Research On Fault Lateral Sealing Ability Of Es₁ And Es₂ Of Wen'an Slope In Jizhong Depression

Huabei Oilfield is one of the important oil and gas fields in China.As the secondary tectonic unit of Baxian Sag,Wen'an slope is the main oil and gas exploration and development area,which has developed a large number of trap structures.The fault controlled trap can often be a good place of oil and gas accumulation,but whether it could play the role of gathering oil and gas or not,is mainly controlled by the seal ability of faults.In the horizontal direction,oil and gas can be migrated along the connected sand body,therefore,to study the lateral sealing capacity of the fault is very critical in finding oil and gas reservoirs.By using the well logging,seismic and other geological data of Wen'an slope,the fault distribution and development characteristics of Es₁ and Es₂ in Wen'an slope were analyzed.According to the principle of lateral sealing ability of fault and the influence factors of fault,the target interval fault sealing type of was determined.Then selected an appropriate evaluation method of slope lateral sealing ability to evaluate and predict the fault seal ability of typical structure in Wen'an slope.At last,we analyzed the sealed faults' control action to hydrocarbon accumulation.The main results include the following aspects:1.The fault sealing type in this area is mainly for the fault rock sealing.Various scales of hydrocarbon reservoirs in different regions showed the strength of fault sealing ability.2.The SGRmin of Es₁ of Wen'an slope is 28%,the value in Es₂ is 29%.On the plat,the fault seal ability of Suqiaonan nose-like structural belt and Shigezhuang nose-like structural belt is better than that of Changfeng Town and Yilunpu.Most sealed faults distribute near Shigezhuang and Changfeng Town nose-like structural belt,some others distribute near Xi'an Town.On the profile,the distribution of sealed and unsealed area in Es₁ and Es₂ are nearly equal.In Yilunpu,the fault seal ability of Es₂ is better than of Es₁.In Shigezhuang,the sealed area has widely expanded to the west.3.The distribution of lateral sealing fault controls the distribution of oil and gas.Generally,oil and gas gathering in the lateral sealing fault controlled traps.4.The value of SGRmin controls the oil and gas enrichment layer.The layer which has the smaller SGRmin value enriches more oil and gas.