The article deals with a possibility of predicting abnormally high reservoir pressure (AHRP) of multiple reservoir systems which are not involved in the development process (oil extraction/water injection). This material will subsequently allow us to introduce tools which minimize the risks of complications originated during the borehole drilling and leading to their redrilling with associated material costs.
The work was carried out on the basis of existing experience of arising complications during the construction of wells with injected fluid inflow during the period fr om 2014 to 2017. The focus of this work is one of the reservoirs of the West Siberian oil and gas province: Priobskoie field, located in Tyumen region, which is unique regarding its reserves. A theory on the occurrence of technogenic AHRP zones was formulated using a number of input data, including the mechanical earth model, the actual data on hydralic fracturin and injection pressures in the system of reservoir pressure maintenance. The reason of the occurrrence of AHRP zones in undeveloped formations was determined, based on the phenomenon of auto hydraulic fracturing. Concomitant signs associated with the areas wh ere technogenic AHRP zones occur were determined. The development of auto hydraulic fractures was imitated taking into account the Mechanical Earth Model of the section, and the adaptation of development parameters in order to understand the mechanism of formation of AHRP zones. Based on the consolidation of factual material obtained during drilling and consolidation of geological information, forecast maps of isobars of multi-zone objects were compiled, specific features were taken into account. It is suggested to increase the forecast quality of the occurrence of AHRP zones and to reduce the number of complications in the course of drilling arising due to this reason in the future.
There is a possibility to replicate this approach for trouble-free drilling in other reservoirs with similar geological conditions of the reservoir structure, as the Priobskoie field has, and principles for the development of oil production facilities.
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