Study On Demarcation Line In Policy Of Development Techniques For Fractured Reservoirs

Fractured reservoirs,with large reserves and growing producing rate year by year, play an important role in petroleum industry, but research of development techniques of fractured reservoirs remains at the beginning. Horizontal well technology, with its growing maturity, shows great advantage in exploitation of fractured reservoirs, however, owing to the complexity of its seepage field, it is badly in need to research the technology policy of horizontal well in fractured reservoirs. In this paper, systematical expanding of horizontal well technique in fractured reservoirs is made basing available researches. Through combination of numerical simulation method and reservoir engineering method, affecting factors of horizontal well deliverability and their laws are achieved. The author not only simulates and optimises the length of horizontal wells through a established single well model, but also optimises the reasonable location of horizontal-well in fractured reservoir with bottom or edge water. With a series of simulation based on double porosity model, the impact of penetration ratio, fracture orientation and horizontal well direction on sweep efficiency and recovery of various well networks. These well networks include horizontal well network and united network made up of vertical well and horizontal well. Also, the author generalizes optimal case for 3-point and 5-point horizontal well network, and optimal case for 5-point, 7-point and 9-point united network. Perforation from both ends toward the middle is superior to any other perforating way. Anyway, the paper gives impact of permeability anisotropy, oil viscosity and reservoir thickness on production rate, also, the paper gives the reasonable production rate according to exploitation of similar reservoirs. Using Orthogonal design method, affecting factors of critical production and breakthrough time—length and location of horizontal well, oil viscosity, permeability anisotropy, reservoir thickness, et al—are determined and nonlinear expression between them is regressed. A set of technology policy limits of horizontal well for fractured reservoir are given in the paper, and provide a theoretical foundation for design optimization of fractured reservoir exploited by horizontal well.