BEGIN:VCALENDAR VERSION:2.0 METHOD:PUBLISH PRODID:-//Tendenci - The Open Source AMS for Associations//Tendenci Codeba se MIMEDIR//EN BEGIN:VEVENT DESCRIPTION:--- This iCal file does *NOT* confirm registration.\r\nEvent d etails subject to change. ---\r\nhttps://www.spegcs.org/events/1929/\r\n\r \nEvent Title: Permian Basin: Production Forecasting in Low Permeability O il Reservoirs\r\nStart Date / Time: Apr 17, 2012 11:30 AM US/Central\r\nLo cation: Westlake Club\r\nSpeaker: W. John Lee\r\nGoogle\r\nhttp://maps.goo gle.com/maps?q=570+Westlake+Park+Blvd,Houston,Texas,77079\r\n\r\nForecast\ nhttp://www.weather.com/weather/monthly/77079\r\n\r\n\r\n Forecasting prod uction and estimating reserves with confidence in unconventional resources , particularly shale reservoirs, is a major unsolved problem in the petrol eum industry. Many would prefer a rigorous analytical or numerical model t o be used as the basis for production forecasting and reserves estimation, but we are limited by two factors: (1) we may not understand the physics of hydraulic fracture stimulation and fluid transport in shales well enoug h to ensure that we are using a model with appropriate physics and appropr iate fracture and formation characteristics, and (2) no long-term producti on histories are available in shales reservoirs with which we can calibrat e our models. The oldest of the major shales plays, the Barnett Shale in T exas, began to use horizontal wells with multi-stage fracturing only in 20 04, so eight years or less of production data are available for wells dril led and completed with the most modern technology, and the wells may have 30-year or longer lives. At this point, we do not know the location of the cracks in the rock and we don&rsquo\;t know the conductivity of proppant in these cracks. Even less is known about oil reservoirs because of more l imited production histories.\r\n\r\n As a result of these problems, most o perators in ultra-low permeability reservoirs use empirical methods, espec ially decline curve analysis or type curves based on decline trends, for p roduction forecasting and reserves estimates. The most commonly used metho d is the traditional Arps hyperbolic decline model coupled with a minimum terminal (exponential) decline rate. This approach, while widely used, has problems: (1) the Arps model assumes stabilized flow with unchanging decl ine constant &lsquo\;b&rsquo\;, whereas the flow in shales wells is transi ent for long periods, perhaps even the life of the well in some instances\ ; and (2) we have no long-term production data which allow to determine th e appropriate terminal minimum decline rate.\r\n\r\n Much field evidence s upports a decline model in which flow is linear in a hydraulically fractur ed shale reservoir for at least a few years, followed by boundary-dominate d flow at the time interference between adjacent hydraulic fractures occur s. This may be followed by linear flow from the formation beyond the stimu lated reservoir volume. Unfortunately, we do not have reliable methods to predict the end of linear flow and the appropriate flow model at this time . Two recent decline models, the Stretched Exponential Model and the Duong Model, can accommodate linear flow and may be able to accommodate flow af ter the time of fracture interference without resorting to uncertain estim ates of formation and fracture properties. \r\n\n\n--- This iCal file does *NOT* confirm registration.Event details subject to change. ---\r\n\r\n-- - By Tendenci - The Open Source AMS for Associations ---\r\n UID:uid1929@spegcs.org SUMMARY:Permian Basin: Production Forecasting in Low Permeability Oil Reservoirs DTSTART:20120417T163000Z DTEND:20120417T180000Z CLASS:PUBLIC PRIORITY:5 DTSTAMP:20240329T072558Z TRANSP:OPAQUE SEQUENCE:0 LOCATION:Westlake Club X-ALT-DESC;FMTTYPE=text/html:
Forecasting production and estimating reserves with confid ence in unconventional resources, particularly shale reservoirs, is a majo r unsolved problem in the petroleum industry. Many would prefer a rigorous analytical or numerical model to be used as the basis for production fore casting and reserves estimation, but we are limited by two factors: (1) we may not understand the physics of hydraulic fracture stimulation and flui d transport in shales well enough to ensure that we are using a model with appropriate physics and appropriate fracture and formation characteristic s, and (2) no long-term production histories are available in shales reser voirs with which we can calibrate our models. The oldest of the major shal es plays, the Barnett Shale in Texas, began to use horizontal wells with m ulti-stage fracturing only in 2004, so eight years or less of production d ata are available for wells drilled and completed with the most modern tec hnology, and the wells may have 30-year or longer lives. At this point, we do not know the location of the cracks in the rock and we don&rsquo\;t kn ow the conductivity of proppant in these cracks. Even less is known about oil reservoirs because of more limited production histories.
As a result of these problems, most operators in ultra-low permeability reserv oirs use empirical methods, especially decline curve analysis or type curv es based on decline trends, for production forecasting and reserves estima tes. The most commonly used method is the traditional Arps hyperbolic decl ine model coupled with a minimum terminal (exponential) decline rate. This approach, while widely used, has problems: (1) the Arps model assumes sta bilized flow with unchanging decline constant &lsquo\;b&rsquo\;, whereas t he flow in shales wells is transient for long periods, perhaps even the li fe of the well in some instances\; and (2) we have no long-term production data which allow to determine the appropriate terminal minimum decline ra te.
Much field evidence supports a decline model in which flow is
linear in a hydraulically fractured shale reservoir for at least a few ye
ars, followed by boundary-dominated flow at the time interference between
adjacent hydraulic fractures occurs. This may be followed by linear flow f
rom the formation beyond the stimulated reservoir volume. Unfortunately, w
e do not have reliable methods to predict the end of linear flow and the a
ppropriate flow model at this time. Two recent decline models, the Stretch
ed Exponential Model and the Duong Model, can accommodate linear flow and
may be able to accommodate flow after the time of fracture interference wi
thout resorting to uncertain estimates of formation and fracture propertie
s.