System and method for deep detection of petroleum and hydrocarbon deposits

A system and method for deep detection of petroleum and hydrocarbon deposits is disclosed. The system includes a sensing array that includes a plurality of electrodes positioned in the ground at a testing site, a sensing device, and a system for generating a seismic event that generates below-ground signals that are received by the sensing array. The system enables detection and depth determination of underground features such as petroleum and hydrocarbon deposits at greater depths compared to conventional systems.

BACKGROUND

Exploring for and determining the presence and size of petroleum and other hydrocarbon deposits is conventionally expensive and time consuming. Locations where such deposits are suspected to exist are first identified and a drilling rig probes each suspected site. Such drilling is expensive, time consuming and the identification rate of viable deposits is extremely low.

Minimally invasive systems and methods for detecting petroleum and other hydrocarbon deposits are therefore desirable because such systems and methods may provide for substantially less expensive and faster exploration for energy resources. A greater number of candidate sites can be tested with substantially less cost than conventional drilling tests. Moreover, testing can occur at sites that may otherwise be inaccessible by bulky and cumbersome drilling equipment.

Such minimally invasive systems are known in the art for detecting underground features, but are deficient for a variety of reasons. For example, many of these systems to not provide accurate and reproducible data. Although many minimally invasive systems provide results that appear to show the location of underground features, these results are difficult to interpret and such interpretations are highly subjective. Accordingly, the results from many minimally invasive tests are speculative, error prone, and have an unacceptably high rate of false positives and false negatives.

Additionally, systems presently known in the art only provide satisfactory results at shallow depths, which make them useless for detecting below ground features that are below this depth range. This may be suitable for shallow water well detection, but given that the vast majority of petroleum and other hydrocarbon deposits are located at depths that are far below the operative depth of presently known minimally invasive testing systems, such systems that are presently known in the art are not a suitable solution for energy exploration.

For example, U.S. Pat. No. 5,903,153 to Clarke et al. teaches an apparatus and method for detecting underground liquids (known as electrokinetic, electroseismic and more recently seismoelectric sensing) in which electrical potential generated by a seismic shock is detected and measured with respect to a base point insulated from the earth. The disclosed electrokinetic (seismoelectric) system teaches remote sensing of water and other below-ground features. However, as depicted inFIG. 4, the Clarke system only has a maximum depth sensitivity less than 80 meters. In practice, commercial products using the Clarke system, and other minimally invasive sensing systems fail to have an operative depth range that exceeds the 80 meter maximum taught in the Clarke patent.

The Clarke system (and other systems like it) are not operable to detect below-ground features for many reasons. For example, such systems operate by ground level detection of signals generated by underground features. Because such signals become increasing attenuated as they travel upward from an underground source, detection of such signals originating from a deep source are typically masked by environmental and system noise. Accordingly, because these systems generate a signal-to-noise ratio that makes it impossible to discern deep-source signals, they do not operate with a gain that would allow them to detect weak deep-source signals, and do not record signals over a time period when deep-source signals would be received.

In view of the foregoing, a need exists for an improved seismoelectric ground feature sensing system and method for deep detection of petroleum and hydrocarbon deposits, in an effort to overcome the aforementioned obstacles and deficiencies of conventional ground feature sensing systems.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Since currently available ground feature sensing systems are deficient because they fail to provide for deep detection of petroleum and hydrocarbon deposits, a system and method for deep detection of petroleum and hydrocarbon deposits can prove desirable and provide a basis for fast, inexpensive and accurate energy exploration. This result can be achieved, according to one embodiment disclosed herein, by a deep sensing system100as illustrated inFIG. 1.

Turning toFIG. 1, the deep detection system100is shown in a network diagram in accordance with an embodiment. The system100comprises a sensing device110that is operably connected to a user device120; to a plurality of electrodes130that define a sensing array140; and to a timing trigger150.

In various embodiments, the user device120, plurality of electrodes130, and timing trigger150may include a wired or wireless connection to the sensing device110. For example, a wired connection may include any suitable wire, cable or the like. A wireless connection may include a direct wireless connection or a connection via a wireless network. Such a wireless connection may comprise Wi-Fi, blue-tooth, a near-field connection, or the like. In an embodiment where a portion of the system100is interconnected via a network, such a network may comprise a local area network (LAN), the Internet, or the like. Additionally, while one connection configuration is depicted in the embodiments ofFIG. 1, in further embodiments, components of the system100may interconnected in any suitable configuration. For example, the sensing array140may be connected directly to the user device120. In further embodiments, any of the components of the system100may absent, present in a suitable plurality or may be combined with other components of the system100. For example, in some embodiments, the sensing device110may be absent or combined with the user device120. Additionally, in further embodiments, there may more or fewer than four electrodes (130A,130B,130C,130D) as shown inFIG. 1.

In various embodiments, the sensing device110may be any device operable for receiving signals obtained by the electrodes130of the sensing array140, and obtaining a signal from the timing trigger150. For example, in some embodiments, the sensing device130may comprise a device, system or portion thereof as disclosed in U.S. Pat. No. 5,903,153 to Clarke et al, which is hereby incorporated herein by reference in its entirety.

Although the user device120is depicted as being a laptop computer inFIG. 1, in further embodiments, the user device120may be any suitable device, including a smart-phone, heads-up display, tablet computer, gaming device, or the like.

In a preferred embodiment, the electrodes130may comprise elongated copper clad steel rods that are 1 meter long; however, in some embodiments, electrodes130of any suitable material, length and diameter may be used, and the electrodes130of the sensing array140may not be the same. Additionally in further embodiments, electrodes need not be elongated rods as depicted inFIG. 1, and electrodes130or sensors of any suitable type may be used in some embodiments.

FIG. 2is an exemplary top view drawing illustrating an embodiment of a sensing array140positioned in the ground205in accordance with an embodiment. The sensing array140comprises a first, second, third and fourth electrode130A,130B,130C,130D that are aligned along an array axis X and symmetrically disposed about the seismic event location210. For example, the second and third electrodes130B,130C are disposed substantially equidistant from the event location210at a first distance D1 and define a first electrode pair232. The first and fourth electrodes130A,130D are disposed substantially equidistant from the event location210at a second distance D2 and define a second electrode pair234.

In some embodiments, as depicted inFIG. 2, it may be desirable for D1 to be substantially smaller than D2; however, in various embodiments, D1 and D2 may be any desirable distance. For example, D1 may equal D2; D1 may be longer than D2; or D1 may be shorter than D2.

FIGS. 3aand 3bare exemplary cross sectional view drawings illustrating embodiments of a sensing array140that respectively depict a seismic event generating plate310and seismic event generating probe350. As shown inFIGS. 3aand 3b, a sensing array140is defined by first, second, third and fourth electrodes330A,330B,330C,330D that are disposed in the ground205that includes a top surface320. The electrodes330may each include a portion that is disposed in the ground205below the top surface320and a portion that extends above the top surface320. In various embodiments, the electrodes130of the sensing array140may be disposed in the ground with any suitable length of the electrodes130disposed in the ground205. In some embodiments, as further disclosed herein, it may be desirable for the electrodes130to be the same length and be disposed within the ground205at the same depth.

As shown inFIGS. 3aand4, a seismic event generating plate310may be disposed at a seismic event location210among the electrodes130. The plate310may be disposed on the top surface320of the ground205as shown inFIG. 3a; however, in further embodiments, it may be desirable to position the plate310below the surface320of the ground205. For example, as shown inFIG. 4, the seismic event location210may be defined by a shallow hole where the plate310may be disposed. This may be desirable because removal of topsoil may allow for the plate310to rest of flat compact ground205, which may provide for an improved seismic event in some embodiments.

A user410may generate a seismic event at the event location210by striking a mallet420against the plate310. Recording and time association of signals received by the sensing array140may be triggered by a timing trigger150disposed on the mallet420that is configured to trigger recording and or timing when the mallet420strikes the plate310. A trigger signal may be sent to the sensing device110via a trigger wire430. As discussed in further detail herein, the timing trigger150may provide an indication of when a seismic event occurs and such an indication may be used to correlate recorded data obtained by the sensing array140with a time relative to the occurrence of the seismic event. Such a correlation may be used to determine the depth of desirable features330in the ground205.

The mallet420and plate310may be any suitable size or shape in various embodiments, and may comprise any suitable material in various embodiments. However, as discussed in further detail herein, it may be desirable to conduct sensing with the sensing array140without metal-to-metal contact. Accordingly, the plate310and head of the mallet420may comprise non-metal materials in various embodiments. For example, in some preferred embodiments, the mallet420or plate310may comprise rubber, plastic, wood, ceramic, glass, a textile, or the like.

While a mallet420and plate310may be used to generate a seismic event as shown inFIGS. 3aand4, in further embodiments, any suitable method, device or system may be used to mechanically generate a seismic event. For example, in some embodiments, a hammer, weight-drop, piston device, or the like may be used to generate a seismic event with or without a plate310, or the like.

In further embodiments, a seismic event may be generated with a charge probe350as depicted inFIGS. 3band5. The charge probe may be disposed in the ground205with a portion that remains extending above the top surface320of the ground205. In various embodiments, the charge probe350may be any suitable length and may extend into the ground205any suitable length. The charge probe350may comprise a charge tip360at a bottom end that is configured to deliver an explosive charge that generates a seismic event in the ground205. In a preferred embodiment as discussed in more detail herein, the charge tip360may discharge a black powder charge; however, in further embodiments, any suitable explosive may be used, which may include trinitrotoluene (TNT), nitrocellulose, nitroamine research department explosive (RDX), pentaerythritol tetranitrate (PETN), nitro amine high melting explosive (HMX), dynamite, ammonium nitrate and fuel oil (ANFO), hydrogen, propane, methane, butane, a compressed gas, or the like.

FIG. 6ais an exemplary side view of an assembled charge probe350in accordance with an embodiment. The charge probe350comprises a probe body605having a top and bottom end606,607. A first and second handle610A,610B are disposed at the top end606along with a trigger assembly615. The charge tip360is disposed at the bottom end607. The charge probe350includes a firing shaft620that slidably resides within the probe body605. As shownFIG. 6b, the elongated firing shaft620comprises a top and bottom end621,622, with a hammer625and trigger slot630at the top end621and a firing pin635at the bottom end622.

As depicted inFIG. 7, the charge probe350may be collapsible and modular, which may be desirable for transportation and shipping of the charge probe350. The charge probe350may be disassembled into a plurality of pieces to reduce the length and width of the charge probe350. For example, in the embodiment depicted inFIG. 7, the handles610A,610B may be removable from the probe body605, and the probe body605may be broken down into first, second and third probe body segments705A,705B,705C. The firing shaft620may also be broken down into first, second and third shaft sections720A,720B,720C. AlthoughFIG. 7depicts the charge probe350operable to be broken down into thirds along its length, in various embodiments, the charge probe350may be configured to be broken down into any suitable way.

As discussed herein, the charge probe350may be used to generate an explosive seismic event. For example, the trigger assembly615may be configured to drive the firing pin635at the bottom end622of the firing shaft620into the primer (not shown) in the head745of a cartridge740disposed in the charge tip360, which triggers an explosive charge in the cartridge740.

In the embodiment depicted inFIG. 7, the trigger assembly615comprises a trigger715having a trigger arm725. The trigger715movably resides in a trigger orifice720at the top end606of the probe body605, and a trigger bolt730extends through the trigger715and into the trigger orifice720, where a trigger tip735at an end of the trigger bolt730is configured to engage with the firing shaft620at the firing shaft top end621. The trigger bolt730may be inwardly biased toward the firing shaft620, with the trigger715operable to pull the trigger bolt730outward.

The firing shaft620may be biased toward the bottom end607of the probe body605, which allows the charge probe350to be cocked by pulling the firing shaft620upward within the probe body605. The firing shaft620may be pulled upward within the probe body605by pulling on the hammer625, or by rocking the hammer625, which may be rotatably coupled to the top end606of the probe body605. As the firing shaft620moves upward within the probe body605, the biased trigger pin735may extend into the trigger slot630at the top end621of the firing shaft620, which holds the firing shaft620in a cocked configuration with the firing shaft620biased toward the bottom end606of the charge probe350.

To fire the cocked charge probe350, a user can actuate the trigger715via the trigger arm720, which pulls the trigger pin735out of the trigger slot630and allows the biased firing shaft to spring downward toward the bottom end606of the charge probe350. The firing pin635strikes and discharges the cartridge740.

In various embodiments, the cartridge740may be a standard shotgun shell of 4-gauge, 8-gauge, 10-gauge, 12-gauge, 16-gauge, 20-gauge, 28-gauge, or the like. Such a cartridge740may comprise a black powder charge of any suitable size, with a projectile such as buck shot, bird shot, or the like being absent from the cartridge740. The charge tip360may be configured to hold one or more standard cartridge740, or may be configured (via a sleeve or the like) to accommodate various standard sizes of cartridge740. In various embodiments, there may be a set of interchangeable charge tips360that are each configured to hold a suitable size of cartridge740. Although various embodiments include standardized shotgun shell cartridges740, further embodiments may include any suitable cartridge740operable to discharge any suitable explosive charge.

In various embodiments, a sensing array140and detection system100(e.g.,FIGS. 1-5) may be used to detect and visualize features that are present with the ground205at various depths. For example, as depicted inFIGS. 3aand 3b, there may be ground205of a first type and a feature330of a second type disposed within the ground205at a depth. The feature340may have an outer edge340that faces the ground205. A feature330may include water, petroleum, a hydrocarbon, coal, tar sands, methane, butane, propane, or the like. In some embodiments, a feature330may include a pocket of resistive fluid disposed in the ground205. A sensing array140and detection system100may be used to detect desired features330at various depths, which may include shallow or deep features330. In accordance with various embodiments, the present system100may be used to detect features330at a depth that is substantially deeper than detection capable with currently available detection systems.

FIG. 8is an exemplary block diagram of a method800for feature detection in accordance with an embodiment. The method800begins, in block810, where a plurality of electrodes130are positioned in the ground205and a seismic event is generated, in block820.

The seismic event generates a sound wave or pulse that propagates in all directions from the source including downward from the source. The pulse propagates through the ground205and into features330that are present in the ground205. In various embodiments, ions in the feature330at the boundary340between the feature330and the ground205decouple from ion pairs in the ground205at the boundary340. This ion decoupling generates an electrical signal that propagates upward toward the sensing array140at about the speed of light.

Depth of the feature boundary is therefore correlated to the propagation time of the seismic pulse through the ground medium and the propagation time of the ion decoupling signal upward to the sensing array140. Returning to the method800, such signals received by the sensing array140are recorded, in block830, and the recorded data is presented, in block840. The method800is done in block899. The form of the signals plotted over time indicates the nature of various features330present at various depths in the ground205. Such sensing can be used to detect desirable features330such as water, hydrocarbon, or petroleum deposits, at both deep and shallow depths.

Conventional systems have been unable to perform deep sensing of desirable features because they are unable to observe a signal above environmental signal noise at deep levels. In other words, the signal-to-noise ratio at deep levels was too low to identify features with a suitable level of confidence. Because electrical signals associated with ion decoupling are attenuated as they propagate through a ground medium, signals generated at deep levels can be very weak by the time they reach a sensing array140.

Given that conventional systems are unable to provide an adequate signal-to-noise ratio, they do not record signals received during a time that corresponded to deep levels (i.e., the recording or timing cutoff is too short to detect signals from deep sources). Additionally, because conventional systems are unable to provide an adequate signal-to-noise ratio, they are not configured to operate at a gain sufficient to detect weak signals that have been substantially attenuated by traveling through a large distance of ground and feature substrate (i.e., signals from a deep source).

However, by positioning and arranging a sensing array140in certain novel ways, according to specific novel protocols, and generating a seismic event in certain novel ways and according to specific novel protocols, embodiments disclosed herein are operable to the novel and unexpected result of generating signal-to-noise ratios that provide for detecting and identifying desirable features at depths that are substantially greater than conventional systems. For example, the present system100may be configured to sense features330at a depth greater than 80 meters, 100 meters, 150 meters, 200 meters, 500 meters, 1000 meters, 1500 meters, 2000 meters, 2500 meters, 3000 meters or the like. The inventor(s) of the disclosed systems and methods discovered such novel and unexpected results after extensive testing and experimentation.

For example, in some embodiments, it is desirable to generate a sensing array140with four substantially straight electrodes130that are driven into the ground such that the electrodes130substantially do not generate a cavity surrounding the electrode130. This may be desirable because additional contact between the ground205and surface of the electrode130allows for increased sensitivity of the sensing array140to ion decoupling signals. Accordingly, weaker signals may be detected with a signal array140constructed in such a way compared to conventional systems.

The conventional method for driving elongated rods into the ground is by hammering the rod with a sledgehammer. Unfortunately, driving a rod into the ground with a sledgehammer, or the like, causes lateral movement of the rod while driving, which forms a cavity in the ground surrounding the driven rod. Accordingly, when driving an electrode130into the ground, in various embodiments it may be desirable to drive the electrode130via a piston or reciprocating driver that focuses energy downward on the electrode130to prevent lateral movement of electrodes130while driving that generates a cavity around the electrodes130of a sensing array140. Conventional systems and methods do not rigorously require, suggest or disclose such a protocol of electrode130driving.

In some embodiments, consistent orientation, position, depth and structure of the electrodes130of a sensing array140may provide for improved sensing of the sensing array140. For example, in various embodiments, it may be desirable for all electrodes130to be substantially identical in length, diameter, and composition. In further embodiments, it may be desirable for all electrodes to be oriented substantially perpendicular to the surface of the ground, gravitational axis of the earth or otherwise oriented in substantially the same way. In some embodiments, it may be desirable for electrode pairs232,234to both be at substantially the same distance from the seismic event source location210and driven to substantially the same depth. Conventional systems and methods do not rigorously require, suggest or disclose such protocols of electrode130positioning, depth and structure.

In further embodiments, it may be desirable to eliminate or neutralize background noise signals so as to increase the signal-to-noise ratio such that weak signals from deep sources can be detected. In some embodiments, it may be desirable to reduce or eliminate metal-to-metal contacts proximate to the time when a seismic event is generated and while signals from features330in the ground205are being received by the sensing array140. For example, when using a mallet420and plate310to generate a seismic event (e.g.,FIG. 4), it may be desirable to use a non-metallic mallet420head and a non-metallic plate310. Similarly, it may be desirable to use a timing trigger150that does not include a metal-to-metal trigger mechanism, which may include a magnetic trigger mechanism. In some embodiments, it may be desirable to insulate, isolate or cover portions of the charge probe350. Conventional systems and methods to not provide for, teach or suggest the minimization or exclusion of metal-to-metal contacts during use of the sensing system.

In various embodiments, generating a seismic event with certain systems, charges or methods may provide for an improved signal-to-noise ratio that allows weak deep-source signals to be observed and identified. For example, after extensive experimentation with various types of explosive charges the inventor(s) of the systems and methods disclosed herein discovered the unexpected result of a black powder charge generating a seismic event providing a substantially improved signal-to-noise ratio that allows for detection of deep-source feature detection. Additionally, after extensive experimentation with various types seismic event generation systems, the inventor(s) of the systems and methods disclosed herein discovered the unexpected result of a below-ground explosive black powder charge using a charge probe350as described herein providing a substantially improved signal-to-noise ratio that allows for deep-source feature detection. Conventional systems fail to teach or suggest, and fail to recognize, the unexpected results of the improved seismic event generating systems and methods described herein.

Signals received by a sensing array140may be recorded, stored and visualized via user device120to provide for the identification of features330in the ground205at a testing site, and to determine the depth of identified features330(FIGS. 3aand 3b). As discussed herein, in some embodiments, a signal may be obtained from two pairs of electrodes130in a sensing array140having four electrodes130A,130B,130C,130D. For example, referring toFIGS. 3aand 3b, one signal data set may be obtained from electrodes130A and130B, and a second data set may be obtained from electrodes130C and130D.FIG. 9is an exemplary graph900of data obtained from a sensing array140in accordance with an embodiment. The graph900includes a first and second curve910A,910B that in some embodiments is derived from signals received from respective pairs of electrodes130in a sensing array140. The graph900is plotted with distance (meters) in the Y-axis against voltage or signal strength in the X-axis.

As discussed herein, data may be received in terms of time and signal strength and time may be converted to distance based on a calculation of propagation time/speed of a seismic pulse in a given medium and propagation time/speed of signals from a transmission source in the ground. Propagation time of a seismic pulse within various ground mediums may vary, and in some embodiments, it may be desirable to plot data in terms of depth based on the propagation speed of a seismic pulse within an identified ground medium. For example, a seismic pulse may travel substantially faster in a dense ground medium such as granite compared to less dense ground mediums such as sandstone. Accordingly, when plotting received data, a different constant may be used when sensing occurs in granite or sandstone. Such constants may be present in ground medium profiles available in a data visualization interface present on user device120. A ground medium profile may include constants corresponding to one or more ground medium (e.g., profiles corresponding to layered or non-layered ground).

As depicted inFIG. 9, a first and second data set are plotted as a first and second curve910A,910B, which may exhibit a similar profile. (As shown and discussed herein, such curves may be more or less corresponding in some embodiments and in some data sets). The profile of various portions of the curves may be indicative of desired features330in the ground205; may be indicative of the ground205; may be indicative of undesirable features330; or may be indicative of noise or outlier data. For example, in some embodiments, pockets of resistive fluids may be indicated by a substantially symmetrical Gaussian-like or Lorenzian-like curve profile portion that is substantially matching in both curves910A,910B as depicted in curve portion920. Such a portion may be indicative of a desirable resistive fluid pocket present at approximately 85 meters (i.e., the peak of the Gaussian-like or Lorenzian-like curve profile portion).

The data910A,910B may also include asymmetrical and non-uniform portions such as portion930, which may be indicative of a signal, but not a signal profile associated with a desired feature330. Such a portion of a set of data910A,910B may therefore be indicative of ground205or other undesirable ground feature330. Similarly, the data910A,910B may also include symmetrical and linear portions such as portion940, which is also indicative of ground205or other undesirable ground feature330.

The systems and methods described herein provide the unexpected result of being capable of consistently generating reproducible data that reliably indicates the location and depth of desirable features330such as water, petroleum and hydrocarbon deposits. The systems and methods disclosed herein provide such results where others in the art have failed in terms of depth and consistency of results.FIGS. 10aand 10bare an exemplary set of data plots1000A-F that depict consistency and reliability of data at depths substantially greater than conventional systems.

For example, plots1000A and1000B depict data obtained at a known productive well site (NHS4) where the data was obtained on two different days (Nov. 9, 2013 and Nov. 17, 2013) with sensing arrays140placed and removed on both days. The data plots1010A,1010B,1010C show a desirable feature profiles1020A,1020B between 1800 and 2000 meters at site NHS4 on both days and with both sensing arrays140. A well was known to be located at site NHS4 at a depth of approximately 1800-2000 meters. (Data plot1010D indicates that no data was received from the set of electrodes—likely due to a disconnected wire).

In another example, plots1000C and1000D depict data obtained at a known productive well site (NHS6) where the data was obtained on two different days (Nov. 9, 2013 and Nov. 17, 2013) with sensing arrays140placed and removed on both days. The data plots1010E,1010F,1010G,1010H show desirable feature profiles1020C,1020D at approximately 1800 meters at site NHS6 on both days and with both sensing arrays140. A well was known to be located at site NHS6 at a depth of approximately 1800 meters. Plot1000E with data set1010I depicts a desirable feature profile1020E identified at a third site NHS13at approximately 1900 meters. A well was known to be located at site NHS13 at a depth of approximately 1900 meters.

Plot1000F depicts data sets1010J and1010K obtained at a drilling site where no productive well was present. The data sets1010J and1010K fail to show a feature profile that is indicative of a desirable feature being present at the site.

In addition to providing information about desirable features330at a single test location, data obtained from a sensing array140or sensing system100may be used to visualize a two-dimensional contour and depth profile of desirable features330present in the ground. In various embodiments, by obtaining data from a plurality of test sites at known distances, a map of desirable features may be generated.FIG. 11is an exemplary graph of data obtained from a sensing array140at six test sites that were 20 meters apart.FIG. 12is an exemplary two dimensional feature profile graph generated with the data depicted inFIG. 11, wherein the profile of a desirable feature is indicated at a depth of approximately 250 meters.

The described embodiments are susceptible to various modifications and alternative forms, and specific examples thereof have been shown by way of example in the drawings and are herein described in detail. It should be understood, however, that the described embodiments are not to be limited to the particular forms or methods disclosed, but to the contrary, the present disclosure is to cover all modifications, equivalents, and alternatives.