A New Paradigm for Automatic Well Path Generation Using Multidisciplinary Constraints

Abstract

The well planning process involves many disciplines. Due to the multidisciplinary nature of the process, many iterations are necessary to generate a well path. This is a time-consuming process that finally leads to chosen planned trajectories that may be sub-optimal. It is proposed to radically revise the well path generation process to reach the vision of planning a well in one day with high quality. Departing from the traditional incremental approach to well path generation, the proposed method relies on the collection of experienced-based constraints from each discipline to generate possible alternatives to the well path. A fundamental difference with the classical well path generation process, which works with one or a handful of planned trajectories, is that an ensemble of possible well paths is generated through the proposed method. If the constraints are loose, many planned trajectories might be generated but if the constraints are tight, there may be very few or possibly no solutions. As a result of this new work process, the multidisciplinary team can focus on the relevance of the constraints rather than on the details of the planned trajectory. Capturing these constraints is the fundamental result of the well planning process; the ensemble of possible well paths being only a byproduct of it. The novel method comes with a set of concepts that provide subject matter experts with greater leeway for defining the well path generation problem in a generic way. These concepts have been designed to seamlessly allow for any subsequent updates of the well plan, whether for the target or group of targets and their associated wellbores, the wellbore architecture and its relation to geo-pressure margins, or the surveying program with regards to wellbore position uncertainty. Whenever possible, characteristics attached to these concepts are described implicitly to cope with mutual interactions between constraints. An extensible classification of the constraints is provided and illustrated with examples commonly used to define drilling programs. As a result of the propagation of user-chosen constraints, complex problems such as finding well paths that respect anti-collision criteria, avoid faults or cross them with a high incidence angle if unavoidable, and satisfy inclination limits to cross certain formation layers are solved completely automatically. Innovation does not come for free: the new paradigm presented in this paper induces a significant transformation of the well planning process. However, the versatility of the approach should largely compensate for the expected change in end-users’ habits both by a faster delivery time of every well plan (or even large-scale field development) and by allowing a seamless update of the latter when drilling operations demand it.