Technology Focus: Horizontal and Complex Trajectory Wells (November 2012)
Authors: Ruszka Jon 
Published: February 2015

Technology Focus
Although horizontal wells were used sporadically in Europe and elsewhere for many years, the technique was not widely employed in oil and gas developments until the Austin chalk oil boom in Texas from the late 1980s to the mid-1990s. As the Austin chalk activity subsided, so did application of horizontal wells in the US. However, the industry took the lessons learned and applied them to an increasingly wide range of reservoirs around the world. This approach delivered massive economic and environmental benefits that expanded as experience grew. The ensuing confidence in horizontal wells attracted investment in technologies targeted at pushing boundaries, increasing value, lowering cost, and predicting horizontal-well effect on reservoir performance. In many locations, field development strategies were totally transformed. Simultaneously, development of unconventional reservoirs was being incentivized in the US. These financial incentives initially encouraged the development of tight gas, frequently using horizontal wells.
By 2006, the lessons learned and technologies developed in US tight gas were being combined with those developed for horizontal wells in more conventional reservoirs around the world. Successes led to the US shale gas boom. This provided a climate conducive to investment in technology aimed at further lowering cost and increasing performance of horizontal wells in shale to drive viability.
These collective lessons and technologies will be instrumental in unlocking the potential of unconventional reservoirs around the world. However, this knowledge transfer will not be easy. Learning curves on the application in new areas should be expected before success can be claimed. Two challenges will be to steepen the learning curves and to gain acceptance. Success will require technical and economic derisking of developments at every stage, along with assured high degrees of technical integrity, efficiency, and predictable performance. Paramount to achieving this is development of people with the right technical skills, coupled with the ability to capture and trans-fer lessons learned across boundaries. New technology advancements will follow as these people identify future requirements.
This overview indicates how far horizontal wells have progressed over 25 years and how critical they remain in maintaining an affordable global energy supply into the future. It also serves as an illustration of the international nature of our industry and gives some insight into what it takes to stimulate advancement.
The papers reproduced here show how horizontal wells enable development of an ever-wider range of reservoir types around the world and how improved modeling, planning processes, and monitoring help reduce the associated risks.
Recommended additional reading at OnePetro: www.onepetro.org.
SPE 142439 Shallowest Horizontal Well Drilled in the Middle East: Challenges and Successes by Abhijit Dutta, KOC, et al. (See JPT, November 2011, Page 88.)
SPE 151466 Using Advanced Drilling Technology To Enable Well Factory Concept in the Marcellus Shale by Olof Hummes, Baker Hughes, et al.
SPE 146104 Strategies To Minimize Frac Spacing and Stimulate Natural Fractures in Horizontal Completions by Nicolas P. Roussel, The University of Texas at Austin, et al.
SPE 143071 Effective Well Placement and Trajectory Planning Approach Through Collaboration Environment Tools by Ahmed M. Al-Baqawi, Saudi Aramco, et al.