Rheological Properties of Drilling Fluid using Abonnema Clay in Kalabari, Rivers State as a Case Study

Abstract

The significance and high dependence of Bentonite as a mud in drilling operations in the oil and gas wells cannot be overemphasized. Currently, the importation and consumption of Bentonite in drilling operations in the oil and gas industry in Nigeria alone plays a notable role. Therefore, the continual dependence on this imported material for an incessant drilling activity is increasing rapidly by the day, which is economically unhealthy and thus negates the promotion of local content development. In order to reduce the importation cost and the high consumption rates of this material, an attempt cropped up to find a local substitute suitable in this regard. This work actually depicts the likelihood of the utilization of local clay samples as a basic material for drilling fluids. Basically, in this work, three clay samples were obtained for analysis at Abonnema, in Kalabari region of Rivers State: Clay samples A, B and C were obtained at a depth of 1m, 1.5m and 2.0m respectively. The clays were pulverized to remove impurities without treating it with chemicals (beneficiation) and their rheological properties evaluated. The rheological properties of the un-beneficiated clay such as viscosity and gel strength were very low when compared to the control sample (Wyoming Bentonite). While, there was no significant difference in viscosity for the three samples, however, there was a slight difference in gel strength with clay samples A, B, and C yielding gel strength of 3.5lb/100ft2, 2lb/100ft2 and 3lb/100ft2 respectively. After treating the clay samples with 22.5g of PACR, there was a tremendous improvement on certain rheological properties such as gel strength, viscosity and swelling power. The gel strength of sample A, B and C rose to 9lb/100ft2, 12lb/100ft2 and 13lb/100ft2 which is about 350% improvement. Furthermore, there was a positive relationship between the gel strength and the samples depth. The same level of improvement was recorded for their viscosities except the swelling power which showed only a slight improvement. Based on the ascertained experimental results obtained, this goes to show that there is a possibility of a better quality drilling fluid being formulated from Abonnema clay that could compete favourably with the API specifications when compared with those of imported Bentonite.

Key words: Rheological Properties, Drilling Fluid, Abonnema Clay, Kalabari.