Abstract
Production optimization problem in hydrocarbon reservoirs has garnered prime importance in the last few years. There are numerous methods to achieve the requisite and desired production rates. One such method is hydraulic fracturing, which has been used since the 1940s. Like many other technologies, hydraulic fracturing considers the usage of various chemicals for formulating the fracturing fluid. It has a concomitant challenge of optimal selection of such fluid as per the given conditions. The objective of this study was to validate the composition of hydraulic fracturing fluid for fracturing jobs in high-temperature Jurassic oil and gas reservoirs located in Western Kazakhstan. A series of laboratory tests were conducted to select suitable chemicals on a scientific and practical basis. Methods used were fluid thermal stability tests, shear test and stability test - all executed on Chandler 5550 rotational viscometer. Several other tests such as emulsion break test, water analysis, crosslinking time, pH measurement and gel tests were also performed. Herein, justifications from known sources are provided alongside the enumerated laboratory tests. Thus, gelling agents, crosslinkers, breakers and various additives such as demulsifiers, pH buffers, clay inhibitors and biocides were selected. Each component has its own chemical equivalent with the desired concentration. The formulated hydraulic fracturing fluid was successfully implemented in 20-ton hydraulic fracturing job in the Jurassic sandstone deposits with bottom-hole temperature up to 105 ℃ and a permeability about 3 mD. The operation was successful and resulted in production increase and promising long-lasting effects. HIGHLIGHTS One of the common problem in hydraulic fracturing jobs is a proper fracturing fluid design in compliance with well and formation conditions Series of lab testing such as fluid thermal stability tests, shear test and stability test, emulsion break test, water analysis, crosslinking time, pH measurement and gel tests were performed for the proposed fracturing fluid composition The optimal formulation of the hydraulic fracturing fluid was selected for operations at high temperatures of the Jurassic clastic formations, in particular at 105 ℃ at depths of more than 2,000 m GRAPHICAL ABSTRACT