DESC:CROSS-REFERENCE TO RELATED APPLICATIONS
[001] The embodiments herein claims the priority of the Indian Provisional Patent Application filed on April 14, 2016 with the number 201641013078 and entitled, “SHOCK/BLAST WAVE ASSISTED FRACKING USING OXY-HYDROGEN GAS MIXTURE DETONATION”, and the contents of which are included in entirety as reference herein.

TECHNICAL FIELD
[002] The present disclosure is related to the field of fracking technology. The present disclosure is particularly related to an apparatus and method for fracking of petroleum wells.
BACKGROUND
[003] Typically, petroleum products such as oil and natural gases are found in underground reservoirs deep inside the earth. The extraction of petroleum products involves drilling wells that vertically extend thousands of meters into the earth to reach the underground reservoirs. The supply of oil/gas within the reservoirs is usually trapped into rocks/rock beds surrounding the petroleum wells. The petroleum wells are also extended in horizontal direction after reaching the desired vertical depth. Further, cracks/fractures are created along the walls of the wells, through which the trapped oil/gas flows into the well to rejuvenate depleted oil and gas supply.
[004] A process named fracking is used for creating fractures or cracks in rocks/rock beds surrounding the petroleum well. The process of fracking involves injection of pressurized fluid (e.g. water, brine solution) into the cracks to force them open (as shown in FIG.1). Typically, water used in this process is induced with additives such as sand, proppants and predetermined thickening agents to prevent the opened-up cracks or fractures from closing when the applied pressure exerted due to injection of pressurized fluid is released. The increased weight of pressurized fluid due to injection exerts a downward force from the surface that results into hydrostatic pressure being built up. This hydrostatic pressure results in creation of newer cracks on the inner surface of the well. Similarly, the exertion of hydrostatic pressure also results into opening up of existing cracks on the inner surface of the petroleum well.
[005] However, some of the drawbacks associated with fracking process include uncontrolled propagation of cracks into the rock beds as the cracks follow path of least resistance. The chances of cracks reaching the underground water reserves surrounding the well increase due to the uncontrolled propagation of cracks. This results into contamination of water present in the underground water reserves.
[006] Therefore, in view of drawbacks discussed hitherto, there is felt a need for an apparatus and method for fracking that overcomes the aforementioned disadvantages. There is also a need for an apparatus and method that replenishes depleted petroleum wells in an eco-friendly manner. Further, there is also felt a need to develop a shock wave apparatus and method for fracking based on oxy-hydrogen gas mixture detonation for controlled propagation of cracks in the petroleum wells. Still further, there is also a need for an apparatus and method for creation of cracks in the rock beds and also for widening of the existing cracks without contamination of the surrounding underground water reserves.
[007] The above mentioned shortcomings, disadvantages and problems are addressed herein and which will be understood by reading and studying the following specification.

OBJECTS
[008] The primary object of the present disclosure is to provide an eco-friendly alternative to the hydrofracking method.
[009] Yet another object of the present disclosure is to provide an apparatus and method for rejuvenating depleted petroleum wells using shock wave assisted fracking.
[0010] Another object of the present disclosure is to provide a shock wave apparatus and method for creation and propagation of cracks in the rock beds and also for widening of the existing cracks in the rock beds surrounding the petroleum wells.
[0011] 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.
[0012] Yet another object of the present disclosure is to develop a shock wave apparatus and method for fracking that uses oxy-hydrogen gas mixture detonation for controlled propagation of cracks in the petroleum wells.
[0013] Yet another object of the present disclosure is to provide an apparatus and method for fracking that facilitates crack propagation in a lateral direction on the inner surface of the petroleum well bore.
[0014] These and other objects and advantages of the present disclosure will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings.

SUMMARY
[0015] The present disclosure envisages an oxy-hydrogen gas-mixture based fracking apparatus for rejuvenating depleted petroleum wells. The present disclosure provides an eco-friendly alternative to hydrofracking method. The present disclosure envisages a shock wave apparatus for creating cracks in the rock beds and also for widening of the existing cracks in the rock beds surrounding the petroleum wells. The apparatus, in accordance with the embodiments cited herein comprises a thickened outer vessel that consists of a first chamber and a second chamber operatively coupled by a valve. The first chamber is filled with an electrolyte solution. The first chamber incorporates a plurality of metal electrodes immersed in the electrolyte solution. The second chamber includes an igniter and a plurality of high-speed valves arranged in a circumferential manner on the outer periphery of the second chamber.
[0016] In accordance with the present disclosure, during the operation of the oxy-hydrogen gas mixture based fracking apparatus, the valve and the high speed valves are closed. Electrical power is supplied to the metal electrodes present in the first chamber to initiate electrolysis of the electrolyte solution present in the first chamber. The electrolysis of the electrolyte solution results in generation of oxy-hydrogen gas. The generated oxy-hydrogen gas settles above the electrolyte solution in the first chamber. The aforementioned process is sustained until the pressure of the oxy-hydrogen gas reaches a predetermined pressure threshold. The generated oxy-hydrogen gas is allowed to enter into the second chamber on reaching the predetermined pressure threshold within the first chamber. The pressure of the generated oxy-hydrogen gas is determined using a pressure sensor incorporated into the first chamber. The oxy-hydrogen gas is confined into the second chamber by closing the valve. The igniter ignites the oxy-hydrogen gas present in the second chamber. The ignition of oxy-hydrogen gas present in the second chamber is synchronized with opening of the high speed valves. The subsequent detonation of the oxy-hydrogen gas generates high pressure gas that is ejected via the high speed valves resulting in plurality of shock waves.
[0017] In accordance with the present disclosure, the rapid ejection of the high pressure/high temperature gas through the fast acting high speed valves results in creation of shock waves which are then exerted upon the inner surface of the petroleum well bore. The sudden impinge of high pressure shock waves on the inner surface of the well results in creation and propagation of newer cracks in the rock beds and also in widening of the existing cracks in the rock beds surrounding the petroleum wells. The operation of the oxy-hydrogen fracking apparatus is preferably repeated until the electrolyte solution is exhausted.
[0018] In accordance with the present disclosure, a method for creating newer cracks or expanding existing cracks on an inner surface of a petroleum well bore using an oxy-hydrogen gas mixture based fracking apparatus is provided. The method comprises: inserting an oxy-hydrogen gas mixture based fracking apparatus comprising of an outer vessel into the petroleum well bore, wherein the outer vessel consists of a first chamber and a second chamber operatively coupled by a valve; incorporating a plurality of metal electrodes into the first chamber and immersing the metal electrodes into an electrolyte solution; initiating generation of oxy-hydrogen gas through electrolysis of the electrolyte solution present within the first chamber, wherein electrical power is supplied from the ground level for initiating the electrolysis; filling the second chamber with the generated oxy-hydrogen gas on reaching a predetermined pressure threshold in the first chamber; controlling the movement of oxy hydrogen gas into the second chamber using the valve; igniting the oxy-hydrogen gas present within the second chamber using an igniter for generating high pressure gas; ejecting the high pressure gas via a plurality of high-speed valves provided in the second chamber resulting in creation of plurality of shock waves, wherein the ignition of oxy-hydrogen gas present in the second chamber is synchronized with opening of the high speed valves; exerting the shock waves onto the inner surface of the petroleum well bore for creating new cracks or for expanding existing cracks.
[0019] In accordance with this embodiment, the method further includes the step of filling the petroleum well bore with brine solution prior to insertion of the oxy-hydrogen gas mixture based fracking apparatus.
[0020] In accordance with this embodiment, the method further includes the step of determining the pressure of the oxy-hydrogen gas generated in the first chamber using a pressure sensor.
[0021] In accordance with this embodiment, the step of filling the second chamber, further includes the step of facilitating a controlled movement of generated oxy-hydrogen gas into the second chamber on reaching a predetermined pressure threshold within the first chamber.
[0022] In accordance with this embodiment, the method of ejecting the high pressure gas, further includes the step of ejecting the generated high pressure gas in a lateral direction.
[0023] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating the preferred embodiments and numerous specific details thereof, are given by way of an illustration and not of a limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRITION OF ACCOMPANYING DRAWINGS
[0024] The other objects, features and advantages will occur to those skilled in the art from the following description of the preferred embodiment and the accompanying drawings in which:
[0025] FIG. 1 illustrates a schematic representation of a manner in which conventional hydraulic fracking apparatus is deployed in a petroleum well, in accordance with the present disclosure.
[0026] FIG.2 illustrates a schematic representation of a manner in which an oxy-hydrogen gas mixture based fracking apparatus is deployed in a petroleum well, in accordance with the present disclosure.
[0027] FIG.3A-3D illustrate various stages of operation of the oxy-hydrogen gas mixture based fracking apparatus, in accordance with the present disclosure.
[0028] FIG. 4 illustrates a flow chart explaining a method for creating and expanding surface cracks on an inner surface of a petroleum well bore using an oxy-hydrogen gas mixture based fracking apparatus, in accordance with the present disclosure.
[0029] Although the specific features of the present disclosure are shown in some drawings and not in others. This is done for convenience only as each feature may be combined with any or all of the other features in accordance with the present disclosure.

DETAILED DESCRIPTION
[0030] In the following detailed description, a reference is made to the accompanying drawings that form a part hereof, and in which the specific embodiments that may be practiced is shown by way of illustration. These embodiments are described in sufficient detail to enable those skilled in the art to practice the embodiments and it is to be understood that the logical, mechanical and other changes may be made without departing from the scope of the embodiments. The following detailed description is therefore not to be taken in a limiting sense.
[0031] In order to overcome the drawbacks discussed hitherto, the present disclosure envisages a shock wave assisted apparatus and method for fracking that uses oxy-hydrogen gas mixture detonation for controlled propagation of cracks in the petroleum wells. The apparatus and method envisaged by the present disclosure, while providing an eco-friendly alternative to the hydrofracking method, also ensures that the underground water resources are not contaminated during the fracking process/method. Further, the fracking apparatus and 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 pressurized water to be filled up in the well.
[0032] Referring to the accompanying drawings, and particularly to FIG.2, the manner in which the oxy-hydrogen gas mixture based fracking apparatus 200 is deployed in petroleum well is illustrated. The apparatus 200 is deployed in the petroleum well bore with the help of a well logging truck as illustrated. The apparatus 200 is designed in a manner to fit within the dimension limits of the production tubing of the petroleum well. Also, the overall weight of the apparatus is constrained to a maximum of about 200 Kilograms which is easily supported by the well logging truck. Thus, the apparatus is conveniently lowered into the well bore using the well logging truck.
[0033] Usually, brine solution is filled in the petroleum well prior to inserting the apparatus as a safety measure to achieve controlled formation pressure (pressure of fluid contained in pores of rock/rock beds) within the well. Unbalanced formation pressures encountered during fracking sometimes cause an influx of formation fluids that may result into a blowout. Thus, filling the well with brine solution helps to maintain the pressure levels within the well.
[0034] The shock waves produced using the apparatus are guided to the bottom of the well bore using a guide tube 202. A set of packer systems 204 is also installed at the bottom of the guide tube 202 to ensure a confined zone around the gas and oil source formation.
[0035] FIG.3A, details the construction of the oxy-hydrogen fracking apparatus 300 in accordance with the present disclosure. The apparatus 300 comprises a thickened outer vessel 302 capable of withstanding higher pressure and temperatures levels (pressure of about 1000 bar and temperature of about 4500 K) generally experienced in petroleum wells. The outer vessel 302 consists a first chamber 304 and a second chamber 306 operatively coupled by a high pressure and high temperature valve 308 (referred to as ‘valve’ hereafter). As shown in FIG.3A, the first chamber 304 is filled with an electrolyte solution. A plurality of metal electrodes are incorporated into the first chamber and are immersed in the electrolyte solution.
[0036] In accordance with the present disclosure, the second chamber 306 comprises an igniter 310. A plurality of high-speed valves (collectively represented by reference numeral 312) are arranged in a circumferential manner on an outer periphery of the second chamber 306. The high speed valves 312 are configured to operate in a unidirectional manner to restrict the flow of brine solution into the first chamber 304 and the second chamber 306.
[0037] In accordance with the present disclosure, during the operation of the oxy-hydrogen gas mixture based fracking apparatus 300, the valve 308 and the high speed valves 312 are closed (as shown in FIG.3B) initially and electrical power is supplied to the metal electrodes (situated in the first chamber 304) from the surface/ground level. The well logging truck/unit typically provides the required electrical power required for the operation of apparatus 300. A voltage and current rating of about 12V and 20A respectively is required for operating the apparatus envisaged by the present disclosure. The resultant electrolysis generates oxy-hydrogen gas which preferably settles above the surface of the electrolyte solution in the first chamber 304. The aforementioned process is sustained until the pressure of the oxy-hydrogen gas reaches a predetermined pressure threshold.
[0038] In accordance with the present disclosure, the valve 308 is (as shown in FIG.3C) opened soon after the pressure of the oxy-hydrogen gas reaches a predetermined pressure threshold for allowing the oxy-hydrogen gas to enter the second chamber 306. The oxy-hydrogen gas is confined to the second chamber 306 by closing the valve 308. Subsequently, the igniter 310 is switched on (as shown in FIG.3D). The igniter 310 ignites the oxy-hydrogen gas present in the second chamber 306. The detonation of oxy-hydrogen gas generates high pressure/high temperature gases which are ejected via the high speed valves 312. The ignition of oxy-hydrogen gas present in the second chamber 306 is synchronized with opening of the high speed valves 312. Dynamic pressures of the order of Giga Pascal are typically produced by detonation of oxy-hydrogen gas. The initial fill pressure (about 50 bars) of the oxy-hydrogen mixture determines the pressure and temperature of the products of detonation.
[0039] In accordance with the present disclosure, the rapid ejection of high pressure/high temperature gas results in generation of shock waves which are exerted onto the inner surface of the well to creates fissures/cracks. The shock waves are exerted upon the existing cracks thereby inducting crack propagation/enhancement. Further, the shock waves also create new cracks/fissures on the inner surface of the petroleum well bore. The operation of the oxy-hydrogen fracking apparatus 300 is preferably repeated until the electrolyte solution is exhausted.
[0040] The apparatus and method envisaged by the present disclosure provides an efficient alternative to the conventional hydrofracking method. The detonation of the oxy-hydrogen mixture, in accordance with the present disclosure results in creation of shock waves that travel laterally into the rock formation. Thus, the cracks are forced to propagate in the direction of the shock wave movement i.e. in lateral direction. The ejection of shock waves is followed by a fast moving jet of steam which additionally aids in the crack creation and propagation. Therefore, the controlled propagation of cracks with prior knowledge of the locations of water reserves and by properly characterizing the rock structure at stipulated depth prevents the contamination of water reserves surrounding the petroleum well. A major byproduct envisaged by present disclosure is water and therefore the method is considered carbon-free and also free of any hazardous chemicals.
[0041] FIG. 4 illustrates a flow chart explaining a method for creating and expanding surface cracks on an inner surface of a petroleum well bore using an oxy-hydrogen gas mixture based fracking apparatus, in accordance with the present disclosure. The method comprises: inserting an oxy-hydrogen gas mixture based fracking apparatus comprising of an outer vessel into the petroleum well bore (402), wherein the outer vessel consists of a first chamber and a second chamber operatively coupled by a valve; incorporating a plurality of metal electrodes into the first chamber and immersing the metal electrodes into an electrolyte solution (404); initiating generation of oxy-hydrogen gas through electrolysis of the electrolyte solution present within the first chamber (406), wherein electrical power is supplied from the ground level for initiating the electrolysis; filling the second chamber with the generated oxy-hydrogen gas on reaching a predetermined pressure threshold in the first chamber (408); igniting the oxy-hydrogen gas present within the second chamber using an igniter for generating high pressure gas (410); ejecting the high pressure gas via a plurality of high-speed valves provided in the second chamber resulting in creation of plurality of shock waves (412), wherein the ignition of oxy-hydrogen gas present in the second chamber is synchronized with opening of the high speed valves; exerting the shock waves onto the inner surface of the petroleum well bore for creating new cracks or for expanding existing cracks (414).
[0042] In accordance with this embodiment, the method further includes the step of filling the petroleum well bore with brine solution prior to insertion of the oxy-hydrogen gas mixture based fracking apparatus.
[0043] In accordance with this embodiment, the method further includes the step of determining the pressure of the oxy-hydrogen gas generated in the first chamber using a pressure sensor.
[0044] In accordance with this embodiment, the step of filling the second chamber, further includes the step of facilitating a controlled movement of generated oxy-hydrogen gas into the second chamber on reaching a predetermined pressure threshold within the first chamber.
[0045] In accordance with this embodiment, the method of ejecting the high pressure gas, further includes the step of ejecting the generated high pressure gas in a lateral direction.

TECHNICAL ADVANTAGES
[0046] The present disclosure envisages an apparatus and method to create cracks in rocks/rock beds surrounding the petroleum well and also to widen the dimensions of existing cracks by using shock waves. The apparatus and method envisaged by the present disclosure provides an eco friendly alternative to the conventional hydrofracking process. The present disclosure provides an efficient and alternate method for replenishing depleted petroleum wells. Crack propagation in a controlled manner is achieved using the proposed apparatus by directing the shock waves in a desired direction on the inner surface of the petroleum well bore. Further, the controlled propagation of cracks with prior knowledge of the locations of underground water reserves prevents the contamination of water reserves surrounding the petroleum well. Also, the apparatus and method envisaged by the present disclosure enables crack propagation only in a lateral direction, inside the petroleum well. Further, the major byproduct of the method envisaged by present disclosure is water, and therefore the method is considered carbon-free and also free of any hazardous chemicals. The apparatus additionally facilitates generation of oxy-hydrogen gas mixture without the need for storage of combustible material.
[0047] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modifications.
[0048] Although the embodiments herein are described with various specific embodiments, it will be obvious for a person skilled in the art to practice the embodiments herein with and without modifications. ,CLAIMS:1. An oxy-hydrogen gas mixture based fracking apparatus, the apparatus comprising:
an outer vessel comprising a first chamber and a second chamber;
a plurality of metal electrodes incorporated into the first chamber, the metal electrodes immersed in an electrolyte solution, said metal electrodes configured to generate oxy-hydrogen gas within the first chamber by electrolysis of the electrolyte solution;
a valve operatively coupling the first chamber and the second chamber, said valve configured to facilitate controlled movement of generated oxy-hydrogen gas into the second chamber on reaching a predetermined pressure threshold within the first chamber, said pressure of the generated oxy-hydrogen gas determined using a pressure sensor incorporated into the first chamber;
an igniter incorporated into the second chamber, said igniter configured to ignite the oxy-hydrogen gas present in the second chamber thereby generating high pressure gas through detonation of oxy-hydrogen gas; and
a plurality of high-speed valves mounted in a circumferential manner on an outer periphery of the second chamber, said high speed valves configured to eject generated high pressure gas resulting in a plurality of shock waves, said shock waves directed onto the inner surface of the petroleum well bore through high speed valves thereby creating newer cracks or expanding the existing cracks.
2. The apparatus as claimed in claim 1, wherein the ingiter is further configured to ignite the oxy-hydrogen gas present in the second chamber in synchronization with the opening of the high speed valves.

3. The apparatus as claimed in claim 1, wherein the high speed valves are further configured to operate in a unidirectional manner to restrict the flow of brine solution present in the petroleum well bore into the first chamber and the second chamber.
4. The apparatus as claimed in claim 1, wherein the high speed valves are further configured to eject the generated high pressure gas in a lateral direction.
5. A method for creating and expanding surface cracks on an inner surface of a petroleum well bore using an oxy-hydrogen gas mixture based fracking apparatus, said method comprising the following steps:
inserting an oxy-hydrogen gas mixture based fracking apparatus comprising of an outer vessel into the petroleum well bore for generating a plurality of shock waves, said outer vessel comprising a first chamber and a second chamber operatively coupled by a valve;
incorporating a plurality of metal electrodes into the first chamber and immersing said metal electrodes into an electrolyte solution;
initiating generation of oxy-hydrogen gas through electrolysis of the electrolyte solution present within the first chamber;
filling the second chamber with the generated oxy-hydrogen gas;
igniting the oxy-hydrogen gas present within the second chamber using an igniter for generating high pressure gas;
ejecting the high pressure gas via a plurality of high-speed valves provided in the second chamber resulting in creation of plurality of shock waves; said shock waves exerted onto the inner surface of the petroleum well bore for creating new cracks or for expanding existing cracks.

6. The method as claimed in claim 5, wherein the method further includes the step of filling the petroleum well bore with brine solution prior to insertion of the oxy-hydrogen gas mixture based fracking apparatus.
7. The method as claimed in claim 5, wherein the method further includes the step of determining the pressure of the oxy-hydrogen gas generated in the first chamber using a pressure sensor.
8. The method as claimed in claim 5, wherein the step of filling the second chamber, further includes the step of facilitating a controlled movement of generated oxy-hydrogen gas into the second chamber on reaching a predetermined pressure threshold within the first chamber.
9. The method as claimed in claim 5, wherein the method of ejecting the high pressure gas, further includes the step of ejecting the generated high pressure gas in a lateral direction.