The Greenhouse Gas (GHG) Reporting Rule, 40 Code of Federal Regulations (CFR) Part 98 under Subpart W, is mandated by the U.S. Environmental Protection Agency (EPA), impacting those production sources annually emitting above an equivalent threshold of 25,000 metric tons of CO2.

The reporting requirements place a tremendous strain on oil and natural gas producers as they struggle with the enormous data volume necessary to comply.

More challenging than just the sheer volume is the complicating fact that the information is tracked by separate functional groups for different purposes, including field operations at the well pad, work order management systems, operations engineering and financial accounting. Often the data are collected in different formats using dissimilar terminology.

Preparation for GHG reporting Subpart W production is highly labor-intensive, often overwhelming the environmental groups in subject organizations with data points exceeding 1 million annually for a company with multiproducing regions. GHG natural gas data required have been estimated at more than two orders of magnitude greater than any previous EPA report.

In October 2015 the EPA amended Subpart W to include onshore production gathering and boosting segments. This amendment was initiated on Jan. 1, 2016, with first reported data due in January 2017. The additional segments add to the data volume and present even more challenges to the reporting entities. Recognizing some emission sources under the gathering and boosting segment might be intertwined with sources under production and processing, extra effort will be needed to extract or aggregate data from data sources used by the other two.

Steps to compliance success
GHG CFR 98.4 states that compliance reporting must be true, accurate and complete to the best of knowledge of the reporters/business owners. How can that be best accomplished in the most efficient and cost-effective way?

The labor-reducing answer lies with an approach involving the automation of data collection, integration and quality control/quality assurance (QC/QA) using a centralized data warehouse and business logic. This procedure was recently completed at a major producer’s southwestern U.S. asset of more than 9,000 well sites with more than 1.2 million data points.

In that specific case, and in other similar applications, a four-phase workflow process was effectively implemented, automating the first three stages to allow validated, consistent reporting. These phases, as depicted in Figure 1, include:

Data collection: During this initial phase, all sources that could provide required GHG data are identified. The main focus at this point is to assure that data from all these sources, regardless of the host system generating them, can be consolidated into a centralized database as a common model. This step segues into further aggregation and integration.

Data integration: This phase provides a more detailed assessment of which data fields are needed to integrate, selecting all relevant parameters and arranging them into a structure for the performance on a common platform. The stage also lays the foundation for a comprehensive QA.

This stage involves four separate steps of its own. First, an assessment is undertaken to determine the primary data spheres needing to be integrated. These can be either direct emission calculation input or taken from indirect data.

Next, a common identifier is found that integrates portions of data from different systems. This is a critical step in the integration and in assuring QC/QA.

Step 3 is needed to recognize relationships between the emission sources according to function and interrelatedness so that data points can be mapped structurally. For example, equipment such as pumps, engines and compressors should be mapped under wellpad in a hierarchical fashion, or nonhierarchically such as the horizontal relationship between engine-driven compressors and engines. Data integration becomes easier once that procedure has been completed. The relationship is driven by its physical data model, illustrated in Figure 2.

The last step in the data integration phase is the actual data aggregation organized by individual well of annual production, activity and equipment.

QC/QA: The compliance mandates of truth, accuracy and completeness in CFR Part 98.4 put additional burden on the reporter/owner to assure that the reporting results are of the required quality. This can be a daunting task when there are multiple dissimilar data systems involved that are not designed for environmental reporting or without standard guidelines for the data tracking of those systems. The task can be further complicated when there are more than one large geographic asset to report or if rigorous data entry protocol is lacking. Not resolving these factors can lead to incomplete, inconsistent or inaccu-
rate information.

Based on the responsibilities inherent in the QC/QA phase, it has proven valuable to develop a series of business logics to integrate previous phases and perform data analyses and validation. To reach the best results from the QC/QA phase, a unique skillset is required that combines onshore upstream knowledge plus abilities and experience in data analysis. The logics performed become part of the common data model to
• Check individual systems for missing, duplicate or inaccurate information;
• Verify the well list and operating status among the equipment inventory, operating activity and production data systems; and
• Substantiate the equipment count based on the mutual relationships.

At the successful conclusion of automating these first three phases, environmental department personnel should be able to generate a clean and validated dataset complete for GHG emissions calculations.

The three phases account for 80% of the total effort. Once completed, the labor savings are enormous. Recently, a large gas producer previously requiring six man-weeks to complete the process dropped its work effort to less than two man-hours with a higher degree of accuracy than had previously been attained.

GHG report filing, feedback
At the final process stage, the reporter can use the previously obtained data output to submit its report to the EPA after sending the report to the data owners for review and any needed corrections. This portion encompasses about 20% of the reporting project. At this stage records can be centrally warehoused to satisfy the requirement of keeping historical records with a transparency for explaining how the information was derived and emissions calculated.

With the increased emissions data requirements mandated by the EPA and the additional volume needed for GHG Subpart W production components, U.S. producers are turning to automation of data collection, integration and QC/QA as a solution. This resolution will dramatically reduce labor time, increase efficiency and improve accuracy.

The data accumulated in this fashion can further allow environmental department personnel the opportunity for additional analysis of operating data for maximizing production while minimizing emissions and provides a reporting methodology for other state and federal agencies that eliminates duplication of effort.

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