PETE 4190 Final Exam - Questions and Answers (Complete Solutions)

PETE 4190 Final Exam - Questions and Answers (Complete Solutions) ______ are the quantities of hydrocarbons initially in place. ______ are those quantities of natural resources remaining to be produced. Resources, Rese ...

PETE 4190 Final Exam - Questions and Answers (Complete Solutions) ______ are the quantities of hydrocarbons initially in place. ______ are those quantities of natural resources remaining to be produced. Resources, Reserves Resources are the quantities of hydrocarbons _______________________ initially in place __________ are the quantities of natural resources remaining to be produced. Reserves In order to be called ______, the oil and gas must be (1) physically producible, (2) economically producible. Reserves In order to be called reserves, the oil and gas must be (1) ___________________, (2) _________________________ physically producible economically producible T or F: Since reserves are remaining volumes, there is a timeline associated with each reserve estimate. True Since reserves are remaining volumes, there is a _______ associated with each reserve estimate. Timeline Since reserves are ___________________, there is a timeline associated with each reserve estimate. remaining volumes Reserves are not yet produced so they cannot be measured but ________ Estimated Original reserves at the time of discovery, which are going to be produced over the lifetime of field/well, are referred to as ____________________ EUR (estimated ultimate recovery). Reserves = ______________________ (w/ regards to initial resource) Resource × RF (Recovery Factor) Reserves = ____________________ (w/ regards to production after time) EUR - Cum. Prod. Reserves = ________________ (all put together) Resource × RF - Cum. Prod For _____________ reservoirs, the reserves and resources are reservoir-scale metrics. Conventional For conventional reservoirs, the reserves and resources are __________________ metrics. reservoir-scale For _________ reservoirs, the resources and reserves are used at well scale for shale resources Unconventional For unconventional reservoirs, the resources and reserves are used at _____________ for shale resources well scale Methods for calculating reserves and resources volumetric material balance production data analysis (DCA and RTA) reservoir simulation analogy ______________ method is based on the static properties including the formation thickness (h), drainage area (A), initial water saturation (Swi), porosity (f), and initial formation volume factor Volumetric Volumetric method is based on the static properties including the formation ___________, ___________________, _________________, ______________, and _____________________ thickness (h) drainage area (A) initial water saturation (Swi) porosity initial formation volume factor (Boi) To obtain reserves, the _______ is needed. RF ________ is not available from static data and require knowledge of operational constraints, recovery mechanisms, fluid property evolution, reservoir heterogeneities, etc. RF _______________ technique requires dynamic data including the average pressures and corresponding produced volumes material balance (MB) Material balance (MB) technique requires ________ data including the average __________ and corresponding produced _____________ Dynamic; pressures; volumes ________ can be used to estimate N (G), EUR, RF, water influx. material balance MB can be used to estimate ___________, _____________, ____________, and __________ N (G) EUR RF Water Influx _________ can be used to estimate the future production versus average pressure. material balance The major problem with MB is that it relies on the __________________ which is difficult to measure for shale reservoirs average pressure The major problem with MB is that it relies on the average pressure which is difficult to measure for shale reservoirs. ___________________ has been introduced to overcome this limitation Flowing material balance (FMB) Only ______________ is required in DCA. rate history Only rate history is required in DCA. RTA also requires ___________________ bottom hole flowing pressure Only rate history is required in _________ DCA __________ requires rate history and bottom hole flowing pressure RTA Reservoir simulation provides reserves estimates as a ________________. by-product For reservoir simulators, rather than assuming the reservoir is a single cell tank, the reservoir is discretized into number of _________________. The flow equations determine the flow between cells over time. interconnected cells Large quantities of data (rock properties, fluid properties, rock-fluid interaction properties, well locations) are required to establish the __________________. reservoir model During reservoir simulation, the properties should be adjusted (within a reasonable limits) to match the ____________________ of the reservoir. production history (history matching) Once your reservoir simulator has been history matched, the model can then be used to predict ____________ under different scenarios. future production For reservoir simulation, there is no guarantee that the future performance _______ the predictions. Matches Requirements for analogy a field/well which is expected to perform similarly Advantages of analogy fast, cheap, and can be done before drilling Disadvantages of analogy accuracy (apples vs. oranges) _________ is done in terms of recovery factor (RF), barrels per acre, EUR. Analogy In shale plays, analogy is used to estimate the expected future shape of the _______________________. decline curve EUR of shale wells tend to be _________________ distributed with many smaller wells and a few larger wells. log-normally EUR of shale wells tend to be log-normally distributed with many ________ wells and a few __________ wells. smaller, larger For moderate-permeability reservoirs (up to 50 md for oil and 1 md for gas), the fracture _____________ production without impacting _____________________. accelerates, well reserves For __________-permeability reservoirs (up to 50 md for oil and 1 md for gas), the fracture accelerates production without impacting well reserves Moderate In _________-permeability reservoirs (less than 1 md for oil and 0.01 md for gas), fracturing contributes both to well productivity and to the well reserves Low In low-permeability reservoirs (less than 1 md for oil and 0.01 md for gas), fracturing contributes both to ______________ and to the _______________ well productivity, well reserves ____________________ is a method to estimate reserves by analyzing and extending the past decline trends of production rates Decline curve analysis The required data for DCA are the __________________ and _______________________________. production rates, cumulative productions versus time The required data for ________ are the production rates and cumulative productions versus time. DCA DCA techniques are generally __________ although, at some instances, they can be derived from ____________________ empirical, fundamental equations For the DCA to be applicable, the _______ conditions (e.g. well damage, choke size, pump, artificial lift) and ________ conditions (e.g. production mechanisms, flow regimes, flow geometries) should be stable well, reservoir For the DCA to be applicable, the well conditions (e.g. well damage, choke size, pump, artificial lift) and reservoir conditions (e.g. production mechanisms, flow regimes, flow geometries) should be __________ Stable For the DCA to be applicable, the well conditions (e.g. well damage, choke size, pump, artificial lift) and reservoir conditions (e.g. production mechanisms, flow regimes, flow