Browsing by Subject "Barnett Shale"
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Item A Methodology to Determine both the Technically Recoverable Resource and the Economically Recoverable Resource in an Unconventional Gas Play(2010-10-12) Almadani, Husameddin Saleh A.During the past decade, the worldwide demand for energy has continued to increase at a rapid rate. Natural gas has emerged as a primary source of US energy. The technically recoverable natural gas resources in the United States have increased from approximately 1,400 trillion cubic feet (Tcf) to approximately 2,100 trillion cubic feet (Tcf) in 2010. The recent declines in gas prices have created short-term uncertainties and increased the risk of developing natural gas fields, rendering a substantial portion of this resource uneconomical at current gas prices. This research quantifies the impact of changes in finding and development costs (FandDC), lease operating expenses (LOE), and gas prices, in the estimation of the economically recoverable gas for unconventional plays. To develop our methodology, we have performed an extensive economic analysis using data from the Barnett Shale, as a representative case study. We have used the cumulative distribution function (CDF) of the values of the Estimated Ultimate Recovery (EUR) for all the wells in a given gas play, to determine the values of the P10 (10th percentile), P50 (50th percentile), and P90 (90th percentile) from the CDF. We then use these probability values to calculate the technically recoverable resource (TRR) for the play, and determine the economically recoverable resource (ERR) as a function of FandDC, LOE, and gas price. Our selected investment hurdle for a development project is a 20 percent rate of return and a payout of 5 years or less. Using our methodology, we have developed software to solve the problem. For the Barnett Shale data, at a FandDC of 3 Million dollars, we have found that 90 percent of the Barnet shale gas is economically recoverable at a gas price of 46 dollars/Mcf, 50 percent of the Barnet shale gas is economically recoverable at a gas price of 9.2 dollars/Mcf, and 10 percent of the Barnet shale gas is economically recoverable at a gas price of 5.2 dollars/Mcf. The developed methodology and software can be used to analyze other unconventional gas plays to reduce short-term uncertainties and determine the values of FandDC and gas prices that are required to recover economically a certain percentage of TRR.Item A Technical and Economic Study of Completion Techniques In Five Emerging U.S. Gas Shale Plays(2010-07-14) Agrawal, Archnamethane and other higher order hydrocarbons, through C4, with interest in further developing reactions important to methane- and ethane-related chemistry. With the increased demand for energy and the declining conventional hydrocarbons worldwide, energy companies, both majors and independents, are turning to unconventional resources to produce the hydrocarbons required to meet market demand. From coalbed methane to low permeability (tight) gas reservoirs and gas shales, energy companies are making substantial progress in developing the technologies required to bring these unconventional reserves to the market. A common misconception is that there are not enough domestic oil and gas reserves to fuel our economy. The United States imports most of the oil used for transportation fuel and several TCF of natural gas annually. However, there is a very large resource of natural gas in unconventional reservoirs, with over 2,200 TCF of gas in place in just the gas shale formations that have been identified in the energy arena (Navigant Study 2008). There are still major gas shale plays and basins that have not been explored and are waiting to be evaluated and developed. The natural gas in shales and other unconventional reservoirs can be used to generate electricity, or it can be turned into liquids and used by the transportation industry. It is also misconstrued that gas shales are relatively new in our industry and something of the future. The first commercially viable gas shale well was drilled in the early 1920s in Pennsylvania, before the famous oil well drilled by Colonel Drake. The objectives of this study are to (1) complete literature review to establish which geologic parameters affect completion techniques in five emerging gas shales: the Antrium, the Barnett, the Haynesville, the Marcellus, and the Woodford; (2) identify the different completion methods; (3) create an economic model for the completion techniques discussed; (4) develop a sensitivity analysis on various economic parameters to determine optimal completion strategy; and (5) create completion flowcharts. Based on the literature review I have done for several gas shale basins, I have identified seven pertinent geologic parameters that influence completion practices. These are depositional environment, total organic content (TOC), average gas content, shale mineralogy, shale thickness, and reservoir pressure. Next, I identified different completion and simulation trends in the industry for the different shale plays. The results from this study show that although there are some stark differences between depths (i.e. the Antrim Shale and the Haynesville Shale), shale plays are very similar in all other geologic properties. Interestingly, even with a large range for the different geological parameters, the completion methods did not drastically differ indicating that even if the properties do not fall within the range presented in this paper does not automatically rule them out for further evaluation in other plays. In addition to the evaluation of geologic properties, this study looked at drilling cost and the production profile for each play. Due to the volatility of the energy industry, economic sensitivity was completed on the price, capital, and operating cost to see what affect it would have on the play. From the analysis done, it is concluded that horizontal drilling in almost any economic environment is economic except for one scenario for the Woodford Shale. Therefore, gas shales plays should still be invested in even in lower price environments and companies should try to take advantage of the lower cost environments that occur during these times. With continual development of new drilling and completion techniques, these plays will become more competitive and can light the path for exploration of new shale plays worldwide.Item An Investigation of Regional Variations of Barnett Shale Reservoir Properties, and Resulting Variability of Hydrocarbon Composition and Well Performance(2010-07-14) Tian, YaoIn 2007, the Barnett Shale in the Fort Worth basin of Texas produced 1.1 trillion cubic feet (Tcf) gas and ranked second in U.S gas production. Despite its importance, controls on Barnett Shale gas well performance are poorly understood. Regional and vertical variations of reservoir properties and their effects on well performances have not been assessed. Therefore, we conducted a study of Barnett Shale stratigraphy, petrophysics, and production, and we integrated these results to clarify the controls on well performance. Barnett Shale ranges from 50 to 1,100 ft thick; we divided the formation into 4 reservoir units that are significant to engineering decisions. All but Reservoir Unit 1 (the lower reservoir unit) are commonly perforated in gas wells. Reservoir Unit 1 appears to be clay-rich shale and ranges from 10 to 80 ft thick. Reservoir Unit 2 is laminated, siliceous mudstone and marly carbonate zone, 20 to 300 ft thick. Reservoir Unit 3 is composed of multiple, stacked, thin (~15-30 ft thick), upward coarsening sequences of brittle carbonate and siliceous units interbedded with ductile shales; thickness ranges from 0 to 500 ft. Reservoir Unit 4, the upper Barnett Shale is composed dominantly of shale interbedded with upward coarsening, laterally persistent, brittle/ductile sequences ranging from 0 to 100 ft thick. Gas production rates vary directly with Barnett Shale thermal maturity and structural setting. For the following five production regions that encompass most of the producing wells, Peak Monthly gas production from horizontal wells decreases as follows: Tier 1 (median production 60 MMcf) to Core Area to Parker County to Tier 2 West to Oil Zone-Montague County (median production 10 MMcf). The Peak Monthly oil production from horizontal wells is in the inverse order of gas production; median Peak Monthly oil production is 3,000 bbl in the Oil Zone-Montague County and zero in Tier 1. Generally, horizontal wells produce approximately twice as much oil and gas as vertical wells.This research clarifies regional variations of reservoir and geologic properties of the Barnett Shale. Result of these studies should assist operators with optimization of development strategies and gas recovery from the Barnett Shale.Item Analysis of Data from the Barnett Shale with Conventional Statistical and Virtual Intelligence Techniques(2011-02-22) Awoleke, Obadare O.Water production is a challenge in production operations because it is generally costly to produce, treat, and it can hamper hydrocarbon production. This is especially true for gas wells in unconventional reservoirs like shale because the relatively low gas rates increase the economic impact of water handling costs. Therefore, we have considered the following questions regarding water production from shale gas wells: (1) What is the effect of water production on gas production? (2) What are the different water producing mechanisms? and (3) What is the water production potential of a new well in a given gas shale province. The first question was answered by reviewing relevant literature, highlighting observed deficiencies in previous approaches, and making recommendations for future work. The second question was answered using a spreadsheet based Water-Gas-Ratio analysis tool while the third question was investigated by using artificial neural networks (ANN) to decipher the relationship between completion, fracturing, and water production data. We will consequently use the defined relationship to predict the average water production for a new well drilled in the Barnett Shale. This study also derived additional insight into the production trends in the Barnett shale using standard statistical methods. The following conclusions were reached at the end of the study: 1) The observation that water production does not have long term deleterious effect on gas production from fractured wells in tight gas sands cannot be directly extended to fractured wells in gas shales because the two reservoir types do not have analogous production mechanisms. 2) Based on average operating conditions of well in the Barnett Shale, liquid loading was found to be an important phenomenon; especially for vertical wells. 3) A neural network was successfully used to predict average water production potential from a well drilled in the Barnett shale. Similar methodology can be used to predict average gas production potential. Results from this work can be utilized to mitigate risk of water problems in new Barnett Shale wells and predict water issues in other shale plays. Engineers will be provided a tool to predict potential for water production in new wells.Item General screening criteria for shale gas reservoirs and production data analysis of Barnett shale(2009-05-15) Deshpande, Vaibhav PrakashraoShale gas reservoirs are gaining importance in United States as conventional oil and gas resources are dwindling at a very fast pace. The purpose of this study is twofold. First aim is to help operators with simple screening criteria which can help them in making certain decisions while going after shale gas reservoirs. A guideline chart has been created with the help of available literature published so far on different shale gas basins across the US. For evaluating potential of a productive shale gas play, one has to be able to answer the following questions: 1. What are the parameters affecting the decision to drill a horizontal well or a vertical well in shale gas reservoirs? 2. Will the shale gas well flow naturally or is an artificial lift required post stimulation? 3. What are the considerations for stimulation treatment design in shale gas reservoirs? A comprehensive analysis is presented about different properties of shale gas reservoirs and how these properties can affect the completion decisions. A decision chart presents which decision best answers the above mentioned questions. Secondly, research focuses on production data analysis of Barnett Shale Gas reservoir. The purpose of this study is to better understand production mechanisms in Barnett shale. Barnett Shale core producing region is chosen for the study as it best represents behavior of Barnett Shale. A field wide moving domain analysis is performed over Wise, Denton and Tarrant County wells for understanding decline behavior of the field. It is found that in all of these three counties, Barnett shale field wells could be said to have established pressure communication within the reservoir. We have also studied the effect of thermal maturity (Ro %), thickness, horizontal well completion and vertical well completion on production of Barnett Shale wells. Thermal maturity is found to have more importance than thickness of shale. Areas with more thermal maturity and less shale thickness are performing better than areas with less thermal maturity and more shale thickness. An interactive tool is developed to access the production data according to the leases in the region and some suggestions are made regarding the selection of the sample for future studies on Barnett Shale.Item Process Design, Simulation and Integration of Dimethyl Ether (DME) Production from Shale Gas by Direct and Indirect Methods(2014-08-11) Karagoz, SecginAs the energy demand is increasing constantly, sustainable energy resources are needed to meet this demand and enable economic stability. In order to attain this goal, researchers continue to develop new technologies and methods in the field of sustainable energy. Over the last decade, the U.S has witnessed substantial growth in shale gas production. Consequently, shale gas has become a competitive feedstock for usage as energy and production of chemicals and petrochemicals. A valuable product which may be obtained from shale gas is dimethyl ether (DME). Dimethyl ether can be used in many areas such as power generation, transportation fuel, and domestic heating and cooking. Dimethyl ether is currently produced from natural gas, coal and biomass through synthesis gas as an intermediate. Recently, the attention to DME has increased because of its potential in addressing energy security and environmental problems. DME is produced conventionally through two steps (indirect process) which are methanol synthesis and dehydration of the methanol to DME. Another way to produce DME is the direct synthesis of DME from syngas. In order to use DME as a fuel alternative, it must be produced at low cost in large quantities. The purpose of this study is to develop a process synthesis, simulation, and integration of a shale gas-to-DME plant by direct and indirect methods. Techno-economic analysis is carried out to assess the profitability of the base-case processes under current market conditions. A sensitivity analysis is also conducted to evaluate the process profitability under variable market conditions. Finally, the both methods are compared in terms of the fixed capital cost, operating cost, return on investment, and CO_(2) and water impact. Indirect and direct process simulation of commercial DME plant was carried out by Aspen Plus. The shale gas feedstock was taken from one of the wells in Barnett shale play. The DME production capacities of the base cases for the direct and indirect processes were set to 3,250 tonnes per day. The direct and indirect process flowsheets were synthesized using five and seven main processing steps, respectively. Pinch analysis was used to conduct heat integration of the process. As a result of study, it was found that the direct method has advantage over the indirect method in terms of the fixed capital cost, operating cost, return on investment, and CO_(2) impact. The capital investment of the direct production method is 25% less than the indirect method. The direct method is more economically attractive than the indirect method. When a sensitivity analysis is considered, the prices of methanol and shale gas are the most important factors impacting the operating cost. The contribution of energy integration on the ROI of the direct method is approximately 2.25%. The ROI of the indirect method is improved by 1.83% after energy integration. In contrast to the other criteria, the indirect way has significant advantage over the direct way by producing almost 1760 ton/d water. The direct method produces less CO_(2) emission than the indirect method because it uses dry reforming to convert CO_(2) to syngas.Item Strategies to reduce terminal water consumption of hydraulic fracture stimulation in the Barnett Shale(2009-08) Harold, Jennifer Marie Secor; Groat, Charles G.; Schuster, Stefan K.; Fialkoff, Jason S.Horizontal drilling and hydraulic fracture stimulation have enabled the economic development of unconventional resource plays. An average horizontal well in the Barnett Shale requires 3 to 4 million gallons of fresh water, 90% of which is used for hydraulic fracture stimulation. While the water consumption of Barnett Shale operations is less than 1% of total Region C consumption, extended drought conditions and competing demands for water resources are placing pressure on operators to reduce terminal water consumption. Strategies which reduce water requirements associated hydraulic fracture stimulation without compromising the efficiency and cost of energy production are essential in developing a comprehensive policy on energy-water management. Recycling and reuse technologies were evaluated on the basis of performance, cost, and capacity to treat reclaimed flowback water and oilfield brine. Recycling flowback fluids for future hydraulic fracture applications is the most practical repurposing of oilfield waste. The low TDS content of flowback derived from water-based fracs permits multiple treatment options. Mobile thermal distillation technology has emerged as the prevailing technique for recycling flowback water, yielding maximum water savings and reduced operating costs. The estimated cost of recycling flowback water by thermal distillation is $3.35/bbl. Compared to the current cost of disposal, recycling provides an opportunity to minimize waste and reduce the fresh water requirements of hydraulic fracture stimulation at an incremental cost. The stewardship role of the Texas Legislature is to protect the water resources of the state and to facilitate the Regional Water Planning Process, ensuring future water needs are met. The support and participation of the Legislature and other planning entities is critical in advancing the energy-water nexus. As operators pursue innovative water management practices to reduce terminal water consumption in the oilfield, the Barnett Shale positions itself as a model for sustainable water use in the development of unconventional shale resources. The cost of recycling and reuse technology limits the participation of small and mid-size operators who possess the greatest market share of the Barnett Shale. Funding for research and implementation of water-conscious strategies such as shared recycling facilities, CO2 capture and storage, and pipeline infrastructure would create multi-user opportunities to promote conservation and reduce net consumption of fresh water supplies. Through the integration of technology and policy, terminal water consumption in the Barnett Shale can be greatly diminished.Item Using Decline Map Anlaysis (DMA) to Test Well Completion Influence on Gas Production Decline Curves in Barnett Shale (Denton, Wise, and Tarrant Counties)(2010-01-14) Alkassim, IbrahimThe increasing interest and focus on unconventional reservoirs is a result of the industry's direction toward exploring alternative energy sources. It is due to the fact that conventional reservoirs are being depleted at a fast pace. Shale gas reservoirs are a very favorable type of energy sources due to their low cost and long-lasting gas supply. In general, according to Ausubel (1996), natural gas serves as a transition stage to move from the current oil-based energy sources to future more stable and environment-friendly ones. By looking through production history in the U.S Historical Production Database, HPDI (2009), we learn that the Barnett Shale reservoir in Newark East Field has been producing since the early 90's and contributing a fraction of the U.S daily gas production. Zhao et al. (2007) estimated the Barnett Shale to be producing 1.97 Bcf/day of gas in 2007. It is considered the most productive unconventional gas shale reservoir in Texas. By 2004 and in terms of annual gas production volume, Pollastro (2007) considered the Barnett Shale as the second largest unconventional gas reservoir in the United States. Many studies have been conducted to understand better the production controls in Barnett Shale. However, this giant shale gas reservoir is still ambiguous. Some parts of this puzzle are still missing. It is not fully clear what makes the Barnett well produce high or low amounts of gas. Barnett operating companies are still trying to answer these questions. This study adds to the Barnett chain of studies. It tests the effects of the following on Barnett gas production in the core area (Denton, Wise, and Tarrant counties): * Barnett gross thickness, including the Forestburg formation that divides Barnett Shale. * Perforation footage. * Perforated zones of Barnett Shale. Instead of testing these parameters on each well production decline curve individually, this study uses a new technique to simplify this process. Decline Map Analysis (DMA) is introduced to measure the effects of these parameters on all production decline curves at the same time. Through this study, Barnett gross thickness and perforation footage are found not to have any definite effects on Barnett gas production. However, zone 3 (Top of Lower Barnett) and zone 1 (Bottom of Lower Barnett) are found to contribute to cumulative production. Zone 2 (Middle of Lower Barnett) and zone 4 (Upper Barnett), on the other hand, did not show any correlation or influence on production through their thicknesses.