Successful Improvement of Ultimate Recovery of Complex Deep Tight Gas Field via Combined Gas Lift De-Liquification Techniques

The Amin top structure is Well defined in seismic data and can be easily interpreted across the entire area of North Oman. It is being identified as an extremely tight, disconnected, low porosity, low permeability, and HPHT reservoir, and thus presents unique challenges to harness its full production potential. Approximately, 15 years after production began with significant pressure depletion below dew point, a significant loss in Well productivity occurred in some of the Wells. Furthermore, during shutdowns or sudden trips of production stations, more Wells faced difficulties to restart again due to mainly, condensate banking and other probable reasons like formation water cross-flow during shut-in, which created a water bank and impaired inflow performance liquid loading due to low Well bore pressure which caused higher static head at the Well tubing. Common practice of N2 lifting CTU becoming no economical with increase number of Wells suffer from Liquid loading and represented a major challenge to look for cheaper economic alternatives. To reduce the higher OPEX associated with nitrogen lifting of Wells, multiple options were considered and evaluated thoroughly including extensive study of several artificial lift methods which were thought to defer liquid loading and mitigate kick-off issues such as Foam lift, Plunger lift, Beam Pump, ESP, Jet Pump and Gas lift (Concentric gas lift). The optimum gas Well de-liquification method has been identified based on the highest UR considering connected GIIP and inflow resistance A (Forchheimer equation Laminar flow). The outcome of the study indicated that a gas lift technology combined with well retubing was recommended as the optimum solution. The injected gas has reduced the density of the liquid resulting in reducing the static head at the tubing which increased the Well bore pressure allowing the Well to flow. A successful robust pilot which has been completed in two Wells and gave conclusive results. The surface development concept encompasses the development, with long term testing. The outstanding successful outcomes of the pilot succeeding in restoring Wells back with economic prolific production rates have led to expedite a full field implementation plan in three fields covering (33 Wells) in the next 5 years. These Wells have similar sub-surface and surface conditions. This paper will highlight the full story of the Gas lift technology implementation and describe in details the entire process starting from the Well candidate selection screening criteria, concept detailed design, critical success factors, project assurances and controls, Injection rate and operating parameters, facility capex, life time cycle and the result tested gas & condensate and water production. Also, the learning and challenges like halite accumulation effects will be shared along with the proven practical mitigation plan that ensured and sustained Well production resulting to significant project success of the technology.

Modeling and Optimization of Gas-Solid Fluidization of Binary Mixtures using Box-Behnken Experimental Design

The influence of different factors on the fluidization of a binary mixture of red mud and aluminum was investigated. A new model was developed for predicting pressure drop through the solid bed using experimental data of other work. Statistical analysis based on response surface methodology has been used to develop correlations for bed pressure drop with three independent factors, minimum fluidization velocity (Umf), red mud to aluminum ratio (R/A), and static head (Hs). The design of experiments offers a best alternative to study the effect of factors and their response with the minimum number of experiments. The hydrodynamic characteristics of fluidization, bed pressure drop, superficial gas velocity (Umf), red mud to aluminum ratio (R/A), and initial static bed height (Hs) were modeled and optimized. ANOVA has been used to analyze the system parameters on bed pressure drop. A model of bed pressure drop was found to have a correlation coefficient of 0.98. The measured values of bed pressure drop from RSM were found to match the experimental values very well.

Applying Criteria Equations in Studying the Energy Efficiency of Pump Systems

This paper presents a method for evaluating the energy efficiency of pump systems used to transport fluids .It is mainly scientifically applied and engineering-applied in nature and aims to propose a new approach (method) to researchers in their study of the energy efficiency of such systems. By applying the well-known scientific method of Dimensional Analysis (Buckingham π-theorem), dimensionless complexes (π-criterions and their relevant equations, which are original (innovative) and are offered for the first time in the scientific literature), used in accomplishing an energy assessment and analysis of such systems, are obtained. The criterion ∏1 = ev/ρgD represents specific energy consumption in kWh/m3 for a given pipe system with an exemplary diameter D. The criterion ∏2 = Q/[n(Hp − Hst)D2] represents a generalized parameter which is characterized by the selected method of flow rate (Q) regulation for a pump system with given static head Hst—by changing the speed of rotation (VFD, Variable Frequency Drive), by throttling, leading to an increase of the system hydraulic losses hv = (HpHst) or by diverting a part of the flow, known as “by-pass”, where the pump operates with the required system head Hp, but ensures higher flow rates, i.e., Qp > Qs. The flow rate criterion ∏3 = Q/(νD) characterizes the flow rate for a pipe system with an exemplary diameter D, used to transport a liquid with known viscosity ν. An example for applying these dimensionless complexes in accomplishing a quantitative evaluation of the energy efficiency of a given pump system is presented. A method for determining the main parameters forming these criterions, used to describe the different methods of flow rate regulation, has been developed. To demonstrate the application of this method, newly proposed by the authors, including obtaining the relevant criteria equations of the type ∏1 = f(∏2, ∏3), a certain pump system was used. This original approach for studying pump systems used to transport fluids can be used both to accomplish an energy analysis of such systems as well as to solve for optimization or other engineering problems.

Search in Dynamic Scenes: Cueing by Body Parts Leads to Transient Covert Attention and Microsaccade Bias while Whole Silhouettes to Sustained

Gaze direction is an evolutionarily important mechanism in daily social interactions. It reflects a person’s internal cognitive state, spatial locus of interest, and predicts future actions. Studies have used static head images presented foveally and simple synthetic tasks to find that gaze orients attention facilitates target detection at the cued location in a sustained manner. Little is known about how people’s natural gaze behavior, including eyes, head, and body movements, jointly orient covert attention, microsaccades, and facilitate performance in more ecological dynamic scenes. Participants completed a target person detection task with videos of real scenes. The videos showed people looking toward (valid cue) or away from a target (invalid cue) location. We digitally manipulated the individuals in the videos directing gaze to create three conditions: intact (head+body movements), floating heads (only head movements), and headless bodies (only body movements). We assessed their impact on participants’ behavioral performance and microsaccades during the task. We show that, in isolation, an individual’s head or body orienting toward the target-person direction led to facilitation in detection that is transient in time (200 ms). In contrast, only whole silhouettes led to sustained facilitation (500 ms). Furthermore, observers executed microsaccades more frequently towards the cued direction for valid trials, but this bias was sustained in time only when full silhouettes were present. Together, the results differ from previous findings with foveally presented static heads. In more real-world scenarios and tasks, sustained attention requires the presence of the whole silhouettes of the individuals dynamically directing their gaze.

Considering Hydrotest Pressure Loading in the Calculation of MAWP of a Pressure Vessel

As defined in UG-98 of the Code, the Maximum Allowable Working Pressure (MAWP), is the maximum pressure permissible at the top of the vessel in its normal operating position. It is the least of the values calculated for each of the vessel part adjusted for the static head and by including the effect of any combination of loadings listed in UG-22 of the Code. Conventional method of calculating the MAWP is to consider only the main pressure parts viz., the shells and the heads and the significant UG-22 loading viz., the wind and the seismic. Once the MAWP is determined, the rest of the vessel design is completed considering this value of MAWP as design pressure combined with any other applicable UG-22 loading. At the end, the vessel is verified for its adequacy to the test condition. It is noted that, the MAWP obtained through this method is often higher than the design pressure thus leading to the overdesign of the vessel. Moreover, higher MAWP results in higher test pressure, which might have a considerable impact of its own on the design of the vessel. The objective of this paper is to propose a design approach in which the test pressure itself is included as one of the governing loads in the determination of the MAWP so that the impact on vessel design, as explained above, is minimized.

Search in Dynamic Scenes: Cueing by Body Parts Leads to Transient Covet Attention and Microsaccade Bias while Whole Silhouettes to Sustained

Gaze direction is an evolutionarily important mechanism in daily social interactions. It reflects a person’s internal cognitive state, spatial locus of interest, and predicts future actions. Studies have used static head images presented foveally and simple synthetic tasks to find that gaze orients attention facilitates target detection at the cued location in a sustained manner. Little is known about how people’s natural gaze behavior, including eyes, head, and body movements, jointly orient covert attention, microsaccades, and facilitate performance in more ecological dynamic scenes. Participants completed a target person detection task with videos of real scenes. The videos showed people looking toward (valid cue) or away from a target (invalid cue) location. We digitally manipulated the individuals in the videos directing gaze to create three conditions: intact (head+body movements), floating heads (only head movements), and headless bodies (only body movements). We assessed their impact on participants’ behavioral performance and microsaccades during the task. We show that, in isolation, an individual’s head or body orienting toward the target-person direction led to facilitation in detection that is transient in time (200 ms). In contrast, only whole silhouettes led to sustained facilitation (500 ms). Furthermore, observers executed microsaccades more frequently towards the cued direction for valid trials, but this bias was sustained in time only when full silhouettes were present. Together, the results differ from previous findings with foveally presented static heads. In more real-world scenarios and tasks, sustained attention requires the presence of the whole silhouettes of the individuals dynamically directing their gaze.

Simple and Efficient Methods to Perform the Optimum Matching Between a Reciprocating Piston Pump and a Wind Machine

One of the major problems facing the use of the wind driven reciprocating lift pump is the problem of starting. The required starting torque of the pump is at least three times the average torque. This means that the pump will need a high wind velocity just to be started, after that it will continue to operate at a lower wind velocity because of the lower average torque, provided that there is enough inertia in the system. For this reason, the torque characteristics of the wind turbine – reciprocating pump combination are very important. Thus, there is a real need to develop new methods in order to reduce this starting performance of the reciprocating pump. This paper presents a theoretical study to reduce the starting torque of a non-conventional reciprocating piston pump using new methods, for example, changing the wind machine parameters, such as the aerodynamics configuration of the rotor and blade elements, or by studying the effect of wind speed velocity on the starting torque. Also by changing the cross-section area of the piston or by changing the static head of the piston pump or by controlling the flow rate of the piston pump.

Relationship Between Flow Instability and Performance of a Centrifugal Pump With a Volute

Flow instability and its correlations with performance characteristics were investigated for a centrifugal pump with a volute. Unsteady three-dimensional Reynolds-averaged Navier–Stokes analysis was performed to analyze the flow and performance characteristics using the shear stress transport (SST) turbulence model. The grid dependence and temporal resolution were tested to evaluate the numerical uncertainties, and the numerical solutions were validated using experimental data. The total-to-static head coefficient, the impeller's total-to-static head coefficient, and the volute static pressure recovery coefficient were selected as performance parameters. To identify the flow instability, pressure fluctuations were monitored upstream of the impeller, at the volute inlet, and on the shroud wall of the impeller. Three different types of flow instability were detected in partial-load conditions: inside the volute, upstream of the impeller, and at the interface between the impeller and volute. The time-dependent flow structures were investigated to obtain insight into the onset of the flow instability. The correlation of the onset of the flow instability with the performance curves was discussed.

the Extraction and determination of benzene from waters and wastewater samples based on functionalized carbon nanotubes by static head space gas chromatography mass spectrometry

In this study, the phenyl sulfonic acid (PhSA) modified carbon nanotubes (CNTs) were used for benzene removal from waters by (D- μSPE). Due to adsorption mechanism, π–π interactions was provided between the aromatic ring of benzene with the surface (SO3H) and phenyl ring (-C6H5) of CNTs, respectively. Therefore, 20-100 mg of sorbent, concentration of benzene (0.1–10 mg L-1), pH (1-12) and contact time (5–120 min) were investigated and optimized for benzene removal from water samples in static system. The concentration of benzene in water was determined by (SHS-GC-MS). The results showed, the Langmuir-Freundlich (LF) isotherm provided the best fit for benzene sorption. By using the Langmuir model, the maximum adsorption capacity of 117.34 and 22.86 mg/g was achieved for benzene removal from waters with CNTs@PhSA and CNTs, respectively. Under optimal conditions, adsorption efficiency of CNTs@PhSA and CNTs was obtained 97.7% and 20.6 % for benzene removal from water samples, respectively.

The importance of static and dynamic head drivers for hyporheic exchange: evaluation of a spectral modelling approach

<p>Groundwater surface water interactions can greatly impact the ecohydrology on a wide range of spatial scales, ranging from biogeochemical reactions under local bedforms to alteration of regional groundwater discharge patterns. Hyporheic exchange fluxes (HEF) are controlled by the streambed geology and driven by hydraulic head fluctuations at the stream bottom, consisting of a static and a dynamic part. Currently, few studies have investigated the relative importance of these two drivers of HEF in the field, which hinder a holistic understanding of the governing processes and may affect predictions of hyporheic exchange intensities.</p><p>This study is based on an extensive field survey of 9 stream reaches located in small, pristine streams in Sweden, with varying hydromorphological characteristics such as slope, bottom material, morphological complexity and stream discharge. The field survey included distributed measurements of the hydraulic head and the hydraulic conductivity along the streambed, as well as tracer tests with Rhodamine WT. The overall aim of the study was to evaluate the relative importance of HEF driven by dynamic and static head fluctuations in streams by usage of a spectral model that decomposes the observed hydraulic head fluctuations on distinctive spatial scales. As a validation, the advective storage path (ASP) transport model was calibrated against the conducted in-stream tracer tests and its parameters compared to the equivalent gained from the spectral model.</p><p>The results showed that the average exchange velocity evaluated by the two models were comparable in most observed cases, validating the usage of the spectral model in small alluvial streams with high slope, and low discharge and stream depth. However, a sensitivity analysis of the two models revealed some degree of equifinality for some of the independent model parameters. Detailed results from the spectral model indicated that the static head was dominating the HEF in all reaches, both on average and when distributed over separate spatial scales. Uncertainty in the results was found, predominantly effecting calculations of the dynamic HEF and connected to (1) the approximation of streambed topography at spatial scales <0.5 m, where the dynamic exchange is assumed to dominate and (2) the use of Fehlman’s constant for estimating the hydrodynamic exchange under complex streambed topographies. Despite those uncertainties, the spectral model approach gives a deeper understanding of the phenomena of HEF by incorporating its multiscale nature and illustrating the fact that static and dynamic drivers might be equally important, only acting on different scales.</p>