An improved model of MUD dispersion has been introduced in this work. The advantages of this model consist of a new analytical correlation for dispersivity by using resistivity log data and using a new aspect of capacitance dispersion model. Mathematical formulations were expressed, solved by numerical model taking advantage of actual log and formation data. Achieved results yielded reasonable values and trends which can be used to predict the drilling FLUID concentration near wellbore region and interpret the well log data. In comparison with the previous models (Civan and Engler, 1994; Donaldson and Chernoglazov, 1987), this model uses more reasonable data and assumptions making it closer to real conditions.

CMC polymer is used as an additive to decrease water loss and MUD-cake-thickness in MUD drilling. In this study, the effect of CMC and CMC nanoparticles on water loss and MUD-cake-thickness in MUD drilling is investigated. CMC nanoparticles are made by using of ball milling and their size is measured by Particle size analyzer. CMC and CMC nanoparticles which were prepared by Hamilton batch mixer and with certain percent suggested by API, were added to the water-based MUD drilling. The amount of water loss and MUD cake thickness was measured by filter press. It was found that adding CMC nanoparticles in comparison with conventional CMC resulted in desirable reduction of amount of water loss and MUD cake thickness.

The processing of hamburger bean (HB) and African oil bean (AF) seeds for local consumption generates large amounts of waste (shells) that are considered an environmental nuisance. This manuscript presents the experimental result from the study on the utilization of HB and AF shell powders as FLUID loss control additives in drilling MUD. The MUD filtration test was conducted at 25oC and 100 psi following with the American Petroleum Institute (API) guidelines for polymer-based MUD. From the study, the HB-based MUD sample showed a progressive decrease in the volume of FLUID loss as the content of the HB additive increased. Furthermore, the FLUID loss from MUD samples with AF increased with an increase in its concentration, producing MUD cake thickness between 2.2 and 2.8 mm. ultimately, the results demonstrate that HB is a cost-effective and sustainable green additive that can serve as a local alternative to the imported and expensive conventional filtrate control additives.

FLUID properties with constant improvement in efficiency have been noticeable as important criteria in drilling operation. The main drilling FLUID properties highly depend on utilization of new polymers with high efficiency in drilling FLUID composition. In this paper, the performance of a new polymer, called partially hydrolyzed polyacrylamide polymer (PHPA), is studied which has recently entered the drilling FLUIDs industry in Iran. Hence viscosity property, FLUID loss control and shale inhibition of this polymer have been evaluated based on an international standard method of API-13-I by considering the drilling and operational priorities of the country. Then the thermal effect, salt contaminants such as sodium chloride, calcium chloride, magnesium chloride and pH tolerance effect as major pollution indicators are also investigated in relation to polymeric FLUID properties. The results obtained by the tests show that furthermore polymer PHPA increases rheological properties (apparent viscosity, plastic FLUIDity and yield point) and it plays important role in increases in FLUID loss. This polymer has also demonstrated acceptable resistance toward sodium chloride contaminants, but its efficiency decreases toward calcium and magnesium ion contaminants. The thermal tests show that polymer PHPA has high thermal stability up to 150°C. This polymer improves shale inhibition property and by encapsulation mechanism prevents dispersion of shale cuttings into the drilling FLUID system as it stops any changes in FLUID properties which will finally results in wellbore stability.