US2021270124A1PendingUtilityA1
Method for distinguishing authenticity of high-pressure physical property parameters of oil reservoirs
Assignee: YANGZHOU JIANGSU OILFIELD RUIDA PETROLEUM ENGINEERING TECH DEVELOPMENT CO LTDPriority: Jan 30, 2019Filed: Aug 8, 2019Published: Sep 2, 2021
Est. expiryJan 30, 2039(~12.5 yrs left)· nominal 20-yr term from priority
Inventors:Haijin Zheng
E21B 49/00E21B 47/009E21B 47/047E21B 49/0875
27
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Claims
Abstract
A method for distinguishing an authenticity of high-pressure physical property parameters of oil reservoirs is provided. The method includes: collecting the high-pressure physical property parameters, screening a standard well, calculating a pump efficiency by means of formulas, then calculating an absolute value Δ=|ηtheory−ηreality| of each group of absolute errors, and taking a smallest absolute value Δmin of the absolute error. wherein Δmin≤ε, ε is a set accuracy, generally, 0≤ε≤0.02, and the high-pressure physical property parameters corresponding to a group of the theoretical pump efficiency ηtheory and the real pump efficiency ηreality are real high-pressure physical property parameters of an oil reservoir to be distinguished. The method provides a fast, simple and practical means for distinguishing correct high-pressure physical property parameters. The method is applicable to an oil well in a certain zone of an oil reservoir to be determined.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1 . A method for distinguishing an authenticity of high-pressure physical property parameters of an oil reservoir, comprising the following steps:
1) collecting the high-pressure physical property parameters: collecting the high-pressure physical property parameters of a sampled well of the oil reservoir to be distinguished, wherein the high-pressure physical property parameters comprise a gas-oil ratio GOR, a solubility coefficient α, a saturation pressure P b , a formation crude oil density ρ o , and a formation crude oil viscosity μ o ; 2) screening a standard well: determining the standard well from multiple oil wells continuously exploited in a same block and a same zone as the sampled well, wherein an indicator diagram of the standard well reflects a pump of the standard well does not leak and a tubing string of the standard well does not leak, and meanwhile, the standard well has a lowest water content, a highest liquid yield and a largest submergence in the multiple oil wells; 3) calculating a pump efficiency: substituting each group of the high-pressure physical property parameters collected in step 1) and related data of the standard well screened in step 2) into the following formula, and calculating a theoretical pump efficiency η theory and a real pump efficiency η reality of the standard well:
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Q
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when P s ≥P b , making P s =P b , wherein if an oil pipe is anchored, L p /f t is not comprised in λ;
η reality =Q reality /Q theory *100%;
Q theory =πD 2 ρgSN/ 4;
Q leak =πDρgδ 3 h /(12 L p /μ);
ρ=(1− f w )*ρ o +f w *ρ w ;
h=h dynamic +1000*( p oil −p casing )* g/ρ;
P s =p casing +( h setting −h dynamic )*ρ o *g/ 1000;
μ= f w +(1− f w )*μ o ;
wherein
Q reality represents a real output of an oil well of the multiple oil wells;
Q theory represents a theoretical displacement of the oil well of the multiple oil wells;
Q leak represents a pump leakage;
the GOR represents the gas-oil ratio and a unit of the GOR is m 3 /m 3 ; α represents the solubility coefficient and a unit of the solubility coefficient is m 3 /(m 3 ·Mpa); P b represents the saturation pressure and a unit of the saturation pressure is Mpa; ρ o represents the formation crude oil density and a unit of the formation crude oil density is t/m 3 ; μ o represents the formation crude oil viscosity and a unit of the formation crude oil viscosity is Pa·S;
λ represents a stroke loss of the standard well and a unit of the stroke loss is m; β represents a gas influence coefficient of the standard well, wherein the gas influence coefficient is dimensionless; ρ represents a mixed liquid density of the standard well and a unit of the mixed liquid density is t/m 3 ; h represents a pump lift of the standard well and a unit of the pump lift is m; P s represents a submergence pressure of the standard well and a unit of the submergence pressure is Mpa; μ represents a hydrodynamic viscosity of the standard well and a unit of the hydrodynamic viscosity is Pa·S; f w represents a rate of a water content of a pumped liquid in the standard well; h dynamic represents a dynamic liquid level depth of the standard well and a unit of the dynamic liquid level depth is m; D represents a pump diameter of the standard well and a unit of the pump diameter is m; h setting represents a pump setting depth of the standard well and a unit of the pump setting depth is m; p oil represents a wellhead oil pressure of the standard well and a unit of the wellhead oil pressure is Mpa; P casing represents a casing pressure of the standard well and a unit of the casing pressure is Mpa; S represents a stroke length of the standard well and a unit of the stroke length is m; N represents a stroke frequency of the standard well and a unit of the stroke frequency is 1/min; L 1 , L 2 and L n respectively represent a length of a first-level rod, a length of a second-level rod and a length of an n-level rod of the standard well and a unit of the length is m; f 1 , f 2 and f n respectively represent a cross-sectional area of a first-level rod, a cross-sectional area of a second-level rod and a cross-sectional area of an n-level rod of the standard well and a unit of the cross-sectional area is m 2 ; L p represents a pump depth of the standard well and a unit of the pump depth is m; f t represents a cross-sectional area of a metal part of the oil pipe of the standard well and a unit of the cross-sectional area is m 2 ; E represents an elastic modulus of a steel of a pumping rod in the standard well, and E is 2.1*10 7 N/cm 2 ; g represents a gravity acceleration of the standard well and a unit of the gravity acceleration is m/s 2 ; δ represents an annular gap between a pump plunger and a pump cylinder of the standard well and a unit of the annular gap is m; L pl represents a length of the pump plunger of the standard well and a unit of the length of the pump plunger is m; and ρ w represents a water density of the standard well and a unit of the water density is t/m 3 ; and
4) screening results: after the pump efficiency is calculated in the step 3), for the standard well screened in step 2) and the each group of the high-pressure physical property parameters collected in step 1), obtaining a group of the theoretical pump efficiency η theory and the real pump efficiency η reality , and for each group of the theoretical pump efficiency η theory and the real pump efficiency η reality , calculating an absolute value Δ=|η theory −η reality | of an absolute error, and taking a smallest absolute value Δ min of the absolute error:
Δ min =|η theory −η reality |;
wherein if Δ min meets a condition: Δ min ≤ε, wherein ε is a set accuracy, and 0≤ε≤0.02,
the high-pressure physical property parameters corresponding to the group of the theoretical pump efficiency η theory and the real pump efficiency η reality , comprising the gas-oil ratio GOR, the solubility coefficient α, the saturation pressure P b , the formation crude oil density ρ o , and the formation crude oil viscosity μ o , are real high-pressure physical property parameters of the oil reservoir to be distinguished.Join the waitlist — get patent alerts
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