Yaerxia Area, Capacity Of Low Permeability Fractured Reservoir Evaluation Research

With the rapid development of our country’s economy, the growing demand for oil resources. For low permeability reservoirs at home and abroad in lately20years of exploration and development dynamics enlarges gradually, in order to meet the urgent demand for energy. In China’s new found nearly half in the reservoir is low permeability oil and gas fields, while the scale of low permeability oil and gas production capacity construction account for over70%of the total oil and gas production capacity construction scale, low permeability oil and gas has become the key battleground of the construction of oil and gas development. In2008alone, low permeability oil production accounted for37.6%of the total oil production and low permeability gas production, accounting for42.1%of the total gas production. Second, the distribution of low permeability oil and gas resources in our country has the oil and gas, reservoir types, wide distribution and under "on gas oil, Marine and continental oil and gas with the main function of gas", the characteristics of the proven reserves, reserves for a high proportion of low permeability oil reservoirs, some accounts for more than two-thirds of the national reserves and huge potential for development. In our country each big oilfield in mid and late into the development, energy shortage situation, tightening of low permeability oil and gas exploration and development have very important realistic and strategic significance.According to the requirement of the joint-stock company, yumen oilfield branch actively carry out the old oil field comprehensive research, the purpose is to make the old oil field bloom, yumen weighing millions of tons at an early age. Research process and the characteristics of the reservoir seepage, analyze and determine the reasonable capacity of oil field, in order to ensure a stable and efficient development of this kind of oilfield, to enhance oil recovery, improve the effect of oilfield development has very important significance. This thesis aims to duck son gorge block complex reservoir capacity evaluation, for duck son gorge of oil and gas production to lay a solid foundation and reference.Oil and gas production of oil and gas field exploration and development effect and economic benefits have a direct impact. Evaluation of oil and gas field production is the comprehensive research on the oil and gas reservoir capacity and comprehensive evaluation of a technology, to improve the efficiency of the exploration on, to reduce the exploration cost has important guiding significance, simultaneously is also the foundation of arrangements for reasonable development of oilfield. Though, to assess the oil and gas production at home and abroad a lot of research, but a large part of all is to obey the darcy’s law of middle and high permeability reservoirs. But more than sixty percent of oil and gas in our country exists in low permeability or extremely low permeability reservoir, but low speed percolation in low permeability reservoir fluid state is not in conformity with the darcy’s law, in addition to a viscous resistance and fluid and the adsorption resistance of the rock or water membrane resistance, only overcome this additional resistance, liquid to flow, the capacity for low permeability of low permeability reservoir evaluation is difficult.For duck son gorge area of reservoir geology and production situation, investigation in a large number of fractured low permeability reservoirs both at home and abroad based on the actual situation of the development research, this article mainly to the ducks gorge block seepage characteristics, based on the production data of low permeable capacity evaluation, pressure sensitive effect on the influence of low permeability oilfield production capacity, production capacity of low permeability research on these aspects were studied.Cretaceous reservoir is characterized by deeply buried, low permeability, high original formation pressure, low saturation pressure, the average density of0.865ground crude oil, crude oil better properties, underground crude oil viscosity is0.26-1.01mPas commonly, low viscosity oil reservoir. Formation oil volume factor of1.284, the bright degree reached11%, the moisture content is11%, is a lithologic trap reservoir construction.General situation of the development of ducks gorge blocks are expounded, including the characteristics of reservoir, reservoir, etc. Duck son gorge area of seepage characteristics is studied, the relative permeability curve analysis of reservoir performance for hydrophilic, the reservoir production period is mainly in the low and medium water cut stage, high water cut stage can’t achieve the goal of oil production plant extract; In mercury injection curve analysis, by using the mercury injection method to calculate the start-up pressure and average permeability of low permeability cores, etc., including pre-production nissan oil relationship, the strength of production, productivity index and yield prediction are studied.In the understanding of the above development status and the characteristics of seepage and research basis, using the duck son gorge area of actual production data capacity of block is evaluated. First of all to block the development of the situation and the present situation of mining have a profound understanding; To research and analyze production changes, according to block production of production Wells in accordance with the size and different stages of grading; Ducks canyon block in different Wells on the reservoir characteristics and production has great difference, accurate assessment of gorge area, production characteristics, the well can be divided into three categories, according to the static and dynamic data, production characteristics, according to the characteristics of various proportion on the well production to carry out comprehensive evaluation.Permeability reservoirs is easy to form fluid retention in the adsorption layer, because oil and water flow channel narrow, on the surface of the small pore throat. Formation of crude oil from the static to the flow must overcome the constraints of the adsorption layer are trapped, stranded on the adsorption layer surface on both sides of the formation fluid flow pressure gradient must be by breaking a critical value, the breaking of the fluid percolation threshold is the start-up pressure gradient. A lot of research data confirmed the existence of start-up pressure gradient, and prove that the lower the permeability, the bigger the start-up pressure gradient. Is established in consideration of stress sensitivity of the influence of porosity and permeability of low permeability oil well to solve the productivity equation, this method make the low permeability reservoir capacity calculation result more accurate; Is established considering the stress sensitive effect and the start-up pressure gradient of low permeability reservoirs vertical well productivity equation. Using the established equation of each block are applied to solve the pressure sensitive coefficient is studied considering the effect of pressure sensitive production change rule. Under the same bottom hole flowing pressure, capacity-the greater the stress sensitivity index, the lower the oil well production, shows that single well production capacity of low permeability reservoir is mainly influenced by strong stress sensitivity.Capacity of low permeability fractured reservoir rule jing are analyzed, this paper expounds the reservoir engineering method and the modern production decline analysis method in duck son gorge cretaceous reservoir in practical application. Practice application shows that capacity attenuation curve method than the production decline curve method has many incomparable advantages. Brief introduction of production decline curve chart and typical low permeability fracturing Wells with seepage model. The actual production data of fracturing Wells was used to study the capacity and influence factor of fracturing Wells. Had a greater influence on the fracture half length of the initial production, with the increase of fracture half-length, initial production, to the early impact is bigger, less effect for late; Had a greater influence on the permeability of the initial production, influence throughout the production stage, the higher the permeability, the higher the initial production, the decline rate, the greater the early decline faster, middle and later decline more slowly.