Developing of Regional Tectonic Stress Map for Two Oil Fields in Western part of Persian Gulf, Acquisition and Preparation of the General Structure of Stress Distribution

Recently, application of stress field data in petroleum industry has significantly increased. Field stress databases are prerequisite data to study reservoir compaction and deformations, wellbore stability, reservoir stimulation, CO2 sequestration and the like. This has convinced petroleum industries and many sponsors to allocate investment for acquiring accurate stress field data and developing stress maps. In southern part of Iran, large scale sedimentation from different geological periods and intense tectonic activities create huge petroleum fields. Persian Gulf located in south to south-west of Iran, contains a great number of the most giant offshore oil and gas reservoirs in the world. The objective of this research is development of a regional tectonic stress map for two fields in western part of the Persian Gulf. For this purpose, standard stress indicators including earthquake focal mechanism solutions, well-bore breakouts and drilling-induced fractures, in-situ stress measurements (LOT, hydraulic fracturing), young geologic data (fault-slip analysis) and core tests (ASR, DSCA, Petal Centerline Fractures) were used to collect and rearrange field stress data. The data are quality ranked according to World Stress Map quality ranking scheme 2008 based on their standard deviation and a tectonic regime is assigned where possible. In these fields some stress indicators like hydraulic fracturing and core tests was not employed before. Primary stress data gathered from focal mechanism confirmed a TF regime in the area mainly with the quality C. WSM database only provides around 14 SH measurement from the northern border of our area. All these data gathered from FMS with quality C. In our study we will add several new stress measurements from other standard stress indicators including LOT, well-bore breakout, drilling induced fractures and core tests with higher quality than C. Almost SH orientation varied between 0 to 90°N based on primary information. On the other hand, long term production caused a great pressure drop in these fields. As it is provided in many references, stress state is a strong function of reservoir pressure. Hence, the stress magnitude of the fields is altered over the reservoir life time. This is considered in this research to ameliorate the accuracy of the prepared data.