Adaptation of Capillary String for the Surfactants Delivery into a Gas Condensate Well and Optimization of its Operation Using Dynamic Multiphase Flow Simulator

The studied productive formation of gas condensate field is at the stage of declining production. The inflow of bottom water due to the rise of the GWC and the design features of horizontal wells (large tubing and liner diameters) create the prerequisites for the development of a liquid loading of wells. This necessitate the optimization of the existing method of liquid unloading by dosing surfactants into the annulus. In order to increase the efficiency of well treatment with a foaming agent, the use of a surfactant injection system through a capillary string suspended inside a tubing is considered. The use of this system allows to increase the speed and depth of surfactant delivery, use the potential of the well by simultaneous work in tubing and annulus during significant watering period (water flow rate: 50 and more m3 / day), reduce reagent losses associated with retention on the casing walls, and reduce the required consumption of surfactant. The capillary string for the pumping surfactant is applicated to ensuring the stable operation of gas condensate wells during liquid loading. But today there are not ready-made applied solutions for correctly accounting surfactant action in unsteady flows conditions in the well. The paper presents the substantiation and analysis of the capillary string introduction into the well for the pumping surfactant using specialized software. In the course of work, the main analysis tool is the dynamic modeling of multiphase flows in the conditions of steady and unsteady processes in wells. This approach use is aimed at determining the optimal depth and diameter of capillary, the required consumption and concentration of surfactant, the rate of its delivery to the bottomhole, and the liquid removal efficiency from the horizontal wellbore.

Application progress of microbial immobilization technology based on biomass materials

In recent years, microbial degradation technology has shown broad potential in the fields of agriculture, industry, and environmental protection. However, in practical applications the technology still encounters many problems, such as low bacterial survivability during dynamic operations, the need to remove bacterial liquid, and low tolerance in high-toxic environments, among other issues. Immobilization technology has been developed to overcome such limitations. Microbial strains have been prepared for a specific range of activities utilizing self-fixation or exosome fixation. Immobilization can significantly improve strain density, toxicity tolerance, and bacterial liquid removal. This review first presents the advantages and disadvantages of the current microbial immobilization technologies and then summarizes the properties and characteristics of various carrier materials. The review focuses on how biomass-derived materials have been used as the carriers in new microbial immobilization technologies. The excellent biocompatibility, unique physical structure, and diversified modification methods of biomass-derived materials have shown excellent prospects in the field of microbial immobilization. Finally, microbial immobilization technologies’ potential applications in agriculture, industry, and environmental applications are considered.

Application progress of microbial immobilization technology based on biomass materials

In recent years, microbial degradation technology has shown broad potential in the fields of agriculture, industry, and environmental protection. However, in practical applications the technology still encounters many problems, such as low bacterial survivability during dynamic operations, the need to remove bacterial liquid, and low tolerance in high-toxic environments, among other issues. Immobilization technology has been developed to overcome such limitations. Microbial strains have been prepared for a specific range of activities utilizing self-fixation or exosome fixation. Immobilization can significantly improve strain density, toxicity tolerance, and bacterial liquid removal. This review first presents the advantages and disadvantages of the current microbial immobilization technologies and then summarizes the properties and characteristics of various carrier materials. The review focuses on how biomass-derived materials have been used as the carriers in new microbial immobilization technologies. The excellent biocompatibility, unique physical structure, and diversified modification methods of biomass-derived materials have shown excellent prospects in the field of microbial immobilization. Finally, microbial immobilization technologies’ potential applications in agriculture, industry, and environmental applications are considered.

CALCULATION METHOD FOR DETERMINING THE GAS FLOW RATE NEEDED FOR LIQUID REMOVAL FROM THE BOTTOM OF THE WELLBORE

As a result of flooding and accumulations of liquid at the bottomholes, the operating conditions of gas wells become complicated, so that they end up selfsqueezing and losing of gas production.A method is proposed for determining the technological parameters of operation of the gas wells with the purpose of removing liquid from the bottom of the wells. Data from the gas dynamics and special studies were used to develop this method, which has been tested on one of the oil and gas condensate fields. It offers the possibility to increase the accuracy of the information provided by the fund and to ensure that the production wells are operated as efficiently as possible with the use of this method. In the case of liquid accumulation in the well that is insignificant, or when water is present in the well, the technique is beneficial in that it allows determining the technological parameters of well operation and ensuring the removal of the liquid from the bottom of the well.

Calculation Method for Determining the Gas Flow Rate Needed for Liquid Removal from the Bottom of the Wellbore

As a result of flooding and accumulations of liquid at the bottomholes, the operating conditions of gas wells become complicated, so that they end up self-squeezing and losing of gas production. A method is proposed for determining the technological parameters of operation of the gas wells with the purpose of removing liquid from the bottom of the wells. Data from the gas dynamics and special studies were used to develop this method, which has been tested on one of the oil and gas condensate fields. It offers the possibility to increase the accuracy of the information provided by the fund and to ensure that the production wells are operated as efficiently as possible with the use of this method. In the case of liquid accumulation in the well that is insignificant, or when water is present in the well, the technique is beneficial in that it allows determining the technological parameters of well operation and ensuring the removal of the liquid from the bottom of the well.

Experimental Separation Performance of In-Line Piggable Liquid Removal Unit – Pseudo Dry Gas Systems

Pseudo Dry Gas (PDG) technology is proposed as an alternative concept for transporting multiphase fluids (gas, condensate and water) for long deep-water subsea tieback developments (Ref 1 - OTC-28949-MS) (Ref 2 - IPTC-19440-MS). Using PDG technology, subsea pipeline networks can be extended to excess of 200 km total length and considerably reduce the backpressure on the wells. This allows improved recovery of the reserves and the ability to reach currently stranded fields, especially deep-water lower-pressure gas fields. The basis of the PDG system is to remove the liquid of the main pipeline system using Piggable Liquid Removal Units. With the removal of the liquid, the gravitational pressure losses in the system are eliminated allowing the pipeline to operate like a "Pseudo" Dry Gas system. The liquid phase is transported back to shore using a second smaller pipeline running in parallel to the main pipeline by means of subsea liquid pumps (Ref 3 - OTC-29332-MS). After techno-economic reports were completed for a known basin of stranded gas in the West of Shetland, an Oil and Gas Technology Centre (OGTC) experimental project was established to determine the operation performance of the element within the PDG technology with lowest Technology Readiness Level (TRL). Currently the liquid removal unit has a TRL2 and a TRL4 will be achieved after the experimental testing programme has been fully completed. This paper assesses the separation performance (Efficiency) of the Piggable Liquid Units or PDG unit. Previous Flow Assurance and Computational Fluid Dynamics (CFD) established expected efficiencies between 84-99% depending on the gas and liquid flow rates and other factors such as unit orientation, liquid type, operating pressure and temperature. Each PDG unit has two modules which allow for gas-liquid separation of the multiphase fluid in the pipeline. A PDG unit prototype has been built and a testing programme has been developed and undertaken in collaboration with Cranfield University (CU) using the large scale Inclinable Multip hase Flow Loop facilities. The testing programme has two test matrices: Matrix 1 which studies the performance of a single module of the PDG unit and Matrix 2 which investigates the efficienc y of the entire PDG unit (two separation modules). Matrix 1 of the testing programme allows to characterise the system varying the flow conditions (flow regime, liquid and gas flow rates), drop out liquid level and size, effect of sand and the inclination and orientation of the unit as would be expected once installed. This paper focuses on the results obtained from Matrix 1 testing programme and compares them with the initia l PDG unit estimated efficiency values used in previous studies to demonstrate the prove of concept of the PDG technology. The overall conclusion is that the performance of the PDG liquid removal unit is greater than the ones originally used in technology assessment reports.

Developing a complex of measures for liquid removal from gas condensate wells and flowlines using surfactants

Purpose: The purpose of this work is to consider the complications that arise while operating gas condensate wells, in particular, the accumulation of hydrocarbon condensate, formation and condensation water at wells and flowlines, to develop a method for removing liquid from wells and flowlines before it entering a gas treatment unit and being treated with surfactants and to develop a method for the foam destruction in the gas-liquid flow. Design/methodology/approach: The operational parameters of gas-condensate wells of the Yuliivske oil and gas condensate field (OGCF) have been analysed. Wells have been identified that are operated in difficult conditions due to the accumulation of the liquid at the bottom hole and in flowlines. The volume of the liquid accumulated at the bottom hole of gas condensate wells is estimated. The quantity of surfactants, the volume and concentration of the solution required to remove the liquid were calculated individually for each well. The program of experimental researches has been made. The efficiency of the application of surfactant solution was experimentally determined and a positive result was achieved in the form of an increase in production by 10%. A new approach to the use of surfactant solution, as well as the foam destruction, has been proposed. The studies were performed within the framework of research and development work by the specialists of the Ukrainian Scientific Research Institute of Natural Gases. Findings: Comprehensive measures are proposed to increase the efficiency of gas condensate wells operation. They are monitoring of operational parameters of wells by pressure and temperature gauges installed at the wellhead and at the inlet gas pipelines of the gas treatment unit; calculation of the volume of accumulated fluid in the wellbore and flowline; installation of a complex of automated feeding a surfactant solution of both in the annulus of the wells and in the flowline. For this purpose, two options for the complex and arrangement are proposed. The proposed options involve the use of various equipment and have a different principle of operation. To prevent foam from entering the gas treatment unit, a method of its destruction has been proposed. The implementation of the proposed comprehensive measures will allow controlling the well operation mode, timely liquid removal from the well and the flowline and ensure stable hydrocarbon production. Research limitations/implications: The obtained results of laboratory and experimental studies have shown that using a surfactant solution is reasonable to remove the liquid from gas condensate wells. To increase the efficiency of the measure, a new method of feeding surfactant solution was developed by installing a unit for automated feeding (UAF) of a surfactant solution at the mouth. Practical implications: The results of laboratory tests allow using a surfactant solution reasonably in order to remove the liquid from gas condensate wells, as well as possible further destruction of foam in the gas-liquid flow for increasing both the efficiency of the extraction and production volume. Originality/value: On the basis of previously performed experimental research, it has been established that it is advisable to use a surfactant solution to remove the liquid from gas condensate wells and flowlines. A new method of removing liquid from gas condensate wells and flowlines has been developed, as well as a method of destroying foam in a gas-liquid flow, which are original and can be implemented.

Predictive modelling of drop ejection from damped, dampened wings by machine learning

The high frequency, low amplitude wing motion that mosquitoes employ to dry their wings inspires the study of drop release from millimetric, forced cantilevers. Our mimicking system, a 10-mm polytetrafluoroethylene cantilever driven through ±1 mm base amplitude at 85 Hz, displaces drops via three principal ejection modes: normal-to-cantilever ejection, sliding and pinch-off. The selection of system variables such as cantilever stiffness, drop location, drop size and wetting properties modulates the appearance of a particular ejection mode. However, the large number of system features complicate the prediction of modal occurrence, and the transition between complete and partial liquid removal. In this study, we build two predictive models based on ensemble learning that predict the ejection mode, a classification problem, and minimum inertial force required to eject a drop from the cantilever, a regression problem. For ejection mode prediction, we achieve an accuracy of 85% using a bagging classifier. For inertial force prediction, the lowest root mean squared error achieved is 0.037 using an ensemble learning regression model. Results also show that ejection time and cantilever wetting properties are the dominant features for predicting both ejection mode and the minimum inertial force required to eject a drop.

A novel way of Subfoveal Perfluorocarbon liquid Removal using 26 gauge spinal anesthesia needle

Introduction: Perfluorocarbon (PFCL) is an essential adjunct of retinal detachment surgery. Subfoveal migration of PFCL is a rare and vision threatening complication of its use. Various techniques have been described for its removal. However, no consensual technique of its removal has been established. We present a nova, relatively atraumatic and cost effective way of PFCL removal using a widely available 26G spinal anesthesia needle. Case: An 18 years old myopic patient who had undergone left eye pars plana vitrectomy (PPV) for myopic Rhegmatogenous Retinal Detatchment (RRD) in the past presented after 1 month with retained subfoveal PFCL. Its subretinal location was confirmed by Optical Coherence Tomography (OCT). He was taken up for early Silicone Oil Removal (SOR) along with removal of retained subfoveal PFCL under high magnification by using a surgical disposable contact macula lens. A 26G spinal anesthesia needle tip was used to dissect a small separation parallel to the nerve fibers at the temporal edge of tense cystic PFCL bleb. Silicone tipped flute cannula was used to passively aspirate the sub retinal PFCL under fluid with no additional intervention. No barrage LASER was done. Observation: Anatomical restoration of the retina was noted both intraoperatively and post-operatively. SD-OCT showed complete restoration of anatomical layers with no presence of intraretinal cystic cleft both at day 1 and 30 days postoperatively. Conclusion: Safe removal of subfoveal PFCL can be done with 26G spinal anesthesia needle which is atraumatic, inexpensive and readily available. However, long term validity of this process needs to be established in a case series.