DESC:TECHNICAL FIELD
[001] The present disclosure relates to the field of fracking. Particularly, the present disclosure relates to the field of shock/blast wave assisted fracking of petroleum wells. More particularly, the present disclosure relates to in-situ generation of shockwaves for expanding the cracks present within a petroleum well, as well as creating new cracks therein.

BACKGROUND
[002] Fracking is the process of creating cracks/fissures in a controlled manner, on the inner surface of deep wells. The process of fracking also incorporates enhancing/extending already existing cracks/fissures of deep wells. After a typical petroleum well is dug and stabilized, lateral cracks are required to be created deep down in the petroleum well in order to ensure the flow of a reasonable amount of crude oil/gas. The cracks/fissures act as a conduit for the flow of raw oil/gas into the petroleum well. One of prior art techniques employed to create lateral cracks deep inside the petroleum wells is hydrofracking (also referred to as hydrofracturing or hydraulic fracturing). Hydrofracking is typically performed in order to enhance the yield/output of an petroleum well.
[003] During the process of hydrofracking, cracks/fissures are created deep inside the well by causing controlled explosions. Subsequently, the well is filled up with pressurized water. The hydrostatic pressure exerted by the pressurized water brings about further enhancement of cracks/fissures. However, one of the drawbacks associated with hydrofracking is that the direction in which the cracks are enhanced could not be controlled and manipulated, since the cracks/fissures extend along a path of least resistance. Therefore, in case of conventional hydrofracking processes, the probability of cracks/fissures extending through underground water resources thereby polluting them remains extremely high. The pressurized water used during the process of hydrofracking is typically induced with additives such as sand, proppants and the like. Therefore, there are high probabilities that the water used for hydrofracking, which is contaminated with sand and proppants reaches underground water reserves and pollutes them.
[004] Therefore, in order to overcome the drawbacks discussed hitherto, there is felt a need for a fracking system and method (of implementing the fracking system) that could replenish depleted petroleum wells using environment friendly measures/principles. Further, there is also felt a need to develop a method alternative to hydrofracking which is proven to bring about harmful side-effects including contamination of ground water resources.

OBJECTS
[005] An object of the present disclosure is to provide an environment friendly alternative to hydrofracking.
[006] Another object of the present disclosure is to provide an efficient and alternate method for replenishing depleted petroleum wells.
[007] Another object of the present disclosure is to provide a method for enhancing crack formation by heating fracking fluid using one of microwave generator and electrical heater.
[008] One more object of the present disclosure is to provide a system and method that enables crack propagation only in a lateral direction, inside the petroleum well.
[009] Still a further object of the present disclosure is to provide a method that efficiently addresses the issue of underground water contamination commonly witnessed during the process of hydrofracking.
[0010] One more object of the present disclosure is to provide a method that enables the creation of cracks and fissures to be efficiently controlled.
[0011] Still a further object of the present disclosure is to provide a method and system that enables the direction of enhancement/elongation of cracks/fissures to be effectively controlled.

SUMMARY
[0012] The present disclosure envisages a shock/blast wave assisted fracking method which includes explosive heating of a fracking fluid. The term ‘explosive heating’ refers to the phenomenon of heating a liquid material beyond its boiling point, and maintaining the liquid material at a predetermined high temperature beyond the boiling point thereof, thereby converting the liquid material into high-pressure vapors. The method envisaged by the present disclosure, while providing an eco-friendly alternative to the hydrofracking method, also ensures that underground water resources are not contaminated during the fracking process/method. Further, the shock/blast wave assisted fracking method envisaged by the present disclosure also ensures that there is no excessive usage of water resources contrary to the process of hydrofracking which requires a huge quantity of water to be filled up in the well in a pressurized state.
[0013] In accordance with the present disclosure, the shock/blast wave assisted method for expanding surface cracks of petroleum well includes heating the fracking fluid to generate high pressure steam which further results in the formation of shockwaves. The fracking fluid is heated using one of an electrical heater, a laser generator and a microwave generator. A plurality of (pilot) cracks are created on the inner circumference of the petroleum well. Further, a chamber is aligned along the inner circumference of the petroleum well. Subsequently, a plurality of heater coils are incorporated within the chamber, and the chamber is filled with fracking fluid, for example, brine solution. The heater coils within the chamber are heated to a predetermined temperature-preferably beyond the boiling point of the brine solution-such that the brine solution which is in contact with the heater coils heats up and transforms into high pressure steam. The high pressure steam is subsequently directed through a plurality of fast actuating valves located (at predetermined locations) within the chamber. The rapid flow/release of the steam through the fast actuating valves results in creation of high velocity shock waves/blast waves. The shock waves/blast waves are directed onto the cracks of the petroleum well, thereby causing the cracks to expand and further causing the formation of new cracks on the inner surface of the petroleum well. The shock waves/blast waves travel outward in all directions from the fast actuating valves, moving at (preferably) a near detonation velocity, and rupturing the rock formation surrounding the bore hole (of the petroleum well). The force/pressure of the shock waves/blast waves travelling outwards from the fast actuating valves typically exceed the compression strengths of the surrounding rock formation, thereby causing the rock formation to bend forward and crack. The force/pressure of the shock waves/blast waves creates new cracks and widens already existing cracks. Cracks thus generated are radial in the sense that they radiate out from the borehole. Further, any cracks, previously present are widened in radial direction subsequent to the propagation of shock waves/blast waves. Further, the shock waves/blast waves propagating through the petroleum well are typically reflected back into the rock formation as tension waves. The reflected tension waves create lateral cracking in the rock formation, between the radial cracks.

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
[0014] The other objects, features and advantages will be apparent to those skilled in the art from the following detailed description and the accompanying drawings in which:
[0015] FIG. 1 is a schematic representation of an petroleum well equipped with electrical heating mechanism, in accordance with the present disclosure;
[0016] FIG.2A is a schematic representation of an petroleum well equipped with a laser resource, in accordance with the present disclosure;
[0017] FIG.2B is a diagram illustrating delivering of laser beams inside the petroleum well;
[0018] FIG.3A is a schematic representation of a petroleum well equipped with a microwave generator, in accordance with the present disclosure;
[0019] FIG.3B is a diagram illustrating delivering of microwaves in to the petroleum well using microwave wave guides; and
[0020] FIG. 4 is a flowchart illustrating a method of expanding surface cracks of petroleum well, in accordance with the present disclosure.
[0021] Certain features of the present disclosure are shown in some drawings and not in others. This has been done only for convenience as each feature may be combined with any or all of the other features, in accordance with the present disclosure.

DETAILED DESCRIPTION
[0022] In order to overcome the drawbacks discussed hitherto, the present disclosure envisages a shock/blast wave assisted fracking method which includes explosive heating of a fracking fluid. The method envisaged by the present disclosure, while providing an eco-friendly alternative to the hydro fracking method, also ensures that underground water resources are not contaminated during the fracking process/method. Further, the shock/blast wave assisted fracking method envisaged by the present disclosure also ensures that there is no excessive usage of water resources contrary to the process of hydro-fracking which requires a huge quantity of water to be filled up in the well in a pressurized state.
[0023] The present disclosure proposes using a predetermined fracking fluid to expand the cracks present on the inner periphery of a petroleum well, as well as create new cracks thereupon. The present disclosure teaches heating the fracking fluid to generate high pressure steam which further result in the formation of shockwaves. The term ‘explosive heating’ refers to the phenomenon of heating a liquid material beyond its boiling point, and maintaining the liquid material at a predetermined high temperature beyond the boiling point thereof, thereby converting the liquid material into high-pressure vapors (high-pressure steam). The high-pressure vapors are directed through a plurality of fast-actuating valves, which enable conversion of high-pressure vapors into shockwaves.
[0024] The shockwaves thus formed are thrust upon the inner periphery of the petroleum well thereby expanding the existing cracks, and creating new cracks thereupon. The fracking fluid is heated using one of an electrical heater, a laser generator and a microwave generator. A plurality of (pilot) cracks are created on the inner circumference of the petroleum well. Further, a chamber is aligned along the inner circumference of the petroleum well. Subsequently, a plurality of heater coils are incorporated within the chamber and subsequently the chamber is filled with brine solution. The heater coils within the chamber are heated to a predetermined temperature, such that the brine solution which is in contact with the heater coils heats up and transforms into high pressure steam. The high pressure steam is subsequently directed through a plurality of fast actuating valves located (at predetermined locations) within the chamber. The rapid flow/release of the steam through the fast actuating valves results in creation of high velocity shock waves/blast waves. The shock waves/blast waves are directed onto the cracks of the petroleum well, thereby causing the cracks to expand. The shock waves/blast waves travel outward in all directions from the fast actuating valves, moving at (preferably) a near detonation velocity, and rupturing the rock formation surrounding the bore hole (of the petroleum well). The force/pressure of the shock waves/blast waves travelling outwards from the fast actuating valves typically exceed the compression strengths of the surrounding rock formation, thereby causing the rock formation to bend forward and crack. The force/pressure of the shock waves/blast waves creates new cracks and widens already existing cracks. Cracks thus generated are radial in the sense that they radiate out from the borehole. Further, any cracks, previously present are widened in radial direction subsequent to the propagation of shock waves/blast waves. Further, the shock waves/blast waves propagating through the petroleum well are typically reflected back into the rock formation as tension waves. The reflected tension waves create lateral cracking in the rock formation, between the radial cracks.
[0025] In accordance with a first embodiment of the present disclosure, the shock/blast wave assisted fracking method includes heating the fracking fluid using an electrical heater or electrical heating tool. In accordance with this embodiment, a petroleum well comprises a plurality of pilot cracks 14, located preferably on the inner walls/inner periphery thereof as shown in FIG.1. A fracking fluid, for example, brine solution 10 is filled up inside the petroleum well to prevent the inner walls from collapsing due to exertion of high levels of atmospheric pressure (approximately 150 Bars). The brine solution 10 is typically confined in a chamber 12 (constructed inside the petroleum well). The chamber 12 incorporates a plurality of heating coils 12A wound around the inner surface thereof. The heating coils 12A are heated by an external energy source (not shown in figures), and the brine solution is heated preferably up to the boiling temperature. The heating coils 12A heat the brine solution 10 so as to ensure that the steam is generated at the prescribed conditions of around 220 atmospheres and 350 °C. Subsequently, the temperature inside the chamber 12 comprising the brine solution 10 is maintained at high levels. The boiling of the brine solution 10 results in formation of high pressure steam, which is subsequently directed through a plurality of fast acting valves, towards the (pilot) cracks 14 inside the petroleum well. The rapid flow/release of the steam through the fast acting valves results in creation of shock waves/blast waves 16. The shock waves 16 are exerted upon the existing cracks 14 thereby causing crack propagation/enhancement, in addition to creating new cracks on the inner periphery of the petroleum well.
[0026] In accordance with a second embodiment of the present disclosure, a laser generator is used to heat the fracking solution (preferably confined in a chamber) to a predetermined temperature, as shown in FIG 2A. In accordance with this embodiment, the fracking fluid is brine solution 10. Preferably, the laser generator 10A (shown in FIG.2B) is located outside the petroleum well, and the laser beams 14B generated by the laser generator 10A are carried down to the location where the chamber 12 is constructed, through suitable fiber optic couplers 14A, as depicted in FIG.2A. Subsequently, the laser beams 14B are focused upon the brine solution 10 via focusing optics 14C as shown in FIG.2A. Subsequently, the brine solution 10 is heated to a predetermined temperature by the laser beams 14B converging thereupon. The heating/boiling of the brine solution 10 results in formation of high pressure steam, which is subsequently directed through a plurality of fast acting valves, towards the (pilot) cracks 12 inside the petroleum well. The rapid flow/release of the steam through the fast acting valves results in creation of shock waves/blast waves 16. The shock waves are exerted upon the existing cracks 12 thereby causing crack propagation/enhancement, in addition to creating new cracks on the inner periphery of the petroleum well.
[0027] In accordance with a third embodiment of the present disclosure, a microwave generator 10B is used to heat the brine solution 10 (confined in the chamber 12) to a predetermined temperature, as shown in FIG 3A. Preferably, the microwave generator 10B (depicted in FIG.3B) is located outside the petroleum well, and the microwave beams (not shown in figures) generated by the microwave generator 10B are carried down to the location of the brine solution, through suitable microwave inlets 14D. Subsequently, the microwave beams (not shown in figures) are focused upon the brine solution 10 via focusing microwave inlets 14D as shown in FIG.3B. Subsequently, the brine solution 10 is heated to a predetermined temperature by the microwave beams converging thereupon. The heating/boiling of the brine solution 10 results in formation of high pressure steam, which is subsequently directed through a plurality of fast acting valves, towards the cracks 14 inside the petroleum well. The rapid flow/release of the steam through the fast acting valves results in creation of shock waves/blast waves. The shock waves are exerted upon the existing cracks thereby causing crack propagation/enhancement, in addition to creating new cracks on the inner periphery of the petroleum well.
[0028] In accordance with the present disclosure, the rapid flow/release of the steam through the fast actuating valves results in creation of high velocity shock waves/blast waves. The shock waves/blast waves are directed onto the cracks of the petroleum well, thereby causing the cracks to expand. The shock waves/blast waves travel outward in all directions from the fast actuating valves, moving at (preferably) a near detonation velocity, and rupturing the rock formation surrounding the bore hole (of the petroleum well). The force/pressure of the shock waves/blast waves travelling outwards from the fast actuating valves typically exceed the compression strengths of the surrounding rock formation, thereby causing the rock formation to bend forward and crack. The force/pressure of the shock waves/blast waves creates new cracks and widens already existing cracks. Cracks thus generated are radial in the sense that they radiate out from the borehole. Further, any cracks, previously present are widened in radial direction subsequent to the propagation of shock waves/blast waves. Further, the shock waves/blast waves propagating through the petroleum well are typically reflected back into the rock formation as tension waves. The reflected tension waves create lateral cracking in the rock formation, between the radial cracks. In accordance with the present disclosure, a plurality of pressure sensors and thermocouples are mounted at appropriate locations of the chamber to monitor the pressure and temperature conditions (inter-alia) therein.
[0029] FIG. 4 is a flowchart illustrating a method for expanding surface cracks of a petroleum well. In accordance with the present disclosure, a plurality of cracks (pilot cracks) are created on inner circumference of the petroleum well (401). Subsequently, a chamber is created abutting the inner circumference of the petroleum well, such that the chamber is accommodated within the inner circumference of the petroleum well (402). Further, a plurality of heater coils are incorporated within the chamber, and thereafter the chamber is filled with brine solution (403). Consequently, the heater coils which are in contact (heater coils are preferably immersed in the brine solution) with the brine solution are heated to a predetermined temperature, thereby resulting in the formation of high pressure steam (404). The high pressure steam is directed through a plurality of fast actuating valves located within the chamber. The fast actuating valves propagate the high pressure steam onto the cracks of the petroleum well, thereby causing the high pressure steam to expand the surface cracks (405) and also create new cracks on the inner periphery of the petroleum well.

TECHNICAL ADVANTAGES
[0030] The technical advantages envisaged by the present disclosure include the realization of an environment friendly alternative to hydrofracking. The present disclosure provides an efficient and alternative method for replenishing depleted petroleum wells. The method envisaged by the present disclosure efficiently addresses the issue of underground water contamination commonly witnessed during the process of hydrofracking. The method envisaged by the present disclosure also provides for the creation of cracks and fissures to be efficiently controlled. The present disclosure envisages a system and method that enable the direction of enhancement/elongation of cracks/fissures to be effectively controlled. Further, the system and method envisaged by the present disclosure enables crack propagation only in a lateral direction inside the petroleum well, thereby ensuring the directionality for propagation of cracks as well as for creation of new cracks. Further, enabling crack propagation only in the lateral direction provides greater control over the creation and enhancement of cracks.
,CLAIMS:We Claim:
1. A method for expanding surface cracks of a petroleum well, said method comprising the following steps:
creating a plurality of cracks on inner circumference of the petroleum well;
creating a chamber abutting the inner circumference of the petroleum well, such that the chamber is accommodated within the inner circumference of the petroleum well;
incorporating a plurality of heater coils within the chamber;
filling the chamber with brine solution;
heating the brine solution to a predetermined temperature and enabling conversion of brine solution into high pressure steam;
directing the high pressure steam through a plurality of fast actuating valves located within the chamber, and propagating the high pressure steam onto the cracks of the petroleum well, thereby employing the high pressure steam to expand the surface cracks.

2. The method as claimed in claim 1, wherein the method of heating the heater coils, further includes the step of heating the heater coils using an electrical heater.

3. The method as claimed in claim 1, wherein the method of heating the heater coils, further includes the step of heating the brine solution using laser beams generated by a laser generator.

4. The method as claimed in claim 1, wherein the method of heating the brine solution, further includes the steps of heating the brine solution using a microwave generator.

5. The method as claimed in claim 3, wherein the step of heating the brine solution using laser beams generated by a laser generator, further includes the step of focusing the laser beams onto the brine solution using a plurality of fibre optic couplers.

6. The method as claimed in claim 4, wherein the step of heating the brine solution using a microwave generator, further includes the step of guiding the microwaves onto the brine solution using a plurality of microwave guides.