scholarly journals A Quadratic Cumulative Production Model for the Material Balance of an Abnormally Pressured Gas Reservoir

2008 ◽  
Author(s):  
Felix E. Gonzalez ◽  
Dilhan Ilk ◽  
Thomas Alwin Blasingame
Keyword(s):  
Material Balance ◽  
Production Model ◽  
Gas Reservoir ◽  
Cumulative Production

Material Balance for a Bottom-Water-Drive Gas Reservoir

1973 ◽  
Vol 13 (06) ◽  
pp. 328-334
Author(s):  
J.M. Dumore
Keyword(s):  
Water Saturation ◽  
Material Balance ◽  
Gas Reservoir ◽  
Gas Field ◽  
Water Contact ◽  
Free Gas ◽  
Water Influx ◽  
Cumulative Production ◽  
Gas Volume ◽  
Limiting Value

Abstract A material balance is developed for a gas reservoir in which the rising gas/water contact remains horizontal. The time-integrated cumulative water influx is introduced, which for numerical computations is sometimes more advantageous than the van Everdingen and Hurst integral. On the basis of the equations developed, material balance calculations of the history of an actual gas field are carried out to calculate the water influx. The strength of the estimated radial, limited aquifer, which must supply the water for the influx, is determined. It appears that the strength decreases with time and asymptotically approaches a limiting value. (Some possible reasons for this decrease are mentioned.) If we take the strength as constant and equal to the limiting value, however, very small deviations from the past pressures occur. With the same value for the strength of the aquifer, the future behavior of the gas reservoir is computed, assuming constant gas production rate and no water production. Introduction For a depletion-type gas reservoir - i.e., when there is no water encroachment - the average gas pressure is a function of the cumulative production pressure is a function of the cumulative production and can easily be calculated from a material balance. For a gas reservoir bounded by an aquifer, the average gas pressure also depends on the water influx, which in turn depends on the rate of pressure decline and thus on the production rate. In this case the material balance is much more complicated. In the following we have developed the material balance of a bottom-water-drive gas reservoir, in which the rising gas/water contact remains horizontal. In a numerical example, the equations are applied to an actual gas field in Northwest Germany. THE GAS RESERVOIR Let us consider a gas reservoir bounded by a horizontal gas/water contact. The bulk area of a horizontal cross-section through the reservoir at a height b above the original gas/water contact is denoted by A(h), and the part of this area taken up by free gas is denoted by F(h). in which and Swc are the average values of porosity and connate water saturation at level h. porosity and connate water saturation at level h. Function F(h) can also be considered as the free gas volume in the reservoir at level h per unit height. Consequently, the free gas volume in the reservoir between the original gas/water contact h = 0 and a certain level h = h' is 0 The total original free gas volume in the reservoir is in which H is the height of the top of the gas-bearing formation above the original gas/water contact; i.e., the closure of the reservoir. The original volume of free gas in place, measured at standard conditions, is where the reciprocal gas formation volume factor is defined by Since in general we may take the average reservoir temperature for Tres, 1/Bg is a function of pressure only. A fair approximation of Eq. 4 is obtained by taking (1/Bg)i independently of h and equal to the value corresponding to the average initial reservoir pressure. Then pressure. Then SPEJ P. 328

High Shut-in Pressure: Good News or Bad News? Maximising Value through Limited Data

2021 ◽  
Author(s):  
Handita Reksi Dwitantra Sutoyo ◽  
Diniko Nurhajj ◽  
Anak Agung Iswara Anindyajati ◽  
Dwi Hudya Febrianto ◽  
Nova Kristianawatie
Keyword(s):  
Early Life ◽  
Capital Expenditure ◽  
Analytical Data ◽  
Material Balance ◽  
Production Performance ◽  
Good News ◽  
Driving Mechanism ◽  
Pressure Data ◽  
Gas Reservoir ◽  
Reservoir Water

Abstract Early production of gas reservoirs is usually associated with a volumetric gas driving mechanism with no water production. Aquifer activity is minimal as well during the early life of the reservoir. In this paper, we will discuss about the good engineering practices based on several shut-in pressure data to observe and maximize marginal gas field value. We will also discuss about the possibility of water drive behavior in this field. Shut-in pressure data plays an important role in determining the in-place and reservoir dynamics of the gas reservoir. High shut-in pressure usually indicates high gas reserves. On the other hand, it shows a very strong water drive existence. The study takes place on a sandstone gas reservoir with an abnormal pressure regime on it. Production performance was then analyzed using the rate transient analysis (RTA) to determine its properties and gas in place and crosschecked with shut-in pressure data. From these steps, we can determine the trend of both static and flowing material balance (FMB) analysis to predict the reservoir dynamics. During the early life of production, it is clear that volumetric reservoir plays an important role in the reservoir dynamics since it produces no reservoir water. However, after 1 year of production, it starts to produce reservoir water. Monitoring starts when the first shut-in pressure shows a quite unexpected value. It puts a sense of both high gas reserves and aquifer activity. After applying all the pressure and production data on FMB and p/Z plot, it shows that both high gas reserves and aquifer activity exist in this field. The results of this study change the development strategy of this field, preventing doing major investment on high capital expenditure (CAPEX) with low results due to high aquifer activity. We can conclude that good reservoir monitoring and analysis combining several analytical methods can enhance our insight into reservoir dynamics. Combining FMB and p/Z, geologist starts to compare aquifer volume based on geological data and found to be similar with the results coming from analytical data. 3D reservoir simulation also confirms similar results based on those analyses.

Calculation Methods of the Dynamic Reserves for Gas Wells in a Low-Permeability Gas Reservoir

2013 ◽  
Vol 295-298 ◽  
pp. 3243-3248
Author(s):  
Lei Zhang ◽  
Lai Bing Zhang ◽  
Jun Jie Zhang ◽  
Feng Lan ◽  
Pan Deng
Keyword(s):  
Pressure Drop ◽  
Material Balance ◽  
Production Method ◽  
Gas Production ◽  
Phase Method ◽  
Low Permeability ◽  
Gas Reservoir ◽  
Two Phase ◽  
Material Balance Method ◽  
Unit Pressure

Accurately calculating dynamic reserves for single well in a low-permeability gas reservoir has an important guiding significance to high efficiency development of the gas reservoir. During the development of the gas reservoir, dynamic analysis methods were often used to calculate dynamic reserves. Dynamic analysis methods mainly include the material balance method, the gas production method in unit pressure drop, the flexible two-phase method and the production unstable method. Dynamic reserves for four types of gas wells in a low-permeability gas field were calculated using these four methods. Calculation results show that dynamic reserves from big to small are respectively obtained using material balance method, gas production method in unit pressure drop, flexible two-phase method and production unstable method. Calculating dynamic reserves obtained by flexible two-phase method and production unstable method are utilized to production dynamic data of gas well, and those obtained by material balance method and gas production method in unit pressure drop are utilized to the reservoir parameters of different state. Therefore, the values of dynamic reserves obtained using flexible two-phase method and production unstable method in the low-permeability gas reservoir may be more accurate than those obtained using the other methods.

Research on Variance Principle of Critical Producing Pressure Drop of Horizontal Well in Gas Reservoir with Bottom Water

2012 ◽  
Vol 616-618 ◽  
pp. 674-679
Author(s):  
Ke Liu Wu ◽  
Xiang Fang Li ◽  
Xiao Ting Gou
Keyword(s):  
Pressure Drop ◽  
Horizontal Well ◽  
Bottom Water ◽  
Material Balance ◽  
Sweep Efficiency ◽  
Gas Reservoir ◽  
Vertical Permeability ◽  
Balance Principle ◽  
Water Viscosity ◽  
The Difference

According to material balance principle, gas/water bearing height in gas reservoir with bottom water could be deduced. Additionally, sweep efficiency could be approximately determined, then based on the equivalent flowing resistance method and critical vertical velocity of bottom water drive, computational model of Critical Producing Pressure Drop during the development of gas reservoir with bottom water could be derived. Therefore, the variance principle of Critical Producing Pressure Drop of horizontal well can be expressed quantitatively, and this paper also analyzes that it is influenced by the ratio of vertical permeability to horizontal permeability, the difference between water and gas density, the ratio of water viscosity to gas viscosity and height for bottom water coning. The results could provide guidelines for the determination of reasonable producing pressure drop and producing rate of horizontal well in gas reservoir with bottom water.

The Research on Material Balance Considering In-Seam and Intrabed Water

2012 ◽  
Vol 233 ◽  
pp. 420-424
Author(s):  
Xi Nan Yu ◽  
Hong Liu ◽  
Ji Hua Cao ◽  
Jin Pang
Keyword(s):  
Balance Equation ◽  
Material Balance ◽  
Material Balance Equation ◽  
Gas Reservoir ◽  
Average Value ◽  
Back Face

The material balance equation of water-drive gas reservoir does not study the effect of in-seam and intrabed water,which results the distortion of reserve.If we take acount of the effect of in-seam and intrabed water,the slope of material balance equation curve is over the back-face,and the dynamic reserve is lower than ignoring the effect of in-seam and intrabed water,the average value of dynamic reserve drops 12.16%,so we must take acount of the effect of in-seam and intrabed water to the dynamic reserve.

scholarly journals Dynamic Material Balance Method for Estimating Gas in Place of Abnormally High-Pressure Gas Reservoirs

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Lixia Zhang ◽  
Yingxu He ◽  
Chunqiu Guo ◽  
Yang Yu
Keyword(s):  
High Pressure ◽  
Material Balance ◽  
Balance Method ◽  
Production Data ◽  
Reservoir Pressure ◽  
Material Balance Equation ◽  
Gas Reservoirs ◽  
Gas Reservoir ◽  
Material Balance Method ◽  
The Relationship

Abstract Determination of gas in place (GIP) is among the hotspot issues in the field of oil/gas reservoir engineering. The conventional material balance method and other relevant approaches have found widespread application in estimating GIP of a gas reservoir or well-controlled gas reserves, but they are normally not cost-effective. To calculate GIP of abnormally pressured gas reservoirs economically and accurately, this paper deduces an iteration method for GIP estimation from production data, taking into consideration the pore shrinkage of reservoir rock and the volume expansion of irreducible water, and presents a strategy for selecting an initial iteration value of GIP. The approach, termed DMBM-APGR (dynamic material balance method for abnormally pressured gas reservoirs) here, is based on two equations: dynamic material balance equation and static material balance equation for overpressured gas reservoirs. The former delineates the relationship between the quasipressure at bottomhole pressure and the one at average reservoir pressure, and the latter reflects the relationship between average reservoir pressure and cumulative gas production, both of which are rigidly demonstrated in the paper using the basic theory of gas flow through porous media and material balance principle. The method proves effective with several numerical cases under various production schedules and a field case under a variable rate/variable pressure schedule, and the calculation error of GIP does not go beyond 5% provided that the production data are credible. DMBM-APGR goes for gas reservoirs with abnormally high pressure as well as those with normal pressure in virtue of its strict theoretical foundation, which not only considers the compressibilities of rock and bound water, but also reckons with the changes in production rate and variations of gas properties as functions of pressure. The method may serve as a valuable and reliable tool in determining gas reserves.

scholarly journals Organoporosity Evaluation of Shale: A Case Study of the Lower Silurian Longmaxi Shale in Southeast Chongqing, China

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Fangwen Chen ◽  
Shuangfang Lu ◽  
Xue Ding
Keyword(s):  
Organic Carbon ◽  
Shale Gas ◽  
Material Balance ◽  
Model Parameters ◽  
Correction Coefficient ◽  
Hydrocarbon Generation ◽  
Gas Reservoir ◽  
Lower Silurian ◽  
Shale Gas Reservoir ◽  
Longmaxi Shale

The organopores play an important role in determining total volume of hydrocarbons in shale gas reservoir. The Lower Silurian Longmaxi Shale in southeast Chongqing was selected as a case to confirm the contribution of organopores (microscale and nanoscale pores within organic matters in shale) formed by hydrocarbon generation to total volume of hydrocarbons in shale gas reservoir. Using the material balance principle combined with chemical kinetics methods, an evaluation model of organoporosity for shale gas reservoirs was established. The results indicate that there are four important model parameters to consider when evaluating organoporosity in shale: the original organic carbon (w(TOC0)), the original hydrogen index (IH0), the transformation ratio of generated hydrocarbon (F(Ro)), and the organopore correction coefficient (C). The organoporosity of the Lower Silurian Longmaxi Shale in the Py1 well is from 0.20 to 2.76%, and the average value is 1.25%. The organoporosity variation trends and the residual organic carbon of Longmaxi Shale are consistent in section. The residual organic carbon is indicative of the relative levels of organoporosity, while the samples are in the same shale reservoirs with similar buried depths.

Formation Pressure Calculation Based on Modified Flowing Material Balance Method

2014 ◽  
Vol 997 ◽  
pp. 868-872
Author(s):  
Quan Hua Huang ◽  
Huai Zhong Wen ◽  
Li Zhang ◽  
Tian Song
Keyword(s):  
Bottom Water ◽  
Material Balance ◽  
Reference Value ◽  
Balance Method ◽  
Formation Pressure ◽  
Gas Reservoir ◽  
Obvious Effect ◽  
Pressure Calculation ◽  
Flowing Material ◽  
Material Balance Method

Formation pressure is an important symbol of driving energy and the key problem of gas reservoir development. Therefore, the formation pressure’s evaluation is a very important work. Due to the invasion of edge-bottom water, using conventional "flow" material balance method to calculate the formation pressure is no longer applicable. According to the theory of reservoir pressure calculation based on flowing material balance method, we established a improved method to calculate the pressure of water drive gas reservoir and verified it by an example. The results show that: edge and bottom water intrusion has obvious effect on the calculation of formation pressure; after considering the influence of water drive, the formation pressure’s calculation results increased, as a consequence the formation pressure’s decreasing range reduced. This research’s result has important reference value for improving the precision of water drive gas reservoir’s formation pressure.

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