MICROSTRUCTURE, MINERALOGY AND PHYSICAL PROPERTIES OF KAOLIN & METAKAOLIN GEOPOLYMERS USED FOR SOLIDIFICATION AND STABILIZATION OF OIL AND GAS DRILLING WASTE OPERATIONS

Abstract

The production of oil and gas includes drilling a number of wells for exploration or production activities. During drilling operations, large volumes of drilling fluids are used to facilitate the process. In Libya, after completion of drilling operations drill cuttings and waste drilling fluids are typically discharged close to the oil fields without treatment. This can result in negative ecological impacts on the surrounding environment e.g. through infiltration of toxic constituents into soils and underground waters. In this work, the sustainable approaches were examined to test their suitability for use in Libyan Desert. The solidification/ stabilisation of drilling waste via geopolymerisation approach was tested using natural kaolin clay. The ability of the geopolymers to stabilise drilling waste by immobilising heavy metals and encapsulating hydrocarbons was evaluated through systematic experiments employing both macro properties and microstructure studies to assess: (i) the transformation of raw materials into cementitious materials; (ii) changes in physical and mechanical properties, (iii) the role of additives in enhancing the degree of geopolymerisation (iv) the leachability of solidified wastegeopolymers produced. The research has resulted in a number of key conclusions related to the feasibility of using Kaolin based geopolymers to stabilise the drilling waste generated from oil and gas industry in Libya. It is found that (S/S) systems composed from kaolin-waste geopolymer able to reduce the contaminants leachability by both physical (adsorption or encapsulation) and chemical (fixation) means, and it is possible to use Kaolin as a sustainable alternative for Portland cement in S/S system to convert the hazardous waste into inert or nonreactive hazardous waste acceptable for selected in-situ environmental engineering applications. The solidified geopolymer matrix found adequate to the requirements of sustainable waste management options such as safe landfill, reuse and recycle in the place of the generation which offering a sustainable, cost-effective approach that brings environmental and economic benefits.