CO2 Minitest, Little Knife Field, ND: A Case History

Abstract

Members SPE-AIME Summary A joint DOE-Gulf oil Corporation Minitest of CO2 miscible flooding was conducted in the Mission Canyon formation of the Little Knife Field, North Dakota. In the five-acre minitest area, a central injection and three observation wells were drilled to form a non-producing, inverted four-spot pattern. A 1:1 CO2 WAG injection sequence (preflush water injection, five alternate slugs of CO2 and water, and drive water injection) was implemented. Prior to the CO2 minitest, a detailed reservoir description of the test area was developed through logging, pulse testing and core analysis. Extensive laboratory pulse testing and core analysis. Extensive laboratory work had been performed to determine miscibility pressure, swelling and viscosity reduction effects. pressure, swelling and viscosity reduction effects. The minitest included continuous bottomhole pressure measurement in all test wells and time-lapse logging to monitor saturation changes as alternate slugs of water and CO2 passed the observation wells. Fluid samples from the observation wells were collected periodically to check for tracers and fluid composition. At the conclusion of drive water injection, a fifth well was drilled behind the CO2, front and pressure-cored to measure the residual oil saturation to the CO2 flood. A Compositional Simulator was used to history match the minitest performance and to evaluate the displacement and sweep efficiency in the project area. Reservoir simulation models were used at various stages of the minitest:to determine the volume and rate of water injection required to raise the reservoir pressure above the minimum miscibility pressure,to calculate co 2 slug size, WAG ratio and project life,to select the location of the fourth observation well behind the CO, front,to predict breakthrough times and concentrations of CO2, and water to decide when to log wells and collect fluid samples,to scale the minitest reservoir description to a typical 160-acre, five-spot pattern for predicting recoveries for a waterflood and the CO2 WAG process, andto perform sensitivity studies for studying the effects of layering, vertical communication and other process parameters. Introduction A joint DOE-Gulf oil Corporation minitest of carbon dioxide miscible flood process was conducted in the Little Knife Field, North Dakota (Figure 1) from December 11, 1980 through September 24, 1981. The objective of this minitest was to show that the CO2, miscible displacement process has potential for commercialization in carbonate oil potential for commercialization in carbonate oil reservoirs in the Rocky Mountain area that have not been extensively waterflooded and have a high remaining oil saturation. A careful monitoring of the field performance of the CO2, minitest using a reservoir simulator was made in order to make a field wide projection of CO2 flood in this field. The Little Knife Field is one of the major reservoirs discovered by Gulf in recent years. The discovery well was completed on February 8, 1977. The original oil-in-place (OOIP) in the Mission Canyon Formation was estimated to be 195 MMSTB. Cumulative oil production through December, 1982 was about 24.4 MMSTB (12.5% of OOIP). The primary recovery mechanism is solution gas drive. primary recovery mechanism is solution gas drive. Currently, there are 124 producing wells on 160 acre spacing, and the average reservoir pressure has been declining from the initial reservoir pressure of 4400 psia to about 2750 psia. It was anticipated that waterflood residual oil saturation would be high and that the CO2, miscible process would be suitable. The work associated with this minitest was divided into five phases: Phase I: Location and Drilling of Minitest Phase I: Location and Drilling of Minitest Pattern Phase II: Laboratory Determination Of CO2/Water Phase II: Laboratory Determination Of CO2/Water Displacement Parameters in Reservoir Cores Phase III: Minitest Area CO2 Simulation Phase III: Minitest Area CO2 Simulation

Unveiling the Effect of Complex Components on CO2-Oil Minimum Miscibility Pressure: Insights from Deep Convolutional Neural Networks

“…Generally, the SVM heavily relies on the completeness of available data. In experiments involving high MMP values (e.g., >16 MPa), pure CO 2 was usually used as the injected gas, ,,,,,− ,,− ,− resulting in several gas components’ mole percentages being zero (e.g., methane, N 2 and H 2 S). This sparse vector of multiple zeros can misalign the calculated support vectors, significantly compromising the reliability of feature spaces.…”

“…Data from 225 samples are collected from the available literature ,,,− ,,− (see Supporting Information Table S2). Their statistical characteristics are calculated and shown in Table .…”

Estimation of minimum miscibility pressure during CO2 flooding in hydrocarbon reservoirs using an optimized neural network

“…The precision of model is strongly dependent on adequate data. In this study, 152 experimental values, including 52 pure CO 2 -oil MMPs and 100 impure CO 2 -oil MMPs, were collected from the open literatures (Adekunle and Hoffman, 2016;Bon et al, 2006;Cardenas et al, 1984;Dicharry et al, 1973;Dong et al, 2001;Eakin and Mitch, 1988;Graue and Zana, 1981;Holm and Josendal, 1974;Kanatbayev et al, 2015;Lai et al, 2017;Lashkarbolooki et al, 2017;Li and Luo, 2017;Li et al, 2012;Li et al, 2018;Metcalfe, 1982;Moudi et al, 2009;Harmon and Grigg, 1988;Sebastian et al, 1985;Spence et al, 1980; Thakur et al, 1984;Zuo et al, 1993) to build a robust model for estimating MMP. Eighty percent (122) of the all experimental values are used for training and the remaining 20% (30) are employed for test.…”

Four Methods to Estimate Minimum Miscibility Pressure of CO2‐Oil Based on Machine Learning

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