Study On Well Test Method Of Cave - Type Carbonate Reservoir

With the continuous development of petroleum exploration on deep marine strata, an increasing number of fractured-vuggy carbonate reservoirs have been discovered, and more and more attention has been paid to fractured-vuggy carbonate reservoirs.Since rook matrix is of low porosity and low permeability on the whole, oil is mostly stored in multi-scale vugs and fractures. Thus it can be seen that fractured-vuggy carbonate reservoirs are much more different from conventional sandstone reservoirs and naturally fractured reservoirs. Unfortunately, current well test interpretation for fractured-vuggy carbonate reservoirs has the problem that large-scale vugs and fractures cannot be well interpreted. Root causes of the above-mentioned problem are analyzed in this paper, and an effective solution to this problem is presented. The main work and achievements of the paper is as follows:(1) Fractured-vuggy carbonate reservoirs characteristics are researched through Tahe Oilfield located in Tarim Basin in China. Tahe Oilfield is an typical fractured-vuggy carbonate reservoirs, and is characterized by multi-scale vugs and fractures;(2) Based on reservoirs characteristics that has been discussed above, different size vugs and fractures are divided into discrete medium and continuous medium. Large-scale vugs and fractures are looked as discrete medium, and the other vugs and fractures are considered as continuous medium;(3) Well test interpretation models in consideration of a single large-scale vug, a large-scale vug with a connected large-scale fracture, two connected large-scale vugs in series through a large-scale fracture and two connected large-scale vugs in parallel with a large-scale fracture, are established and solved, corresponding well test curves are drew and analysed.