Study On Fault Distribution Characteristics Of Kalatar Formation In Kekeya Gas Field,Tarim Basin

The study area is located in the Kekeya tectonic belt in the southwest of Tajikistan,bordered by the Yecheng depression in the north,and belongs to the second row of tectonic belts in front of the Kunlun Mountains.This area is a key exploration block in the piedmont zone of southwest Ta in recent years.The overall tectonic morphology of the Kekeya tectonic belt is relatively unified and simple,with a single anticline from shallow to deep,and the structure was formed in the Early Hishan period.The area is rich in resources and rich in oil and gas,but it is deeply buried and has strong heterogeneity.In the early stage,the fault of the Karatal Formation reservoir was not well understood,so this paper analyzes the correlation between the fault and the reservoir based on the seismic data of the actual work area and the dynamic data of the well,and re-realizes that the strike-slip fault in the reservoir has an important role in the transformation and reservoir control,so this study conducts a detailed study of the strike-slip fault.The tectonic movement in the study area is mainly affected by the stresses in two directions,namely the horizontal stress and the vertical stress.The horizontal tectonic stress mainly controls the formation of normal and reverse faults in the target layer,while the vertical stress adjusts the structure longitudinally,forming the main anticline structural features and forming a high-angle strike-slip fault.Based on the fact that the strike-slip fault angle is almost perpendicular to the ground,the fault distance is small,and it is difficult to identify on the profile,while the normal fault and reverse fault angle are small,the fault distance is large,and it is easy to identify on the profile,and the sensitive attributes such as inclination scanning and coherent body extraction are extracted and optimized,and the distribution rules of thrust fault,compression-torsional fracture and strike-slip fault can be obtained more clearly in the plane,and improved on the profile,so as to combine with each other.The above studies show that the faults of the target layer are mainly divided into three stages,the first stage is thrust fault,the second stage is compression-torsional fault,and the third stage is strike-slip fault.Its main characteristics are as follows:thrust faults are more in the west and less in the east;The compression-torsional fracture is thrust fracture,strike-slip rotation,and then active,with more on both wings and less in the middle;The strike-slip is mostly north-south and divided into four groups from west to east,with the second group having the largest number.Based on the above understanding,the author reconstructed the geological structure model of the study area.In order to explore more connections between reservoirs and faults in the Karatal Formation,the authors compared the connection between the well dynamic data and the reservoirs,and made a more detailed description of the strike-slip faults,and found that the strike-slip faults are closely related to the oil and gas diversion and storage of the reservoirs.Combined with the data of oil and gas detection,fracture prediction and reservoir inversion,we have a deeper understanding of the dolomite reservoirs of the Karatal Formation,and it is found that the wells with good oil and gas display have the characteristics of "far slip,near-thrust,fracture development and good reservoir",which are mainly located in the fracture intensive development area in the study area,which is closely related to the relative position of the fault zone.Based on the above studies,the following conclusions are drawn:strike-slip faults can not only communicate the upper and lower strata and control the accumulation of oil and gas in the reservoir,but also may penetrate the target layer and thus have the risk of damaging the reservoir.The study of strike-slip faults can update the understanding of reservoirs,so as to clarify the distribution range of favorable reservoirs,which is one of the main bases for well location deployment and exploration and development in the next study area.