WO2022120504A1 - System and method of hydraulic fracturing by dynamic multi-stage methodology - Google Patents

System and method of hydraulic fracturing by dynamic multi-stage methodology Download PDF

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Publication number
WO2022120504A1
WO2022120504A1 PCT/CL2020/050172 CL2020050172W WO2022120504A1 WO 2022120504 A1 WO2022120504 A1 WO 2022120504A1 CL 2020050172 W CL2020050172 W CL 2020050172W WO 2022120504 A1 WO2022120504 A1 WO 2022120504A1
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Prior art keywords
pressure
fracturing
flow
pump
propagation
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PCT/CL2020/050172
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Spanish (es)
French (fr)
Inventor
Kurt Arthur KANDORA MONTRONE
Pablo Rodrigo RIVEROS OYARCE
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Georock S.A.
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Priority to PCT/CL2020/050172 priority Critical patent/WO2022120504A1/en
Publication of WO2022120504A1 publication Critical patent/WO2022120504A1/en

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Classifications

    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21C—MINING OR QUARRYING
    • E21C37/00—Other methods or devices for dislodging with or without loading
    • E21C37/06—Other methods or devices for dislodging with or without loading by making use of hydraulic or pneumatic pressure in a borehole
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21C—MINING OR QUARRYING
    • E21C45/00—Methods of hydraulic mining; Hydraulic monitors
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH DRILLING; MINING
    • E21C—MINING OR QUARRYING
    • E21C45/00—Methods of hydraulic mining; Hydraulic monitors
    • E21C45/02—Means for generating pulsating fluid jets
    • E21C45/04—Means for generating pulsating fluid jets by use of highly pressurised liquid

Definitions

  • Hydraulic fracturing systems are systems used in the exploitation of underground mines in which the extraction of the ore is carried out by the force of gravity, a method called sinking. And as illustrated in Figure 1, it consists of dividing the mineralized body into rectangular blocks and breaking each of these separately following a sequence, by means of explosives placed at its base, sinking level. In this way, the block is broken into fragments, which are removed from its lower part, the production level. Then the ore is transported through pits and/or galleries to the crushing room or plant.
  • FFHH Hydraulic Fracturing
  • PA rock Mass Pre-conditioning
  • FFHH Hydraulic Fracturing
  • the global objective of the application of the pre-conditioning of the rock mass (PA) consists of drilling in the rock mass and then, through the injection of water at high pressures, to carry out its fracturing. This unitary operation is known as Hydraulic Fracturing (FFHH), which changes the "in situ" conditions of the rock mass, especially stress.
  • FFHH Hydraulic Fracturing
  • the reliability for the materialization of the mining plan is improved, due to the generation of a granulometry such that it facilitates the extraction of the ore.
  • the (PA) manages to reduce the probability of occurrence of unwanted events, such as rock bursts and collapses.
  • the process includes the following stages: a) preparation: which is the process of construction of an infrastructure of tunnels and constructions that allow the collection of the ore, b) drilling vertically in order to apply hydraulic fracturing, c) in which once said fracturing is completed, a second stage of vertical drilling is carried out in order to apply confined and controlled detonation, so that the expansive waves of said confined and controlled detonation cause stresses of traction in the rock that generate more fractures than those already generated with said hydraulic fracturing until artificially creating structures, that is, cracks that, when the conditions of the rock change, facilitate its collapse and allow its subsequent extraction; and d) collapse of the hill or massif and in order to start production with the extraction of broken ore.
  • the workings are located in sectors of greater stress that are ultimately more susceptible to rock bursts or collapses, thus releasing the tension stored in the premise.
  • the rock burst occurs instantaneously and violently, generating a local seismic event, which is manifested by the detachment and projection of large volumes of rock at high speed. This represents a great risk for people, equipment and facilities.
  • the mechanical variables are directly related to the characteristics and elements of the hydraulic fracturing equipment. These are of special interest for purposes of the invention, since they are the parameters directly related to the characteristics of the equipment, and that these are key to the success of generating the fracture: Pressures: either due to inflation of mechanical plugs or plugs (“packers”) in drilling and rock fracture.
  • the variables of the rock mass are related to the geomechanical, geological and lithological parameters of the rock, which can be grouped according to:
  • Intrinsic factors that depend on the nature of the rock such as the type (Andesite, calcite, etc.); its main mineralization (Quartz, Anhydrite, Feldspar, Chlorite, Chalcopyrite, Pyrite, etc.); rock properties such as Cohesion, Toughness, Young's modulus, Poisson's ratio.
  • Extrinsic factors that depend on the behavior of the rock based on external factors such as: Confining Efforts (Their behavior is different depending on whether the rock is confined or not).
  • Confining Efforts Their behavior is different depending on whether the rock is confined or not.
  • the pressure of the hydrostatic column which increases with the location of the body in depth.
  • the propagation pressure of a fracture is proportional to the volume of fluid used
  • Fracture length (or radius) is a function of pumping time
  • the energy required to extend the fracture must be equal to the work done by the pressure within the fracture to open a given additional width. Then, the speed of the fluid (or injected flow), will allow the fracture radius to increase for a while until the efforts are balanced (power of the equipment vs. effect of the rock mass).
  • the fracture radius increases rapidly and then increases as it propagates, to a point such that the propagation curve behaves asymptotically. At this time, the efforts are balanced and the propagation process stops.
  • the radius of influence of a hydraulic fracture is also conditioned by the geomechanical, geological and lithological parameters of the sector or section of the rock mass. It has been verified that the more unfavorable the rock mass condition, the more effort the equipment will require to propagate a hydraulic fracture.
  • the fracturing process of a rock mass at medium and high depths of the present invention contemplates: a high pressure pump that delivers the flow of water for filling the hydrofacture column, at a pressure in a value of 35 to 80 mega Pascals; and elements to drive pressurized water into the well, to a device that is introduced at the fracturing level.
  • the main function of this device is the confinement or sealing of the point of entry of the fracture water.
  • the expandable elements are arranged at the ends of the tool, which, when filled with water and due to the effect of the increase in internal pressure, inflate radially, thus generating the seal against the internal surface. of the probing.
  • the pressure of the "packers” must reach a higher value than the fracture. Once the hydro-fracturing point is sealed, hydraulic fracturing begins, always maintaining a pressure differential between the packer inflation pressure and the fracture pressure. The pressure of the "packers” must be greater to avoid loss of the seal and accidents due to sudden displacement of the assembly.
  • Rocks that behave elastically against a stress of a certain intensity can deform plastically, or even fracture, if the stress acts for a sufficient period of time. If the strain rate is high, the time will be short and the rock will respond with stiffness; if the deformation takes place at a slow rate and for a longer time it will respond more plastically.
  • a dynamic modality is incorporated in the inflation of "packers". This consists of inflating the "packers” to a lower pressure in such a way that when the fracture flow begins, it generates an increase in the pressure of the "packers" up to the working pressure.
  • the successive start-up of the pumps makes it possible to attenuate the drop in the propagation velocity;
  • the use of more pumps that provide the propagation flow allows a greater total flow to be achieved and therefore a greater fracture radius;
  • the equipment configuration allows to generate a higher net pressure, increasing the width of the fracture at the beginning; Fracturing is ensured, preventing pillars from remaining in the training; fracturing is achieved with less need for electrical power; it is possible to reach a higher propagation rate, generated in successive stages, in such a way that the necessary energy is lower; and the use of the dynamic modality in the inflation of "packers" allows to obtain a greater duration of these elements, achieving a better operational efficiency.
  • this packer inflation option influenced by the fracture pressure is the previously called “Dynamic Mode", which results in a lower operating pressure of these.
  • the multistage system of the present consists of 2 or more pumps that operate in parallel and sequentially, in such a way that their flow rates can be added synchronously. For this, the moment in which each pump starts is configured according to the design of the fracturing process, then:
  • a first pump adjusts the pressure and flow ramp to ensure the breaking of the rock mass.
  • the pressure will depend on the tenacity of the particular sector.
  • a second pump starts its operation at the moment of the break, to add its flow and maintain the propagation process.
  • the third and subsequent pumps come into operation in order to maintain the propagation speed.
  • its role is related to the design radius of the fracture.
  • a fracturing device in one embodiment hereof, includes: a fracturing tool to be inserted into the rock mass, comprising a pressure hose connected to a drilling head connected to a tool having packers, rods drilling standard, an injector head, a packer inflation pump and a connection to a fracturing water hose.
  • the water for fracturing is placed in a tank, from which the packer inflation pump is first primed by means of a priming pump.
  • the pressure of the water flow is managed with pressure limiting valves and another "packers" pressure regulator. There is also an indicator of the applied inflation pressure.
  • the tool is anchored against the rock mass wall.
  • the fracturing water circuit is activated, for this, the high pressure pump for fracturing is primed by means of the pump, the pressures are managed with two valves, a pressure limiter, arranged so as not to exceed the pressure maximum working pressure and another modulating valve for fracturing pressure. There is also an indicator of the applied pressure.
  • the fracturing water flow enters through the injection head.
  • the multi-stage system also includes two or more pumps that operate in parallel in such a way that their flows can be added.
  • a fracturing process in another embodiment, includes: a Start of water injection with the first pump. The circuit is filled and the pressure begins to increase when the flow stops. b After filling the hydraulic circuit, the pressure rises and reaches the breaking pressure. At that moment the injection by the second pump starts. The increased flow avoids the characteristic drop in pressure observed in FFHH in one stage. c The surface pressure reading is briefly stable. Then, the massif offers resistance to propagation, but the flow provided by the second pump increases the pressure of the system until a new propagation cycle begins. d The propagation speed of step (c) is reduced. Here comes into operation the third pump. e The surface pressure reading is briefly stable.
  • the solid again offers resistance to propagation, but the flow provided by the third pump increases the pressure of the system until the last propagation cycle begins. If necessary, additional successive pump cycles can be incorporated to achieve the flow rates required for the propagation design.
  • the pressure reaches a maximum due to the effect of the total flow supplied with the three pumps.
  • the system equilibrates with the stabilized flow rate and the pressure drops, similar to the one-stage process, reaching the final propagation pressure.
  • h Increasing the radius of the fracture (increases the volume) and lowers the speed of propagation. The system pressure is not able to overcome the massif resistance and the flow stops. Pumping is then stopped and the instantaneous closing pressure is measured (ISIP Test).
  • Figure 1 shows an isometric view of how the sinking exploitation method is carried out.
  • Figure 2 shows an operation diagram of an equipment for hydraulic fracturing by dynamic multistage methodology in rock mass at medium and high depth.
  • Figure 3 shows the packer system in formation, in the initial situation without inflation.
  • Figure 4 shows the "packers" system in the formation and in the initial pressurized state of "packers".
  • Figure 5 shows the system in the formation, in a fractured state.
  • Figure 6 shows an equipment for hydraulic fracturing by dynamic multistage methodology.
  • Figure 7 shows an operation diagram of a complete single-stage system.
  • Figure 2 shows a typical embodiment of the multi-stage invention which, although not limiting, is characterized in three stages.
  • the fracturing tool to be inserted into the rock mass is assembled, for which one end of the pressure hose 24 is connected to a drilling head 27. Then this head is connected to the flow of inflation water by thread a a tool 28 that has the "packers" 29, is connected to the first rod of the drill string.
  • the assembly is introduced into the well and standard drilling rods 25 are successively assembled, until the required depth is achieved from the level of the gallery 20.
  • the injector head 21 is fixed to the last drilling rod. Once the necessary torque has been applied, the connection coupling 24 is fixed on a conical thread of the nozzle of the injector head 21, applying the necessary torque.
  • the hose 22 that comes from the packer inflation pump 3 is connected to the connection coupling 24.
  • the fracturing water hose 23 is connected to the head 6 and this to the head nozzle conical thread 21 . In this way, the assembly is assembled and connected to the water supply, ready to start the fracturing process.
  • the water for the fracture It is arranged in a tank 1, from which firstly, by means of pump 2, the priming of the "packers” inflation pump 3 is carried out.
  • the pressure of the water flow is managed with two valves, a pressure limiter 4, in order not to exceed the maximum working pressure, another “packers” pressure regulator 5.
  • a pressure limiter 4 in order not to exceed the maximum working pressure
  • another “packers” pressure regulator 5 There is also an indicator of the applied inflation pressure 6.
  • the flow of inflation water enters through the injection head 21, in connecting 24.
  • the “packers” 29 which inflate with the increase in pressure.
  • the tool is anchored against the wall of the rock mass 30.
  • the fracturing water circuit is activated, to do this, by means of pump 7, the priming of the high pressure pump for fracturing 8A.
  • Pressures are managed with two valves, a pressure limiting valve 9A, arranged so as not to exceed the maximum working pressure, and another modulating valve 1 1 for fracturing pressure. There is also an indicator of the applied pressure 12.
  • the flow of fracturing water enters through the injection head 21 .
  • the pressure is increased until fracture is achieved, at which point a decrease in pressure is detected. the pressure when the water flow is generated in the fracture 30. This pressure must always be less than the inflation (internal) pressure of the “packers” 29.
  • the multi-stage system includes two or more pumps 8A, 8B and up to 8N that operate in parallel, and sequentially and with the same means as the pump of stage 1 or for a system single-stage, but in such a way that their flows can be added.
  • the moment in which each pump starts is configured according to the design of the fracturing process.
  • the second pump 8B is adjusted to ensure the propagation of the rock mass break. The pressure will depend on the tenacity of the particular sector.
  • the third pump 8c starts its operation before the break propagation speed falls, to add its flow and continue the propagation process. Since the speed decreases with increasing radius, the third and following pumps come into operation in order to maintain the propagation speed.
  • An 8A low-flow, high-pressure pump is used in the first stage to ensure the breakage of the solid, and a second and third 8B, 8C pumps are used with higher flow and lower pressure, but with a sufficient level to maintain the propagation of the fracture. .
  • Dynamic mode is incorporated in the inflation of "packers” 29. This consists of inflating the "packers” 29 at a lower pressure in such a way that when the fracture flow begins, by reaction principle, the water is compressed and generates an increase pressure from the sealed section to the wall of the "packers” 29, which increases its internal pressure, up to the working pressure.
  • the fracture circuit 23 must be depressurized, for which the pressure is released through the valve 13, which allows the circuit to drain.
  • the packers circuit line is depressurized through valve 5. Then the procedure can be stopped, proceeding to disarm or the "packer" 29 is relocated to a new level of the perforation, restarting the fracture process again in a new position.
  • the successive start-up of the pumps 8A, 8B up to 8N allows to attenuate the drop in the propagation speed.
  • the use of more pumps that contribute the propagation flow allows to achieve a higher total flow rate and a larger fracture radius.
  • the above equipment configuration allows generating and maintaining a higher net pressure, increasing the width of the fracture at its starting or generation point.
  • Figure 3 shows the system of "packers" in training.
  • Qp is the water flow rate for inflating the packers
  • the fracture flow rate is Qf equals zero
  • the pressure P2 of fracturing and final inflation pressure of packers P3 are equal to zero.
  • Figure 4 shows the system in the formation and in the initial pressurized state of "packers", where the pressure of "packers" P1 is equal to the initial working pressure PPO, and the fracture flow is zero and the pressure Fracture P2 equals zero.
  • the packer pressure P1 will reach the working pressure PP when the fracture water enters and exerts additional pressure on the internal face of the packer.
  • Figure 5 shows the system in the formation, in a state of fracturing.
  • the inflation flow to "packers" Qp is equal to zero.
  • a fracturing device or machinery for the present multistage mode is illustrated in Figure 6, highlighting the definition of three pumps 8A, 8B and 8C.

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Abstract

A system and method of multi-stage hydraulic fracturing is disclosed for medium to deep underground rock masses, wherein for a first stage of fracturing, a first fracturing water drive pump is connected to the water injection head; this is low-flowrate and high-pressure, to ensure the rupture of the rock mass; in successive second or third stages at least one second and third pump with a greater flowrate and a lower pressure than the first pump, connected to the water injection head, enable the propagation of the hydraulic fracture to be maintained. With this invention, fracturing is ensured, preventing pillars from remaining in the formation, achieving the fracturing with a lesser requirement of electrical power, enabling the generation of progressive propagation, generated in successive stages, such that less power is required; and furthermore, a dynamic modality is employed in the inflation of the packers that enables the obtaining of a longer life of these elements, achieving greater operational efficiency.

Description

SISTEMA Y MÉTODO DE FRACTURAMIENTO HIDRAULICO POR METODOLOGIA MULTIETAPA DINAMICA. SYSTEM AND METHOD OF HYDRAULIC FRACTURING BY DYNAMIC MULTISTAGE METHODOLOGY.
Campo de la Invención field of invention
Proporcionar un sistema de fracturamiento hidráulico por metodología multietapa dinámica en macizo rocoso a mediana y alta profundidad, en donde se utiliza una bomba de menor caudal y mayor presión en la primera etapa que asegure el quiebre del macizo y luego se utiliza una segunda, tercera o más bombas adicionales con mayor caudal y menor presión, pero de nivel suficiente para mantener la propagación de la fractura. Provide a hydraulic fracturing system by dynamic multistage methodology in rock mass at medium and high depth, where a pump with lower flow and higher pressure is used in the first stage that ensures the rupture of the mass and then a second, third or third is used. more additional pumps with higher flow and lower pressure, but with a sufficient level to maintain the propagation of the fracture.
Antecedentes de la Invención Background of the Invention
Los sistemas de fracturamiento hidráulico son sistemas utilizados en explotación de minas subterráneas en que la extracción del mineral se realiza por la fuerza de gravedad, método denominado hundimiento. Y como se ¡lustra en la figura 1 consiste en dividir el cuerpo mineralizado en bloques rectangulares y quebrar cada uno de estos en forma separada siguiendo una secuencia, mediante explosivos colocados en su base, nivel de hundimiento. De esta forma, el bloque se rompe en fragmentos, los que son retirados desde su parte inferior, nivel de producción. Luego el mineral es transportado a través de piques y o galerías hasta la sala o planta de chancado. Hydraulic fracturing systems are systems used in the exploitation of underground mines in which the extraction of the ore is carried out by the force of gravity, a method called sinking. And as illustrated in Figure 1, it consists of dividing the mineralized body into rectangular blocks and breaking each of these separately following a sequence, by means of explosives placed at its base, sinking level. In this way, the block is broken into fragments, which are removed from its lower part, the production level. Then the ore is transported through pits and/or galleries to the crushing room or plant.
La técnica denominada Pre-Acondicionamiento del Macizo Rocoso, y en este caso el Fracturamiento Hidráulico (FFHH) permite modificar las propiedades de la roca “in situ”, es decir de una roca primaria a una secundaria. Logrando finalmente una roca menos competente en donde el método de explotación por hundimiento es posible aplicar. El Objetivo global de la aplicación del pre-acondicionamiento del macizo rocoso (PA) consiste en realizar perforaciones en el macizo rocoso y luego, mediante la inyección de agua a elevadas presiones, realizar su fracturamiento. Esta operación unitaria es la conocida como Fracturamiento Hidráulico (FFHH), que cambia las condiciones “in situ” del macizo rocoso, en especial, las de esfuerzos. Con esto se mejora la confiabilidad para la materialización del plan minero, debido a la generación de una granulometría tal que facilita la extracción del mineral. Así también, el (PA) logra disminuir la probabilidad de ocurrencia de eventos no deseados, como estallidos de rocas y colapsos. The technique called Rock Mass Pre-conditioning, and in this case Hydraulic Fracturing (FFHH) allows to modify the properties of the rock “in situ”, that is, from a primary rock to a secondary one. Finally achieving a less competent rock where the sinking exploitation method can be applied. The global objective of the application of the pre-conditioning of the rock mass (PA) consists of drilling in the rock mass and then, through the injection of water at high pressures, to carry out its fracturing. This unitary operation is known as Hydraulic Fracturing (FFHH), which changes the "in situ" conditions of the rock mass, especially stress. With this, the reliability for the materialization of the mining plan is improved, due to the generation of a granulometry such that it facilitates the extraction of the ore. Also, the (PA) manages to reduce the probability of occurrence of unwanted events, such as rock bursts and collapses.
En el arte previo existen varias tecnologías de hidrofracturamiento, por ejemplo en la solicitud CL200802639 & CL049624, se define un proceso dirigido a la intervención de un macizo rocoso (acondicionar) antes de su explotación, para facilitar su extracción del mineral mediante el método de hundimiento de bloques o paneles, en que dicha intervención se realiza después de haber realizado la preparación del panel o bloque y antes de producir el hundimiento, el proceso comprende las siguientes etapas: a) preparación: el cual es el proceso de construcción de una infraestructura de túneles y construcciones que permiten la recolección del mineral, b) perforar en forma vertical sondajes con el fin de aplicar fracturamiento hidráulico, c) en que una vez finalizada dicha fracturación, se lleva a cabo una segunda etapa de perforación vertical con el fin de aplicar detonación confinada y controlada, de modo que las ondas expansivas de dicha detonación confinada y controlada provocan esfuerzos de tracción en la roca que generen más fracturas a las ya generadas con dicho fracturamiento hidráulico hasta crear en forma artificial estructuras, es decir grietas que al cambiar las condiciones de la roca, faciliten el colapso de esta y permita su posterior extracción; y d) hundimiento del cerro o macizo y de modo de comenzar la producción con la extracción del mineral quebrado. In the prior art there are several hydrofracturing technologies, for example in the application CL200802639 & CL049624, a process is defined aimed at the intervention of a rock mass (conditioning) before its exploitation, to facilitate its extraction of the ore by means of the sinking method. of blocks or panels, in which said intervention is carried out after having carried out the preparation of the panel or block and before producing the sinking, the process includes the following stages: a) preparation: which is the process of construction of an infrastructure of tunnels and constructions that allow the collection of the ore, b) drilling vertically in order to apply hydraulic fracturing, c) in which once said fracturing is completed, a second stage of vertical drilling is carried out in order to apply confined and controlled detonation, so that the expansive waves of said confined and controlled detonation cause stresses of traction in the rock that generate more fractures than those already generated with said hydraulic fracturing until artificially creating structures, that is, cracks that, when the conditions of the rock change, facilitate its collapse and allow its subsequent extraction; and d) collapse of the hill or massif and in order to start production with the extraction of broken ore.
Los parámetros operacionales de esta técnica dependen de la profundidad y tipo de medio ya sea, Secundario, Intermedio o Primario. La minería subterránea actual está desarrollándose principalmente en mineral primario, donde los cuerpos mineralizados se encuentran a mayores profundidades. The operational parameters of this technique depend on the depth and type of medium, whether Secondary, Intermediate or Primary. underground mining is being developed mainly in primary ore, where ore bodies are found at greater depths.
Al incrementar la profundidad de los cuerpos mineralizados, las labores se emplazan en sectores de mayores esfuerzos que finalmente son más susceptibles a estallidos de roco o colapsos, liberándose así la tensión almacenada en el macizo. By increasing the depth of the mineralized bodies, the workings are located in sectors of greater stress that are ultimately more susceptible to rock bursts or collapses, thus releasing the tension stored in the massif.
El estallido de roca ocurre en forma instantánea y violenta, generándose un evento sísmico local, que se manifiesta mediante el desprendimiento y proyección de grandes volúmenes de roca a gran velocidad. Esto representa un gran riesgo para las personas, equipos e instalaciones. The rock burst occurs instantaneously and violently, generating a local seismic event, which is manifested by the detachment and projection of large volumes of rock at high speed. This represents a great risk for people, equipment and facilities.
Para el macizo primario emplazado a mayores profundidades y para lograr el proceso de hidrofracturamiento, se requieren de mayores presiones para el quiebre y la propagación de las fracturas. Para ello se debe aumentar la capacidad de los equipos utilizados, en términos de su capacidad y por tanto sus dimensiones y necesidad de potencial eléctrica. For the primary massif located at greater depths and to achieve the hydrofracturing process, higher pressures are required for the fracture and the propagation of the fractures. For this, the capacity of the equipment used must be increased, in terms of its capacity and therefore its dimensions and need for electrical potential.
Aun cuando las dimensiones del equipo pueden ser ajustadas para su traslado al interior de la mina, la potencia disponible en muchos de los casos se encuentra limitada por la capacidad de las sub- estaciones eléctricas. Even when the dimensions of the equipment can be adjusted for its transfer to the interior of the mine, the power available in many cases is limited by the capacity of the electrical substations.
Del mismo modo, junto a las altas presiones que deben alcanzar los equipos para el quiebre del macizo rocoso (inicio de la fractura), para su propagación, se debe mantener una condición de lato flujo de agua y alta presión. In the same way, together with the high pressures that the equipment must reach to break the rock mass (initiation of the fracture), for its propagation, a condition of high water flow and high pressure must be maintained.
Las variables que participan en el proceso de fracturamiento hidráulico se dividen en 2 categorías: variable mecánicas y variables del macizo rocoso: The variables that participate in the hydraulic fracturing process are divided into 2 categories: mechanical variables and rock mass variables:
- Las variables mecánicas están relacionadas directamente con las características y elementos del equipo de fracturamiento hidráulico. Estas son de especial interés para efectos de la invención, dado que son los parámetros directamente relacionados con las características del equipo, y que estas son claves en el éxito de la generación de la fractura: Presiones: ya sea de inflado de los obturadores mecánicos o tapones (“packers”) en la perforación y de fractura de la roca. - The mechanical variables are directly related to the characteristics and elements of the hydraulic fracturing equipment. These are of special interest for purposes of the invention, since they are the parameters directly related to the characteristics of the equipment, and that these are key to the success of generating the fracture: Pressures: either due to inflation of mechanical plugs or plugs (“packers”) in drilling and rock fracture.
Caudales: Para la propagación de la fractura en la roca. Flows: For the propagation of the fracture in the rock.
Tiempo de inyección. injection time.
Calidad del agua. Water quality.
Potencia eléctrica Disponible v/s Requerida. Electrical power Available vs. Required.
Estas variables tienen un objetivo en particular en el fracturamiento hidráulico, el cual es generar un radio de fractura, que permita cambiar favorablemente la condición de esfuerzo, para lograr la granimetría y mitigar el riesgo de estallido de roca. These variables have a particular objective in hydraulic fracturing, which is to generate a fracture radius, which allows the stress condition to be favorably changed, to achieve granimetry and mitigate the risk of rock burst.
- Las variables del macizo rocoso tienen relación con los parámetros geomecánicos, geológicos y litológicos de la roca, los cuales se pueden agrupar según: - The variables of the rock mass are related to the geomechanical, geological and lithological parameters of the rock, which can be grouped according to:
Factores intrínsecos: que dependen de la naturaleza de la roca como el tipo (Andesita, calcita, etc.); su mineralización principal (Cuarzo, Anhidrita, Feldespato, Clorita, Calcopirita, Pirita, etc.); propiedades de la roca tales como Cohesión, Tenacidad, módulo de Young, relación de Poisson. Intrinsic factors: that depend on the nature of the rock such as the type (Andesite, calcite, etc.); its main mineralization (Quartz, Anhydrite, Feldspar, Chlorite, Chalcopyrite, Pyrite, etc.); rock properties such as Cohesion, Toughness, Young's modulus, Poisson's ratio.
Factores extrínsecos: que dependen del comportamiento de la roca en función a factores externos tales como: Esfuerzos Confinantes (Su comportamiento es distinto dependiendo si la roca si está confinada o no). La presión de la columna hidrostática la cual se incrementa en la medida del emplazamiento del cuerpo en profundidad. Extrinsic factors: that depend on the behavior of the rock based on external factors such as: Confining Efforts (Their behavior is different depending on whether the rock is confined or not). The pressure of the hydrostatic column which increases with the location of the body in depth.
Una fractura hidráulica se propagará en un medio, siempre y cuando el sistema pueda mantener una presión y un caudal constante, dentro de la abertura que se haya generado en roca. En primer lugar, de los estudios de modelamiento del proceso y verificaciones empíricas, por su relación con esta invención, se puede indicar que: A hydraulic fracture will propagate in a medium, as long as the system can maintain a constant pressure and flow, within the opening that has been generated in the rock. In the first place, from the modeling studies of the process and empirical verifications, due to its relationship with this invention, it can be indicated that:
La presión de propagación de una fractura es proporcional al volumen de fluido utilizado; The propagation pressure of a fracture is proportional to the volume of fluid used;
La longitud de la fractura (o radio) es función del tiempo de bombeo; y Fracture length (or radius) is a function of pumping time; Y
La energía necesaria para extender la fractura debe ser igual al trabajo realizado por la presión dentro de la fractura, para abrir un ancho adicional determinado. Entonces, la velocidad del fluido (o caudal inyectado), permitirá aumentar el radio de fractura durante un tiempo hasta que se equilibran los esfuerzos (Potencia del equipo v/s efecto del macizo rocoso). The energy required to extend the fracture must be equal to the work done by the pressure within the fracture to open a given additional width. Then, the speed of the fluid (or injected flow), will allow the fracture radius to increase for a while until the efforts are balanced (power of the equipment vs. effect of the rock mass).
Luego de la fractura inicial (el quiebre del macizo), en los primeros minutos de inyección, el radio de fractura se incrementa rápidamente para luego ir aumentando mientras se propaga, hasta un punto tal que la curva de propagación se comporta de manera asintótica. En este momento, los esfuerzos se equilibran y se detiene el proceso de propagación. After the initial fracture (the break of the massif), in the first minutes of injection, the fracture radius increases rapidly and then increases as it propagates, to a point such that the propagation curve behaves asymptotically. At this time, the efforts are balanced and the propagation process stops.
El radio de influencia de una fractura hidráulica también está condicionado por los parámetros geomecánicos, geológicos y litológicos del sector o sección del macizo rocoso. Se ha verificado que, mientras más desfavorable es la condición del macizo rocoso, más esfuerzo requerirá el equipo para propagar una fractura hidráulica. The radius of influence of a hydraulic fracture is also conditioned by the geomechanical, geological and lithological parameters of the sector or section of the rock mass. It has been verified that the more unfavorable the rock mass condition, the more effort the equipment will require to propagate a hydraulic fracture.
El proceso de fracturamiento de un macizo rocoso a medianas y altas profundidades de la presente de la presente invención y en forma muy resumida contempla: una bomba de alta presión que entregue el caudal de agua para el llenado de la columna de hidrofacturar, a una presión en un valor de 35 a 80 mega Pascales; y elementos para conducir el agua a presión al interior del pozo, hasta un dispositivo que se introduce en el nivel de fracturamiento. Este dispositivo tiene como función principal el confinamiento o sellado del punto de ingreso del agua de fractura. The fracturing process of a rock mass at medium and high depths of the present invention and in a very summarized form contemplates: a high pressure pump that delivers the flow of water for filling the hydrofacture column, at a pressure in a value of 35 to 80 mega Pascals; and elements to drive pressurized water into the well, to a device that is introduced at the fracturing level. The main function of this device is the confinement or sealing of the point of entry of the fracture water.
Para lo indicado, en los extremos de la herramienta se encuentran dispuestos los elementos expansibles, denominados “packers” los que, al llenarse con agua y por efecto del aumento de la presión interna, se inflan radialmente, generando así el sello contra la superficie interna del sondaje. Aquí es importante destacar que se requiere dos flujos de agua independientes, de diferentes caudales y presiones. La presión de los “packers” debe alcanzar un mayor valor que la de fractura. Una vez sellado el punto de la hidro-fractura, se inicia el fracturamiento hidráulico, manteniendo siempre un diferencial de presión entre la de inflado de los “packers” y la de fractura. La presión de los “packers” debe ser mayor para evitar la pérdida del sello y accidentes por desplazamientos bruscos del conjunto. For what is indicated, the expandable elements, called "packers" are arranged at the ends of the tool, which, when filled with water and due to the effect of the increase in internal pressure, inflate radially, thus generating the seal against the internal surface. of the probing. Here it is important to note that two independent water flows are required, with different flow rates and pressures. The pressure of the "packers" must reach a higher value than the fracture. Once the hydro-fracturing point is sealed, hydraulic fracturing begins, always maintaining a pressure differential between the packer inflation pressure and the fracture pressure. The pressure of the "packers" must be greater to avoid loss of the seal and accidents due to sudden displacement of the assembly.
Las rocas que se comportan elásticamente frente a un esfuerzo de una determinada intensidad pueden deformarse plásticamente, o incluso fracturarse, si dicho esfuerzo actúa durante un periodo de tiempo suficiente. Si la velocidad de deformación es alta, el tiempo será breve y la roca responderá con rigidez; si la deformación se desarrolla a una velocidad lenta y durante más tiempo responderá más plásticamente. Rocks that behave elastically against a stress of a certain intensity can deform plastically, or even fracture, if the stress acts for a sufficient period of time. If the strain rate is high, the time will be short and the rock will respond with stiffness; if the deformation takes place at a slow rate and for a longer time it will respond more plastically.
Por otro lado, el punto donde las rocas podrían fracturarse más fácilmente es cerca de la superficie, puesto que a grandes profundidades se comportan más plásticamente, por lo que se facilita la deformación dúctil. On the other hand, the point where the rocks could fracture more easily is near the surface, since at great depths they behave more plastically, thus facilitating ductile deformation.
Con lo anterior en la presente se tienen las siguientes consideraciones: With the foregoing, the following considerations are taken into account:
Utilizar una bomba de bajo caudal y alta presión en la primera etapa que asegure el quiebre del macizo. Use a low-flow, high-pressure pump in the first stage to ensure the breakage of the solid.
Utilizar una segunda, tercera o más bomba con mayor caudal y menor presión, pero de nivel suficiente para mantener la propagación de la fractura. Use a second, third or more pump with a higher flow rate and lower pressure, but with a sufficient level to maintain the propagation of the fracture.
Se incorpora una modalidad dinámica en el inflado de “packers”. Esta consiste en inflar los “packers” a una menor presión de tal forma que cuando comienza el flujo de fractura, genera un aumento de la presión del “packers” hasta la presión de trabajo. A dynamic modality is incorporated in the inflation of "packers". This consists of inflating the "packers" to a lower pressure in such a way that when the fracture flow begins, it generates an increase in the pressure of the "packers" up to the working pressure.
En la presente invención, la puesta en operación en forma sucesiva de las bombas, permite atenuar la caída en la velocidad de propagación; El uso de más bombas que aporten el flujo de propagación permite alcanzar un caudal total mayor y por lo tanto un mayor radio de fractura; La configuración de equipos permite generar una mayor presión neta, incrementando el ancho de la fractura al inicio; Se asegura el fracturamiento, evitando que queden pilares en la formación; el fracturamiento se logra con una menor necesidad de potencia eléctrica; se permite alcanzar un caudal de propagación mayor, generado en etapas sucesivas, de tal forma que la energía necesaria resulta menor; y el uso de la modalidad dinámica en el inflado de “packers” permite obtener una mayor duración de estos elementos, lográndose una mejor eficiencia operacional. In the present invention, the successive start-up of the pumps makes it possible to attenuate the drop in the propagation velocity; The use of more pumps that provide the propagation flow allows a greater total flow to be achieved and therefore a greater fracture radius; The equipment configuration allows to generate a higher net pressure, increasing the width of the fracture at the beginning; Fracturing is ensured, preventing pillars from remaining in the training; fracturing is achieved with less need for electrical power; it is possible to reach a higher propagation rate, generated in successive stages, in such a way that the necessary energy is lower; and the use of the dynamic modality in the inflation of "packers" allows to obtain a greater duration of these elements, achieving a better operational efficiency.
Finalmente, esta opción de inflado de “packers” influido por la presión de fractura, es el antes denominado “Modo Dinámico”, que resulta en una menor presión de operación de estos. Finally, this packer inflation option influenced by the fracture pressure, is the previously called "Dynamic Mode", which results in a lower operating pressure of these.
De lo visto anteriormente, es posible identificar los parámetros de diseño para el proceso de fracturamiento hidráulico multietapa. Para ello se tienen las siguientes consideraciones: From the above, it is possible to identify the design parameters for the multistage hydraulic fracturing process. For this, the following considerations are taken:
El sistema multietapa de la presente consiste en 2 o más bombas que operan en forma paralela y secuencial, de tal forma que sus caudales se pueden sumar sincronizadamente. Para ello se configura el momento en que cada bomba parte de acuerdo con el diseño del proceso de fracturamiento, entonces: The multistage system of the present consists of 2 or more pumps that operate in parallel and sequentially, in such a way that their flow rates can be added synchronously. For this, the moment in which each pump starts is configured according to the design of the fracturing process, then:
Una primera bomba se ajusta la rampa de presión y caudal para asegurar el quiebre del macizo rocoso. La presión dependerá de la tenacidad del sector en particular. A first pump adjusts the pressure and flow ramp to ensure the breaking of the rock mass. The pressure will depend on the tenacity of the particular sector.
Una segunda bomba inicia su operación al momento del quiebre, para sumar su caudal y mantener el proceso de propagación A second pump starts its operation at the moment of the break, to add its flow and maintain the propagation process.
Como la velocidad disminuye al aumentar el radio, la tercera y siguientes bombas entran en operación de tal forma de mantener la velocidad de propagación. De esta forma, su rol está relacionado con el radio de diseño de la fractura. As the speed decreases with increasing radius, the third and subsequent pumps come into operation in order to maintain the propagation speed. In this way, its role is related to the design radius of the fracture.
En una modalidad de la presente se define un dispositivo de fracturamiento que incluye: una herramienta de fracturamiento a insertar en el macizo rocoso, que comprende una manguera de presión conectada en un cabezal de perforación conectado a una herramienta que tiene los “packers”, barras de perforación estándar, un cabezal inyector, una bomba de inflado de “packers” y una conexión a una manguera de agua de fracturamiento. In one embodiment hereof, a fracturing device is defined that includes: a fracturing tool to be inserted into the rock mass, comprising a pressure hose connected to a drilling head connected to a tool having packers, rods drilling standard, an injector head, a packer inflation pump and a connection to a fracturing water hose.
El agua para la fractura se dispone en un estanque, desde el cual en primer lugar mediante una bomba de cebado se realiza el cebado de la bomba de inflado de “packers”. La presión del flujo de agua se maneja con válvulas limitadoras de presión y otra reguladora de presión de “packers”. También se cuenta con un indicador de la presión de inflado aplicada. The water for fracturing is placed in a tank, from which the packer inflation pump is first primed by means of a priming pump. The pressure of the water flow is managed with pressure limiting valves and another "packers" pressure regulator. There is also an indicator of the applied inflation pressure.
Una vez alcanzada la presión de inflado de los “packers”, se logra el anclaje de la herramienta contra la pared del macizo rocoso. A continuación, se activa el circuito de agua de fracturamiento, para ello, mediante la bomba se efectúa el cebado de la bomba de alta presión para fracturamiento, las presiones se manejan con dos válvulas, una limitadora de presión, dispuestas para no exceder la presión máxima de trabajo y otra válvula moduladora para la presión de fracturamiento. También se cuenta con un indicador de la presión aplicada. El flujo de agua de fracturamiento ingresa a través de la cabeza inyectora. Once the packer inflation pressure is reached, the tool is anchored against the rock mass wall. Next, the fracturing water circuit is activated, for this, the high pressure pump for fracturing is primed by means of the pump, the pressures are managed with two valves, a pressure limiter, arranged so as not to exceed the pressure maximum working pressure and another modulating valve for fracturing pressure. There is also an indicator of the applied pressure. The fracturing water flow enters through the injection head.
Respecto de un sistema monoetapa en el sistema multietapa se incluyen además dos a más bombas que operan en paralelo de tal forma que sus caudales se pueden sumar. Regarding a single-stage system, the multi-stage system also includes two or more pumps that operate in parallel in such a way that their flows can be added.
En otra modalidad de la invención se define un proceso de fracturamiento que incluye: a Inicio de inyección de agua con primera bomba. Se llena el circuito y la presión empieza a aumentar al detenerse el flujo. b Luego de llenado el circuito hidráulico, la presión sube y alcanza la presión de quiebre. En ese momento se inicia la inyección por la segunda bomba. El incremento de caudal evita la característica caída en la presión observada en FFHH en una etapa. c Se mantiene estable la lectura de presión en la superficie brevemente. Entonces, el macizo ofrece resistencia a la propagación, pero el caudal aportado por la segunda bomba aumenta la presión del sistema hasta iniciar un nuevo ciclo de propagación. d Se reduce la velocidad de propagación de la etapa (c). Aquí entra en operación la tercera bomba. e Se mantiene estable la lectura de presión en la superficie brevemente. Entonces, el macizo nuevamente ofrece resistencia a la propagación, pero el caudal aportado por la tercera bomba aumenta la presión del sistema hasta iniciar el último ciclo de propagación. Si fuera necesario, se puede incorporar ciclos adicionales sucesivos de bombas para alcanzar los caudales requeridos para el diseño de la propagación. f La presión alcanza un máximo por el efecto del caudal total aportado con las tres bombas. g El sistema se equilibra con el caudal estabilizado y la presión cae, de forma similar al proceso en una etapa, alcanzando la presión de propagación final. h Aumento del radio de la fractura (aumenta el volumen) y baja la velocidad de propagación. La presión del sistema no es capaz de vencer la resistencia del macizo y el caudal se detiene. Entonces se detiene el bombeo y se mide la presión de cierre instantáneo (ISIP Test). In another embodiment of the invention, a fracturing process is defined that includes: a Start of water injection with the first pump. The circuit is filled and the pressure begins to increase when the flow stops. b After filling the hydraulic circuit, the pressure rises and reaches the breaking pressure. At that moment the injection by the second pump starts. The increased flow avoids the characteristic drop in pressure observed in FFHH in one stage. c The surface pressure reading is briefly stable. Then, the massif offers resistance to propagation, but the flow provided by the second pump increases the pressure of the system until a new propagation cycle begins. d The propagation speed of step (c) is reduced. Here comes into operation the third pump. e The surface pressure reading is briefly stable. Then, the solid again offers resistance to propagation, but the flow provided by the third pump increases the pressure of the system until the last propagation cycle begins. If necessary, additional successive pump cycles can be incorporated to achieve the flow rates required for the propagation design. f The pressure reaches a maximum due to the effect of the total flow supplied with the three pumps. g The system equilibrates with the stabilized flow rate and the pressure drops, similar to the one-stage process, reaching the final propagation pressure. h Increasing the radius of the fracture (increases the volume) and lowers the speed of propagation. The system pressure is not able to overcome the massif resistance and the flow stops. Pumping is then stopped and the instantaneous closing pressure is measured (ISIP Test).
Otras áreas de aplicabi lidad de la presente invención resultarán evidentes a partir de la descripción detallada proporcionada a continuación. Se debe entender que la descripción detallada y los ejemplos específicos, aunque indican las modalidades preferidas de la invención, están destinadas únicamente a fines ilustrativos y no están destinadas a limitar el alcance de la invención. Other areas of applicability of the present invention will become apparent from the detailed description provided below. It is to be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for illustrative purposes only and are not intended to limit the scope of the invention.
Breve Descripción de las Figuras Brief Description of the Figures
La presente invención se entenderá más completamente a partir de la descripción detallada y las figuras que se acompaña, que no se encuentran necesariamente a escala, en las cuales: The present invention will be more fully understood from the detailed description and accompanying figures, which are not necessarily to scale, in which:
La Figura 1 muestra un isométñco de cómo se realiza el método de explotación por hundimiento. La Figura 2 muestra un diagrama de operación de un equipamiento para fracturamiento hidráulico por metodología multietapa dinámica en macizo rocoso a mediana y alta profundidad. Figure 1 shows an isometric view of how the sinking exploitation method is carried out. Figure 2 shows an operation diagram of an equipment for hydraulic fracturing by dynamic multistage methodology in rock mass at medium and high depth.
La Figura 3 muestra el sistema de “packers” en la formación, en la situación inicial sin inflado. Figure 3 shows the packer system in formation, in the initial situation without inflation.
La Figura 4 muestra el sistema de “packers” en la formación y en estado de presurizado inicial de “packers”. Figure 4 shows the "packers" system in the formation and in the initial pressurized state of "packers".
La Figura 5 muestra el sistema en la formación, en estado de fracturamiento. Figure 5 shows the system in the formation, in a fractured state.
La Figura 6 muestra un equipamiento para fracturamiento hidráulico por metodología multietapa dinámica. Figure 6 shows an equipment for hydraulic fracturing by dynamic multistage methodology.
La Figura 7 muestra un diagrama de operación de un sistema completo mono- etapa. Figure 7 shows an operation diagram of a complete single-stage system.
Descripción de las Modalidades Preferidas Description of Preferred Modalities
La siguiente descripción de las modalidades de la presente invención es simplemente de naturaleza ejemplar y de ninguna manera pretende limitar la invención, su aplicación o usos. La presente invención tiene una amplia aplicación potencial y utilidad, que es considerado adaptable en una amplia gama de industrias. La siguiente descripción es proporcionada aquí únicamente a modo de ejemplo con el fin de proporcionar una descripción habilitante de la invención, pero no limita el alcance o la substancia de la invención. The following description of the embodiments of the present invention is merely exemplary in nature and is not intended to limit the invention, its application or uses in any way. The present invention has wide potential application and utility, which is considered adaptable in a wide range of industries. The following description is provided herein by way of example only for the purpose of providing an enabling description of the invention, but does not limit the scope or substance of the invention.
En la figura 2 se muestra una modalidad típica de la invención multi-etapa que, aunque no limitante, se caracteriza en tres etapas. En primer lugar, se ensambla la herramienta de fracturamiento a insertar en el macizo rocoso, para lo cual se conecta un extremo de la manguera de presión 24 en un cabezal de perforación 27. Luego este cabezal se conecta el flujo de agua de inflado mediante rosca a una herramienta 28 que tiene los “packers” 29, se conecta la primera barra del tren de perforación. Se introduce el conjunto en el pozo y se arma en forma sucesiva barras de perforación estándar 25, hasta lograr la profundidad requerida desde el nivel de la galería 20. Luego se fija el cabezal inyector 21 a la última barra de perforación. Una vez aplicado el torque necesario, se fija el acoplamiento de conexión 24 en un hilo cónico de la boquilla del cabezal inyector 21 , aplicando el torque necesario. Luego, por el lado exterior se conecta la manguera 22 que viene de la bomba de inflado de “packers” 3, en el acoplamiento de conexión 24. Igualmente, se conecta la manguera de agua de fracturamiento 23 en el cabezal 6 y ésta en el hilo cónico de la boquilla del cabezal 21 . De esta forma, el conjunto está armado y conectado al suministro de agua, en condiciones de iniciar el proceso de fractura. Figure 2 shows a typical embodiment of the multi-stage invention which, although not limiting, is characterized in three stages. First of all, the fracturing tool to be inserted into the rock mass is assembled, for which one end of the pressure hose 24 is connected to a drilling head 27. Then this head is connected to the flow of inflation water by thread a a tool 28 that has the "packers" 29, is connected to the first rod of the drill string. The assembly is introduced into the well and standard drilling rods 25 are successively assembled, until the required depth is achieved from the level of the gallery 20. Then the injector head 21 is fixed to the last drilling rod. Once the necessary torque has been applied, the connection coupling 24 is fixed on a conical thread of the nozzle of the injector head 21, applying the necessary torque. Then, on the outside, the hose 22 that comes from the packer inflation pump 3 is connected to the connection coupling 24. Similarly, the fracturing water hose 23 is connected to the head 6 and this to the head nozzle conical thread 21 . In this way, the assembly is assembled and connected to the water supply, ready to start the fracturing process.
Para iniciar el proceso, al igual que para el sistema monetapa que aparece ¡lustrado en la figura 7 con los mismos números de referencia, en un sistema multietapa, específicamente para este caso de tres etapas, en una primera etapa, el agua para la fractura se dispone en un estanque 1 , desde el cual en primer lugar mediante la bomba 2 se efectúa el cebado de la bomba de inflado de “packers” 3. La presión del flujo de agua se maneja con dos válvulas, una limitadora de presión 4, para no exceder la presión máxima de trabajo, otra reguladora de presión de “packers” 5. También se cuenta con un indicador de la presión de inflado aplicada 6. El flujo de agua de inflado ingresa a través de la cabeza inyectara 21 , en conectar 24. Los “packers” 29, que se inflan con el aumento de presión. To start the process, as for the single-stage system that appears illustrated in figure 7 with the same reference numbers, in a multi-stage system, specifically for this three-stage case, in a first stage, the water for the fracture It is arranged in a tank 1, from which firstly, by means of pump 2, the priming of the "packers" inflation pump 3 is carried out. The pressure of the water flow is managed with two valves, a pressure limiter 4, in order not to exceed the maximum working pressure, another “packers” pressure regulator 5. There is also an indicator of the applied inflation pressure 6. The flow of inflation water enters through the injection head 21, in connecting 24. The “packers” 29, which inflate with the increase in pressure.
Una vez alcanzada la presión de inflado de los “packers”, se logra el anclaje de la herramienta contra la pared del macizo rocoso 30. A continuación, se activa el circuito de agua de fracturamiento, para ello, mediante la bomba 7 se efectúa el cebado de la bomba de alta presión para fracturamiento 8A, Las presiones se manejan con dos válvulas, una válvula limitadora de presión 9A, dispuesta para no exceder la presión máxima de trabajo y otra válvula moduladora 1 1 para la presión de fracturamiento. También se cuenta con un indicador de la presión aplicada 12. El flujo de agua de fracturamiento ingresa a través de la cabeza inyectara 21 . En función de la competencia de la roca a fracturar, se aumenta la presión hasta lograr la fractura, punto en el cual se detecta una disminución de la presión al generarse el flujo de agua en la fractura 30. Esta presión debe ser siempre menor a la de inflado (interna) de los “packers” 29. Once the packer inflation pressure is reached, the tool is anchored against the wall of the rock mass 30. Next, the fracturing water circuit is activated, to do this, by means of pump 7, the priming of the high pressure pump for fracturing 8A. Pressures are managed with two valves, a pressure limiting valve 9A, arranged so as not to exceed the maximum working pressure, and another modulating valve 1 1 for fracturing pressure. There is also an indicator of the applied pressure 12. The flow of fracturing water enters through the injection head 21 . Depending on the competence of the rock to be fractured, the pressure is increased until fracture is achieved, at which point a decrease in pressure is detected. the pressure when the water flow is generated in the fracture 30. This pressure must always be less than the inflation (internal) pressure of the “packers” 29.
Como se observa respecto de un sistema monoetapa en el sistema multietapa se incluyen de dos a más bombas 8A, 8B y hasta 8N que operan en paralelo, y en forma secuencial y con los mismos medios que la bomba de la etapa 1 o para un sistema monoetapa, pero de tal forma que sus caudales se pueden sumar. Para ello se configura el momento en que cada bomba parte de acuerdo con el diseño del proceso de fracturamiento. Para ello la segunda bomba 8B se ajusta para asegurar la propagación del quiebre del macizo rocoso. La presión dependerá de la tenacidad del sector en particular. La tercera bomba 8c inicia su operación antes que caiga la velocidad de propagación del quiebre, para sumar su caudal y continuar el proceso de propagación. Como la velocidad disminuye al aumentar el radio, la tercera y siguiente bombas entran en operación de tal forma de mantener la velocidad de propagación. De esta forma, su rol está relacionado con el radio de la fractura diseñado. Se utiliza una bomba 8A de bajo caudal y alta presión en la primera etapa que asegure el quiebre del macizo y se utiliza una segundas y tercera bombas 8B, 8C con mayor caudal y menor presión, pero de nivel suficiente para mantener la propagación de la fractura. As observed with respect to a single-stage system, the multi-stage system includes two or more pumps 8A, 8B and up to 8N that operate in parallel, and sequentially and with the same means as the pump of stage 1 or for a system single-stage, but in such a way that their flows can be added. For this, the moment in which each pump starts is configured according to the design of the fracturing process. For this, the second pump 8B is adjusted to ensure the propagation of the rock mass break. The pressure will depend on the tenacity of the particular sector. The third pump 8c starts its operation before the break propagation speed falls, to add its flow and continue the propagation process. Since the speed decreases with increasing radius, the third and following pumps come into operation in order to maintain the propagation speed. Thus, its role is related to the designed fracture radius. An 8A low-flow, high-pressure pump is used in the first stage to ensure the breakage of the solid, and a second and third 8B, 8C pumps are used with higher flow and lower pressure, but with a sufficient level to maintain the propagation of the fracture. .
Se incorpora modalidad dinámica en el inflado de “packers” 29. Esta consiste en inflar los “packers” 29 a una menor presión de tal forma que cuando comienza el flujo de fractura, por principio de reacción, el agua se comprime y genera un aumento de la presión desde la sección sellada hasta la pared del “packers” 29, lo que aumenta su presión interna, hasta la presión de trabajo. Dynamic mode is incorporated in the inflation of "packers" 29. This consists of inflating the "packers" 29 at a lower pressure in such a way that when the fracture flow begins, by reaction principle, the water is compressed and generates an increase pressure from the sealed section to the wall of the "packers" 29, which increases its internal pressure, up to the working pressure.
Una vez fracturado se debe despresurizar el circuito de fractura 23, para lo cual se libera la presión mediante la válvula 13, que permite el drenaje del circuito. Luego de la despresuñzación del circuito de fractura, mediante la válvula 5 se despresuriza la línea de circuito de “packers”. Entonces se puede detener el procedimiento, procediendo al desarme o se reubica el “packer” 29 en un nuevo nivel de la perforación, reiniciando nuevamente el proceso de fractura en una nueva posición. La puesta en operación en forma sucesiva de las bombas 8A, 8B hasta 8N permite atenuar la caída en la velocidad de propagación, El uso de más bombas que aporten el flujo de propagación permite alcanzar un caudal total mayor y un mayor radio de fractura. Once fractured, the fracture circuit 23 must be depressurized, for which the pressure is released through the valve 13, which allows the circuit to drain. After depressurization of the fracturing circuit, the packers circuit line is depressurized through valve 5. Then the procedure can be stopped, proceeding to disarm or the "packer" 29 is relocated to a new level of the perforation, restarting the fracture process again in a new position. The successive start-up of the pumps 8A, 8B up to 8N allows to attenuate the drop in the propagation speed. The use of more pumps that contribute the propagation flow allows to achieve a higher total flow rate and a larger fracture radius.
La configuración de equipos anterior permite generar y mantener una mayor presión neta, incrementando el ancho de la fractura en su punto de inicio o generación. The above equipment configuration allows generating and maintaining a higher net pressure, increasing the width of the fracture at its starting or generation point.
En la figura 3 se muestra el sistema de “packers” en la formación. En la situación inicial, siendo Qp el caudal de agua para inflado del “packers”, este se encuentra sin inflar con una presión de “packers” P1 igual a cero, el caudal de fractura es Qf es igual a cero y la presión P2 de fracturamiento y presión de inflado final de “packers” P3 son ¡guales a cero. Figure 3 shows the system of "packers" in training. In the initial situation, where Qp is the water flow rate for inflating the packers, this is found without inflating with a packers pressure P1 equal to zero, the fracture flow rate is Qf equals zero and the pressure P2 of fracturing and final inflation pressure of packers P3 are equal to zero.
En la figura 4 se muestra el sistema en la formación y en estado de presuhzado inicial de “packers”, donde la presión de “packers” P1 es igual a la presión de trabajo inicial PPO, y el caudal de fractura es cero y la presión P2 de fracturamiento es igual a cero. Figure 4 shows the system in the formation and in the initial pressurized state of "packers", where the pressure of "packers" P1 is equal to the initial working pressure PPO, and the fracture flow is zero and the pressure Fracture P2 equals zero.
La presión de “packers” P1 alcanzará la presión de trabajo PP al ocurrir el ingreso de agua de fractura y ejercer una presión adicional en la cara interna del “packer”. The packer pressure P1 will reach the working pressure PP when the fracture water enters and exerts additional pressure on the internal face of the packer.
En la figura 5 se muestra el sistema en la formación, en estado de fracturamiento. El caudal de inflado a “packers” Qp es igual a cero. El caudal de fracturamiento QF ingresa al pozo, generando un incremento de la presión de fracturamiento P2, a medida que aumenta y se acerca a la de fractura. De este modo, esta presión incrementa la presión de “packers” P1 = PP > PPO. Figure 5 shows the system in the formation, in a state of fracturing. The inflation flow to "packers" Qp is equal to zero. The fracturing flow QF enters the well, generating an increase in the fracturing pressure P2, as it increases and approaches the fracturing pressure. In this way, this pressure increases the packers pressure P1 = PP > PPO.
De esta forma, se logra operar con una presión de “packers” adecuada, a la vez que se efectúa el sello. In this way, it is possible to operate with an adequate packer pressure, while the seal is made.
En la figura 6 se ¡lustra un dispositivo o maquinaria de fracturamiento para la modalidad multietapa de la presente, destacándose la definición de tres bombas 8A, 8B y 8C. A fracturing device or machinery for the present multistage mode is illustrated in Figure 6, highlighting the definition of three pumps 8A, 8B and 8C.
Por lo tanto, los expertos en la materia entenderán fácilmente que la presente invención es susceptible de una amplia utilidad y aplicación. Muchas modalidades y adaptaciones de la presente invención distintas de las aquí descritas, así como muchas variaciones, modificaciones y disposiciones equivalentes, serán evidentes o razonablemente sugeridas por la presente invención y la descripción anterior de la misma, sin alejarse de lo substancial o alcance de la presente invención. Por consiguiente, aunque la presente invención ha sido aquí descrita en detalle en relación con su modalidad típica o preferida, se debe entender que esta descripción es solo ilustrativa y ejemplar de la presente invención y es realizada simplemente con el propósito de proporcionar una descripción completa y habilitante de la invención. La descripción anterior no pretende ni debe ser interpretada para limitar la presente invención o para excluir cualquier otra modalidad, adaptaciones, variaciones, modificaciones y disposiciones equivalentes. Therefore, those skilled in the art will readily understand that the present invention is capable of wide utility and application. Many modalities and adaptations of the present invention other than those described herein, as well as many variations, modifications and equivalent arrangements, will be evident or reasonably suggested by the present invention and the previous description of the same, without departing from the substance or scope of the present invention. Accordingly, although the present invention has been described herein in detail in connection with its typical or preferred embodiment, it is to be understood that this description is illustrative and exemplary only of the present invention and is made merely for the purpose of providing a complete description and enabler of the invention. The foregoing description is not intended and should not be construed to limit the present invention or to exclude any other embodiments, adaptations, variations, modifications, and equivalent arrangements.

Claims

PLIEGO DE REIVINDICACIONES Un sistema de fracturamiento hidráulico por metodología multietapa dinámica en macizo rocoso a mediana y alta profundidad, generando un caudal de propagación en etapas sucesivas que permite asegurar el fracturamiento, con una menor necesidad de potencia eléctrica, alcanzando un caudal total mayor y un mayor radio de fractura, por lo tanto, lográndose una mejor eficiencia operacional, que incluye: una herramienta de fracturamiento a insertar en el macizo rocoso, que comprende una manguera de presión conectada en un cabezal de perforación conectado a una herramienta que tiene los tapones o “packers”, barras de perforación estándar, un cabezal inyector de agua, una bomba de inflado de “packers”, una conexión a una manguera de agua de fracturamiento, medios para una primera etapa de fraccionamiento que comprenden una primera bomba de impulso de agua de fracturamiento, un circuito de agua de fracturamiento, con a lo menos una válvula limitadora de presión, dispuesta para no exceder la presión máxima de trabajo y a lo menos una válvula moduladora para la presión de fracturamiento, CARACTERIZADO porque además comprende: Que la primera bomba de impulso de agua de fracturamiento conectada al cabezal inyector de agua es de bajo caudal y alta presión para la primera etapa de fracturamiento que asegure el quiebre del macizo rocoso; ySPECIFICATION OF CLAIMS A hydraulic fracturing system by dynamic multistage methodology in rock mass at medium and high depth, generating a propagation flow in successive stages that allows fracturing to be ensured, with a lower need for electrical power, reaching a greater total flow and a larger fracture radius, thus achieving better operational efficiency, including: a fracturing tool to be inserted into the rock mass, comprising a pressure hose connected to a drill head connected to a tool having the plugs or packers, standard drill rods, a water injection head, a packer inflation pump, a connection to a fracturing water hose, means for a first fractionating stage comprising a first water booster pump fracturing system, a fracturing water circuit, with at least one pressure limiting valve, ta so as not to exceed the maximum working pressure and at least one modulating valve for the fracturing pressure, CHARACTERIZED because it also includes: That the first fracturing water impulse pump connected to the water injection head is of low flow and high pressure for the first stage of fracturing that ensures the breakage of the rock mass; Y
A lo menos una segunda y tercera bomba de mayor caudal y menor presión que la primera bomba, conectadas al cabezal inyector de agua, para mantener la propagación de la fractura hidráulica. El sistema de fracturamiento hidráulico por metodología multietapa dinámica, según la reivindicación 1 , CARACTERIZADO porque las bombas se disponen en paralelo, de tal forma que sus caudales se pueden sumar. Sistema de fracturamiento hidráulico por metodología multietapa dinámica, según la reivindicación 2, CARACTERIZADO porque la primera bomba, que asegura el quiebre del macizo rocoso, genera una presión determinada por la tenacidad del sector en particular, y la segunda y tercera bombas inician su operación al momento del quiebre, para sumar su caudal e iniciar el proceso de propagación. Sistema de fracturamiento hidráulico por metodología multietapa dinámica, según la reivindicación 1 , CARACTERIZADO porque la bomba de inflado se conecta al cabezal para permitir el inflado de los “packers”. Sistema de fracturamiento hidráulico por metodología multietapa dinámica, según la reivindicación 1 , CARACTERIZADO porque las bombas se conectan al cabezal, para proporcionar el agua para el proceso de fractura. Sistema de fracturamiento hidráulico por metodología multietapa dinámica, según la reivindicación 1 , CARACTERIZADO porque dos válvulas permiten controlar la presión del flujo de agua, una para no exceder la presión máxima de trabajo, y la otra para regular la presión de los “packers”. Un procedimiento de fracturamiento hidráulico por metodología multietapa dinámica en macizo rocoso a mediana y alta profundidad, que permite asegurar el fracturamiento, evitando que queden pilares en la formación, una menor necesidad de potencia eléctrica, generar un caudal de propagación en etapas sucesivas, una mayor duración de “packers”, por lo tanto, lográndose una mejor eficiencia operacional, que utiliza el sistema de la reivindicación 1 , CARACTERIZADO porque utiliza las siguientes etapas: a. inyectar agua con una primera bomba, de bajo caudal y alta presión, llenando el circuito y aumentando la presión hasta alcanzar la presión de quiebre; b. inyectar agua con una segunda bomba, de alto caudal y baja presión, en donde, el incremento de caudal evita la característica caída en la presión; c. mantener estable, por un breve periodo de tiempo, la lectura de presión en la superficie, ofreciendo el macizo una resistencia a la propagación, 17 pero, el caudal aportado por la segunda bomba aumenta la presión del sistema hasta iniciar un nuevo ciclo de propagación, pero a velocidad reducida; d. inyectar agua con una tercera o más bombas, de alto caudal y baja presión; e. mantener estable, por un breve periodo de tiempo, la lectura de presión en la superficie, ofreciendo el macizo nuevamente una resistencia a la propagación, pero el caudal aportado por la tercera bomba aumenta la presión del sistema, alcanzando un máximo por el efecto del caudal total aportado con las tres o más bombas, iniciando el último ciclo de propagación; f. alcanzar la presión de propagación final, en donde el sistema se equilibra con el caudal estabilizado y la presión cae, g. Aumento del radio de la fractura (aumenta el volumen) y baja la velocidad de propagación, en donde la presión del sistema no es capaz de vencer la resistencia del macizo y el caudal se detiene; y h. Entonces se detiene el bombeo y se mide la presión de cierre instantáneo. El procedimiento de fracturamiento hidráulico por metodología multietapa dinámica en macizo rocoso a mediana y alta profundidad, según la reivindicación 7, CARACTERIZADO porque comprende el paso de incorporar una modalidad dinámica en el inflado de “packers”, que consiste en inflar los “packers” a una menor presión, de tal forma que cuando comienza el flujo de fractura, genera un aumento de la presión del “packers” hasta la presión de trabajo. El procedimiento de fracturamiento hidráulico por metodología multietapa dinámica, según la reivindicación 7, CARACTERIZADO porque la presión del flujo de agua se maneja con dos válvulas, una válvula para no exceder la presión máxima de trabajo, y otra válvula regula la presión de los “packers”. 18 El procedimiento de fracturamiento hidráulico por metodología multietapa dinámica, según la reivindicación 9, CARACTERIZADO porque se aumenta la presión hasta lograr la fractura, punto en el cual se detecta una disminución de la presión al generarse el flujo de agua en la fractura, esta presión debe ser siempre menor a la de inflado de los “packers”. At least a second and third pump with a higher flow rate and lower pressure than the first pump, connected to the water injection head, to maintain the propagation of the hydraulic fracture. The hydraulic fracturing system by dynamic multistage methodology, according to claim 1, CHARACTERIZED because the pumps are arranged in parallel, in such a way that their flows can be added. Hydraulic fracturing system by dynamic multistage methodology, according to claim 2, CHARACTERIZED in that the first pump, which ensures the breaking of the rock mass, generates a pressure determined by the tenacity of the sector in particular, and the second and third pumps start their operation at moment of the break, to add its flow and start the propagation process. Hydraulic fracturing system by dynamic multistage methodology, according to claim 1, CHARACTERIZED in that the inflation pump is connected to the head to allow the inflation of the "packers". Hydraulic fracturing system by dynamic multistage methodology, according to claim 1, CHARACTERIZED because the pumps are connected to the head, to provide the water for the fracturing process. Hydraulic fracturing system by dynamic multistage methodology, according to claim 1, CHARACTERIZED in that two valves allow controlling the pressure of the water flow, one not to exceed the maximum working pressure, and the other to regulate the pressure of the "packers". A hydraulic fracturing procedure using a dynamic multistage methodology in rock mass at medium and high depths, which ensures fracturing, preventing pillars from remaining in the formation, less need for electrical power, generating a propagation flow in successive stages, greater duration of "packers", therefore, achieving a better operational efficiency, which uses the system of claim 1, CHARACTERIZED because it uses the following stages: a. inject water with a first low-flow, high-pressure pump, filling the circuit and increasing the pressure until the break pressure is reached; b. inject water with a second pump, high flow and low pressure, where the increase in flow prevents the characteristic drop in pressure; c. keep stable, for a short period of time, the pressure reading on the surface, offering the massif a resistance to propagation, 17 but, the flow provided by the second pump increases the pressure of the system until starting a new cycle of propagation, but at reduced speed; d. inject water with a third or more pumps, high flow and low pressure; and. keep stable, for a short period of time, the pressure reading on the surface, again offering the massif a resistance to propagation, but the flow provided by the third pump increases the system pressure, reaching a maximum due to the effect of the flow total contributed with the three or more pumps, starting the last propagation cycle; F. reach the final propagation pressure, where the system equilibrates with the stabilized flow rate and the pressure drops, g. Increase in the radius of the fracture (increases the volume) and slows down the propagation speed, where the pressure of the system is not able to overcome the resistance of the massif and the flow stops; and h. Pumping is then stopped and the instantaneous closing pressure is measured. The hydraulic fracturing procedure by dynamic multistage methodology in rock mass at medium and high depth, according to claim 7, CHARACTERIZED because it comprises the step of incorporating a dynamic modality in the inflation of "packers", which consists of inflating the "packers" to a lower pressure, in such a way that when the fracture flow begins, it generates an increase in the pressure of the "packers" up to the working pressure. The hydraulic fracturing procedure by dynamic multistage methodology, according to claim 7, CHARACTERIZED because the pressure of the water flow is managed with two valves, a valve not to exceed the maximum working pressure, and another valve regulates the pressure of the "packers ”. 18 The hydraulic fracturing procedure by dynamic multistage methodology, according to claim 9, CHARACTERIZED because the pressure is increased until the fracture is achieved, at which point a decrease in pressure is detected when the flow of water is generated in the fracture, this pressure It must always be less than the inflation of the "packers".
PCT/CL2020/050172 2020-12-11 2020-12-11 System and method of hydraulic fracturing by dynamic multi-stage methodology WO2022120504A1 (en)

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CN104234681A (en) * 2013-06-18 2014-12-24 中国石油天然气股份有限公司 Sea fracturing method
CL2016001972A1 (en) * 2016-08-04 2017-02-17 Georock S A System for hydraulic fracturing in applications for preconditioning of rock in underground mining and ground tests in hydroelectric projects, with design that prevents the entrapment of the column of bars in the drilling, both in fracture operations in ascending and descending perforations.
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