Predicting Emissions from Oil & Gas Exploration and Production in the Uinta Basin

Transcription

1 Predicting Emissions from Oil & Gas Exploration and Production in the Uinta Basin J. Wilkey, T. A. Ring, J. Spinti, D. Pasqualini, K. Kelly, M. Hogue, and I.C. Jaramillo Institute for Clean and Secure Energy University of Utah

2 HELPING DAQ PREDICT THE FUTURE OF OIL AND GAS E&P IN UINTA BASIN Oil and Gas Production in Uinta Basin Highly paid jobs in Uinta Basin $300 million Tax and Royalty Revenue to State of Utah in FY ,811 ac used in 2011 Water use Contributor to Wintertime Ozone Pollution VOC and NO x and Sunlight combine to produce Ozone (75 ppb EPA limit) November 25, EPA proposes strengthening the National Ambient Air Quality Standards for ozone to 65 to 70 ppb

3 Production from Oil or Gas Well Greater Uinta Basin Cumulative Impacts Technical Support Document, Data Obtained August 2011 Productive Wells Oil 3,471 Gas 9,036 Active Wells 4,090 Abandoned & Plugged Wells 2,575 Total Wells 15,701 % Directional Wells 18.9% Horizontal wells 112 Vertical Directional 2,849 After a short initial period production peaks and then declines to ever lower monthly production rates. Monthly Oil Production from a Single Well

4 Key Concern Wells Drilled Previously with Older Technology will Continue to Produce albeit at Lower Rates for Years to Come Reworked well gives renewed life Continue to Generate VOC Emissions for Years to Come Older technologies tend to generated more VOC emissions than new technologies With Mix of Old Declining Wells and New Wells, What Emissions are Expected? Do they meet Air Quality Regulations? Future Regulations May be Imposed at Some Point by US-EPA or by State of Utah. How do New Regulations Effect Emissions? Goal is to Find a Balance - Allow as much new drilling & production as possible and still meet Air Quality Regulations.

5 Project Objectives Incorporate a methodology to track production on a yearly basis so that varying VOC emission factors (with uncertainty) can be applied to old and (+10 yrs) new wells based on a regulatory schedule that is phased in over different time periods; Account for a fraction of existing wells that are reworked (or fracked) to stimulate production from wells existing before an air quality regulation is imposed; and Provide some initial consultation for set up and use of the software currently configured in the R programming language for DAQ staff so that it can become a DAQ tool for analysis.

6 Methodology: Algorithm Summary 1. Estimate the number of wells drilled (drilling schedule) using Oil and Gas Price Forecasts (EIA - High, Reference & Low Price Forecasts) based upon equation using Historical Uinta Basin Data 2. Estimate oil and gas production from each well each month 1. Monte Carlo Simulation using Probability Distributions Obtained from Historical Uinta Basin Data 3. Apply emissions factors to drilling, production, and transportation events. Emission Factors may be changed to evaluate future regulations. 4. Sum for All Wells with Various Technologies to Predict Emissions Inventory in Future.

7 Methodology: Validation and Uncertainty Methodology Testing: Cross-Validation Training period: Jan to Dec Test period: Jan to Dec Fit to full dataset for predicting future 2014 and beyond Uncertainty Quantification: Probabilistic Sensitivity Analysis Describe uncertainty of inputs with probability distributions (PDs) PDs give the Range of Uncertainty in Input Parameters Monte-Carlo simulation 10,000 s of drilling scenarios examined with statistical analysis of these results

8 Wells Drilled Price Formula for Wells Drilled W t = aop t + bgp t + cw t 1 + d Oil Price Gas Price a, b, c, d are determined from Historical Uinta Basin Drilling Data EIA Oil and Gas Price Forecast

9 R 2 = 0.91 Training Period Test Period

10 Oil and Gas Production Declines with Time Oil Production Model Reworking Wells Arps relative decline rate fit

11 Total Oil Production Preliminary Result Training Period Test Period

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14 Product to be Delivered to DAQ Uinta Basin Monte Carlo Oil and Gas Production Model Field Specific Oil & Gas Drilling Schedule based upon Oil and Gas Price Forecast EIA Price Forecast for High, Reference and Low Well Reworking Schedule Based Upon Historical Frequencies Predict Oil & Gas Production on a Monthly Basis Use Emission Factors to Determine Criteria Emissions (VOC, NO x, etc) Test Various Regulatory Concepts and Start Times Provide a Working Tool to DAQ and Training