Widening supply and demand gap in natural gas industry, the advent of tight gas policy and increasing interest of operators in tight gas sands and shale has opened new venues for development of unconventional plays in Pakistan.
Middle Indus Basin hosts important gas fields of Pakistan. Most of the wells in this basin are completed in conventional lower Goru Sands. Lower Goru formation consists of inter-bedded sequences of sands and shale. Its unconventional sand and shale plays hold immense potential which has not yet been exploited due to lack of technology and promising economics. Moreover, Sembar shale is the well known source rock in this basin holding large shale gas potential. GIIP estimates for Lower Goru tight sands excluding the shale prospects are 8.4 TCF which are considered pessimistic due to lack of data in many fields.
From the currently suspended or abandoned wellbores of the Middle Indus Basin, a pilot project needs to be defined in each of the fields, to prove the technical and economical feasibility of tight Gas Potential of the Basin. Commencement of production from unconventional sands will enhance the production in a cost effective manner due to availability of infrastructure and facilities.
This paper focuses on the utilization of existing wellbores as well as data set and highlighting additional data acquisition requirements coupled with completion and multi-stage fracturing techniques for designing a pilot project. Case study of a pilot project in one of the fields of this basin is discussed. It encompasses the basic workflow, candidate selection criterion, Geo-mechanics, sector modeling, hydraulic fracture design and risk evaluation coupled with its use in full field development projects.
Background and Introduction
Pakistan's last year 2010-2011 production was about 3.91bcf/d, while its demand was (4.2bcf/d) and supply gap was also started. Since then the production from the conventional fields has decreased, while demand has been increased due to infrastructure and human needs. This huge shortfall in the gas market cannot be fulfilled with existing number of completions/producers. The conventional reserves of the country were 56 TCF out of which the country has already produced 50% of its conventional reserves. The recoverable remaining reserves are 24-28TCF, but will be produced at much lower production rate and in much longer period of time. The country has an infrastructure of Gas Processing Facilities 5bcf/d.