碳酸盐岩缝洞型油藏储层发育受控因素复杂、非均质性强、储集岩类型多样,整个油藏储集单元内部存在洞穴、孔洞和裂缝等多种储集体类型,传统的单一参数体系描述制约了对地下地质体的精细描述。按照SEC准则如何建立科学的地质模型,确定证实面积、证实有效厚度、采收率等参数,估算原地量和技术可采量,确定证实未开发钻井数,预测未来油藏合理的证实储量挑战较大。以顺北油田某典型断裂带的SEC储量评估为实例,运用该地区成熟的储层预测技术,将该井区奥陶系油藏细分为三类储集体,即洞穴、孔洞和裂缝储集体,分别计算其原地量。在证实储量评估时采用静态法、类比法和动态法等多种评估方法相结合,一方面对已开发井的动态规律运用递减法进行评估,对比其实际递减与预测递减验证其合理性,另一方面从断溶体的展布规律判断其未开发井位的证实级别可靠性,同时从投产后的实际产量变化验证预测的可信度。该应用实例初步形成了一套针对此类油藏SEC储量评估的技术和方法,对保证此类油藏SEC储量评估的合理性具有指导和借鉴意义。

Carbonate fractured-vuggy reservoir is the most complex reservoir type in the world because of its complex controlled factors, strong heterogeneity and diverse reservoir rock types. There are many reservoir types such as caves, holes and fractures in the whole reservoir unit. The traditional description of single parameter system restricts the detailed description of underground geological bodies. According to the standards of SEC proved reserves, how to establish a scientific geological model, determine the parameters such as proved area, proved effective thickness and recovery rate, estimate various levels of geological reserves and technical recoverable reserves, confirm the number of undeveloped wells, and predict the reasonable proved reserves in the future is facing a great challenge. Therefore, the SEC reserve evaluation of a typical fault zone in Shunbei Oilfield is taken as an example, and the Ordovician reservoir in this well area is subdivided into three types, namely cavern reservoir, hole reservoir and fracture reservoir, to calculate the geological reserves respectively by using the mature reservoir prediction technology in this area. When confirming reserve evaluation, by combining a variety of the evaluation methods, such as static proved reserves evaluation method, analogy method and dynamic method, on the one hand, evaluating the dynamic rules of the developed wells to contrast its actual diminishing and forecast for verifying its rationality; on the other hand, confirming the reliability of the position of undeveloped wells by the judgment of distribution rule of fault-karst reservoir, and verifying the reliability of the forecast by the actual production changes after putting on production. Finally, a set of techniques and methods for SEC reserve evaluation of such reservoirs is formed, which has guiding and reference significance for ensuring the rationality of evaluation.