ABSTRACT:

Decreasing development costs and risks involves optimizing field development plans, refining drilling programs and making good predictions of production rate. In achieving these goals, it is important to investigate the geomechanical behavior of the reservoir. All data and information recorded during exploration, drilling and production are used for estimating the mechanical properties and earth stresses in the stratigraphic section by constructing a Mechanical Earth Model (MEM). We focus here on building a 1D MEM for one well in a reservoir in southwest Iran, and then we apply the model to well design and construction for field development through generation of a drilling mud weight strategy based on the MEM. General lack of calibration data, especially for stress measurements, means it is necessary to use different methods to determine the rock properties and the stress state. Since there is limited knowledge about the stress state, different stress states are discussed and possible principle stresses are determined based on the comparisons of drilling reports, image logs, and wellbore stability conditions. These considerations and comparisons suggest that the ratio of horizontal to vertical stresses should be less than 0.7, which means that the stress regime of the study area is one of normal faulting.

1. INTRODUCTION

Understanding and managing risks associated with rock deformation (borehole instability, changes in productivity, hydraulic fracture treatment design…) through analysis provides engineers with both technical and economical means to effectively identify, predict, and prevent costly events and to optimally manage drilling and operation of oil wellbores [1]. A production development plays a prominent role in all phases of exploration, drilling and production. In the oil and gas industry, well-constrained predictions undoubtedly increase economic benefits, whereas unmanaged uncertainty leads to losses during drilling and completion activities, and even reduced production capacity during the exploitation phase [2].

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