Multiphase Flow Boosting Without Using a Mechanical Multiphase Pump – Use of Innovative Surface Mounted Technology for Boosting Production from Inactive Multiphase Wells

Depleting reservoir pressures of mature fields or wells backing out due to high production line pressures can cause severe restriction in production from many oil wells, eventually leading to a complete cessation of production. These wells, however, still have considerable hydrocarbon reserves that can be recovered. Conventional methods to bring such marginal or inactive wells back into production involve power hungry multi-phase pumps or well intervention techniques such as N2 injection, workover, redrilling and artificial lift systems. Such methods are highly expensive and may require substantial infrastructure, especially on offshore satellite platforms which have limited facilities and space. Multi-Phase Surface Jet Pumps (MPSJPs), innovatively combined with novel compact separation, provide a surface mounted, compact, maintenance free and simpler method for boosting production from inactive multi-phase wells, without consuming any electrical power or fuel gas and avoiding any well intervention. Multi-Phase Surface Jet Pumps (MPSJPs) are passive devices which use the energy of existing high pressure single/multi-phase fluids to reduce the Flowing Wellhead Pressure (FWHP) of low pressure multi-phase wells and boost their pressure to the downstream production header pressure. This patented system involves the use of a compact in-line separator upstream of the MPSJP to separate the gas & liquid phases and use the predominant liquid phase as the high-pressure motive fluid. MPSJPs can be used on their own or in combination with other boosting systems (e.g. ESPs, gas lift etc.). The applications also include revival of watered out, idle oil and gas wells. Results from multiple worldwide applications have shown that MPSJPs can successfully boost production from low producers as well as revive dead wells that have not been flowing for a period of time. Wellhead pressures have been considerably reduced and production increases have ranged from 20% to 40% per well. The advantages that MPSJPs offer over conventional technologies such as Multi-phase pumps, ESPs and well intervention techniques are several. MPSJPs are surface mounted (so well intervention is not required), comparatively low cost, have no moving parts, consume zero fuel gas/electrical power, have low footprint and use already available fluid energy. They are tolerant to variations in flow conditions, gas volume fractions (GVF) and associated slugging. They reduce the CO2 footprint by not consuming power and provide a radical, innovative, economical and environmentally friendly alternative to conventional methods. This paper discusses the use of MPSJPs and cites various case studies. The design and operational criteria are also highlighted.

Study of the salinity and pH dilution pattern of discharged brine of the Konarak desalination plant into the Chabahar bay: a case study

This research aims to study the salinity and pH dilution pattern of discharged brine of the Konarak desalination plant into the Chabahar bay, their relation on coastal environment, and type of its brine discharge. Due to the shallow water depth of the coast and type of brine discharge, evaluating the salinity and pH was done with a sampling of surface seawater. The type of brine disposal is a direct surface discharge of negatively buoyant flow in the coastal environment of Chabahar bay. The brine discharge mechanism is a shore-attached surface jet, which is most likely influenced by the cross-flow deflection, dynamic shoreline interaction, and more minor by bottom attachment factors. The laboratory simulations using actual brine and seawater and either satellite pictures support the finding dilution pattern. The zone of initial dilution is under 50 m which, in the long run, can affect the quality of water of intake seawater pool of the plant.

Hydraulic characteristics of countercurrent jets on adverse-sloped beds

The counter-current jet (CCJ) acts like a reverse surface jet layer covering the free jump surface and has potential applications in the energy dissipation of hydraulic engineering. The present study investigated the hydraulic characteristics of CCJs on adverse-sloped beds. The results showed that, compared to the horizontal bed, the slope didn't increase the energy dissipation rate of CCJ but reduced the return flow length and upstream depth. The velocity distribution along the depth was divided into the boundary layer region, mixing region, and reverse surface jet region. The velocity distribution in the boundary layer region and the mixing region was similar to the classical wall jet. The jet Froude number and the bed slope had no significant effect on the turbulence intensity distribution and turbulence kinetic energy (TKE) distribution of CCJ. The distribution of TKE was similar to that of a submerged jump. The maximum absolute turbulence intensity appeared at exactly half of the maximum velocity. The maximum TKE appeared at the mixing region. Besides, empirical formulas for estimating length scales and maximum velocity attenuation are proposed. The results could provide a reference for the potential application of CCJ in energy dissipation in hydraulic engineering.

Stratified shear instabilities in diurnal warm layers

In low winds (≲2 m s−1), diurnal warm layers form but shear in the near-surface jet is too weak to generate shear instability and mixing. In high winds (≳8ms−1), surface heat is rapidly mixed downward and diurnal warm layers do not form. Under moderate winds of 3–5 m s−1, the jet persists for several hours in a state that is susceptible to shear instability. We observe low Richardson numbers of Ri ≈ 0.1 in the top 2 m between 10:00 and 16:00 local time (from 4 h after sunrise to 2 h before sunset). Despite Ri being well below the Ri = 1/4 threshold, instabilities do not grow quickly, nor do they overturn. The stabilizing influence of the sea surface limits growth, a result demonstrated by both linear stability analysis and two-dimensional simulations initialized from observed profiles. In some cases, growth rates are sufficiently small (≪1 h−1) that mixing is not expected even though Ri < 1/4. This changes around 16:00–17:00. Thereafter, convective cooling causes the region of unstable flow to move downward, away from the surface. This allows shear instabilities to grow an order of magnitude faster and mix effectively. We corroborate the overall observed diurnal cycle of instability with a freely evolving, two-dimensional simulation that is initialized from rest before sunrise.

METHODOLOGY FOR CALCULATING JET EJECTORS, USED IN HYDROMECHANIZATION

Purpose: to develop a methodology for calculating jet devices used in hydromechanization for the development of soils and cleaning reservoirs from sediments using the results of our own research and the theoretical and empirical dependences presented in the literature. Materials and Methods: on the example of a diagram of an annular two-surface jet ejectors with increased energy characteristics, a method has been developed and the calculation of the relative and actual geometric and hydraulic parameters of its elements is shown for use as a suction tip on suction dredgers at the necessity to increase the suction height and development depth of centrifugal dredgers. Results. Based on the initial data (the values of the hydraulic resistance coefficients of the inlet section, diffuser, nozzle, the distance from the nozzle edge to the beginning of the mixing chamber, mixer, operating parameters of the pump – pump head and flow rate, pipeline diameters), the pulp density in the suction nozzle, the weight coefficient of ejection, geometric characteristic, relative optimum head, actual heads of the jet apparatus and pump-blower, volumetric total flow, volumetric consistency of the pulp in the suction pipeline, performance over the ground, actual dimensions. Conclusions: the developed methodology will allow calculating the optimal dimensions of jet enjector of a new design and developing a design for the suction tip of a suction dredger for various in pressure, flow rate and development depth of operational options for removing bottom sediments in water bodies.