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Make Your Oil and Gas Assets Smarter by Implementing Predictive Maintenance with Databricks

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How to build an end-to-end predictive data pipeline with Databricks Delta and Spark Streaming
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Maintaining assets such as compressors is an extremely complex endeavor: they are used in everything from small drilling rigs to deep-water platforms, the assets are located across the globe, and they generate terabytes of data daily.  A failure for just one of these compressors costs millions of dollars of lost production per day. An important way to save time and money is to use machine learning to predict outages and issue maintenance work orders before the failure occurs.

Ultimately, you need to build an end-to-end predictive data pipeline that can provide a real-time database to maintain asset parts and sensor mappings, support a continuous application that processes a massive amount of telemetry, and allows you to predict compressor failures against these datasets.

Our approach to addressing these issues is by selecting a unified platform that offers these capabilities. Databricks provides a Unified Analytics Platform that brings together big data and AI and allows the different personas of your organization to come together and collaborate in a single workspace.  Other important advantages of the Databricks Unified Analytics Platform include the ability to:

  • Spin up the necessary resources and have your data scientists, data engineers, and data analysts making sense of their data quickly.
  • Have a multi-cloud strategy allowing everyone to use the same collaborative workspace in Azure or AWS.
  • Stand up a diverse set of instance type combinations to optimally run your workloads
  • Schedule commands (including REST API commands) that allows you to auto-create and auto-terminate your clusters.
  • Quickly and easily enable access control to assign permissions as well as enable access tokens for secure REST API calls when productionizing your solution.

In this blog post, we will show how you can make your oil and gas assets smarter by:

  • Using Spark Streaming in Databricks to process the immense amount of sensor telemetry.
  • Building and deploying your machine learning models to predict asset failures before they happen.
  • Creating a real-time database using Databricks Delta to store and stream sensor parts and assets.

Establishing your Kinesis Stream

To predict catastrophic failures, we need to combine the asset sensors continuous stream of data from Kinesis, Spark Streaming, and our Streaming K-Means model.  Let’s start by configuring our Kinesis stream using the code snippet below. To dive deeper, refer to Databricks - Amazon Kinesis Integration.


// === Configurations for Kinesis streams ===
val awsAccessKeyId = "YOUR ACCESS KEY ID"
val awsSecretKey = "YOUR SECRET KEY"
val kinesisStreamName = "YOUR STREAM NAME"
val kinesisRegion = "YOUR REGION" // e.g., "us-west-2"

import com.amazonaws.services.kinesis.model.PutRecordRequest
import com.amazonaws.services.kinesis.AmazonKinesisClientBuilder
import com.amazonaws.auth.{DefaultAWSCredentialsProviderChain, BasicAWSCredentials}
import java.nio.ByteBuffer
import scala.util.Random

With your credentials established, you can run a Spark Streaming query that reads words from Kinesis and counts them up with the following code snippet.


// Establish Kinesis Stream 
val kinesis = spark.readStream
  .format("kinesis")
  .option("streamName", kinesisStreamName)
  .option("region", kinesisRegion)
  .option("initialPosition", "TRIM_HORIZON")
  .option("awsAccessKey", awsAccessKeyId)
  .option("awsSecretKey", awsSecretKey)
  .load()

// Execute DataFrame query agaijnst the Kinesis Stream
val result = kinesis.selectExpr("lcase(CAST(data as STRING)) as word")
  .groupBy($"word")
  .count()

// Display the output as a bar chart
display(result)

To configure your own Kinesis stream, write those words to your Kinesis Stream by creating a low-level Kinesis client such as the following code snippet that loops every 5s.


// Create the low-level Kinesis Client from the AWS Java SDK.
val kinesisClient = AmazonKinesisClientBuilder.standard()
  .withRegion(kinesisRegion)
  .withCredentials(new AWSStaticCredentialsProvider(new BasicAWSCredentials(awsAccessKeyId, awsSecretKey)))
  .build()

println(s"Putting words onto stream $kinesisStreamName")
var lastSequenceNumber: String = null

for (i 



Explore your Sensor Data

Before we can build our model to predict healthy vs. damaged compressors, let’s start by doing a little data exploration.  First, we need to import our healthy and damaged compressor data; the following code snippet imports the healthy compressor data that is in CSV format into a Spark SQL DataFrame.


// Read healthy compressor readings (represented by `H1` prefix)
val healthyCompressorsReadings = sqlContext.read.format("com.databricks.spark.csv")
    .schema(StructType(
       StructField("AN10", DoubleType, false) :: 
       StructField("AN3", DoubleType, false) :: 
       StructField("AN4", DoubleType, false) :: 
       StructField("AN5", DoubleType, false) :: 
       StructField("AN6", DoubleType, false) :: 
       StructField("AN7", DoubleType, false) :: 
       StructField("AN8", DoubleType, false) :: 
       StructField("AN9", DoubleType, false) :: 
       StructField("SPEED", DoubleType, false) :: Nil)
    ).load("/compressors/csv/H1*")

// Create Healthy Compressor Spark SQL Table
healthyCompressorsReadings.write.mode(SaveMode.Overwrite).saveAsTable("compressor_healthy")

// Read table from Parquet
val compressor_healthy = table("compressor_healthy")

We also save the data as a Spark SQL table so we can query it using Spark SQL.  For example, we can use the Databricks display command to view the table statistics of our damaged compressor table.


display(compressor_damaged.describe())

After taking a random sample of healthy and damaged data using the following code snippet:


// Obtain a random sample of healthy and damaged compressors
val randomSample = compressor_healthy.withColumn("ReadingType", lit("HEALTHY")).sample(false, 500/4800000.0)
            .union(compressor_damaged.withColumn("ReadingType", lit("DAMAGED")).sample(false, 500/4800000.0))

we can use the Databricks display command to visualize our random sample of data using a scatter plot.


// View scatter plot of healthy vs. damaged compressor readings
display(randomSample)

Building our Model

The next steps for implementing our predictive maintenance model is to create a K-Means model to cluster our datasets to predict damaged vs. healthy compressors. In addition to K-Means being a popular and well-understood clustering algorithm, there is also the benefit of using a streaming k-means model allowing us to easily execute the same model in batch and in streaming scenarios.

The first thing we want to do is to determine the optimal k value (i.e. optimal number of clusters). As we are currently identifying the difference between healthy and damaged, intuitively the value of k is 2 but let’s validate. As noted in the following code snippet, we will build an ML pipeline so we can easily re-use the model for our new dataset (i.e. the streaming dataset upstream). Our ML pipeline is relatively straightforward using VectorAssembler to define our features involving the Air and Noise columns (i.e. columns preceding with AN) and scaling it using MinMaxScaler.


import org.apache.spark.ml._
import org.apache.spark.ml.feature._
import org.apache.spark.ml.clustering._
import org.apache.spark.mllib.linalg.Vectors

// Using KMeansModel
val models : Array[org.apache.spark.mllib.clustering.KMeansModel]  = new Array[org.apache.spark.mllib.clustering.KMeansModel](10)

// Use VectorAssembler to define our features based on the Air + Noise columns (and scale it)
val vectorAssembler = new VectorAssembler().setInputCols(compressor_healthy.columns.filter(_.startsWith("AN"))).setOutputCol("features")
val mmScaler = new MinMaxScaler().setInputCol("features").setOutputCol("scaled")

// Build our ML Pipeline 
val pipeline = new Pipeline()
  .setStages(Array(vectorAssembler, mmScaler))

// Build our model based on healthy compressor data
val prepModel = pipeline.fit(compressor_healthy)
val prepData = prepModel.transform(compressor_healthy).cache()

// Iterate to find the best K values
val maxIter = 20
val maxK = 5
val findBestK = for (k 



We run a number of iterations to determine the best k value though, for the purpose of this demo, we <em>init</em> ourselves to k values [2...5] and set the max iterations to 20. The goal is to iterate through the various k and <em>WSSSE</em> (Within Set Sum of Squared Error) values; the optimal k value (the ideal number of clusters) is the one where there is an “elbow” in the WSSSE graph. We can also calculate the highest derivative of the graph with the following code snippet.




// Calculate Derivative of WSSSE val previousDf = kWssseDf.withColumn("k", $"k"-1).withColumnRenamed("wssse", "previousWssse") val derivativeOfWssse = previousDf.join(kWssseDf, "k").selectExpr("k", "previousWssse - wssse derivative").orderBy($"k") // find the point with the "highest" derivative // i.e. optimal number of clusters is bestK = 2 val bestK = derivativeOfWssse .select( (lead("derivative", 1).over(Window.orderBy("k")) - $"derivative").as("nextDerivative") ,$"k").orderBy($"nextDerivative".desc).rdd.map(_(1)).first.asInstanceOf[Int] 

Now that we have identified the optimal k value, we can now build our model with 2 clusters. The code snippet below creates our KMeans model (bestModel) against our healthy compressor data (prepData) and calculates the WSSSE (wssse).


// Create our `kmeans` model 
val kmeans = new KMeans()
.setK(bestK)
.setSeed(1L)
.setMaxIter(100)
.setFeaturesCol("scaled")
val bestModel = kmeans.fit(prepData)
val wssse = bestModel.computeCost(prepData)

// Output
kmeans: org.apache.spark.ml.clustering.KMeans = kmeans_aeafe51274c3
bestModel: org.apache.spark.ml.clustering.KMeansModel = kmeans_aeafe51274c3
wssse: Double = 329263.3539615829

We can quickly observe the difference between the healthy vs. damaged compressors via the WSSSE values by applying the damaged compressor data to the same ML pipeline and model.


// Calculate WSSSE of damaged compressors
val prepDamagedModel = pipeline.fit(compressor_damaged)
val prepDamagedData = prepModel.transform(compressor_damaged).cache()
val bestDamagedModel = kmeans.fit(prepDamagedData)
val wssse = bestDamagedModel.computeCost(prepDamagedData)

// Output
prepDamagedModel: org.apache.spark.ml.PipelineModel = pipeline_70af6bee9dad
prepDamagedData: org.apache.spark.sql.Dataset[org.apache.spark.sql.Row] = [AN10: double, AN3: double ... 9 more fields]
bestDamagedModel: org.apache.spark.ml.clustering.KMeansModel = kmeans_aeafe51274c3
wssse: Double = 1440111.9276810554

Deploying the model using Streaming K-Means

While we have a potentially viable model to predict compressor failure, executing this model in real-time (vs. batch) allows us to build a continuous application that constantly receives asset sensor streams. We can now potentially predict compressor failure even earlier thus providing us more time to fix or replace the compressor prior to a catastrophic failure.

The following code snippet creates our Streaming KMeans model using the same bestK value for the setK property (i.e. 2 clusters). To dive deeper into the Streaming K-Means algorithm, refer to the MLlib Programming Guide > MLlib Clustering > Streaming K-Means.


// Create StreamingKMeans() model
val kMeansModel = new StreamingKMeans()
  .setDecayFactor(0.5)
  .setK(2)
  .setRandomCenters(8, 0.1)

Next we create our streaming function using the StreamingContext to calculate the WSSSE for each mini-batch.


// Function to create a new StreamingContext and set it up
def creatingFunc(): StreamingContext = {
    
  // Create a StreamingContext
  val ssc = new StreamingContext(sc, Seconds(batchIntervalSeconds))
  val batchInterval = Seconds(batchIntervalSeconds)
  ssc.remember(Seconds(300))
 
  val dstream = ssc.queueStream(queue)
  
  // As the DStream receives data, we calculate the WSSSE for each mini-batch
  // and save this data out to DBFS
  kMeansModel.trainOn(dstream)
  dstream.foreachRDD {
    rdd => 
      val wssse = kMeansModel.latestModel().computeCost(rdd)
      val timestamp = System.currentTimeMillis / 1000
      sc.parallelize(
          Seq(
            WsseTimestamps(timestamp, wssse)
          )
        ).toDF().write.mode(SaveMode.Append).json("/tmp/compressors")
  }
  
  println("Creating function called to create new StreamingContext for Compressor Failure Predictions")
  newContextCreated = true  
  ssc
}

With Streaming K-Means model and Spark Streaming function created, the following code snippet now starts our Spark Streaming context.


// Execute the Spark Streaming Context 
val ssc = StreamingContext.getActiveOrCreate(creatingFunc)
if (newContextCreated) {
  println("New context created from currently defined creating function") 
} else {
  println("Existing context running or recovered from checkpoint, may not be running currently defined creating function")
}

// Start Spark Streaming Context
ssc.start()

To persist our data, as noted in the Spark Streaming function, we have saved the timestamp and WSSSE values as JSON to DBFS (in this example, within /tmp/compressors). Files in DBFS persist to blob storage, so you won’t lose data even after you terminate a cluster. The following code snippet allows you to view the stream of WSSSE calculations by timestamp thus allowing you to predict the failure rate of your compressors as the sensor data is being received.


// Read the StreamingKMeans() results from DBFS
val compressorsResults = sqlContext.read.json("/tmp/compressors")

// View the model in action
display(compressorsResults.orderBy("ts"))

We can rely on Apache Spark Streaming to process all of our asset telemetries because it provides strong guarantees about system state: at any time, the output of the application is equivalent to executing a batch job on a prefix of the data. This consistency rule makes it easy to reason about past streaming challenges. Spark Streaming in Databricks provides the power of easily creating continuous applications, simplifying the maintenance of your streaming applications, and the power of the Databricks integrated workspace.

Re-train your model using a real-time database using Databricks Delta

While we have a viable Streaming K-Means model, it is very common to re-train our model as new rows and/or new attributes of data are received. A powerful option would be to create a real-time database that has the ability to store both your legacy (e.g. healthy and damaged compressor data) and new transactions as they are streaming in a consistent manner. To do this, we can use Databricks Delta which provides the performance and reliability of a data warehouse (for the large volumes of legacy compressor data) and the ability to allow for ‘real-time’ updates (for asset telemetry).

In the previous section, we created the table using saveAsTable instead we can use the USING DELTA option such as the following code snippet.


// Create Healthy Compressor Databricks Delta Table
CREATE TABLE compressor_healthy (
 AN10 double,
 AN3 double,
 AN4 double,
 AN5 double,
 AN6 double,
 AN7 double,
 AN8 double,
 AN9 double, 
 SPEED double
)
USING DELTA 
OPTIONS (PATH "/compressors/delta/healthy/")

This Spark SQL statement creates a Databricks Delta table on which you can train and retrain your model that also provides:

  • Ensure data integrity with transactional guarantees.
  • Enable the most consistent view of your streaming writes.
  • Accelerate query speeds through indexing and caching.

Summary

In this blog post, we demonstrated how you can implement predictive maintenance with the Databricks Unified Analytics Platform by combining Spark Streaming, machine learning, and Databricks Delta.   Within a single notebook, you can read and write to a Kinesis stream, build a K-Means model within a ML pipeline, and apply a model to Spark Streaming so you can predict compressor failures as the data is received.  With the Databricks Unified Analytics Platform you can remove the data engineering complexities commonly associated with such data pipelines and easily work with three different data paradigms - streaming, SQL, and machine learning - to potentially prevent failures for any of your assets.

Read More

For more information on Databricks Delta and Structured Streaming read these sources:

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