Pressure curve characteristics for wells drilled in cave of fracture-cavity carbonate reservoirs
Online published: 2012-04-20
Drilling stem emptying, massive mud leakage and acidification transformation appeared during the drilling process of fracture-cavity reservoirs, which increased difficulties for reservoir well test interpretation if using triple porosity well test method. It has great actual significance to establish well test interpretation model for wells drilled in cave and carry out well test interpretation of this reservoir. Based on the double porositymodel, taking inner cave as an equipotential body whose internal pressure was equal everywhere, making outer fluid flow observe Darcy law, and according to cave mass conservation equation, a new well test interpretation model for wells drilled in cave was presented. Laplace transform and Stehfest reverse method were used to solve the model. The influences of cave storage ratio, size of cave, matrix interporosity flowcoefficient and fracture storage ratio on the bottom pressure were analyzed. And the double log curve for wells drilled in cave of fracture-cavity carbonate reservoirs was used to interpret the measured pressure of some well in TZ area. Good results have been obtained, and this research can provide theory guidance for fracture-cavity reservoirs well test interpretation.
Key words： lake shoreline; deep lake line; slope break zone; sand bodygenesis; Yanchangstage; OrdosBasin
PANG Jungang , LU Tao , GUO Ji’an , LI Wenhou . Pressure curve characteristics for wells drilled in cave of fracture-cavity carbonate reservoirs[J]. Lithologic Reservoirs, 2012 , 24(2) : 124 -128 . DOI: 10.3969/j.issn.1673-8926.2012.02.024
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