塔河油田碳酸盐岩储层有效性测井评价实践与思考

塔河油田奥陶系已经勘探开发十几年了,目前除了在塔河继续精细勘探,也正在加大塔河之外的勘探.近几年塔中、玉北奥陶系碳酸盐岩储层勘探实践表明,储层有效性评价越来越显得重要.针对塔河油田奥陶系碳酸盐岩缝洞型储层,从测井响应特征分析入手,在岩心、成像测井、常规测井相互标定的基础上,细化溶孔、裂缝和溶洞型储层的分类,建立塔河油田奥陶系碳酸盐岩储层有效性测井识别与评价方法.对溶洞型储层采用自然伽马与视地层水电阻率交会方法进行有效性评价.对于裂缝孔洞型储层还可以利用电成像局部电阻率法评价储层有效性.实践表明,这两种方法可以较好解决因泥质充填造成的储层有效性评价问题.对于因储层类型不同,或具体说因裂缝发育强弱造成储层有效性差异的裂缝孔洞型储层有效性评价,通过"四性"关系及数模研究,提出定渗透率、变孔洞孔隙度、变裂缝孔隙度的储层渗流评价模型.实际应用表明,储层渗流评价方法提高了测井解释符合率,为塔里木盆地碳酸盐岩储层有效性评价、完井方案制定和储量参数计算提供了依据.

Logging evaluation of carbonate reservoir effectiveness in Tahe oilfield,Tarim Basin

The exploration and development of the Ordovician in Tahe Oilfield have been undertaken for more than ten years. In addition to the fine exploration in Tahe Oilfield, exploration is also performed outside of Tahe at present. In recent years, the exploration of the Ordovician carbonate reservoirs in Yubei and Tazhong shows that the reservoir effectiveness evaluation has been becoming more and more important. On the basis of the logging response characteristics and the mutual calibration of the core analysis, imaging logging and conventional logging, the dissolved pore reservoirs, fractured reservoir sand fractured-vuggy reservoirs are further subdivided, and well logging identification and evaluation methods are put forward for the effectiveness evaluation of the Ordovician carbonate reservoirs in Tahe Oilfield. The effectiveness of vuggy reservoirs is evaluated through cross-plotting of natural gamma and apparent formation water resistivity. Additionally, the effectiveness of fractured-vuggy reservoirs is evaluated by using the electric imaging local resistivity method. The practices show that these two methods can better solve the problem of reservoir effectiveness evaluation caused by filling of clay. For the different types of fractured-vuggy reservoirs whose effectiveness is influenced by the strength of fracture development, we studied the relationships between lithology, electrical property, porosity and oil-bearing property and performed mathematical simulation. Based on these studies, we put forward the evaluation model featuring in constant permeability, mutative vuggy porosity and fracture porosity. The application of this model shows that the coincidence rate of the logging interpretation has been improved. It provides evidences for the reservoir effectiveness evaluation, the formulation of completion scheme and the calculation of reserve parameters.