Comprehensive Review on Exploration and Drilling Techniques for Natural Gas Hydrate Reservoirs

Abstract

With the depletion of conventional oil reservoirs and concerns about the increasing carbon footprint of coal, natural gas is poised to play a much bigger role in sustainable economic growth. Gas hydrates being an abundant source of clean methane have created great interest among academia and industry. Its demographic occurrence in shallow depths has motivated industry and academia to explore its abundance and exploitation potential. Despite being shallow, offshore gas hydrate exploration and drilling is a deepwater endeavor, which was considered expensive and risky as a result of its narrow thermodynamic stability and lack of exploitation experience. However, with recent advancement in technology and long-term field trials, it has been universally accepted that methane production from marine hydrate reservoirs is achievable with innovative drilling techniques and proper well design pertaining to the appropriate location and layout of wells, efficient well orientation, competent casing and tubing design, and completion design requirements for long operating life and reliability of the well. Much has been discussed about exploration and production, but very little has been addressed about the drilling technologies that have the potential for safe and effective exploitation of this resource in commercial quantities. The objective of this review is to enlighten the readers with exploration techniques used to locate gas hydrate reservoirs and discuss drilling tools and techniques that have the potential to avoid premature hydrate dissociation around the wellbore and enhance production life of the well with minimum interventions. The techniques discussed are mostly the learnings from the international drilling projects on different types of gas hydrate reservoirs. This review also focuses on different drilling fluids, pressurized coring systems, and well logs suitable for hydrate reservoirs. We believe that this review will provide a scientific reference material to engineers for safe exploration and drilling and stimulate upcoming exploration and drilling activities in the field of gas hydrates.

Enrichment of gas storage in clathrate hydrates by optimizing the molar liquid water–gas ratio

“…8 Natural hydrates are ascertained to be a future energy source if used with feasible technology and will have economic value. 9 The synthetic hydrates provide multifaceted applications such as storage media for greenhouse gases, [10][11][12][13][14][15][16] carbon dioxide capture from fuel gas, 17 methane recovery from coal mine gas, 18,19 desalination, [20][21][22] cold storage, [23][24][25][26][27] and gas transportation. 12,28 Because of their structural properties and selectivity, this process slowly escalates to address various food technology issues.…”

Explicating the amino acid effects for methane storage in hydrate form

“…It is specied that if 15% of these hydrate resources are exploited, it could fulll the world's energy needs for more than 100 years at the current consumption rate. 4 Feasible technology to recover methane from the natural hydrates reserves is developing. 5,6 If feasibly exploited from the hydrate source, massive storage units/tanks are required to preserve and transport the gas.…”

Kinetics of Methane Hydrate Formation in the Presence of 1-Dodecyl-2-pyrrolidinone and Tetrahydrofuran in Pure Water

“…NG hydrates are nonstoichiometric solid compounds composed of a three-dimensional hydrogen-bonded network of water cages that can trap gas molecules under low-temperature and high-pressure conditions . There are three commonly known hydrate structures, namely, structure I, structure II, and structure H .…”

“…NG hydrates are nonstoichiometric solid compounds composed of a three-dimensional hydrogen-bonded network of water cages that can trap gas molecules under lowtemperature and high-pressure conditions. 2 There are three commonly known hydrate structures, namely, structure I, structure II, and structure H. 3 Each of these structures has a characteristic cage size, lattice parameter, and number of water molecules forming a unit structure. The type of hydrate structure depends on the molecular size of the guest involved and the conditions of hydrate formation.…”