Tight Oil Reservors Seepage Law And Influencing Factors

The reservoirs of N block are low permeability tight reservoirs in Huaqing, due to the special nature of the low permeability reservoirs(low permeability and low porosity, pore complex structure), which is often associated with a fluid seepage law in the presence of a large reservoir permeability differences. In this paper the basic of understanding geological characteristics in the reservoir block N, the oil andwater of seepage characteristics and influencing factors were experimentally studied through core flooding experiments seepage and water flooding oil experiments in microscopic models in laboratory. Been recognized by the following main research article:1. In the study area in the reservoir rock cements hydromica, ankerite, chlorite is one of the main factors leading to poor reservoir properties.2. Reservoir pore types in the study area is mainly primary intergranular porosity, secondary intergranular porosity, micro pores and microcracks. The main flow channel of the reservoir rock is more than 0.4μm pore throats, when the permeability of less than 0.1m D, penetration the main contribution rate for the pore throat radius larger than the hole in the throat 2μm.3. The core slip coefficient b of the range is between 0.00930 ~ 0.290MPa-1 in tight reservoir, and the slip coefficient is no significant relationship with Klinefelter permeability.In order to reduce the impact of gas slippage effect of dense core when test gas permeability, air pressure when measures dense core permeability should be recommended stable at the time of 0.5MPa or more.4. Study area core has stronger stress sensitivity, tight reservoir dense core permeability decline overlying pressure generally within the range of 60% to 90%; not overburden pressure in the study area tight reservoir rock porosity overall impact, but when the core permeability is less than 0.1m D and the porosity is less than 8%, the study area is more obvious presence of tight reservoir porosity pressure inflation phenomenon, lower permeability, porosity phenomenon is more significant inflation pressure.5. Fluids in Study area tight reservoir has obvious non-uniformity, perform non-uniform flooding and flooding waterways. Microvadose processes are clearly related to the pressure. There are four forms about the residual oil in the model, including flow around the core model of residual oil, film and oil patchy residual oil, residual oil edge corner, showing clusters, clumps and oil bead distribution of residual oil.6. Single-phase oil and single-phase flow of water seepage were obvious non-Darcy flow nonlinear characteristics in the study area. Starting pressure gradient of single-phase water seepage ranged at 0.0124 ~ 0.08 MPa / cm, single-phase oil flow in the range of starting pressure gradient at 0.0135 ~ 0.183 MPa / cm, starting pressure gradient of residual oil in the water ranged at 0.0108 ~ 0.0569 MPa / cm;7. The flow capacity of residual oil into the water is relative to the worst. When the core permeability is less than 0.1m D in the study area, water flooding efficiency averaged 47.9%, without significant relationship between permeability.