非在来型原油・天然ガスの生産性向上手法の紹介

抄録

Unconventional oil and gas attract attention as next generation energy, because of their vast amount of resources. A part of the unconventional oil and gas has been already produced on a commercial scale, while the development of some of them is still in the stage of research. This paper first reviews the methodologies for producing unconventional oil and gas, which are already utilized on a commercial basis or are considered to be promising in the research stage. It is, then, introduced how the existing production methods are being improved/modified to increase the productivity of unconventional oil and gas.
In the development of heavy oil/extra heavy oil/bitumen, advanced production methods including the combination of steam and solvent injection as well as the in-situ upgrading are investigated besides conventional steam injection and in-situ combustion. In the shale gas/oil exploitation, it is well-known that the improvement and integration of horizontal well, multi-stage hydraulic fracturing and micro-seismic technologies have made it possible to dramatically increase the production rate. However, the area of high productivity, which is called a ‘sweet spot,’ is confined to small parts of a formation. Toward the identification of this sweet spot, there is a variety of research work conducted, including the examination of the effects of reservoir properties such as natural fracture permeability, matrix permeability and hydraulic fracture length on gas/oil production, and the investigation of the fluid flow mechanism through micro organic pores. The research work for the development of methane hydrate has started recently. Although the superiority of the depressurization method over other methods such as thermal methods has been revealed, the recovery of methane by depressurization is expected to be not more than 50-60%. The methodologies that can be applied in conjunction with and/or after depressurization are being pursued.