Application of Microemulsion Systems in the Formulation of Biodegradable Pre-Flush Fluid for Primary Cementing

Oil well cleanup fluids (pre-flushes) are intermediate fluids pumped ahead of the cement slurry; they are able to clean the well walls by removing the filter cake formed by the drilling fluid, and leave the surface water-wet. This work’s main objective was to use biodegradable microemulsion systems as cleanup fluids in order to reduce the environmental impact. Three microemulsion systems were formulated, each composed of an oil phase, a surfactant and three different aqueous phases: glycerol, glycerol:water (mass ratio 1:1), and fresh water. The results show that all microemulsion systems were effective with 100% filter cake removal, with a removal time of less than 60 s. The wettability test and fluid compatibility analyses exhibited advantageous performances, without phase separation, variations in viscosity, gelation, or flocculation. The compressive strength and X-ray diffractometry (XRD) analysis showed the influence of the glycerol on the cement slurry properties, with the compressive strength resistance ranging from 8.0 to 10.7 MPa, and resulted in the formation of portlandite.

Study on Gap Phenomena Before and After the Breakout Event of Fast Electrical Discharge Machining Drilling

Fast electrical discharge drilling is broadly used to manufacture small holes on molds, dies, filters, and automobile and aerospace components. Breakout is the event when the tool electrode reaches the opposite surface of the workpiece. When a breakout happens, the machining efficiency drops sharply and the process becomes unstable. To gain a deep understanding of the breakout process, this paper observed the gap phenomena before and after the breakout with cameras through a quartz glass flake. Experiments were conducted on the workpiece tilted to 45 deg. From the observation, it was found that the deformation of the electrode was not negligible. The electrode would vibrate or shake before and after the breakout. Side-gap sparks were common in the process, and even more were observed after the breakout. The fluid flow in the discharge gap and the side gap did not vanish immediately when a breakout happened and could still evacuate debris for a short period. The debris gradually accumulated as the fluid flow in the gap vanished. A series of simulations were conducted to study the fluid flow and debris movement after the breakout. And simulations were also performed to find the influence on electrode vibration of high-pressure flush fluid and discharge location. The results of simulations agreed well with the observed phenomena. From the observation and simulation results, the deformation or vibration of the electrode and the accumulation of debris were found to be the main factors that led to the low machining efficiency after the breakout.

Analysis of the uterine flush fluid proteome of healthy mares and mares with endometritis or fibrotic endometrial degeneration

The objective of this study was to evaluate the differences in the uterine flush fluid proteome between healthy mares and mares with endometritis or fibrotic endometrial degeneration (FED). Uterine flush fluid samples were collected from healthy mares (n=8; oestrus n=5 and dioestrus n=3) and mares with endometritis (n=23; oestrus n=14 and dioestrus n=9) or FED (n=7; oestrus n=6 and dioestrus n=1). Proteomic analysis was performed using label-free liquid chromatography–tandem mass spectrometry. Of 216 proteins identified during oestrus, 127 were common to all three groups, one protein was exclusively detected in healthy mares, 47 proteins were exclusively detected in mares with endometritis and four proteins were exclusively detected in mares with FED. Of 188 proteins identified during dioestrus, 113 proteins were common between healthy mares and mares with endometritis, eight proteins were exclusively detected in healthy mares and 67 proteins were exclusively detected in mares with endometritis. Quantitative analysis revealed a subset of proteins differing in abundance between the three groups during oestrus and between healthy mares and mares with endometritis during dioestrus. These results provide a springboard for evaluation of specific proteins as biomarkers of uterine health and disease and for investigation of their roles in the establishment and maintenance of pregnancy.

Reform of Mechanical Shaft Sealing Self-Flush System of Petrochemical Hot Oil Centrifugal Pump

Mechanical seal leakage of centrifugal pumps (especially hot oil pumps) is the main fault reason of the petrochemical equipments. The fuction of the sealing flush system is to maintain the mechanical shaft seal function correctly. The misconduct of flush system settings will directly lead to the failure of mechanical seal. In this paper, the problems are analyzed for the present mechanical seal flushing system. When the centrifugal pump is in a standby state, flushing system may not provide normal flush flow in self-flush plan. This may lead to surface fouling of the hot mechanical shaft seal, resulting in seal failure. Our research focus on solving these problems. The way is to change the source of flush fluid, that is to change the flush plan to external flush plan or toChange the fluid pipe position.

Cleaning Technology on Filter Cake of Silicate-Based Polymer Drilling Fluid

In order to evaluate the cleaning effect on filter cake, a set of test device was designed. The cleaning fluid formula and parameters which were elected by experiments were optimized. The weight of the filter cake before and after cleaning was analyzed by wet weight method. New alkaline flush fluid formula was confirmed finally and the washing technology suitable for filter cake of silicate-based polymer drilling fluid has been studied out. The effect of core permeability after cleaning has also been evaluated. The experimental results showed that No.5 formula was suitable for the cleaning filter cake of silicate-based drilling fluid filter, and the weight loss rate could reach 94.09% when cleaning time was 60 minutes. The rotating speed played a minor role in cleaning effect. Weight loss rates increased with the increase of temperature. The weight loss reached 100% when temperature was 90°C. The cleaning fluid could inprove the core permeability up to 900.13% after cleaning, which indicated that the cleaning fluid formula had efficient effect on cleaning filter cake of silicate-based polymer drilling fluid.

Research on Conjugate Heat Transfer in Mechanical Seals of the Aircraft Engine

According to the mechanical seals’ characters of the aircraft engine: no special flush fluid equipment and the limited space etc, a numerical model of conjugate heat transfer between seal rings and seal chamber is presented. And the flow channel and the flow quantity in the mechanical seal are studied, which will affect the heat transfer between the surface of the seal ring and the flush fluid. At last, the studied results are validated by the test.

Design and Analysis of a Novel Radial Mud Pump Directly Driven by Permanent Magnet Disc Synchronous Motor

Mud pump is an important component of drilling equipments, which transports flush fluid like mud or water into bore in order to cool drill and carry debris. In this paper, a novel radial mud pump directly driven by permanent magnet disc synchronous motor (PMDSM) is designed, the influence of different numbers of plunger cylinders on the pump’s flow pulsation is analyzed to determine the pump’s configuration and driving requirement, and the structure and performance parameters of the direct drive PMDSM are calculated by finite element analysis. Compared with conventional mud pumps, the novel pump is characteristic that the structure is simple, working stability and efficiency are greatly improved, also the life of the equipment is extended.

Numerical Simulations of the Flow Field Around the Rings of Mechanical Seals

The flow inside a seal chamber as induced by the influx of the flush fluid and the rotation of the primary ring is analyzed. The 3-D flow characteristic around the mating ring and the rotating ring are predicted by solving the Navier-Stokes equations in cylindrical coordinates. For this purpose, the pressure correction method was used in conjunction with the SIMPLE algorithm. A series of numerical solutions is presented that show the flow mechanism within the gap between the rings and the gland. The implication of the flow characteristic on the cooling of the rings is discussed.