SU1199923A1 - Method of determining overflows of formation fluids in producing well - Google Patents

Abstract

1. METHOD FOR DETERMINING PLASTIC LIQUID FLOWS IN THE EXTRACTION WELL, including sampling fluid from each formation in the reference wells, sampling from the producing well, analyzing samples for the content of monitored fluids and comparing the results of the analysis of the samples, characterized in that in order to improve the accuracy of determination overflows in the presence of non-perforated formations in the production well, change the depression in the production well, and a sample is taken every time after the establishment of a new mode of operation mining skvaS zhiny. 2. A method according to claim 1, ex ((l) in order to determine relative inflows of fluid from the formations and layers, including non-perforated ones, when analyzing the samples, h -1 controllable signs of the fluid are determined.

Description

1 The invention relates to the oil industry and can be used to control the development of myoplast oil fields. The purpose of the invention is to improve the accuracy of determining flows in the presence of non-perforated formations in the production well, as well as to determine the relative flow of liquid in the presence of several perforated and non-perforated formations in the well. The essence of the method is to preliminarily take samples of fluid from each layer in the reference wells, analyze the samples for the content of control signs, then take and analyze the sample from the production well, change the depression in the production well and after the establishment of a new regime

"-O (a-O. +,., Chkp,., To-to"

(()

() b (, - kG) gp. where K is the average value of the J-th feature for the i -th stratum CJ.J - the relative fluid inflow from the i -th stratum (. 1) and the value of the j -th feature n according to the analysis of the sample from the well under study. where 6 and TO are, respectively, general and particular, determine whether systems of equations. Using as a sign of the flow the change in the characteristic of a fluid when the mode of operation of the well being studied is based on the following. Suppose that in the well under study there are dtc, besides perforated and non-perforated layers, from which fluid can flow into the well as a result of the flow. In this case, all the layers have a hydrodynamic connection with the well. X1 each of the segments of the reservoir-bore 232 work wells are again selected and analyzed samples. After that, the results of analysis of samples obtained under different conditions are compared with the results of analysis of samples from reference wells. A change in the value of the feature for different modes indicates the presence of overflows regardless of the number of non-perforated formations. Determination of sources of flow of fluid from non-perforated formations is achieved by the fact that for the fluid of each of the formations (including perforated in the well under study), AND -1 signs are found that contrast and unambiguously vary between the formations, and the flow sources are determined by relative fluxes of fluids the values of which are solved by a system of linear equations can be represented as a tube for the flow of fluid. At one end, all the tubes are interconnected and under the same pressure, determined by the pressure in the well. The pressures at the other ends of the tubes are reservoir, which, as a rule, are not the same. The flow of fluid into the well through each tube is determined by the pressure difference at its ends and the hydraulic resistance. The ratio of relative fluid inflows between the tubes is maintained if the pressures at the ends of the tubes (reservoir and in the well) are constant. A change in pressure in a well (an increase or decrease in depression in a well by increasing or decreasing its flow, respectively) results in a redistribution of relative fluid inflows. The latter is reflected in the value of the signs — in a sample of fluid taken at the mouth of the well under study. If at different modes of operation of the well, the fluid enters it only from one layer, then a change in the regime only leads to a change in the flow of fluid from this reservoir, but the fluid characteristic remains unchanged. Whether in this case the source is a perforated formation (no flow) or non-perforated (presence of flow), this is unambiguously determined by comparing the obtained values of fluid characteristics from the studied well with reference values for each formation. The use of the reduced system of equations for determining the relative inflows of fluids is based on the fact that the chosen controlled signs follow the principle of additivity, i.e. the value of each attribute for a mixture of liquids is equal to the sum of their weighted average values. The method is carried out by performing the following operations. In the area where the production well is located, for each of the formations, including those that are perforated in the production well, reference wells are selected in which only one formation is perforated and fluid flows in which between the perforated and non-perforated formations are excluded. At the wellhead of each well, one fluid sample is taken (oil or water, depending on the problem to be solved). Samples are analyzed for several characteristics. According to the analysis, the characteristics of the fluid that unambiguously and contrastly change between the layers are selected as controlled signs. The total number of selected features should be equal to И -1, where AND is the number of all formations, possible sources of fluid inflow into the well, including the formation perforated in the production well. Their various physical and chemical properties, such as density, optical properties, paramagnetism, elemental composition, etc., can be used as controlled signs of fluid. For each stratum, the average values of each of the h -1 signs considered further as reference values. At the steady state of its operation, a fluid sample is taken from the production well. The fluid sample is analyzed by AND -1 signs. The results of the analysis of the sample from the production well are compared with the reference values. If the values coincide with the reference values of one of the non-perforated formations or with the reference values of the perforated formation, it is concluded accordingly about the existence of the overflow and its source or about the absence of the overflow. Research on. this ceases. Upon receipt of intermediate characteristic values by analyzing a sample from a production well, research continues. The mode of operation of the production well changes (decreases or increases - depression in the well by responsiblely reducing or increasing the total withdrawal of fluids from the well). This results in the redistribution of fluid inflows from perforated and non-perforated formations, if the latter are sources of overflows. A second fluid sample is taken from the mouth of the production well at the steady state of its operation. An analysis of the fluid sample is made on the basis of AND -1 signs. The results of the first and second screenings are compared with each other and with the reference values, on the basis of which it is concluded that there is a flow. In this case, for the considered (intermediate values of attributes) the following situations are possible. The results of the analysis of samples of the first and second sampling are the same. It is concluded that there is no flow to the well. The intermediate values of the attributes are due to a local change in fluid from the perforated formation that is not associated with the overflow. . The results of the analysis of samples of the first and second sampling are significantly different. with . It is concluded that there is a flow of fluid from at least one non-perforated formation. If the well in question is

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one non-perforated formation, it is also a source of overflow. If there are several non-perforated formations in the well that can be sources of overflow, then to determine the latter, relative fluid inflows for each of the formations are estimated by making and solving a reduced system of linear equations.

The use of the invention may be effective in multilayer fields with separate or partially separate operation. Plastics. Reasonably accurate and productive determination of the properties of the plate

These fluids (oil or water), which are selected as controlling signs, can be carried out using atomic absorption, neutron activation, X-ray radiometric, EPR spectroscopy, optical and other methods. These methods can be used separately or together depending on

the number of reservoirs in the section of the production well and the contrast of differences in reservoir fluids. The required sample volume for analysis does not exceed 3 cm. Performance

analysis is 20-40 samples for 7 hours.

Claims (2)

1. METHOD FOR DETERMINING FLOWS OF PLASTIC LIQUIDS In an PRODUCING WELL, including sampling 'fluid from each formation in reference wells, sampling from a producing well, analyzing samples for the content of controlled signs of fluid, and comparing the results of the analysis of the samples, characterized in that, in order to increase the accuracy of determining cross-flows in the production well of non-perforated reservoirs, the depression in the production well is changed, and a sample is taken each time after establishing a new operating mode of the production well _β . in 2. The method of pop. 1, which requires that, in order to determine the relative inflows of fluid from and reservoirs, including non-perforated ones, in the analysis of samples, h -1 of the controlled signs of the fluid are determined. (eleven)