scholarly journals Case study on diagnosis and identify the degree of bottom hole liquid accumulation in double-branch horizontal wells in PCOC

2021 ◽  
Vol 248 ◽  
pp. 01071
Author(s):  
Tingwei Yao ◽  
Yang Zhang ◽  
Minhao Guo ◽  
Zhilin Tuo ◽  
Haiyang Wang ◽  
...  
Keyword(s):  
Natural Gas ◽  
Large Scale ◽  
Gas Flow ◽  
Continuous Production ◽  
Production Performance ◽  
Gas Wells ◽  
Gas Reservoirs ◽  
Gas Recovery ◽  
Bottom Hole ◽  
Natural Gas Reservoirs

In the process of continuous production of natural gas wells, formation pressure and gas flow rate decrease continuously. The ability to carry liquid decreases continuously, thus gradually forming bottom hole liquid. Bottom hole liquid accumulation is an important reason for the decrease of production or shutdown of natural gas wells. How to diagnose whether there is liquid accumulation in natural gas wells and identify the degree of liquid accumulation, to adopt drainage gas recovery operation in time, is the research focus of efficient development of natural gas reservoirs. In this paper, a method for diagnosing bottom hole liquid accumulation combining production performance curve and modified Fernando inclined well critical liquid-carrying model is designed for a large scale double-branch horizontal well used in unconventional reservoirs. The method is applied to the Well X2 of He 8 Member in PCOC. The application results showed that there was no liquid accumulation in the horizontal and vertical sections of the Well X2. The liquid in the wellbore was generated at the bottom of the inclined section and the liquid accumulation is upward along the wellbore from the bottom of the inclined section, with the height of 3 m.

Rare gas studies of basin scale fluid movement

1993 ◽  
Vol 344 (1670) ◽  
pp. 141-156 ◽  
Keyword(s):  
Natural Gas ◽  
Large Scale ◽  
Sedimentary Basins ◽  
Rare Gas ◽  
Rare Gases ◽  
Gas Reservoirs ◽  
Fluid Movement ◽  
Basin Scale ◽  
Subsurface Fluid ◽  
Natural Gas Reservoirs

Rare gases are conservative tracers of subsurface fluid movement. The mass balance of atmosphere-derived and crustally produced radiogenic and nucleogenic rare gases in natural gas reservoirs allows straightforward constraints to be placed on scales of fluid movement in sedimentary basins. The details of large-scale fluid movements in Neogene sedimentary basins appear to differ according to their thermal structures.

scholarly journals Approbation of the technology for displacing residual gas with nitrogen for the conditions of a depleted gas reservoir in the VS-9 horizon of the Lyubeshivske gas field

2020 ◽  
pp. 16-23
Author(s):  
R. M. Kondrat ◽  
L. I. Khaidarova
Keyword(s):  
Natural Gas ◽  
Gas Reservoirs ◽  
Gas Field ◽  
Recovery Coefficient ◽  
Gas Recovery ◽  
Production Wells ◽  
Depleted Gas Reservoirs ◽  
Reser Voirs ◽  
Residual Gas ◽  
Natural Gas Reservoirs

Most natural gas reservoirs of Ukraine are depleted to some extent; still they contain significant tail gas reserves. A promising direction for increasing gas recovery from depleted gas reservoirs is the displacement of tail gas from the porous medium with nitrogen which is easily accessible and does not cause corrosion of the down-hole equipment. This article characterizes the technologies for increasing gas recovery from depleted gas reser-voirs by injecting nitrogen into them. The technology of replacing tail gas with nitrogen is tested on the example of the depleted reservoir of ND-9 horizon of Lyubeshivskyy gas field, the productive deposits of which are composed mainly of sandstones with interlayers of limestone and clay. The authors consider fifteen options of injecting ni-trogen into the reservoir, including options of treating the bottom-hole of low-production wells at the beginning of the process of further reservoir development and at the beginning of the injection of nitrogen into the reservoir. In all cases, the reservoir is first redeveloped in the depletion mode until the reservoir pressure decreases to 0,1 from the initial value. After that, nitrogen is injected into one of the producing wells which is transferred to the injection well. The injection of nitrogen into the reservoir continues until the nitrogen content in the last produc-ing well is less than 5 % vol. All options are characterized by high values of the gas recovery coefficient and close values of the dura-tion of the reservoir further development. The positions of the front of the displacement of natural gas by nitrogen at various time points are given. According to the research results, the gas recovery coefficient for tail gas for var-ious options varies from 14,12 to 34,58 %. With the introduction of the technology of injecting nitrogen into the reservoir, the overall gas recovery coefficient increases from 72,25 % (at present development system) to 80,28 % when the residual gas is displaced by nitrogen.

Production-Data Analysis of Gas Reservoirs With Apparent-Permeability and Sorbed-Phase Effects: A Density-Based Approach

SPE Journal ◽  
2015 ◽  
Vol 20 (01) ◽  
pp. 99-111 ◽  
Author(s):  
Pichit Vardcharragosad ◽  
Luis F. Ayala H.
Keyword(s):  
Gas Flow ◽  
Liquid Solution ◽  
Gas Production ◽  
Production Performance ◽  
Production Data ◽  
Gas Reservoirs ◽  
Apparent Permeability ◽  
Gas Slippage ◽  
Natural Gas Reservoirs ◽  
Sorbed Phase

Summary Accounting for depletion-dependent permeability and sorbed-phase effects is an important step toward achieving reliable analysis of production performance in unconventional gas systems. This study demonstrates how to account for pressure-dependent apparent-permeability (e.g., gas-slippage) and desorption effects in gas-production analysis of boundary-dominated data with a density-based approach. In this work, apparent-permeability and desorption models are incorporated into the original density-based approach by modifying the definitions of depletion-driven variables that are the basis of the density-based type of analysis. The proposed modification of the original approach successfully enables associated analysis techniques to be applicable to natural-gas reservoirs with gas slippage and adsorbed gas. Results indicate that by modifying the definitions of the depletion-driven variables, the density approach can effectively and successfully capture the effects from gas slippage and desorption. Through a number of case studies, we show that gas-flow rate can be successfully predicted by rescaling liquid solution with the modified density-based variables. As an illustration, we show that resource calculations able to fully take into account these effects are possible when long-term production data are available. This work details the methodology required to do so, and illustrates its application to production-data prediction analysis for unconventional assets.

scholarly journals Differential hydrocarbon enrichment in deep Paleogene tight sandstones of the Dongpu Depression in Eastern China

2021 ◽  
pp. 014459872098811
Author(s):  
Yuanyuan Zhang ◽  
Zhanli Ren ◽  
Youlu Jiang ◽  
Jingdong Liu
Keyword(s):  
Natural Gas ◽  
Crude Oil ◽  
Large Scale ◽  
Eastern China ◽  
Continuous Distribution ◽  
Gas Reservoirs ◽  
Pyrolysis Gas ◽  
Hydrocarbon Charging ◽  
Dongpu Depression ◽  
Kerogen Pyrolysis

To clarify the characteristics and enrichment rules of Paleogene tight sandstone reservoirs inside the rifted-basin of Eastern China, the third member of Shahejie Formation (abbreviated as Es3) in Wendong area of Dongpu Depression is selected as the research object. It not only clarified the geochemical characteristics of oil and natural gas in the Es3 of Wendong area through testing and analysis of crude oil biomarkers, natural gas components and carbon isotopes, etc.; but also compared and explained the types and geneses of oil and gas reservoirs in slope zone and sub-sag zone by matching relationship between the porosity evolution of tight reservoirs and the charging process of hydrocarbons. Significant differences have been found between the properties and the enrichment rules of hydrocarbon reservoirs in different structural areas in Wendong area. The study shows that the Paleogene hydrocarbon resources are quasi-continuous distribution in Wendong area. The late kerogen pyrolysis gas, light crude oil, medium crude oil, oil-cracked gas and the early kerogen pyrolysis gas are distributed in a semicircle successively, from the center of sub-sag zone to the uplift belt, that is the result of two discontinuous hydrocarbon charging. Among them, the slope zone is dominated by early conventional filling of oil-gas mixture (at the late deposition period of Dongying Formation, about 31–27 Ma ago), while the reservoirs are gradually densified in the late stage without large-scale hydrocarbon charging (since the deposition stage of Minghuazhen Formation, about 6–0 Ma). In contrast, the sub-sag zone is lack of oil reservoirs, but a lot of late kerogen pyrolysis gas reservoirs are enriched, and the reservoir densification and hydrocarbon filling occur in both early and late stages.

Sign in / Sign up

Export Citation Format

Share Document