Abstract:

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.

Key words: SEC, proved reserves, carbonate fractured-vuggy rock, reliable technology, evaluation methods