Local Starch Filtration Control Additives in Water-Based Mud for Drilling Operations

Abstract

Conventional application of polyanionic cellulose (Pac L and Pac R) as fluid loss agents in water-based mud has been proven to improve oilfield drilling over the years, however, these fluid loss agents are imported and therefore increase the capital cost of oil and gas drilling operations in Nigeria. Meanwhile, research has shown that the raw materials of most of these imported oilfield chemicals can be obtained locally. Therefore, it is imperative to identify local additives and determine their suitability as substitutes. The study evaluated the fluid loss control performance of selected local starch samples (TME 419, 1632, 0581, TME 416, PS, and CEMA) and compared their results with imported conventional polymer samples X, Pac L, Pac R. Fluid loss results from six local cassava starch samples (TME 419, 1632, 0581, TME 416, PS, CEMA) respectively, and four imported samples(X, Pac L, Pac R, Bentonite) respectively were evaluated. The calculated filtrate values were determined, and results of 4.2 ml, 4.0 ml, 6.3 ml, 3.6 ml, 5.3 ml, 5.3 ml, 3.6 ml, 3.2 ml, 3.8 ml, and 3.4 ml of the samples respectively were obtained. Tests were repeated with 0.5 % and the fluid loss was determined as applicable, the results of 3.9 ml, 3.8 ml, 3.5 ml, 3.0 ml, 5.0 ml, 4.9 ml, 3.4 ml, 2.6 ml, 3.3 ml, and 3.1 ml respectively were obtained. It was observed that there was a decrease in fluid loss volume with an increase in the concentration of the fluid loss agents (local starch and imported samples) respectively. This implies that all the samples are candidates for fluid loss control. However, among the six samples of the local cassava starches, TME 416 exhibited the best fluid loss control and compared favorably with the imported samples. Depending on the level of drilling operations, it is advocated that fluid loss value should be in the range of 10 ml filtrate volume (API Recommended Practice 29), all the local cassava starches meet this range of 10 filtrate volume and therefore are good candidates for filtration control and could be used as substitutes for imported samples