WO2016011626A1 - Dual pipe network water injection system pressure dividing point determination method - Google Patents

Abstract

A dual pipe network water injection system pressure dividing point determination method, comprising the following steps: step 1, acquiring technical parameters of a water injection system and an individual well governed thereby; step 2, establishing an operation efficiency and pressure dividing point mathematical model of "Single water injection system and dual pressure system water injection pipe network", and acquiring relationship functions between operation efficiency and pressure and the water quantity according to the mathematical model; step 3, setting up an iteration simulation method to calculate the calculation range and calculation step length of pressure dividing points; step 4, substituting each parameter value into the mathematical model to conduct iterative solving so as to obtain the solution set of the operation efficiency, and drawing the solution set data curve of the operation efficiency via the solution set, the curve being a parabolic curve; step 5, the top point of the parabola is the highest point of a pipe network efficiency, and a pressure point numerical value corresponding to the top point is the best pressure dividing point for outward delivery.

Description

 Method for determining partial pressure point of two casing network water injection system

 The invention relates to a method for determining a partial pressure point of a water injection system of a two-casing net, belonging to the technical field of oilfield water injection.

Background technique

 Most of the existing water injection systems are dry pressures of a single water injection system. However, due to the large difference in water injection pressure between the individual wells, some even reach lOMPa or more, resulting in a mismatch between the dry pressure of the water injection system and the single well oil pressure. In order to solve the problem of mismatch between system dry pressure and oil pressure, two casing network water injection technology was implemented. Two pressure systems were used in the same water injection system to reduce the pressure between the dry pressure of the water injection system and the single well oil pressure. difference. Said that the two pressure systems reduce the pressure difference between the dry pressure of the water injection system and the oil pressure of the single well to a certain extent, but there has been no

 Book

The effective method accurately divides the pressure dividing point, that is, which pressure point is the pressure threshold, and divides the injection well above the threshold into a set of pressure system, and divides the injection well below the threshold into another set of pressure System, but no technician can determine the most suitable partial pressure point. For many years, technicians have only determined the partial pressure point by experience. The scientific nature of the partial pressure point directly affects the energy consumption of the system and the efficiency of the pipe network. Therefore, how to scientifically and accurately divide the voltage dividing point is an important issue that must be solved. .

Summary of the invention

 In order to overcome the deficiencies of the prior art, the present invention provides a method for determining a partial pressure point of a two-casing net water injection system.

 A method for determining a pressure dividing point of a two-casing net water injection system, characterized in that the method comprises the following steps;

 Step 1. Collect the technical parameters of the water injection system and the single well under its jurisdiction:

a. The single well water injection quantity of the pressure system above the partial pressure point ^, the unit: m ³ /d, the value of the water quantity is the data extracted from the single well water meter;

 b. Single well oil pressure of the pressure system above the partial pressure point, unit: Mpa; The value of the oil pressure is the data measured from the single well pressure gauge;

c. The single well water injection amount of the pressure system below the partial pressure point, unit: m ³ /d, the value of the water quantity is the data extracted from the single well water meter;

 d. Single well oil pressure of the pressure system below the partial pressure point, unit: Mpa, the value of the oil pressure is the data measured from the single well pressure gauge; e, the dry pressure of the pressure system above the partial pressure point, unit: Mpa, The value of the oil pressure is the data measured from the main line pressure gauge of the water injection system;

Step 2: Establish a mathematical model of operating efficiency and partial pressure point of "two sets of water injection system for water injection system"; Through the mathematical model, the relationship between operating efficiency and pressure and water volume is obtained. The established mathematical model is as follows:

∑ G _is - ^., +∑ G _{J d} · Corpse

7 effects (corpse, G) ~~ - _k ^J ———

The mathematical model includes a total of 7 parameters, each parameter is described as follows: 7 ⁷ effect is a set of water injection system two pressure system water injection network operating efficiency % ·, Q ^{i 8} is the single well water injection volume of the pressure system above the partial pressure point, Unit: m3/d; Γ ^{ί 8} is the single well oil pressure of the pressure system above the partial pressure point, unit: Mpa; β·^ ^ώ is the single well water injection volume of the pressure system below the partial pressure point, unit: m3/d; The single well oil pressure of the pressure system below the partial pressure point, unit: Mpa; 8 ⁸ is the dry pressure of the pressure system above the partial pressure point, unit: Mpa;

 p

f y. ^d is the partial pressure point, unit: Mpa;

What is the efficiency of the pipe network described in the model? _3⁄4 , the specific calculation method is solved by iterative method;

 Step 3. Set an iterative simulation method to calculate the calculation range of the partial pressure point and the calculation step size;

Since the partial pressure point is determined, the value of the partial pressure point must be between 0 and the dry pressure of the highest water injection system, so the calculation range of the partial pressure point is determined as Pf.yd e (0, Pg.g); to ensure the required accuracy of calculation dividing point, the calculated step size determined to find O. lMPa; step 4, each parameter value is substituted into the mathematical model iterative solution obtained solution set efficiency η, and thus draw ⁷⁷ solution set effect The solution data curve, which is a parabolic curve;

 Step 5. The apex of the parabola is the highest efficiency of the pipe network, and the corresponding pressure point value is the optimal partial pressure point.

detailed description

 It is apparent that many modifications and variations made by those skilled in the art based on the teachings of the present invention are within the scope of the present invention. Example 1

 A method for determining a pressure dividing point of a two-casing net water injection system, comprising the following steps;

Step 1. Establish a mathematical model of operating efficiency and partial pressure point of "two sets of water injection system water injection system". Through the mathematical model, the relationship between operating efficiency and pressure and water volume is obtained. The mathematical model established is as follows: k effect (corpse, G) =

 The mathematical model includes a total of seven parameters, each of which is described as follows:

⁷⁷ effect water injection system two pressure system water injection network operation efficiency %·,

Single well water injection volume of pressure system above ^{Qi g} pressure point, unit: m3/d; single well oil pressure of pressure system above pressure point, unit: Mpa; d single well water injection volume of pressure system below pressure point, unit : m3/d;

^{Pj d} pressure point below the single well hydraulic pressure, unit: Mpa; P ^gs pressure point above the pressure system dry pressure, unit: Mpa;

 p

f ^y ' ^d partial pressure point, unit: Mpa

The pipe network operation efficiency described in the model is _3⁄4 , and the specific calculation method is solved by an iterative method. Iteration is a process in numerical analysis that solves a problem by finding a series of solution sets from an initial estimate. The methods applicable to achieve this process are collectively called iterative methods. The iterative method is a numerical processing method well known to the skilled person and will not be described in detail herein.

 Step 2: Set the iterative simulation method to calculate the calculation range of the partial pressure point and the calculation step size.

 Since the partial pressure point is determined, the value of the partial pressure point must be between 0 and the dry pressure of the highest water injection system, so the calculation range of the partial pressure point is determined as Pf.yd e (0, Pg.g); In order to ensure the accuracy of the partial pressure point, the step size is determined to be 0.1 MPa.

Step 3: Collect the technical parameters of the water injection system and the single well under its jurisdiction, and prepare for the calculation of the mathematical model: a. The single well water injection volume of the pressure system above the pressure point, unit: m ³ /d, the value of the water quantity is Extract data from a single well water meter.

 b. Single well oil pressure corresponding to the pressure system above the partial pressure point, unit: Mpa. The value of this oil pressure is taken from the data measured by a single well pressure gauge.

c. The single well water injection amount of the pressure system below the partial pressure point, unit: m ³ /d, the value of the water quantity is the data extracted from the single well water meter.

d. Single well oil pressure ^P ^ of the pressure system below the partial pressure point, unit: Mpa, the value of the oil pressure is extracted from a single well The data measured by the pressure gauge.

 e. Dry pressure of the pressure system above the partial pressure point, unit: Mpa, the value of the oil pressure is the data measured from the main line pressure gauge of the water injection system.

 Step 4: Substituting each parameter value into a mathematical model for iterative solution, and extracting the solution set, and extracting the solution data curve of ?7 by using the solution set, the curve is a parabolic curve.

 Step 5: The apex of the parabola is the highest point of the pipe network efficiency, and the corresponding pressure point value is the optimal partial pressure point derived.

 As described above, the embodiments of the present invention have been described in detail, but it will be apparent to those skilled in the art that the invention may be modified without departing from the scope of the invention. Therefore, such modifications are also fully included in the scope of the present invention.

Claims

Claim 1. A method for determining a pressure dividing point of a two-casing net water injection system, characterized by comprising the following steps;  Step 1. Collect the technical parameters of the water injection system and the single well under its jurisdiction: a. The water injection amount of the single well belongs to the pressure system above the pressure point, the unit is: m ³ /d, and the value of the water quantity is the data extracted from the single well water meter;  b. Single well oil pressure of the pressure system above the partial pressure point, unit: Mpa; The value of the oil pressure is the data measured from the single well pressure gauge; c. The single well water injection amount of the pressure system below the partial pressure point, unit: m ³ /d, the value of the water quantity is the data extracted from the single well water meter;  d. Single well oil pressure of the pressure system below the partial pressure point, unit: Mpa, the value of the oil pressure is the data measured from the single well pressure gauge;  e. Dry pressure of the pressure system above the partial pressure point ^, unit: Mpa, the value of the oil pressure is the data measured from the main line pressure gauge of the water injection system;  Step 2. Establish a mathematical model of the operating efficiency and partial pressure point of the "two sets of water injection system of a water injection system"; obtain the function of the relationship between operating efficiency and pressure and water volume through a mathematical model; the mathematical model is as follows: Effect (corpse, O = ~~- _k ―—— ^ ^,., -∑ -. _g + ^.,.. The mathematical model consists of 7 parameters. The parameters are as follows:  ^ 3⁄4 is a set of water injection system two pressure system water injection network operation efficiency, Q _lg is the single well water injection volume of the pressure system above the partial pressure point, unit: m ³ /d; is the single well oil pressure of the pressure system above the partial pressure point, unit: Mpa; Q _jd is the single well water injection amount of the pressure system below the partial pressure point, and the unit is m ³ /d _; Pj- _d is the single well oil pressure of the pressure system below the partial pressure point, unit: Mpa; P _g . _g is the dry pressure of the pressure system above the partial pressure point, unit: Mpa; Pf .yd is the partial pressure point, unit: Mpa; Q _ig , _--... The meaning of the lower corner parameter: i is any well in a single well to which the pressure system is above the partial pressure point; therefore,  The range of values of i is: 1, 2, 3, ..., k; k means that the pressure system above the partial pressure point includes a k-port injection well; g is a symbolic sign, indicating that the corresponding single well is a pressure system above the partial pressure point. Water injection well; used to distinguish from single well in pressure system below pressure point; Q _jd , Pj. _d ... meaning of the lower corner parameter: j is any well in a single well to which the pressure system is below the partial pressure point, therefore,  The range of j is: 1, 2, 3, ..., m; m means that the pressure system below the partial pressure point includes m injection wells; d is the symbol mark, indicating that the corresponding single well is the pressure system below the partial pressure point. Injecting well in the middle; used to distinguish from a single well in a pressure system above the partial pressure point; ... - meaning the angle parameters: gg is an identification symbol indicating dry lamination or more dividing point pressure of the system; Pf _{y d} - ... meaning the angle parameters:.. Fyd for the sake of calculating the dividing point identification symbol, Pf _{y.. d} is the calculated partial pressure point; The pipe network operation efficiency described in the model is _3⁄4 , and the specific calculation method is solved by an iterative method;  Step 3. Set an iterative simulation method to calculate the calculation range of the partial pressure point and the calculation step size; Since the partial pressure point is determined, the value of the partial pressure point must be between 0 and the dry pressure of the highest water injection system, so the calculation range of the partial pressure point is determined as Pf.yd e (0, Pg.g); In order to ensure the accuracy of the partial pressure point, the calculation step is determined as O. lMPa; Step 4, substituting each parameter value into a mathematical model for iterative solution, and _obtaining a solution set of 7 3⁄4, and extracting r/ by this solution set The solution data curve, which is a parabolic curve;  Step 5. The apex of the parabola is the highest efficiency of the pipe network, and the corresponding pressure point value is the optimal partial pressure point.