An Innovation in Designing Underbalanced Drilling Flow Rates: A Gas-Liquid Rate Window (GLRW) Approach

2002 ◽  
Author(s):  
Boyun Guo ◽  
Ali Ghalambor
Keyword(s):  
Flow Rates ◽  
Underbalanced Drilling ◽  
Rate Window

Reduction of Wellbore Effects on Gas Inflow Evaluation Under Underbalanced Conditions

SPE Journal ◽  
2008 ◽  
Vol 13 (02) ◽  
pp. 216-225 ◽  
Author(s):  
Olukayode J. Aremu ◽  
Samuel O. Osisanya
Keyword(s):  
Drilling Fluid ◽  
Inflow Rate ◽  
Gas Reservoir ◽  
Flow Rates ◽  
Underbalanced Drilling ◽  
Reservoir Fluid ◽  
Wellbore Storage ◽  
Outflow Rate ◽  
Drilling Operations ◽  
Fluid Inflow

Summary Wellbore storage effects have been identified to significantly smear the accuracy of evaluating reservoir productivity through the fluid outflow rate from the annulus during underbalanced drilling. Such effects have continuously introduced considerable errors in characterizing the reservoir during underbalanced drilling. Conceptually, because of the ready volume-changing ability of the gas, wellbore storage becomes a determining factor during underbalanced drilling of a gas reservoir. Wellbore storage could either cause decrease (unloading effects) or increase (loading effects) in the annular gas density, depending on the choke opening procedures. Correspondingly, annular fluid outflow rate is considerably affected. Because it is practically difficult to deduct the fluid-flow rate attributable to the wellbore storage from the total fluid outflow rate, reducing the influence of wellbore effects on the evaluation of gas-reservoir productivity is presented in this study. Volumetric production analysis at the wellbore-sand face is introduced through a mathematical modeling of inflow of gas bubbles into the wellbore. This mathematical modeling utilizes forces such as the viscous force, drilling fluid ejecting forces from the bit nozzles, buoyancy, interfacial tension, and gas-reservoir forces for its analyses. Some analytical results that are overshadowed by wellbore storage are presented and supported by extensive experimental studies. Introduction One of the derivable benefits from underbalanced drilling is the ability to evaluate the productivity of a reservoir during drilling operations (Beiseman amd Emeh 2002). Other benefits include little to no invasive formation damage; higher penetration rate, especially in hard rocks; and lower cost of drilling operations if underbalanced drilling could consistently be maintained (Bennion et al. 2002). However, from the real-time bottomhole pressure measurements taken while drilling, it is obvious that continuous maintenance of underbalanced conditions at the bottomhole is difficult. Pressure surges that occur during some subsidiary operations such as pipe connections and surveys tend to jeopardize the avoidance of invasive formation damage (Yurkiw et al. 2002). From the recent literature, reservoir evaluation has been approached through the estimation of the reservoir fluids flow rates into the wellbore. Assumption of the reservoir fluid inflow rate being the difference in the drilling fluid surface injection rate and the fluid outflow rate from the annulus has consistently been used (Kardolus and van Kruijsdijk 1997; Larsen and Nilsen 1999; Hunt and Rester 2000; Kneissl 200l; Lorentzen et al. 2001; Vefring et al. 2002; Biswas et al. 2003). So far, efforts in modeling reservoir fluid inflow have been concentrated on the oil inflow (Kardolus and van Kruijsdijk 1997; Larson and Nilsen 1999; Hunt and Rester 2000; Kneissl 200l; Lorentzen et al. 2001; Vefring et al. 2002; Biswas et al. 2003). These present approaches to production evaluation and characterization of gas formation recognize the important effects of wellbore phenomena, but have not been able to provide adequate means of reducing the influences. These wellbore phenomena include the gas-bubble coalescence and breakage, and bubble expansion and compression that are not possible to practically quantify during bubble annular upward flow. Because the present approaches involve the comparison of the surface fluid injection rate with the annular outflow rate, the influence of these phenomena on the gas formation evaluation is inevitable. Unfortunately, all of these wellbore phenomena cause additional annular flow rates that cannot be individually and practically measured, and thus the reservoir fluid inflow rate at the bottomhole cannot be practically modified for their influences. Not recognizing the impact of such additional annular flow rates could cause misjudgment of the inflow capabilities of the gas reservoir. In order to properly alleviate these effects on gas-inflow analyses, a volumetric production analysis at the wellbore-sand face contact is presented in this study. The conduction of gas-inflow analyses have been similarly performed as the liquid inflow in the petroleum engineering sectors. Practically speaking, gas inflow into a denser fluid system is bubbly in character, while liquid inflow is streaky. It is, therefore, proper to mathematically couple the forces of the viscosity, surface tension, inertia, and buoyancy that are responsible for gas-bubble formation or development to the drilling-fluid-ejecting forces from the bit nozzles and the reservoir forces in modeling gas-inflow scenarios. Therefore, with the existence of underbalanced pressure conditions at the bottomhole, the modeling procedures presented in this study could be used for predicting the total volume of gas inflow with significantly reduced wellbore effects while drilling. This is possible as long as an underbalanced condition is maintained at the bottomhole. This is a computer-simulation approach that utilizes real-time surface measurable underbalanced drilling data to predict quantitative gas volumes at the wellbore-sand face during drilling. As an additional advantage, the analyses do not involve knowing the gas inflow rate at the sand face, which could be difficult to accurately measure during underbalanced drilling operations. Standard engineering concepts are used to estimate downhole conditions for the analyses. Among the benefits from this study are reduced influences of the wellbore effects on the evaluation of gas-reservoir volumetric productivity during underbalanced drilling, the revealing of possible greater near-wellbore damage in some gas reservoirs, and possible in-situ permeability impairment through pore space compression.

Optimization of Required Volumetric Flow Rates for Aerated Mud Underbalanced Drilling

2008 ◽  
Vol 26 (12) ◽  
pp. 1403-1423
Author(s):  
E. Al-Safran ◽  
J. F. Owayed ◽  
T. Al-Bazali ◽  
A. Sunthankar
Keyword(s):  
Flow Rates ◽  
Underbalanced Drilling

Automation of Process Control in Chemical Plant

2015 ◽  
Vol 2 (1) ◽  
pp. 6-12
Author(s):  
Agus Sugiarta ◽  
Houtman P. Siregar ◽  
Dedy Loebis
Keyword(s):  
Process Control ◽  
Pid Control ◽  
Control Algorithm ◽  
Chemical Engineering ◽  
Chemical Plant ◽  
Raw Material ◽  
Flow Rates ◽  
Material Supply ◽  
Wide Range ◽  
Inherent Problem

Automation of process control in chemical plant is an inspiring application field of mechatronicengineering. In order to understand the complexity of the automation and its application requireknowledges of chemical engineering, mechatronic and other numerous interconnected studies.The background of this paper is an inherent problem of overheating due to lack of level controlsystem. The objective of this research is to control the dynamic process of desired level more tightlywhich is able to stabilize raw material supply into the chemical plant system.The chemical plant is operated within a wide range of feed compositions and flow rates whichmake the process control become difficult. This research uses modelling for efficiency reason andanalyzes the model by PID control algorithm along with its simulations by using Matlab.

A generic fluticasone propionate and salmeterol dry powder inhaler: Evidence of usability, function, and robustness

2021 ◽  
Vol 42 (1) ◽  
pp. 30-35 ◽  
Author(s):  
Donald P. Tashkin ◽  
Arkady Koltun ◽  
Róisín Wallace
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Fluticasone Propionate ◽  
Healthy Volunteers ◽  
Pulmonary Disease ◽  
Dry Powder Inhaler ◽  
Chemical Degradation ◽  
Chronic Obstructive ◽  
Dry Powder ◽  
Obstructive Pulmonary Disease ◽  
Flow Rates

Background: A generic combination of fluticasone propionate and salmeterol xinafoate inhalation powder in a premetered, multidose, nonreusable inhaler was recently approved. Objective: To assess the performance of the generic device. Methods: Findings from three studies with regard to device usability, function, and robustness were reviewed. Results: In a study to assess device function in patients and healthy volunteers, the generic device was successfully used by patients with asthma and chronic obstructive pulmonary disease who were either dry powder inhaler users or dry powder inhaler‐naive, even though they were not trained beyond being provided the instructions for use. In a study to measure inhaled flow rates generated by patients and healthy volunteers, the generic device consistently simulated the delivery of a full dose of drug, even to patients with severe respiratory disease and reduced inspiratory flow rates. Although the generic device had a slightly higher airflow resistance, this study demonstrated that this difference did not result in any clinically meaningful differences in terms of drug delivery. Pressure drop, a key parameter that drives the fluidization and aerosolization of the powder dose, was found to be comparable between the devices. In an open-label study, the generic device met all U.S. Food and Drug Administration specifications for device robustness after 21.5 days of twice-daily dosing via oral inhalation among 111 participants with asthma or chronic obstructive pulmonary disease. All inhalers tested demonstrated conformity with a pharmacopeia with respect to key quality parameters (assay, delivered dose uniformity, aerodynamic size distribution). There was no evidence of chemical degradation of the active ingredients, nor of microbial or water ingress into the powder, as a result of inhaler use.

Nitrogen Removal from Anaerobically-Treated Leachate

1984 ◽  
Vol 19 (1) ◽  
pp. 87-100
Author(s):  
D. Prasad ◽  
J.G. Henry ◽  
P. Elefsiniotis
Keyword(s):  
Nitrogen Removal ◽  
Air Flow ◽  
Operating Conditions ◽  
Air Flow Rate ◽  
Flow Rates ◽  
Anaerobic Filter ◽  
Ph Values ◽  
Wide Range ◽  
Ammonia Desorption ◽  
Effects Of Ph

Abstract Laboratory studies were conducted to demonstrate the effectiveness of diffused aeration for the removal of ammonia from the effluent of an anaerobic filter treating leachate. The effects of pH, temperature and air flow on the process were studied. The coefficient of desorption of ammonia, KD for the anaerobic filter effluent (TKN 75 mg/L with NH3-N 88%) was determined at pH values of 9, 10 and 11, temperatures of 10, 15, 20, 30 and 35°C, and air flow rates of 50, 120, and 190 cm3/sec/L. Results indicated that nitrogen removal from the effluent of anaerobic filters by ammonia desorption was feasible. Removals exceeding 90% were obtained with 8 hours aeration at pH of 10, a temperature of 20°C, and an air flow rate of 190 cm3/sec/L. Ammonia desorption coefficients, KD, determined at other temperatures and air flow rates can be used to predict ammonia removals under a wide range of operating conditions.

The Control of Iron Bacterial Plugging of a Well by Tyndallization Using Hot Water Recycling

1986 ◽  
Vol 21 (1) ◽  
pp. 50-57 ◽  
Author(s):  
D. R. Cullimore ◽  
N. Mansuy
Keyword(s):  
Direct Injection ◽  
Small Diameter ◽  
Hot Water ◽  
Water Recycling ◽  
Water Heater ◽  
Time Intervals ◽  
Flow Rates ◽  
Water Well ◽  
Flow Loss ◽  
The Town

Abstract A small diameter water well drilled in 1977 in the Town of Bulyea, Saskatchewan generated such a rapid plugging (biofouling) that by 1979 the flow rate was reduced by 59%. Heavy growths of non-specific iron bacteria were found in the water and biofouling projected to be the principal cause of the flow loss. Tyndallization (repeated pasteurizations) treatment was applied using a hot water recycling system installed above the well head. Using a displacement passive gravity direct injection of hot water at 82°C from a water heater into the well, a sequential elevation of water column temperatures occurred until bio-film dispersion occurred (pasteurization) at 45°C+. A recovery to original flow specifications was repeatedly obtained at time intervals ranging from 6 to 403 days. Between treatments, a recurrence of biofouling was noted with flow reductions of 0.06 – 0.07 1/min/day frequently being noted. The rate of plugging appeared to be affected by the previous sequence of pasteurization treatments. Tyndallization was found to satisfactorily control iron bacterial biofouling and maintain flow rates.

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