The Jacob field was discovered in the year 1931. In the year 2002, due to the low productivity of the field, the company wanted to determine whether to keep operating, abandon or sell the field. So they asked Texas A&M University to perform the study, determine the oil potential, and make recommendations to improve production. Since no previous reservoir study was performed in this field, the original oil in place and the current status of depletion was unknown. Therefore a complete integrated study was needed in order to learn about the reservoir and evaluate it in a qualitative and quantitative manner, before making any recommendation. The current pay zone underlying the Jacob field forms a monocline structure composed of unconsolidated young clastic sediments deposited in the Eocene epoch of the stratigraphic column of the Nueces River Basin, mainly due to a fluvial deltaic system developed in south Texas. The original oil in place for this pay zone was estimated to be 18.12 MMSTB and the cumulative production as of October 2003, 3.8 MMSTB. The analysis of the production data available had shown that the pay zone is being flooded by a strong water encroachment from the lower sides of the structure. This behavior was confirmed by the anisotropy analysis from core and log data, which shows that the reservoir tends to be more homogeneous in the direction of the water encroachment. It seems that there is not much room for further development in the current pay zone in the Jacob field (the remaining reserves were estimated to be 10 MSTB as of October 2003). However, the presence of a continuous shallow clean sandstone, not properly tested, of better reservoir properties than the actual pay zone was noticed. Moreover, this clean sandstone showed oil and gas presence in thirteen wells in the drilling cuttings. Therefore further development should concentrate more on investigating and developing the oil potential of the latter sandstone as well as accelerating the reserves production in the actual pay zone by means of waterflooding and/or infill drilling.

Carbonate reservoirs are characteristically heterogeneous in reservoir quality and performance owing to the variety of processes that influence pore formation. Additionally, porosity and permeability do not conform to depositional facies boundaries in carbonate reservoirs affected by diagenesis or fracturing; consequently, conventional methods of petrophysical characterization of flow units based on depositional facies are unreliable as predictors of reservoir behavior. We provide an integrated stratigraphic, petrographic, and petrophysical study of the San Andres reservoir at Sunflower field that identifies and quality-ranks flow units on the basis of genetic pore types. A total of 12 full-diameter cores were analyzed revealing three primary depositional facies and cyclical patterns of deposition identified as parasequences. From the cores, 73 samples were chosen for thin sections. Through petrographic analysis, pores were classified using the Ahr 2005 method and four distinct, genetic pore types were identified. Petrophysical rock types were established by identifying which genetic pore types correspond to high poroperm values, and where they occur within the stratigraphic framework of the reservoir. Sixteen coherent plugs were also subjected to mercury injection capillary pressure analysis in order to quantify pore – pore throat relationships. The data were then evaluated by facies, porosity type, and cycle position using graphical methods, such as k/phi, Winland R35, and Lorenz plots. The results of this study reveal that the most effective way of characterizing petrophysical flow units is the combination of k/phi ratio analyses and genetic pore typing.

Polyvinylidene Fluoride (PVDF) is a common piezoelectric polymer. It is widely utilized because of its advantageous mechanical, chemical, and electromechanical properties. An interesting application for its properties lies in using it as an actuator, specifically for a microgripper device. The microgripper has many applications such as surgeries, microassembly, and micromanipulation. The friction force is an important criterion that greatly affects the gripping. This research studies the frictional behavior of the PVDF and effects of applied electrical potential. Approaches include tribological investigation of the polymer associated with surface properties. The surface characterization was conducted using a profilometer and an Atomic Force Microscope (AFM). In addition, the application of a PVDF material as a microgripper is addressed along with the design of the gripper. It was found that the friction could be turned-on and off because of external applied electrical potential. Such behavior was associated with the microstructure, where dipoles were aligned in an electrical field. Such active-friction has not been reported in the past. This work opens new areas of research in fundamental friction that benefits the design and development of small devices such as a microgripper.

Consider a single-server queueing system with an unreliable server and service repetition. In this system, if the service is interrupted, the service is restarted anew immediately and ends whenever the service period is failure free. In this paper, we give some characterization of the exponential distribution by the constancy of total service time in this system. The result can be viewed as a kind of memoryless property of the exponential distribution.

The Jacob field was discovered in the year 1931. In the year 2002, due to the low productivity of the field, the company wanted to determine whether to keep operating, abandon or sell the field. So they asked Texas A&M University to perform the study, determine the oil potential, and make recommendations to improve production. Since no previous reservoir study was performed in this field, the original oil in place and the current status of depletion was unknown. Therefore a complete integrated study was needed in order to learn about the reservoir and evaluate it in a qualitative and quantitative manner, before making any recommendation. The current pay zone underlying the Jacob field forms a monocline structure composed of unconsolidated young clastic sediments deposited in the Eocene epoch of the stratigraphic column of the Nueces River Basin, mainly due to a fluvial deltaic system developed in south Texas. The original oil in place for this pay zone was estimated to be 18.12 MMSTB and the cumulative production as of October 2003, 3.8 MMSTB. The analysis of the production data available had shown that the pay zone is being flooded by a strong water encroachment from the lower sides of the structure. This behavior was confirmed by the anisotropy analysis from core and log data, which shows that the reservoir tends to be more homogeneous in the direction of the water encroachment. It seems that there is not much room for further development in the current pay zone in the Jacob field (the remaining reserves were estimated to be 10 MSTB as of October 2003). However, the presence of a continuous shallow clean sandstone, not properly tested, of better reservoir properties than the actual pay zone was noticed. Moreover, this clean sandstone showed oil and gas presence in thirteen wells in the drilling cuttings. Therefore further development should concentrate more on investigating and developing the oil potential of the latter sandstone as well as accelerating the reserves production in the actual pay zone by means of waterflooding and/or infill drilling.

This research combines a statistical tool called experimental design/response surface methodology with reservoir modeling and flow simulation for the purpose of reservoir characterization. Very often, it requires large number of reservoir simulation runs for identifying significant reservoir modeling parameters impacting flow response and for history matching. Experimental design/response surface (ED/RS) is a statistical technique, which allows a systematic approach for minimizing the number of simulation runs to meet the two objectives mentioned above. This methodology may be applied to synthetic and field cases using existing statistical software tools. The application of ED/RS methodology for the purpose of reservoir characterization has been applied for two different objectives. The first objective is to address the uncertainties in the identification of the location and transmissibility of flow barriers in a field in the Gulf of Mexico. This objective is achieved by setting up a simple full-factorial design. The range of transmissibility of the barriers is selected using a Latin Hypercube Sampling (LHS). An analysis of variance (ANOVA) gives the significance of the location and transmissibility of barriers and comparison with decline-type curve analysis which gives us the most likely scenarios of the location and transmissibility of the flow barriers. The second objective is to identify significant geologic parameters in object-based and pixel-based reservoir models. This study is applied on a synthetic fluvial reservoir, whose characteristic feature is the presence of sinuous sand filled channels within a background of floodplain shale. This particular study reveals the impact of uncertainty in the reservoir modeling parameters on the flow performance. Box-Behnken design is used in this study to reduce the number of simulation runs along with streamline simulation for flow modeling purposes. In the first study, we find a good match between field data and that predicted from streamline simulation based on the most likely scenario. This validates the use of ED to get the most likely scenario for the location and transmissibility of flow barriers. It can be concluded from the second study that ED/RS methodology is a powerful tool along with a fast streamline simulator to screen large number of reservoir model realizations for the purpose of studying the effect of uncertainty of geologic modeling parameters on reservoir flow behavior.

Automated detection of geological boundaries and determination of cyclic events controlling deposition can facilitate stratigraphic analysis and reservoir characterization. This study applies the wavelet transformation, a recent advance in signal analysis techniques, to interpret cyclicity, determine its controlling factors, and detect zone boundaries. We tested the cyclostratigraphic assessments using well log and core data from a well in a fluvio-eolian sequence in the Ormskirk Sandstone, Irish Sea. The boundary detection technique was tested using log data from 10 wells in the Apiay field, Colombia. We processed the wavelet coefficients for each zone of the Ormskirk Formation and determined the wavelengths of the strongest cyclicities. Comparing these periodicities with Milankovitch cycles, we found a strong correspondence of the two. This suggests that climate exercised an important control on depositional cyclicity, as had been concluded in previous studies of the Ormskirk Sandstone. The wavelet coefficients from the log data in the Apiay field were combined to form features. These vectors were used in conjunction with pattern recognition techniques to perform detection in 7 boundaries. For the upper two units, the boundary was detected within 10 feet of their actual depth, in 90% of the wells. The mean detection performance in the Apiay field is 50%. We compared our method with other traditional techniques which do not focus on selecting optimal features for boundary identification. Those methods resulted in detection performances of 40% for the uppermost boundary, which lag behind the 90% performance of our method. Automated determination of geologic boundaries will expedite studies, and knowledge of the controlling deposition factors will enhance stratigraphic and reservoir characterization models. We expect that automated boundary detection and cyclicity analysis will prove to be valuable and time-saving methods for establishing correlations and their uncertainties in many types of oil and gas reservoirs, thus facilitating reservoir exploration and management.

The characterization of water treatment residuals containing arsenic was investigated in the first study. Arsenic desorption and leachability from the residuals were the focus of this study. Arsenic leaching from water treatment residuals was found to be underestimated by the toxicity characteristic leaching test (TCLP) due to the pH of the leachates being favorable for As(V) adsorption. Competitive desorption of arsenic with phosphate was significant because phosphate tends to compete with As(V) on the surface of the metal hydroxide for adsorption sites. However, arsenic desorption by the competition of sulfate and chloride was found to be negligible. The pH in the leachate was a critical variable in controlling arsenic stability in the residuals. The release of arsenic from the residuals was elevated at low and high pH due to the increase dissolution of the adsorbents such as Fe and Al hydroxides. In the second phase of the study, the stabilization techniques for arsenic contained residuals and were examined to develop methods to suitably stabilize arsenic to eliminate and/or minimize leaching. A decrease of arsenic leaching was achieved by the addition of lime to the residuals and believed to be due to the formation of less soluble and stable calcium-arsenic compounds. However, it is suggested that the ordinary Portland cement (OPC) should be added with the lime for the long term stabilization because lime can be slowly consumed when directly exposed to atmospheric CO2. The solidification and stabilization (S/S) technique with lime and OPC was shown to be successfully applied by the immobilization of a wide variety of arsenic tainted water treatment residuals.

The need for characterization of the Germania unit has emerged as a first step in the review, understanding and enhancement of the production practices applicable within the unit and the trend area in general. Petrophysical characterization of the Germania Spraberry units requires a unique approach for a number of reasons ?? limited core data, lack of modern log data and absence of directed studies within the unit. In the absence of the afore mentioned resources, an approach that will rely heavily on previous petrophysical work carried out in the neighboring ET O??Daniel unit (6.2 miles away), and normalization of the old log data prior to conventional interpretation techniques will be used. A log-based rock model has been able to guide successfully the prediction of pay and non-pay intervals within the ET O??Daniel unit, and will be useful if found applicable within the Germania unit. A novel multiple regression technique utilizing non-parametric transformations to achieve better correlations in predicting a dependent variable (permeability) from multiple independent variables (rock type, shale volume and porosity) will also be investigated in this study. A log data base includes digitized formats of gamma ray, cased hole neutron, limited resistivity and neutron/density/sonic porosity logs over a considerable wide area.

In the wake of global warming and fossil fuel depletion, renewed attention has been paid to shifting away from the use of petroleum based fuels. The world?s energy demand is commencing its dependency on alternative fuels. Such alternative fuels in use today consist of bio-alcohols (such as ethanol), hydrogen, biomass, and natural oil/fat derived fuels. However, in this study, the focus will be on the alternative fuel derived from natural oils and fats, namely biodiesel. The following study characterizes the performance of a medium-duty diesel engine fuelled with biodiesel and conventional diesel. The objective is accomplished by taking measurements of manifold pressure and temperature, fuel flow, air flow, and torque. The study first characterizes a John Deere 4.5 liter 4 cylinder direct injection engine with exhaust gas recirculation (EGR), common rail fuel injection, and variable turbo-charging with conventional petroleum diesel to set a reference for comparison. The study then proceeds to characterize the differences in engine performance as a result of using biodiesel relative to conventional diesel. The results show that torque decreases with the use of biodiesel by about 10%. The evaluation of engine performance parameters shows that torque is decreased because of the lower heating value of biodiesel compared to conventional diesel. The insignificant difference between the other performance parameters shows that the ECM demands the same performance of the engine regardless of the fuel being combusted by the engine.