The last stage of mature oil fields development leads to necessity of exploration and extraction of oil from formations with complex geology. One of such objects is the Tyumen suite. It is represented by Middle and Upper Jurassic formations in transgressional stage of sedimentary sheath development, when continental and deltaic depositional environment interchanges occurred. These deposits are characterized by low reservoir permeability and porosity and both lateral and vertical heterogeneity of sand bodies, which is primarily, associated with the generation and accumulation conditions.
This paper covers the complex analysis of geomechanical properties, estimation of drilling risks and defines development plan for Tyumen suite deposits of X field. The key issues are drilling problems associated with drilling horizontal wells parallel to regional stress, for example, sidewall sticking, tight pull, inability of casing landing due to the wellbore collapse, and problems during hydraulic fracturing. That facts lead to re-drilling horizontal wells and significant increasing drilling cost. It should be noted that actual and planned starting characteristics for each horizontal well were not confirmed, also actual ratio of liquid rate of the horizontal well to liquid rate of the directional well was only 1,3 (planned ratio was 2,3). Calibrated geomechanical model helped to assess drilling problems and optimize drilling schedule.
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