Method for extracting oil and gas by using bottom water resource of oil and gas reservoir

Abstract

Under the action of the movement of the formation crude oil and the production pressure difference, the upper part of the water layer of the oil and gas reservoir is continuously heated within a certain pressure range. The water continues to boil, and the bottom water vapor is used to inhibit and delay the intrusion of bottom water into the oil layer, and the combined driving force of bottom water vapor flooding, bottom hot water flooding formed by the uplift of the oil-water interface and reservoir thermal expansion elastic pressure flooding is used to recover oil and gas.

1 . A method for exploiting oil and gas by utilizing bottom water resources of oil and gas reservoirs, wherein the oil and gas reservoir containing an edge-bottom water layer and having an original stratigraphic condition A (P o , T o ) and current development state B (P i , T i ), comprising:
 continuously heating the upper part of the edge-bottom water layer in reservoir within a certain pressure range according to the reservoir geological characteristics, original reservoir formation pressure, fracture pressure, prediction curve of the temperature and pressure of the water boiling point;   getting the formation water directly into the boiling state and continuously generating the vapor by controlling and stabilizing the pressure under the condition of movable formation crude oil and difference of production pressure;   converting the bottom water of the oil and gas reservoir to an overall upward pushing power;   producing the comprehensive oil and gas production driving energy primarily by the area driving force mainly in bottom water steam flooding and hot bottom water flooding, and reservoir thermal expansion elastic pressure throughout the reservoir and production process, at the same time compensating the energy deficit in the reservoir simultaneously; and   dredging, utilizing rather than preventing and blocking natural formation water resources, and changing the harmful side of edge and bottom water intrusion into oil layer into the beneficial side to production, so as to improve the level of producing reserve and recovery of various oil and gas reservoirs containing bottom water.   
     
     
         2 . The method according to  claim 1 , wherein, the principle of energy saving and efficiency enhancement, including, comprising:
 recycling part of the heat energy transferred downward depending on the formation water under the action of thermal dynamics;   continuously heating formation water under certain stable pressure for the reason that the temperature of the water does not rise any more when the water gets into boiling state, the continuously heating energy is mainly used for the vaporization of the water;   extending the stable oil and gas production time and improving the input-output ratio by using the heat storage function of heated water;   reducing heat loss, cold damage and permeability damage in oil and gas reservoir relying on the heated formation water intruding into the reservoir;   heating formation water instead of surface water to reduce heat loss in well bore and pipeline;   optimizing the layout of heating horizontal well according to the characteristics of oil and gas reservoirs which located at the upper part of the edge-bottom water layer near the water-oil contact;   using graphene materials to reduce the heat loss of wire;   improving the problem of fracture closure and environmental protection in tight reservoirs by overpressure fracturing;   reducing the operation cost caused by cold formation water intrusion in surface water injection oil and gas recovery by means of bottom water steam flooding and bottom hot water flooding;   providing driving energy for oil and gas production in the production stage and compensating for the formation energy deficit to improve the level of producing reserves and recovery and the oil and gas input-output ratio;   controlling reservoir temperature and recovering oil at high temperature to reduce wellbore oil extraction cost and pipeline gathering and transportation cost;   converting water or steam injection wells into production wells to save the drilling cost of production wells and improve the level of production;   Utilizing natural bottom water resource of oil and gas reservoir to save surface water resource and reduce the cost of environmental protection;   injecting heat energy and production kinetic energy required at a time through formation water to save costs of operation and time wherein centralized thermal recovery plays roles to the scale effect.   
     
     
         3 . The method according to  claim 1 , wherein, the oil recovery mechanism of this method, comprising:
 Carrying out concentrated operation in the process of heating and production which brings forth scale effect;   Reducing crude oil viscosity by preheating and bottom water steam flooding and hot bottom water flooding;   vaporizing the bottom water to compensate the formation energy deficit and further to increase the producing degree of the reservoir according to the phenomenon that the volume of steam with the same mass is about 17 times that of water, which is easier to diffuse into any micro-space of the reservoir;   utilizing the comprehensive oil recovery driving energy based on bottom water steam flooding, bottom hot water flooding and reservoir thermal expansion elastic pressure driving, to improve the final recovery degree of the reservoir.   
     
     
         4 . The method according to  claim 1 , wherein, the mechanism of driving force of oil and gas production, comprising:
 forming oil and gas area displacement with bottom water vapor by means of stabilizing pressure and continuously heating as the water vapor is easy to spontaneously form an upward thermal driving force along the entire oil-water contact, and the water vapor is easier to diffuse than water;   under the action of bottom water steam driving and production pressure difference, utilizing bottom water advances integrally to form hot bottom water driving with oil-water contact interface rising;   continuously heating the formation water and promoting the thermal expansion of reservoir particles, fluid, the overflow of dissolved gas and water vapor to form reservoir thermal expansion elastic pressure driving throughout the reservoir and production process;   increasing reservoir permeability by means of heating the bottom water layer of oil and gas reservoirs resulting in the heterogeneous distribution of temperature and pressure, when the pressure exceeds the reservoir fracturing pressure, the oil and gas reservoirs will produce microfractures;   continuously heating the formation water to keep the bottom water vapor continuously generating and driving upward, then to keep the reservoir microfracture opening.   
     
     
         5 . The method according to  claim 1 , comprising applying the method to various oil and gas reservoirs containing edge and bottom water layers, tight oil and gas reservoirs, heavy oil and high pour point oil and gas reservoirs that need to be developed by thermal recovery, and ordinary oil and gas reservoirs that need to be developed by water injection. 
     
     
         6 . The method according to  claim 1 , comprising controlling the pressure of general oil and gas reservoirs except for tight oil and gas reservoirs to be under the fracture pressure of the reservoir during the heating process, wherein, the pressure controlling method:
 producing to depressurize,   adjusting the heating pattern of formation water, or   a combination of the two methods.   
     
     
         7 . The method according to  claim 1 , wherein, within a certain pressure range, the formation water is boiled and the bottom water vapor is continuously generated by means of the pressure control and stabilization, the pressure of oil and gas reservoir is fixed while the formation water is continuously heated at relatively low pressure, and the bottom water steam flooding and hot bottom water flooding are formed under the production pressure difference. 
     
     
         8 . The method according to  claim 1 , comprising, for thermal recovery of the oil and gas reservoir, preheating the bottom water to get the crude oil in the formation movable, and then heating the formation water under pressure control and stabilization to keep the formation water boiled, and under the action of the production pressure difference, using the comprehensive exploitation of oil and gas driving energy to carry out oil and gas extraction. 
     
     
         9 . The method according to  claim 1 , comprising generating the steam needed in the bottom water steam flooding by means of getting the bottom water boiled and vaporizing the bottom water invading into the oil layer where the temperature is higher than the boiling temperature corresponding to pressure. 
     
     
         10 . The method according to  claim 1 , comprising increasing the level of producing and recovery of the reservoir, including the increase in the process of concentrated thermal recovery, and the increase of the residual oil due to the continuous provision of driving energy in the oil production stage. 
     
     
         11 . The method according to  claim 1 , comprising improving permeability of the tight oil and gas reservoirs by continuously heating the formation water and pressure control and voltage stabilization, as well as the action of the production pressure difference until the reservoir ruptures, and then utilizing the bottom water vapor flooding method, or, under the condition of lower and close to the reservoir rupture pressure, directly to avoid the closure of the reservoir fractures. 
     
     
         12 . The method according to  claim 1 , comprising heating the formation water of non-thermal recovery medium and high permeability ordinary oil and gas reservoirs under low pressure and pressure stabilization conditions to make it continue to boil, and then keeping the pressure slightly higher than the original formation pressure by means of pressure control and pressure stabilization, and carrying out oil and gas extraction by comprehensive oil recovery driving energy. 
     
     
         13 . The method according to  claim 1 , wherein the methods of heating the edge and bottom water of oil and gas reservoirs according to the geological characteristics of different oil and gas reservoirs, comprising
 {circle around (1)} continuously heating the formation water to the boiling point temperature of the water under the condition of pressure relief and pressure stabilization in open oil and gas reservoirs, and then continuously heating under the stable pressure to form an effective bottom water steam flooding;   {circle around (2)} heating the formation water to the boiling point temperature under the condition of open oil and gas reservoir pressure control, and then continuously heating under constant pressure until an effective bottom water vapor flooding is formed;   {circle around (3)} heating the formation water under the condition of pressure control in open oil and gas reservoirs, when the pressure is slightly higher than the original formation pressure, then keep the pressure and continuously heating until effective bottom water steam flooding is formed;   {circle around (4)} continuously heating the formation water under the condition of pressure control in open oil and gas reservoirs, when the pressure is close to the fracture pressure of the reservoir, then stabilizing the pressure and heating until an effective bottom water steam flooding is formed;   {circle around (5)} continuously heating the formation water under the condition of pressure control in open oil and gas reservoirs to the boiling point temperature of water, and the pressure slightly higher than the fracture pressure of the reservoir, and then continuously heating under constant pressure to form an effective bottom water vapor flooding;   {circle around (6)} continuously heating the formation water under the condition of pressure control in the open oil and gas reservoir, when the pressure is slightly higher than the fracture pressure of the reservoir, and then stabilizing and continuously heating until an effective bottom water steam flooding is formed;   {circle around (7)} continuously heating the formation water to the boiling point temperature of the water under pressure relief and pressure stabilization conditions in closed oil and gas reservoirs, and then continuously heating under constant pressure until an effective bottom water vapor flooding is formed;   {circle around (8)} continuously heating the formation water to the boiling point temperature of the water under the condition of pressure control in closed oil and gas reservoirs, and then continuously heating under constant pressure until an effective bottom water vapor flooding is formed;   {circle around (9)} continuously heating the formation water under the condition of pressure control in closed oil and gas reservoirs, when the pressure is slightly higher than the fracture pressure of the reservoir, then stabilizing the pressure and continuously heating continues until an effective bottom water steam flooding is formed;   {circle around (10)} continuously heating the formation water under pressure control conditions in closed oil and gas reservoirs, when the pressure is close to the fracture pressure of the reservoir, stabilizing the pressure and continuously heating until effective bottom water steam flooding is formed;   {circle around (11)} continuously heating the formation water under pressure control conditions in closed oil and gas reservoirs, when the pressure is slightly higher than the fracture pressure of the reservoir, stabilizing the pressure and continuously heating until an effective bottom water steam flooding is formed.   
     
     
         14 . The method according to  claim 1 , wherein the principle of heating the edge and bottom water layers of oil and gas reservoirs, comprising
 keeping the dynamic pressure of the reservoir greater than or equal to P o ;   for thermal recovery reservoirs, getting the formation crude oil movable before bottom water steam-flooding;   During the period;   Stage I, the reservoir pressure is between (P i , P o ), the power consumption is small, but the formation energy is deficient. It is suitable for ordinary oil and gas reservoirs with good oil properties and medium and high permeability that do not require high temperature, and ordinary heavy oil reservoirs and high pour point oil reservoirs with low temperature thermal recovery;   Section II, the reservoir pressure is between (P o , P b ), the formation energy is supersaturated, and the temperature of the oil and gas reservoir is high. It is suitable for medium and high permeability reservoirs, requiring high temperature thermal recovery of heavy oil and gas reservoirs and high pour point oil and gas reservoirs;   In stage III, the reservoir pressure is greater than or equal to the fracture pressure P b  of the reservoir, and the high temperature and high pressure state is beneficial to the overflow of low abundance oil and gas, and is suitable for tight oil and gas reservoirs requiring high pressure steam injection or hydraulic fracturing.   
     
     
         15 . The method according to  claim 1 , comprising heating side and bottom water layer including,
 various electric heating and nuclear heating;   heating wells for heating edge and bottom water layers can be various types of horizontal wells;   the heaters placed in the horizontal wells can be of various energy-efficient models of heating equipment.