Wilton, Derek (Earth Sciences, Memorial University) | Feely, Martin (National University of Ireland) | Carter, James (Nalcor Energy - Oil & Gas) | Costanzo, Alessandra (National University of Ireland) | Hunt, Jon (National University of Ireland)
MLA-SEM analyses can quantitatively define the modal mineralogy of detrital components in a variety of sample material including offshore well cuttings such that the possible source(s) of the detrital material might be ascertained. The MLA data can be queried for combinations of detrital minerals that might reflect a specific source terrane (e.g., igneous suite, metamorphic complex,
This paper summarizes the development and application of a multi-layer reservoir description for the Gas Research Institute (GRI) Comprehensive Study Well 2 (CSW2), which is completed in the Devonian Shales and located in Calhoun Co., WV. We determined that a two-layer reservoir description best describes the complex reservoir and hydraulic fracture system of the CSW2. This reservoir description, determined using a numerical simulator, matched all the data collected, including pre- and post-fracture flow/buildup tests, muld-layer communication tests, individual-layer injection/ falloff tests and pre- and post-fracture production data.
The results of this study indicate that a multi-layer reservoir description provides better estimates of post-fracture performance compared to a more conventional, single-layer reservoir description. This result also explains previous, optimistic estimates of post-fracture well performance which were based on single-layer interpretations of pre-fracture test data. This paper reviews and discusses briefly the many diagnostic tests performed on the CSW2, but focuses on the history match analysis and results determined with a two-layer reservoir model. The testing and analysis approach presented in this paper can be applied generally to other tight formations.
The Devonian Shales of the eastern U.S. are a significant source of domestic U.S. natural gas. The complex storage and production mechanisms of the Shales have been studied extensively. In mid-1987, GRI initiated a multi-year research effort on several highly-instrumented study wells in the Devonian Shales of the Appalachian Basin. These wells, called Comprehensive Study Wells (CSW's), were drilled and studied in cooperation with Appalachian Basin operators. Extensive data were collected and special experiments were conducted on these wells in addition to the operator's normal operations. The objectives of the CSW program were (1) to develop a better understanding of the geologic controls on production, (2) to refine previously developed formation evaluation tools for selecting completion intervals, and (3) to improve reservoir description and stimulation practices in the Devonian Shales.
In the CSW program, we first began evaluating the Devonian Shales using simple, single-layer reservoir models until, as this paper demonstrates, the need to develop more complex models become evident. Now, it appears the large intervals completed in the Shales cannot generally be analyzed or classified as an equivalent single-layer system; they are much more complex. In the CSW2, the post-fracture production performance was much less than we predicted using a single-layer reservoir and fracture description based on pre-fracture well Lest analysis results and the fracture treatment design. Our initial post-fracture well test analysis results indicated a short, 28-ft, infinite-conductivity hydraulic fracture, using a single-layer reservoir description . Because of these results, several post-stimulation diagnostic tests were performed to evaluate the location and geometry of the propped hydraulic fracture, to provide a more detailed reservoir description, and to determine the cause of the less-than-predicted post-fracture well performance.
The purpose of this paper is to present our CSW2 reservoir description based on results obtained using a two-layer reservoir model to history match all the numerous field data collected. Our analysis results indicate an unusual and complex hydraulic fracture geometry which intersects more than one "pay" layer, but only communicates with the wellbore in one layer. A more detailed discussion of our results can be found in Reference 6.
This paper summarizes a series of experiments performed on the Gilbert Exploration Emma Preece No. 1 well in Martin Co., KY which have led to a better understanding of fracture geometry and post-stimulation well performance in the Devonian Shales. The post-stimulation well performance in the Devonian Shales. The Preece well, like many Devonian Shale wells, was perforated and Preece well, like many Devonian Shale wells, was perforated and stimulated with a single treatment over a large, perforated interval (727 ft). Post-fracture well tests performed after initial completion indicated little improvement over pre-fracture well performance. In 1989, the treated interval was sub-divided into four distinct zones to further evaluate the fracture treatment using isolation, communication, nitrogen injection/falloff, and flow/buildup tests. Results of these tests indicate (1) that the large completion interval was not uniformly stimulated by the fracture treatment and (2) that reservoir quality was different for each perforated interval, indicating the completion interval should be treated as a layered reservoir. These results help explain the apparent short fracture half-length and the less-than-expected flow rates for this well following stimulation.
In 1989-1990, contractors for the Gas Research Institute (GRI) performed detailed fracture diagnostic tests on the Emma Preece No. performed detailed fracture diagnostic tests on the Emma Preece No. 1 well located in Martin Co., KY. The overall purpose of these tests was to determine why stimulation treatments in the Shales are not more effective. This paper summarizes the work performed and the data gathered on this well including the conclusions/observations developed based on analysis of the data.
The testing performed on the Emma Preece well was designed to help answer several key questions about stimulating the Devonian Shales. These questions were:
What is the geometry of created fractures in the Shales, and are multiple fracture created?
Can large intervals in a single wellbore be stimulated effectively?
Can we develop different procedures for evaluating stimulation treatments?
Is formation sensitivity to water-based fluids a damage mechanism in the Shales?
Each of these questions were answered, at least in part, by analysis of the data gathered on the Preece well.
Fig. 1 shows the location of the Emma Preece well in Martin Co., KY. The Emma Preece well had previously been studied 1 as a cooperative well in GRI's research program entitled "ExplorationProduction Studies in Newly Drilled Devonian Shale Gas Wells". This program was designed to gather data for the purpose of determining the factors which control and influence gas production. Numerous types of data were gathered including mud log, production log, sidewall core, well test, and stimulation data. production log, sidewall core, well test, and stimulation data. In July 1989, after unsuccessful completion attempts in the Shale and the Injun Sand formations by Gilbert Exploration, the operator of the Preece well, GRI contractors obtained permission to use the well for detailed fracture diagnostic testing. These detailed tests included isolation, communication, flow/buildup, nitrogen injec-tion/falloff, and in-situ fluid sensitivity tests. This paper discusses the objectives, procedures, and analysis results for these tests.
Gilbert Exploration spudded the Emma Preece No. 1 well on October 28, 1985, and the well reached a total depth of 3,293 ft on November 1. An air dryer was used during drilling to remove water from the air, to maintain a cleaner wellbore environment and to better identify hydrocarbons entering the wellbore.
I would like to begin my address by thanking the Society of Petroleum Engineers for the opportunity to speak to your Annual Petroleum Engineers for the opportunity to speak to your Annual Conference about Canadian Natural Gas prospects and how they fit into the energy requirements of the North American continent over the next 20 years. It seems somehow an appropriate topic since the theme of this conference is "Energy Frontiers".
We in Canada are very optimistic about our future energy potential. We are one of the few industrialized countries which has potential. We are one of the few industrialized countries which has benefited materially from the increase in real energy prices over the past 10 years, there is some truth in the comment that if OPEC had not existed Canada would have had to invent it. The fact of the matter is that Canada is a country which has a very large resource base and has a very exiciting energy future if energy prices are high but we are energy paupers if energy is cheap and abundant.
Our energy supplies are high cost compared to the costs of producing oil in the Middle East and if cheap energy prices, producing oil in the Middle East and if cheap energy prices, such as prevailed over the 1950's and 1960's, continued through the 1970's or 1980's much of our energy resource base would not be economic:
Few engineers in supervisory positions have received formal training in the techniques of managing. This paper calls to their attention some of the peculiarities of engineers and recommends a philosophy of supervision which is designed for engineers' temperaments. The engineering supervisor is asked to discard the presupposition that engineers are like any other group of employees; he is asked to reject the popular concept of directing by political authority; and his subordinates are asked to assume more responsible, aggressive roles within their spheres.
In recent years the position of the engineer in industry has undergone a transition. Because he brings a higher level of skill to his profession. greater performance is expected by his employer. As the engineering function has grown, many people with technical backgrounds have found their way into management positions. In consequence, engineers often are being supervised by engineers. Sound management is based on methods that have proved successful in practice. The current unusual rate of attrition from many oil companies, along with growing staff discontent, signals a warning that engineering management as traditionally practiced is not so sound. The supervising engineer has no universal set of rules prescribing a methodology for successful management practices-he operates by the principle of uncertainty. Although he may define the scope of the efforts of his subordinates, he is unable to quantify their motivations or productivity in tangible terms. His ability to elicit better performance from the staff depends on his ability to recognize and to react properly and promptly to a variety of human needs and characteristics.
Characteristics and Demands Of Engineers
According to the management literature. today's engineering supervisor has the challenge of directing an unusual type of employee. Engineers are described as being different from other employees. Barlow, Deutsch and Hinrichs have categorized engineers as types whose eccentricities are acquired in the process of attaining a disciplined, professional education. Some of the more common accusations are: engineers "are too factual", "are too introverted", "are not human relations oriented", "have a peculiar type of mind", "cannot adequately express themselves", "have limited perspective", "are perfectionists" and "are intolerant of non-engineering problems". One is led to believe that industry has acquired a group of prima donnas who could quite conceivably be more of a problem than an asset. Attitude surveys reveal that engineers generally are dissatisfied and frustrated with their work environment. They are antagonistic toward management and its concept of executive authority. French and Gatlin list these factors as causes for engineers' dissatisfaction: (1) engineers consider themselves underpaid; (2) they feel that their talents are misused and that they are forced into overspecialization; and (3) they contend that many technical tasks are beneath their capability. Their education and value- orientation characteristics lead engineers to ask for the following in their job and work environment: better salaries, worthwhile and stimulating work. adequate facilities with technician help. association with high-caliber colleagues, a technically trained management, freedom in choosing problems. an organization with a reputation for scientific advancement, opportunity for advancement, job security, a location where formal education can be continued, treatment as individuals. freedom to publish and suitable living conditions. Barnes maintains that if a company attempted to provide in full measure each of these demands it could very well find itself in poor financial health. Of all the engineers' demands, recognition appears to be the most sought after reward. Unlike his fellow professionals-physicians, teachers and lawyers-the engineer is engaged in work that is submerged and anonymous. He rarely comes in contact with the public; his professional life is limited to association with fellow engineers. According to Cronstedt: "The recognition he receives and the social stature he acquires must come from sources other than public acclaim". As a consequence of this anonymity, Barlow claims that engineers become subject to many of the ills of group psychology: "The herd instinct shows itself as engineers try to draw strength and support from each other".