Abstract

Over the past two decades the Geomechanics community has made substantial contributions to the petroleum industry in reducing well construction costs, maximizing production and increasing the life of the well. Borehole (in)stability, lost circulation, stuck pipe, sand production, casing collapse, well failures, and sub-salt related issues are real and can happen unannounced when we are not vigilant and proactive in avoiding them. Prevention is always better than the cure and we all should strive towards preventing these geomechanics related non-productive time (NPT) crises. This paper will be focused on the sustainable technology deployment to bridge the gap and realize the rewards associated with it.

The technical issues that are addressed in this paper are:

  • Deployment of technical resources to solve borehole (in)stability-related problems, which cost the industry billions of dollars.

  • Using the right resources (i.e., man power, budget, data, etc.) to bridge the gap. However, in order to bridge the gap, geomechanics technologists should be more proactive in capturing the value of technology successes and continuously educating management about the value it creates.

In summary, the industry cannot afford to lose billions of dollars on geomechanics-related NPT and associated lost revenue. Hence, it is critical to manage the available geomechanics resources in the optimum manner. It is important to identify challenging wells and get the right geomechanics resources committed. This commitment needs to be made early in the planning stage of the well construction, and sustained throughout the well delivery cycle. The paper will describe how geomechanics related technology deployment has saved millions of dollars in reducing NPT and achieving business objectives.

Introduction

Engineering knowledge and tools for dealing with borehole (in)stability problems have been significantly upgraded in the last 20 years in the oil and gas industry. However, the cost associated with borehole (in)stability remains high so that it affects the total well cost in many drilling operations and becomes a big factor that cannot be overlooked in oil and gas field development projects. The major hurdles in borehole stability studies currently are often due to, but not limited to, the following factors:

  1. The majority of easily accessible oil and gas reservoirs have already been exploited. The trend in hydrocarbon exploration is steadily moving to deeper and more complex environments (e.g., in deep water, sub-salt, HPHT and other challenging environments).

  2. Data regarding rock mechanical properties, in-situ stress states and geological structures cannot be accurately defined and are often provided with large uncertainties.

  3. Well engineers, petrophysicists and drillers who are directly involved in well delivery may not have adequate time and training in identifying and managing borehole (in)stability issues.

  4. Due to lack of resources and time constraints, well operations After Action Reviews (AAR) typically gets lower priority and as a consequence these learning's may not be well documented.

BHS related downtime associated with well construction is typically 10–15% of total well cost (about 50% of total NPT)1. However the material impact to the business enterprise can be substantially higher if we consider the opportunity cost and subsequent incremental costs associated with re-drill campaigns to reach objectives. An appropriate level of BHS analysis needs to be performed depending on the well construction challenges. For high material value wells and complex field development projects it is strongly recommended that an upfront geomechanics and wellbore stability study should be initiated as early in the field development cycle as possible. Early establishment of the geomechanics earth model enhances understanding of field development options and improves well delivery through an optimized and integrated approach.

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