Shale Reservoir Characterisation, Micro Crack Studies and Multi stage Fracturing: A Case Study Form Cambay Basin

Abstract

With rapid depletion of producing reservoirs and technically challenging hostile environments, it becomes imperative to look for the unconventional sources of energy. Unconventional reservoirs have burst with considerable force in oil and gas production worldwide. To achieve commercial production, these reservoirs should be stimulated through massive hydraulic fracturing and frequently, through horizontal wells as a means to enhance productivity. And with advancement of technology and increasing demand for oil and gas the E&P industries world over have been resorting to shale gas and shale oil as major unconventional source. The term ―unconventional reservoir‖ covers a wide range of hydrocarbon-bearing formations and reservoir types that generally do not produce economic rates of hydrocarbon without stimulation. Unconventional reservoirs include: Tight-Gas Sandstones, Gas Hydrates, Oil Shale Formation, Heavy Oil Sandstone and Shale gas. Here, in this dissertation our main focus is Shale Gas. Shale natural gas is either biogenic in origin, formed by the action of biologic organisms breaking down organic material within shale, or of thermo genic origin formed at depth and high temperature. This study is focused on characterization and stimulation of Cambay Shale formations. This dissertation summarizes various geophysical analysis of TOC (Total organic carbon-Pyrolysis) and elemental analysis (X-Ray Fluorescence) of various shale samples of Cambay Basin and Interpretation of image logs provided by GSPC to identify structure and fractures in the upper and lower Cambay shale formation. Image logs of upper and lower Cambay shale formations gives an idea about dip angle, strike directions (Azimuth) and maximum stress direction. Geo mechanical study carried out on Shale core samples of Cambay field to calculate three principle stress and best suitable azimuth lateral direction for horizontal drilling and also best fracturing zones. After identifying suitable fracturing zone we go for multi stage fracturing. Hydraulic fracturing is a key technique that has enabled the economic production of natural gas from shale deposits, or plays. The development of large-scale shale gas production is changing the U.S. energy market, generating expanded interest in the usage of natural gas in sectors such as electricity generation and transportation. At the same time, there is much uncertainty of the environmental implications of hydraulic fracturing and the rapid