Abstract

It has been known that infill drilling can improve the recovery of hydrocarbon by accelerating the hydrocarbon productions because most reservoirs in the real world are not homogeneous. With the increasing demand for energy and higher oil and gas prices, more and more fields all over the world are undergoing infill drilling.

This paper discusses the two recently developed fast techniques to determine the infill drilling potential in large tight gas reservoirs in the petroleum industry and it summarizes what petroleum engineers have learnt about the application of those two techniques. Field examples are also included in this paper to demonstrate the usefulness as wells as limitations of the techniques to help independent operators develop operation and design strategies for current and future infill drilling projects in large, tight gas basins.

Introduction

The importance of enhanced oil recovery technology (EOR) cannot be overemphasized, especially in the context of a mature petroleum province or a country, such as the U.S., with declining domestic production and increasing imports. The decline of domestic production and increasing of petroleum imports reminds us of our increasing dependence on foreign petroleum supplies. Combined with the fact that the probability of finding new discoveries is continually decreasing reinforces the need for EOR oil recovery technology.

The significance of EOR lies in the promise it holds for increasing the expected production from existing oil fields. In mature petroleum provinces, such as the onshore US in general, growth of reserves in existing oil fields typically contributes more to the industry's continued viability than the discovery of new fields. In other words, in thoroughly explored provinces, better technology, more accurate reservoir characterization, and more effective production from known fields typically add new reserves faster than exploration for new fields.

It has been known that infill drilling can improve the recovery of hydrocarbon by accelerating the hydrocarbon productions because most reservoirs in the real world are not homogeneous.1–7 Driscoll1 and Gould et al. 2, 4 summarized the various factors that contribute to increased recovery after infill drilling:

  • Improved areal sweep

  • Area heterogeneity

  • Improved vertical sweep

  • Lateral pay connectivity

  • Recovery of "Wedge-edge oil"

  • Reduced economic limits

Infill drilling of additional wells after initial development (primary and/or secondary) played an important role in improving the oil and gas recovery in the tight hydrocarbon reservoirs. 6 Generally speaking, the reservoir heterogeneity and layer continuity can be changed by the well spacing. The infill drilling wells reduce the well spacing of the hydrocarbon fields and then enhance the well connectivity. Wu, et al. 7 reported the results of their study to determine the impact of infill drilling on the waterflood recovery in West Texas carbonate reservoir. Their study shows a certain degree of correlation between the waterflood recovery and well spacing.

Recently, with the increasing demand for energy and favorable oil and gas prices, more and more fields all over the world are undergoing infill drilling.

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