WORK CYCLE DETERMINATION SYSTEM FOR A PUMP

Abstract

A work cycle determination system for a fracking pump is provided. The work cycle determination system includes a pressure sensor adapted to generate a signal indicative of a pressure generated by the fracking pump, and a controller communicably coupled to the pressure sensor. The controller receives the signal indicative of the pressure generated by the fracking pump over a predefined period of time. The controller identifies a boundary of a work cycle within the predefined period of time by analyzing the signal. The controller also determines a peak pressure of the work cycle and a time duration of the work cycle. The controller further determines a type of the work cycle of the fracking pump based on the peak pressure and the time duration of the work cycle.

Description

TECHNICAL FIELD

The present disclosure relates to a work cycle determination system for a pump. More particularly, the present disclosure relates to the work cycle determination system for a fracking pump used in oil and gas industry.

BACKGROUND

Generally, fracking pumps are employed during downhole activities in oil and gas industry. Such activities may include perforation and fracking for production of oil and/or gas from rock formations. In some situations, multiple fracking pumps may be used in tandem to perform perforation and fracking in a. cyclic manner or as per operational requirements. Further, multiple fracking pumps may be grouped together to improve fluid flow and fluid pressure. In such a situation, different groups of the fracking pumps may be assigned preset activities, such as either perforation or fracking, to be performed sequentially or as per operational requirements.

The fracking pump includes an intake manifold at low pressure and a discharge manifold at high pressure. The high discharge pressure, in turn may induce excessive stress on components of the fracking pump, such as one or more valves, seals, bearings, and so on. Furthermore, different activities may induce varying levels of stress on the components of the fracking pump, in turn limiting use of the fracking pump for different activities. For example, higher stress activities may limit an operation of the fracking pump for a limited number of hours before the fracking pump may be operated again for the same or a different activity. Also, higher stress activities may require frequent servicing of the fracking pump in order to identify worn out components and limit breakdown of the fracking pump during an ongoing activity. Moreover, the fluid pumped by the fracking pump may be gritty and corrosive leading to early failure of the fracking pump. The failure of the fracking pump may result in downtimes amounting to loss of time and money to the site operator.

U.S. Pat. No. 5,353,637 describes a modular sonde for obtaining various measurements in open or cased boreholes. The sonde is conveyed on an electric wire line with or without a coiled tubing for conveying hydraulic energy from a surface. Modules common to the configurations include telemetry electronics, orientation, hydraulic energy accumulator, fluid chambers, hydraulic power, pump out, and flow control. Each configuration has a stress/rheology module suited to the borehole situation. An open-hole sonde configuration has a stress/rheology module with an instrumented, inflatable packer module, an orienting module, and a probe module. A second open-hole sonde configuration has a stress/rheology module with an instrumented straddle packer assembly. A cased-hole sonde configuration has a gun block assembly, a gun block orienting module hydraulics for formation pre-test and hydraulics for stressing the formation to obtain data related to formation stress characteristics. A second cased-hole sonde configuration has a straddle-packer assembly, a casing perforation device in the straddle interval, and hydraulics for stressing the formation to obtain data related to formation stress characteristics.

SUMMARY OF THE DISCLOSURE

In an aspect of the present disclosure, a work cycle determination system for a fracking pump is provided. The work cycle determination system includes a pressure sensor associated with the fracking pump. The pressure sensor is adapted to generate a signal indicative of a pressure generated by the fracking pump. The work cycle determination system includes a controller communicably coupled to the pressure sensor. The controller receives the signal indicative of the pressure generated by the fracking pump over a predefined period of time. The controller identifies a boundary of a work cycle within the predefined period of time by analyzing the signal. The controller also determines a peak pressure of the work cycle and a time duration of the work cycle. The controller further determines a type of the work cycle of the fracking pump based on the peak pressure and the time duration of the work cycle.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a work cycle determination system, according to one embodiment of the present disclosure;

FIG. 2 is a graphical representation of pressure generated by a fracking pump with respect to time, according to one embodiment of the present disclosure; and

FIG. 3 is a flowchart of working of the work cycle determination system of FIG. 1, according to one embodiment of the present disclosure.

DETAILED DESCRIPTION

Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. Referring to FIG. 1, a schematic representation of a work cycle determination system 10 for a fracking pump 12 is illustrated. The fracking pump 12 may be any pump known in the art, such as a positive displacement pump. The fracking pump 12 is associated with oil and gas industry and employed at a site (not shown) during a fracking process. The fracking process refers to a process of drilling down into the earth and directing high pressure fluid at a rock formation (not shown) to release trapped oil and/or gas which may be pumped to the ground level. In various embodiments, one or more fracking pumps may be combined to improve fluid flow and fluid pressure. The fracking process may also be referred to as a hydro-fracturing process, micro-hydraulic fracturing process or a hydro-fracking process.

The fracking pump 12 provides flow of one or more fluids at a high pressure for the fracking process, The fluid may include, but not limited to, water, sand, chemicals, and so on, or a combination thereof. During the fracking process, the fluid is pressurized by the fracking pump 12 and injected through a well (not shown) into the rock formation at high pressure.

The high pressure of the fluid forces oil and/or gas trapped within the rock formation to flow out to a head (not shown) of the well. The fracking process may be carried out by drilling vertically or horizontally to the rock formation based on application requirements. The fracking process creates new pathways for release of the oil and/or gas therein or may be used to extend existing channels. More specifically, the fracking process refers to fracturing of the rock formation using high pressure fluid in order to release the oil and/or gas trapped therein.

The fracking pump 12 may operate in various types of work cycles, namely, a system test cycle, a fracking cycle, and a perforation cycle. If the fracking pump 12 is not working, the fracking pump 12 is referred to as in an idle work cycle. Each type of the work cycle has one or more characteristics such as a peak pressure, an average pressure, a time duration, and the like that may be different from the other types of the work cycles.

The work cycle determination system 10 includes a pressure sensor 14 associated with the fracking pump 12. The pressure sensor 14 may be any pressure sensor known in the art, such as a piezo-resistive type pressure sensor, a piezo-electric type pressure sensor, a capacitive type pressure sensor, an electromagnetic type pressure sensor, an optical type pressure sensor, a potentiometric type pressure sensor, and so on.

The pressure sensor 14 is adapted to generate a signal indicative of a discharge pressure of the fracking pump 12. In one embodiment, the pressure sensor 14 may be coupled to any portion of the fracking pump 12, such as outlet discharge manifold (not shown) thereof. In another embodiment, the pressure sensor 14 may be coupled to any portion of the well, such as the head of the well, within the well as a downhole device, and so on. The pressure sensor 14 may be further adapted to capture the signal at a high frequency.

The work cycle determination system 10 also includes a controller 16 communicably coupled to the pressure sensor 14. Accordingly, the controller controller 16 is adapted to receive the signal indicative of the pressure generated by the fracking pump 12 and to identify a boundary of a work cycle of the fracking pump 12. The controller 16 may store the pressure signals received from the pressure sensor 14. More specifically, in the illustrated embodiment, the signal generated by the pressure sensor 14 is stored in a database 18 communicably coupled to the controller 16. In other embodiments, the signal generated by the pressure sensor 14 is stored in an internal memory (not shown) of the controller 16. In one embodiment, the controller 16 is a part of onboard analytics system (not shown) and adapted to analyze the signals received from the pressure sensor 14. Alternatively, the controller 16 may be communicably coupled to the onboard analytics system.

The controller 16 is configured to retrieve the signal indicative of the pressure generated by the fracking pump 12 over a predefined period of time from the database 18 or the internal memory of the controller 16 based on application requirements. In an exemplary embodiment, the controller 16 may retrieve pressure signals data of four hours for further processing. The controller 16 is configured to analyze the signal and identify one or more work cycles of the fracking pump 12 within the predefined period of time.

In one embodiment, the controller 16 may include a low pass filter 20 for processing the signal prior to identifying the work cycles of the fracking pump 12. The low pass filter 20 is adapted to filter out high frequency components in the signal received from the pressure sensor 14. Accordingly, the controller 16 generates the filtered signal indicative of the pressure generated by the fracking pump 12 over the predefined period of time. In another embodiment, the controller 16 may perform backlash filtering in order to filter out minor variations in the signal prior to identifying the work cycles of the fracking pump 12 based on application requirements.

The controller 16 analyzes the signal to determine one or more characteristics of each of the identified work cycles. The signal characteristics include the peak pressure, the average pressure, the time duration, and the like. The controller 16 is configured to determine a type of the work cycle of the fracking pump 12 based on the one or more characteristics. In other words, the controller 16 identifies that the fracking pump 12 is operating in one of the system test cycle, the fracking cycle, and the perforation cycle. A person skilled in the art will appreciate that various other signal characteristics may be used to aid in the identification of the type of the work cycle.

FIG. 2 illustrates a graph 22 of the pressure generated by the fracking pump 12 with respect to time according to an example embodiment of the invention. The graph 22 shows a pressure profile 24 which refers to discharge pressure values corresponding to the signals received from the pressure sensor 14 plotted against time. Moreover, the graph 22 shows the pressure profile 24 after the signals is filtered through the low pass filter 20. Data corresponding to the pressure profile 24 may be stored in the database 18. In the illustrated embodiment, the pressure profile 24 shown in the graph 22 is for the time interval of 40,000 seconds and the time interval may vary based on application requirements.

The graph 22 shows different types of work cycles of the fracking pump 12 namely, the system test cycle, the fracking cycle and the perforation cycle. During the system test cycle, the fracking pump 12 is subjected to system test involving very high pressures to identify any potential failure such as leakage. Further, the system test cycle has very short time duration, for example, 10 minutes. The system test may be performed by the site operator after every fracking and perforation operation or as per the application requirements. During the fracking cycle, the fracking pump 12 discharges fluid at high pressure to the rock formation having trapped oil and/or gas. This result in fracturing of the rock formation leading to increased fluid flow and drop in discharge pressure of the fracking pump 12. During the fracking cycle, the rock formation may be fractured multiple times resulting in one or more small pressure humps in the pressure profile 24. Typically, the fracking cycle has time duration more than the system test cycle and the perforation cycle.

During the perforation cycle, a perforation gun (not shown) is lowered down the drill pipe. Once the perforation gun reaches the required position, the perforation gun is fired to expose the rocks to the fracking fluid. One or more large pressure humps are typically seen during the perforation cycle. Further, the time duration of the perforation cycle is greater than the time duration of system test cycle but less than the time duration of the fracking cycle.

The controller 16 is configured to identify a boundary (also referred as “cycle boundary”) of a work cycle of the fracking pump 12 within the predefined period of time. In one embodiment, the controller 16 determines one or more cycle boundaries from the analysis of the pressure profile 24. A cycle boundary corresponding to a work cycle may be identified from a slope of the graph 22. Each cycle boundary corresponds to either a cycle start or a cycle end corresponding to the work cycle. Further, the cycle boundaries are associated with a high value of positive slope or a low value of negative slope in the graph 22. The controller 16 may determine one or more cycle boundaries based on whether the slope of the graph 22 is greater than a positive slope threshold or lesser than a negative slope threshold.

For example, in the illustrated embodiment, the controller 16 determines a first cycle boundary “B1” indicating a start of a first work cycle. At the first cycle boundary “B1”, the graph 22 has a first slope that exceeds the positive slope threshold. In the illustrated embodiment, the positive slope threshold is 10, and may vat based on application requirements. Further, the controller 16 determines a second cycle boundary “B2” indicating an end of the first work cycle. At the second cycle boundary “B2”, the graph 22 has a second slope that is less than the negative slope threshold. In the illustrated embodiment, the negative slope threshold is negative (−) 5. Similarly, the controller 16 determines a third cycle boundary “B3” indicating a start of a second work cycle.

At the third cycle boundary “B3”, the graph 22 has a third slope that that exceeds the positive slope threshold. Further, the controller 16 determines a fourth cycle boundary “B4” indicating an end of the second work cycle. At the fourth cycle boundary “B4”, the graph 22 has a fourth slope that is less than the negative slope threshold, In a similar manner, the controller 16 determines a fifth cycle boundary “B5” indicating a start of a third work cycle and a sixth cycle boundary “B6” indicating an end of the third work cycle. The first work cycle, the second work cycle, and the third work cycle are denoted in the graph 22 as “W1”, “W2”, and “W3” respectively. A person skilled in the art will appreciate that use of slope data for identifying the cycle boundaries is merely for illustrative purposes and one can employ any other parameter apart from the slope data to identify the cycle boundaries. The slope threshold may be stored in the database 18 or the internal memory of the controller 16 and may be retrieved by the controller 16 by any known data retrieving method.

It should be noted that in other embodiments, the graph 22 may include multiple cycle boundaries without any limitation. Also, the controller 16 may be configured with a plurality of positive and negative slope thresholds for different cycle boundaries based on application requirements. In other embodiments, based on the number of cycle boundaries, the controller 16 may determine a single or multiple work cycles in the graph 22 without any limitation, Using the cycle boundaries, the controller 16 is configured to determine duration of each work cycle identified from the analysis of the data.

The controller 16 is configured to determine one or more characteristics of the signal using the pressure profile 24. In one embodiment, the controller 16 determines the peak pressure of each work cycle. For example, the peak pressure in the first work cycle “W1” is denoted by “PP1” in FIG. 2 corresponding to 64000 Pressure per Square Inch (PSI). Similarly, the controller 16 determines the peak pressure of the second work cycle “W2” and the third work cycle “W3” denoted by “PP2” and “PP3” respectively. The controller 16 is further configured to compare the peak pressure with one or more peak pressure thresholds. The controller 16 may be configured with different peak pressure thresholds for different work cycles. For example, a peak pressure threshold for the system test cycle is 60000 PSI, a peak pressure threshold for the fracking cycle is 40000 PSI, and a peak pressure threshold for the perforation cycle is 25000 PSI. The peak pressure thresholds may be stored in the database 18 or the internal memory of the controller 16 and may be retrieved by the controller 16 by any known data retrieving method. Using these peak pressure thresholds, the controller 16 identifies the type of the work cycle for each of the work cycles.

In one embodiment, the controller 16 is configured to use the time duration of the work cycle to determine the type of the work cycle. The controller 16 may be provided with time ranges for each type of the work cycle. For example, the system test cycle has very small duration of around 30 minutes. Thus, the controller 16 determines the first work cycle “W1” as the system test cycle. In a similar manner, the controller 16 determines the second work cycle “W2” as the fracking cycle and the third work cycle “W3” as the perforation cycle. The time ranges for each type of the work cycle may be stored in the database 18 or the internal memory of the controller 16 and may be retrieved by the controller 16 by any known data retrieving method.

The controller 16 may be configured to use various other characteristics of the signal to aid in determination of the type of the work cycle. In one embodiment, the controller 16 determines a number of small humps in the pressure profile 24 within each work cycle. Small hump is defined as a hump having magnitude of more than 400 PSI and less than 10,000 PSI in an example embodiment. Referring to FIG. 2, the controller 16 determines that there are 4 small humps during the second work cycle “W2”. In another embodiment, the controller 16 determines a number of large humps in the pressure profile 24 within each work cycle. Large hump is defined as a hump having magnitude of more than 10,000 PSI. Referring to FIG. 2, the controller 16 determines that there is one large hump in the third work cycle “W3”. Using the count of small humps and large humps, the controller 16 may determine the type of the work cycle. For example, if there are more than 3 small humps in the work cycle, the controller 16 determines that the work cycle is the fracking cycle.

In various embodiments, the controller 16 uses various machine learning algorithms to determine the type of the work cycle. In machine learning algorithms, a labeled data set is prepared for training and testing the algorithm. Data corresponding to at least one of the signal characteristics such as peak pressure, time duration of work cycle, number of small humps, and number of large humps may be included in the labeled data set. As an example, 70% of the labeled data set is used for training the algorithm and 30% of the labeled data set is used for testing the algorithm. The controller 16 further identifies one or more signal characteristics which are suitable for machine learning. Techniques such as box plot and scatter plot may be used to identify suitable parameters for machine learning.

In one embodiment, Linear Discriminant Analysis (LDA) algorithm is used for determining the type of the work cycle. In another embodiment, Ensemble Subspace Discriminant Analysis algorithm is used for determining the type of the work cycle. A person skilled in the art will appreciate that Linear Discriminant Analysis algorithm and Ensemble Subspace Discriminant Analysis algorithm are mentioned merely for illustration purposes and various other machine learning algorithms may be used by the controller 16. For example, algorithms such as Support Vector Machines, k Nearest Neighbors, Random Forest, Bagged and Boosted Trees may be used as machine learning algorithm by the controller 16. Confusion matrix and True Positives graph may be plotted for the aforementioned machine learning algorithms to evaluate the performance of the algorithms.

It should be noted that a sequence of the system test cycle, the fracking cycle, and the perforation cycle described herein is merely exemplary and may vary based on application requirements. For example, in other embodiments, each of the first work cycle “W1”, the second work cycle “W2”, and the third work cycle “W3” may be any of the system test cycle, the fracking cycle, and the perforation cycle in any order based on application requirements.

INDUSTRIAL APPLICABILITY

The present disclosure relates to a method 26 of working of the work cycle determination system 10 for determining the work cycle of the fracking pump 12. Referring to FIG. 3, a flowchart of the method 26 is illustrated. At step 28, the controller 16 receives the signal indicative of the pressure generated by the fracking pump 12 from the pressure sensor 14. The controller 16 receives the signal over the predefined period of time. Additionally, the low pass filter 20 provides filtering of the high frequency components from the signal. In some embodiments, backlash filtering may be performed in order to filter out minor variations in the signal.

At step 30, the controller 16 identifies a boundary of a work cycle from the analysis of the signal. In one embodiment, the controller 16 determines the first cycle boundary “B1”, the second cycle boundary “B2”, and so on based on the slope thresholds. At step 32, the controller 16 determines the peak pressure of the work cycle. The controller 16 compares the peak pressure of the work cycle with one or more peak pressure thresholds. The controller 16 may be configured with various peak pressure thresholds corresponding to different types of the work cycles.

At step 34, the controller 16 determines the time duration of the work cycle. The controller 16 may be configured with various time ranges corresponding to different types of the work cycles. At step 36, the controller 16 determines the type of the work cycle of the fracking pump 12 based on the peak pressure and the time duration of the work cycle. The work cycle may be one of the system test cycle, the perforation cycle, and the fracking cycle.

The work cycle determination system 10 provides a simple, efficient, and cost effective method 26 of determining the type of the work cycle of the fracking pump 12. The determination of the work cycle may he further used for additional operational analysis of the fracking pump 12 such as performance evaluation, determining service schedule, component replacement schedule, pump utilization, and so on. The work cycle determination system 10 may be incorporated in any system with little or no modification to the existing system.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the aft that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of the disclosure. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Claims

1. A work cycle determination system for a fracking pump, the work cycle determination system comprising:

a pressure sensor associated with the fracking pump, the pressure sensor adapted to generate a signal indicative of a pressure generated by the fracking pump; and

a controller communicably coupled to the pressure sensor, the controller configured to: receive the signal indicative of the pressure generated by the fracking pump over a predefined period of time; identify a boundary of a work cycle within the predefined period of time by analyzing the signal; determine a peak pressure of the work cycle; determine a time duration of the work cycle; determine a type of the work cycle of the fracking pump based on the peak pressure and the time duration of the work cycle.

2. The system of claim 1, wherein the type of the work cycle is at least one of a system test cycle, a perforation cycle, and a fracking cycle.

3. The system of claim 1, wherein the controller is configured to filter the signal received from the pressure sensor through a low pass filter.