Affiliation:
1. U. of Louisiana at Lafayette
2. Daqing Petroleum Institute
Abstract
Abstract
Development of oil and gas fields with low-permeability reservoirs presents a unique challenge to the energy industry due to the low productivity of individual wells and the high cost of drilling and fracturing a large number of wells. This study investigated the possibility of using fishbone wells to maximize the net-present value (NPV) of field development. A comparison of multi-fractured horizontal wells and fishbone wells for tight gas field development is presented in this paper. Multi-fractured horizontal wells have been used to improve oil and gas production from low-permeability reservoirs for over a decade. The problems associated with this type of wells are well productivity decline due to fracture closure with time and uncertainty of fracture propagation due to the lack of knowledge of formation stresses. The disadvantages of multi-fractured horizontal wells may be avoided by using fishbone wells, a new technology developed in the recent years. In this study, we compared the net present values (NPV) of two development plans for a generic gas field using multi-fractured horizontal wells and fishbone wells. We found that these two types of wells can generate comparable NPV values. We conclude that as the drilling technology develops, use of fishbone wells with increased number of rib holes will be more beneficial than multi-fractured wells in developing tight gas fields.
Introduction
Oil and natural gas from unconventional reservoirs such as tight-gas sands is being targeted to contribute a significant share of the world's energy supply in the next two decades. These reservoirs have common characteristics and geographical uniqueness technically and economically. Several obstacles remain in their developments. The challenge is not in discovering the reservoirs, but is the lack of technology and knowledge to obtain high-productivity of wells.
Over the last two decades, horizontal well has become a well-established technology for the recovery of oil and gas from low-permeability reservoirs. The major advantages of using horizontal wells are increasing productivities, minimizing gas and water coning, extending areal sweep, and connecting vertical fractures. However, unfractured single-bore horizontal wells still do not deliver economical oil and gas production rates in many low-permeability reservoirs. Therefore, multi-fractured horizontal wells have been employed, with significant added-cost, in the oil and gas industry. The major problems associated with this type of wells are rapid well productivity decline due to fracture closure and uncertainty of fracture placement due to the lack of knowledge of formation stresses. The recent advances in drilling multilateral wells have opened another alternative for cost-effective development of low permeability oil and gas fields. This paper reports our comparison of using multi-fractured horizontal wells and using fishbone wells, a special category of multilateral wells, for development of a tight-gas reservoir. The conclusions should be equally valid for tight-oil reservoirs.
Cited by
6 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献