:
 a plurality of n well-stimulation apparatuses for isolating a plurality of n downhole portions of a wellbore and stimulating the plurality of isolated wellbore portions, n being an integer greater than or equal to 1, and each well-stimulation apparatus comprising an activation circuit for activating at least a well stimulation process thereof; and   a controller for controlling the activation circuits of the plurality of well-stimulation apparatuses, the activation circuits being numbered from downhole to uphole as the first, second, . . . , the n-th activation circuit;   wherein the controller comprises n pressure-actuated switches, with the 0-th switch being a normally-open two-way switch and the first to the (n−1)-th switches being three-way switches,   wherein the first terminal of the 0-th switch is connected to a power source and the second terminal thereof is connected to the common terminal of the 1st switch,   wherein for the k-th switch (k being an integer and 0<k<n−1), the common terminal thereof is connected to the normally-open terminal of the (k−1)-th switch, the normally-closed terminal thereof is connected to the k-th activation circuit, and the normally-open terminal thereof is connected to the common terminal of the k-th switch, and   wherein for the (n−1)-th switch, the common terminal thereof is connected to the normally-open terminal of the (n−2)-th switch, the normally-closed terminal thereof is connected to the (n−1)-th activation circuit, and the normally-open terminal thereof is connected to the n-th activation circuit.   
     
     
         21 . The well-stimulation system of  claim 20  wherein the m-th switch is switchable under a threshold switching pressure P_m, with m being an integer and 0≤m≤n−1; and wherein P_0<P_1< . . . <P_(n−1). 
     
     
         22 . A method for stimulating a targeted portion of a geological formation, the method comprising steps of:
 isolating a portion of a wellbore that is proximal the target portion by actuating one or more sealing elements into an active condition;   deflagrating a stimulant material for generating a pressure event; and   focusing at least part of an energy of the pressure event into the targeted portion.