Improving the cuttings transport performance of water-based mud through the use of polypropylene beads

This research work presents the experimental results of the effect of polypropylene beads’ concentrations in water-based mud on wellbore cleaning. A comparative study of cuttings transport performance (CTP) of water-based mud and water-based mud with polypropylene beads were carried out at different hole angles of 0°, 30°, 60°. 75° and 90° in a 13 ft (3.96 m) acrylic concentric annulus flow test section, having a 2 in (50.8 mm) casing ID and a fixed 0.79 in (20 mm) inner pipe OD. A total of 100 runs had been accomplished using fine sands (from Tanjung Balau, Johor Bahru, Malaysia), of size ranging from 5/127 - 6/127" (1.0 – 1.2 mm) and density 2.4 g/cc (2400 kg/m3), with the mud density and viscosity maintained at 9 ppg (1078 kg/m3) and 5 cp (0.005 Pa.s), respectively, in a flow velocity of 2.1 ft/s (0.64 m/s). Polypropylene beads used in this study have the following properties: 290 kg/cm2 of tensile strength at yield, 0.86 g/cc (860 kg/m3) density, 4 mm (20/127") size, 82 R scale Rockwell hardness, 13,500 kg/cm2 flexural modulus, 85°C heat deflection temperature at 4.6 kg/cm2, 4 g/10 min melt flow rate at 230°C and spherical in shape. The experimental findings showed that commingling the basic mud with polypropylene beads has successfully introduced a buoyant force which was found to have improved the cuttings transport performance by more than 10% when weight concentration of the polypropylene beads was increased to 1.5% as compared with the performance obtained from the basic water-based mud. The improvement of cuttings transport performance was found to be more significant in a vertical hole

Effects of nanoparticle types on carbon dioxide foam flooding in enhanced oil recovery

Enhancement of foam stability has been recently evidenced with addition of nanoparticles (NPs), especially in the case of CO2 foams. Stabilized foams via solid NPs can potentially withstand high reservoirs temperatures. Studies have been conducted to examine the effect of NPs on foam stability; however, more research is required for various types of NPs. Therefore, the authors aimed to investigate the performance of silicon dioxide (SiO2), aluminum oxide (Al2O3), copper oxide (CuO), and titanium dioxide (TiO2) of different sizes in the presence of fixed concentration of anionic surfactant (AOS) on foam stability. Nano particle concentrations of (0.1 wt%, 0.3 wt%, 0.5 wt%, and 1 wt%) were used to investigate the foam stability, displacement test were performed to determine oil recovery at the optimum concentrations for each nanoparticle. The stability of the aqueous foam was evaluated by the Ross-Miles method using half-life measurements. All experiments were conducted at room temperature and pressure. The results revealed that all different NPs used were able to improve the stability of CO2 foam at certain concentrations. However, aluminum oxide NPs showed better results compared to others in terms of foam stability and half-life time. In addition, 0.1 wt% of all NPs types gave the highest foam stability and half-life time. In conclusion, a low concentration of NPs is recommended regardless of type for improving form stability

Effect of emulsified water on the wax appearance temperature of water-in-waxy-crude-oil emulsions

The article concentrates on the effect of emulsified water on the wax appearance temperatures (WATs) of water-in-waxy-crude-oil emulsions. Water-in-oil (w/o) emulsion samples with various water volume fractions (WVFs) were prepared by mixing a waxy crude oil with deionized water at three different stirring speeds. The WAT of each sample was attained via differential scanning calorimetry and was compared with that of the dehydrated crude. In addition, the effects of the WVF and the mean droplet size on the WAT of the emulsions were theoretically evaluated based on the relationship between the wax solubility in the crude oil and the Gibbs free energy concept. The results indicate a sharp increase in the WAT with the presence of water in the system, regardless of the volume of water. Greater deviations became apparent at higher WVFs and rotational speeds, which resulted in the formation of a larger number of droplets

Improving the Cuttings Transport Performance of Water-based Mud Through the Use of Polypropylene Beads

This research work presents the experimental results of the effect of polypropylene beads’ concentrations in water-based mud on wellbore cleaning. A comparative study of cuttings transport performance (CTP) of water-based mud and water-based mud with polypropylene beads were carried out at different hole angles of 0°, 30°, 60°. 75° and 90° in a 13 ft (3.96 m) acrylic concentric annulus flow test section, having a 2 in (50.8 mm) casing ID and a fixed 0.79 in (20 mm) inner pipe OD. A total of 100 runs had been accomplished using fine sands (from Tanjung Balau, Johor Bahru, Malaysia), of size ranging from 5/127 - 6/127" (1.0 – 1.2 mm) and density 2.4 g/cc (2400 kg/m3), with the mud density and viscosity maintained at 9 ppg (1078 kg/m3) and 5 cp (0.005 Pa.s), respectively, in a flow velocity of 2.1 ft/s (0.64 m/s). Polypropylene beads used in this study have the following properties: 290 kg/cm2 of tensile strength at yield, 0.86 g/cc (860 kg/m3) density, 4 mm (20/127") size, 82 R scale Rockwell hardness, 13,500 kg/cm2 flexural modulus, 85°C heat deflection temperature at 4.6 kg/cm2, 4 g/10 min melt flow rate at 230°C and spherical in shape. The experimental findings showed that commingling the basic mud with polypropylene beads has successfully introduced a buoyant force which was found to have improved the cuttings transport performance by more than 10% when weight concentration of the polypropylene beads was increased to 1.5% as compared with the performance obtained from the basic water-based mud. The improvement of cuttings transport performance was found to be more significant in a vertical hole

An experimental study of flow patterns pertinent to waxy crude oil-water two-phase flows

Flow patterns encountered during the flow of a waxy crude oil and water in a horizontal pipeline were experimentally studied at a temperature 4 °C greater than the wax appearance temperature (WAT). The visual observation technique along with the analysis of the associated pressure drops and free water measurement were used to identify the flow patterns and their transitions. Designing a specific multiphase flow test facility and applying a newly proposed technique for controlling the mixture temperature also allowed the examination of the recently discovered phenomenon regarding the effect of emulsified water droplets on accelerating the wax crystallization process above the WAT under dynamic conditions. The results of this study showed the deposition of wax crystals on the pipe wall for some of the flow patterns which, by implication, authenticates the influence of emulsified water on elevating the WAT even in dynamic flow conditions. Classification of the flow patterns based on the wax deposition yielded an original flow pattern map composed of nine patterns among which new configurations were evidenced for annular flows. In addition, all the flow patterns were affected by the entrance effect and a layer of water-in-oil emulsion was observed for all the flow conditions. The influential parameters in the formation of such flow patterns are theoretically discussed in details. Since the waxy crude oil in two-phase flow is a relatively uncharted area of study, the results of this study can provide a platform for furthering research

Mixture temperature prediction of waxy oil-water two-phase system flowing near wax appearance temperature

Temperature sensitivity of waxy crude oils makes it difficult to study their flow behaviour in the presence of water especially near their wax appearance temperature (WAT). In this study a method was proposed and implemented to mitigate such difficulties which was applied in predicting mixture temperatures (Tm) of a typical Malaysian waxy crude oil and water flow in a horizontal pipe. To this end, two analytical models were derived firstly from calorimetry equation which based on developed two correlations for defining crude oil heat capacity actualized from the existed specific heat capacities of crude oils. The models were then applied for a set of experiments to reach the defined three predetermined Tm (26°C, 28°C and 30°C). The comparison between the predicted mixture temperatures (Tm,1 and Tm,2) from the two models and the experimental results displayed acceptable absolute average errors (0.80%, 0.62%, 0.53% for model 1; 0.74%, 0.54%, 0.52% for model 2). Moreover, the average errors for both models are in the range of standard error limits (± 0.75%) according to ASTM E230. Conclusively, the proposed model showed the ease of obtaining mixture temperatures close to WAT as predetermined with accuracy of ± 0.5°C approximately for over 84% of the examined cases. The method is seen as a practical reference point to further study the flow behaviour of waxy crudes in oil-water two-phase flow system near sensitive temperatures