S-WAVE VELOCITY ESTIMATION AND RESERVOIR TYPE IDENTIFICATION BASED ON PARTIALLY CONNECTED POROSITY MODEL OF CARBONATE RESERVOIR

摘要

With the deepening of global oil and gas exploration and development, theexploration direction has gradually shifted from conventional oil and gas reservoirs tospecial oil and gas reservoirs, such as carbonate reservoirs and tight reservoirs, whichoften have very complex pore structures. The partially connected pore model is anequivalent medium model to describe the multi pore structure. The model divides thepores into an isolated pore system dominated by micropores and a connected pore systemdominated by macropores, which has achieved good results in the application of tight gasbearing sandstone. But when the model is applied in carbonate reservoirs, due to a hugeamount of model parameters and complex mineral composition of carbonate rocks, theeffect of direct application of the model is non-ideal. In this paper, through the steps ofenvironmental correction, optimization log interpretation, sensitivity analysis of modelparameters and determination of key parameters, a petrophysical modeling processsuitable for carbonate reservoirs is established, and the S-wave velocity of two differentreservoir space types of the Dengying Formation in Central Sichuan paleo-uplift ispredicted, and considerable results are obtained. In addition, the soft pore scale factorinversed in the modeling process has indicative significance for the identification anddivision of reservoir space types.