No description available.

No description available.

This thesis dea1s with mode11ing of formation damage resu1ting from invading s01ids, particu1ar1y in re1ation to water injection schemes Where10wconcentration micron and sub-micron s01ids are concerned. Ear1ier investigations were considered inadequate for study of formation damagedue to partic1e invasion in manyrespects such as the nature of damage, depth of damage characteristics and the inf1uence of various parameters on the damagedata. A porosity mode1(in 1inear and radia1 forms) based on mass ba1ance of partic1es and a pore size distribution based 3Dcapi1lary network model are presented. The network model uses various particle capture criteria including a newprobability criteria to model particle retention. The resu1ts from rock core based f10wtests are presented and ana1yzed. The f10w tests were conducted on 00x25 •4na-dia. sandstone cores of permeabi1ity range of 250 to 1000 md using 1-15 ppm concentrations of O-3~ a1umina partic1es at flow-rates of 0.45-1.00 mils up to 150 hours equiva1ent to over 40000 core pore v01umes. The experimental invastigations showthe importance of depth of damageand 10ng duration experiments on formation damagedata studies. Experimental permeability shows si.mp1e semi-1og dec1ine with gross f10w ve1ocity. serious occurs even for the 10w concentration systems. The iBIporta.nce of core preparation is stressed, where the use of brok.en faced cores is shown to be more appropriate for conducting partic1e inv . . as1.onexperuaents as comparedto the conventiona1 sa.wn-facedcores. Both the porosity mode1and the network.mode1predictions are shownto agree reasonab1y we11with the experimenta1 data.

No description available.

No description available.

Seabed environmental monitoring programmes have been conducted at oil installations in the North Sea for many years. Such studies seek to determine the areal extent of the spread of contaminated cuttings and effects on assemblages of benthic organisms. Survey programmes usually follow a prescriptive programme with respect to the numbers of samples, mesh size and level of taxonomic identification. This thesis examines the effects of altering these survey components on the information content of three commonly used ordination methods, PCA, DCA and CA, with the aim of determining the minimum necessary expenditure to show the same outputs. The use of microbial bioassays was investigated as a potential alternative means of assessing the extent of infaunal disturbance. <I>Minimum number of replicates</I>. When analysing data from a strong environmental gradient, one replicate sample per station provided the same visual information as the total data set of two replicates. The DCA and CA procedures provided outputs which were easily interpretable ecologically, but the PCA biplots were difficult to interpret. Analysis of data from a weak environmental gradient required a higher number of replicates for each technique and outputs were more variable at low replicate numbers. <I>Taxonomic resolution</I>. When infauna were aggregated to the taxonomic level of class, the information content of the three ordination methods was the same as recorded for species level. However, at the taxonomic levels of order and phylum the information on the bi-plots was difficult to interpret. Although this suggests that there exists the potential for reducing the cost of analysis, further corroboration with different data sets would be required. <I>Sieve size</I>. Primary screening of 0.5 mm mesh fauna by a 1.0 mm mesh may be a more cost effective strategy than either a 1.0 mm or 0.5 mm fraction although there was some loss of information on the ordination bi-plots.

In 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.

Differential-algebraic equations (DAEs) result in many areas of science and engineer- ing. In this thesis, numerical methods for solving DAEs are compared for two prob- lems, energy-economic models and traffic flow models. An energy-economic model is presented based on the Hubbert model of oil production and is extended to include economic factors for the first time. Using numerical methods to simulate the DAE model, the resulting graphs break the symmetry of the traditional Hubbert curve. For the traffic flow models, a numerical method is developed to solve the steady-state flow pattern including the linearly unstable regime, i.e. solutions which cannot be found with an initial value solver. / UOIT

In 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.

Differential-algebraic equations (DAEs) result in many areas of science and engineer- ing. In this thesis, numerical methods for solving DAEs are compared for two prob- lems, energy-economic models and traffic flow models. An energy-economic model is presented based on the Hubbert model of oil production and is extended to include economic factors for the first time. Using numerical methods to simulate the DAE model, the resulting graphs break the symmetry of the traditional Hubbert curve. For the traffic flow models, a numerical method is developed to solve the steady-state flow pattern including the linearly unstable regime, i.e. solutions which cannot be found with an initial value solver.