塔里木盆地富满大型碳酸盐岩油气聚集区走滑断裂控储模式

塔里木盆地台盆区深层海相油气勘探目标由层间岩溶向断控岩溶转变,并在处于坳陷区的富满地区发现了以走滑断裂为主控因素的断控型油田。富满地区储层特征与盆地内古隆起区、斜坡区均有不同,因此需要建立适合研究区的走滑断裂控储模式。本次研究通过高密度三维地震资料刻画了研究区走滑断裂的分布,利用岩心、测井、试井资料以及缝洞体识别技术明确了不同类型的储层分布,分析了研究区走滑断裂样式与差异变形对储层发育的影响,建立了走滑断裂控储模式。研究结果表明:(1)富满大型碳酸盐岩油气聚集区储集空间主要由多期走滑构造破裂作用与岩溶作用形成的洞穴型、裂缝-孔洞型、裂缝型与孔洞型空间组成;(2)走滑断裂活动性越强,断裂带宽度越大,储层发育规模越大,张扭段与压扭段断层破碎带型储层较平移段平面分布范围更广,纵向发育深度更大;(3)张扭段为汇水区,断裂联通性好,有利于大气流体下渗以及热流体上涌从而对储层进行溶蚀改造;压扭段为分流区,岩溶储层多发育于断裂带两侧,断裂开启程度低,受流体改造程度低于张扭段。

Control of strike-slip fault on the large carbonate reservoir in Fuman,Tarim Basin—a reservoir model

The exploration target for deep marine hydrocarbon in the platform basin area, Tarim Basin has changed from interlayer karst to fault-controlled reservoir, and a strike-slip fault- controlled oilfield is discovered in the Fuman depression area. The strike-slip fault and reservoir characteristics of the Fuman area differ from the paleo-uplift slope area of the basin. Therefore, it is necessary to establish a fault-control reservoir model for the study area. In this paper, the strike-slip fault system is described based on high-density 3D seismic data; the distribution pattern of different types of reservoirs is revealed by core, logging, and fracture-cavity recognition technology; the impact of strike-slip fault style and differential deformation on reservoir development is analyzed; and a strike-slip fault-control reservoir model is established. Here are the main conclusions: (1) The large carbonate hydrocarbon accumulation area of Fuman mainly contains cave, fracture-hole, fracture, and hole-pore type reservoirs formed by multi-stage strike-slip faulting and karstification. (2) Differential deformation of strike-slip faults controls the reservoir type and reservoir distribution by influencing the extent of the fracture zone and the fluid activity range—larger activity range corresponds to larger fracture zone, and reservoir development in the tenso- and compresso-shear sections is better than in the linear section. (3) The tenso-shear section is a catchment area with good fault connectivity conducive to meteoric water infiltration and thermal fluid upwelling for carbonate dissolution. The compresso-shear section, on the other hand, is a distributary area, where karst reservoirs developed mostly on the two sides of the fault zone, with relatively small fracture opening thus lesser fluid transformation compared to the tenso-shear section.