The use of carboxymethyl cellulose (CMC) in oil and gas well drilling operations has improved the filtration loss and mud cake properties of drilling muds. The introduction of starch has also reduced, for example, the viscosity, fluid loss, and mud cake properties of the drilling fluids. However, normal starch has some drawbacks such as low shear stress resistance, thermal decomposition, high retrogradation, and syneresis. Hence, starch modification, achieved through acetylation and carboxymethylation, has been introduced to overcome these limitations. In this study, modified starches, from cassava and maize, were used to enhance the properties of water-based muds under high-pressure high temperature (HPHT) conditions, and their performances were compared with that of the CMC. The mud samples added with acetylated cassava or maize starch exhibited the smallest filtrate volumes and filtrate losses within the American Petroleum Institute specification. Therefore, these modified starch-added muds could replace CMC as fluid loss agents since, unlike it, they can withstand HPHT conditions.

High molecular weight paraffin/wax precipitates in the solution of crude oil when the surrounding temperature falls below the wax appearance temperature, which causes the problem of wax deposition in pipelines. To enhance the rheology of the crude oil and lessen wax deposition, pour point depressants (PPDs) and flow enhancers were utilized. These substances change the wax crystals’ morphology, reducing crystal interlocking and preventing wax agglomeration from facilitating wax dispersion. However, recent research prompted a further investigation to improve the performance of conventional polymeric PPD and to address wax accumulation in a safe and environmentally responsible way. This is because of their poor performance at high shearing, expensive preparations, limited biodegradability, and toxicity. The primary objective of this study is to provide a thorough summary of current studies on the use of seed oil extracts rich in unsaturated fatty acids as an alternative for polymeric PPD. Important studies on the use of nanoparticles to improve the performance of conventional PPD, as well as strategies put into place to overcome issues with nanoparticle application, are also highlighted. Finally, an outlook of potential research ideas to develop pour point depressants is provided.

Resolution of water-in-oil emulsion is a major crude oil processing requirement in oil industry. To improve the quality of the oil and fulfill regulatory requirements numerous chemical demulsifiers of varying efficiencies and effectiveness have been developed over the years. In this study, we have investigated the effects of water content, temperature, and different concentrations of Sodium Methyl Ester Sulfonate (SMES) on emulsion viscosity profiles and stability under distinct levels of salinities. The water content was measured with the American Standard Testing Method ASTM D4928 while SARA analysis was conducted using the ASTM D3279 and ASTM D6591 methods. The density and viscosity of the samples were measured following the ASTM D5002 and ASTM D445 techniques respectively while the emulsion stability was evaluated based on the rate of sedimentation, flocculation and coalescence from Turbiscan classic MA 2000. Refractometer with the aid of a light-emitting diode, a sapphire prism and a high-resolution optical sensor was used to measure the refractive index while interfacial tension was measured with spinning drop tensiometer. The emulsion samples were investigated at 25, 50 and 75°C. Analyses show that the interactions of the constituents of a crude oil system, the produced water system and the emulsion system play major roles in the characterization of water-in-crude oil emulsions. Hence, the stability of water-in-crude oil emulsions is related to the viscous force presented by the continuous phase, water cut and salinity.