The Fault And Its Controlling Function On Gas Accumulation In Xunshen Gas Field

Xushen gas field is an important gas block in Xujiaweizi fault Depression，but becausethe faults in Xushen gas field are complicated and the control functions of gas reservoir are notclear enough, therefore, this paper carried out this research on control functions of faults ongas accumulation in Xushen gas field. This paper is mainly based on the data of seismicinterpretation for contiguous work area in Xujiaweizi fault Depression and used the data ofwell logging, logging, testing, and other dates at the same time to do the research on tectonicevolution and control functions of construction in the deep of the Xujiaweizi fault Depression.According to drilling, logging and analysis of test data, using the fault geometry features(fault strike, fault density, vertical throw, extended length, etc.) to kinematics characteristics(fault growth index, fault activity rate, stretching rate and tectonic evolution sections), todetermine the main activity period of Xushen gas field. Dividing the fault system on this basis.To get blocking and transporting type faults, for blocking type faults studies on lateral sealingability according to the results of faults systems. First of all, analyzed distribution anddevelopment of caprock of the top of K1yc1andcaprock of K1d2and the matching relationshipbetween faults and caprock in Xushen gas field, Secondly, researched the relationshipbetween faults and reservoir of volcanic cone and volcanic. Thirdly, analyzed transformingfunction of cracks near the faults to reservoir, Finally, analyzed the controlling function offaults on the construction-lithologic oil-gas reservoir trap through the study of lateral sealingability of faults,.The above research results shows: the main activity period of the faults since ancienttimes in Xushen gas field fault were K1h,K1sh,K1yc1,K1q,,k1y sedimentary period. Fault in the gasfield can be divided into early stretch fault system (Ⅰ) and early strike-slip stretching faultsystem (Ⅱ), late stretch fault system (Ⅲ), late transtensional fault system (Ⅳ), strike-slipstretching-late early fault system (Ⅴ), early strike-slip stretching-late transtensional faultsystem (Ⅵ), strike-slip fault system (Ⅶ). Ⅴ, Ⅵ, Ⅶ type fault systems is gas source fault.Fault destroy caprock of the top of K1yc1greater than caprock of the K1d2, resulting incaprock seal gas ability of K1yc1weaker than caprock seal gas ability of K1d2.Gas distributesin K1yc1and K1d2;development of Xuzhong fault controls the distribution of the volcanicrock cone, Simultaneously cracks near the faults has good modification effect on volcanicrock reservoir, makes the faults near the volcanic rock has good reservoir properties to gas;gas source faults and high tectonic position control planar distribution position of gas, Now industrial gas Wells distributed in3km to the source faults in the area of volcanic rocks. Inthe case of contacting between volcanic rock and fault of densification or conglomerate ofK1yc4can form the effective traps. According to the above research results of fault controllingof the gas distribution set up controlling model of gas of K1ycin Xushen gas field.