<em>In this research, bagasse NaLS surfactant was used as an injecting reservoir fluid at low salinity. The purpose of this study was to observe the effect of IFT and thermal stability on oil recovery factors in various compositions. The material used in this study isbagasse based NaLS surfactant, light oil and sandstone, while spinning drop is used to measure the interface tension. The oven was used for thermal stability testing and core flooding equipment for the surfactant injection. The success in this study was based on the value of the recovery factor, the small IFT value, and stability of IFT in the thermal stability test. The IFT results obtained for CF1, CF5,and CF7 were 10.4 mN / m, 4.09 mN / m, and 4.34 mN / m, respectively. Based on The results of the thermal stability test only the CF7 was stable with an IFT value of 2.11 mN / m, while the other two variations were unstable. The recover factor of CF1, CF5, and CF7 was 3.24%, 3.52%, and 5.34%, respectively. It can be concluded that IFT as well as thermal stability affect the frecovery factor.</em>

Enhanced Oil Recovery (EOR) is an effort to increase oil recovery after primary recovery and secondary recovery. One method used is chemical injection using surfactants. Sodium Lignosulfonate (SLS) is one of the anionic surfactants commonly used in the EOR process. Sodium Lignosulfonate can be made by bagasse synthesis, as an alternative to the use of lignosulfonate surfactant. The purpose of this study was to determine the effect of the middle phase emulsion and interfacial tension on the recovery factor results. The method used is the core injection. The injection fluid used is Sodium Lignosulfonate surfactant which has been tested for its characteristics. This research uses core flood devices and synthesized Berea cores. Core injection is carried out in several variations of salinity and surfactant concentration. The results of the study show that the largest recovery result is at 1.5% 15000 ppm with a recovery factor of 5.34% where the emulsions are the least among other compositions but the emulsions are stable at 48 hours and the IFT value is also relatively low at 4.34 mN/m. The lowest recovery results are at 1.5% 4000 ppm with a recovery factor of 3.24% where the emulsions are highest but the emulsions are stable at 336 hours, and the IFT value is relatively high at 10.40 mN / m. Based on this study it can be concluded that if the middle phase emulsion is quickly stable and the IFT value is low it will result in enhanced oil recovery.

Indonesia is one of the largest sugarcane producing countries in the world. At present, the use of bagasse is only as compost, electricity generation, etc. In the oil industry, bagasse can use as a base material in making surfactants that function as fluid reservoir oil injection to improve oil recovery factors, so it is good to develop a type of plant-based local surfactant with a lot of raw materials in Indonesia. The purpose of this study was to see that bagasse can increase the oil recovery factor at low salinity. The methods used is a laboratory study using a concentration of 1%; 1.5%; 2%; 2.5% and 3% NaLS and salinity of 4000 ppm, 5000 ppm, and 15000 ppm NaCl. The Surfactant first conducted a compatibility test then core flooding was carried out to obtain the recovery factor value. The results obtained were surfactants with variations of 1.5% 4000 ppm; 1.0% 15000 ppm; and 1.5% 15000 ppm which passes the compatibility test with the recovery factor value sequentially is 3.24%; 3.62%; and 5.34%. It shows that NaLS surfactant can increase the oil recovery factor at low salinity by 5.34% by optimizing 1.5% NaLS 15000 ppm concentration.

Salah satu metode dalam Enhanced Oil Recovery adalah Chemicalflooding. Pada penelitian laboratorium ini dilakukan injeksi larutan surfaktan berbahan dasar AOS pada batuan sandstone dengan konsentrasi 05%, 1%, dan 2% dalam masing-masing salinitas 5.000 ppm dan 10.000 ppm. Hal ini bertujuan untuk mengetahui pengaruh kenaikan konsentrasi pada surfaktan terhadap perolehan minyak. Sebelum dilakukan tahapan injeksi, terlebih dahulu dilakukan uji fisik larutan surfaktan, sehingga dapat ditentukan larutan yang akan diinjeksikan ke dalam batuan. Dari proses uji fisik didapati bahwa semakin tinggi konsentrasi larutan makan nilai dari densitas, viskositas, dan spesific gravity akan turut meningkat. Dalam prakteknya, larutan surfaktan akan menurunkan nilai tegangan antarmuka (IFT) sehingga dapat meningkatkan perolehan minyak yang tersisa dalam pori-pori batuan. Nilai IFT terendah adalah pada surfaktan dengan konsentrasi 2%, sedangkan yang tertinggi surfaktan dengan konsentrasi 0,5%. Pengaruh kenaikan konsentrasi surfaktan terbukti lebih optimal, memiliki nilai recovery factor sebesar 43,89% dengan konsentrasi 2% salinitas 10.000 ppm.

Zeolite as a catalyst can increase its activity by carrying out physical and chemical activation processes. Physical activation can be activated by reducing the size of the zeolite through grinding and sieving methods, from the physical activation process it can increase the surface area of the zeolite. In this study, zeolite was chemically activated by acid activation method by immersing natural zeolite with HCl and HF. The oxide compound in the activated zeolite was characterized using XRF. The activated zeolite was used to reduce the free fatty acid levels with variations in the addition of 7 to 10 grams of zeolite. The content of free fatty acids is then compared with the quality requirements of cooking oil according to SNI 01-3741-2013. The results of the research conducted showed that there were differences in the content of oxide compounds in zeolite before and before activation with differences in SiO2 content, namely 69.4% before activation and an increase of 82.1% after activation. The results of the state test including physical properties, odor, and taste tests of used cooking oil that have been purified indicate that used cooking oil that has been purified meets the quality requirements of cooking oil based on SNI 01-3741-2013. Used cooking oil that has been purified has a normal taste, does not smell. rancid and yellow. The content of free fatty acids meets the requirements of SNI 01-3741-2013 for all variations of the addition of zeolite with the highest decreasing value obtained at the addition of 10 g of zeolite with a free fatty acid content value of 0.22%.

Oil and gas industry are an industry with a high cost and high risk, artificial intelligence will help the work of humans to minimize the risk of accidents, reduce processing time and improve corporate profits. So, the work becomes more efficient. The aims of the study give information that the artificial intelligence help the work to evaluate the initial gas in place on reservoir and comparison the results between software and manual Material Balance (MBAL). Additional research is needed to know the type of reservoir and drive mechanism. The method used is the research on reservoir RGN, the data used are based on real data in field. This research uses artificial intelligence MBAL software and calculation with manual MBAL. Based on the analysis, the result of reservoir type dry gas reservoir with drive mechanism is depletion drive. Calculation initial gas in place using artificial intelligence MBAL software, get the initial gas in place result of 50661,3MMscf. And calculation using manual MBAL, get the initial gas in place result of 50063,59MMscf. There is a difference in the results of the initial gas content in place of 597.4 MMscf. Based on the analysis, there are differences in the results between using artificial intelligence and manual MBAL.

Reservoir ZX merupakan reservoir gas basah ( wet gas reservoir ) yang diketahui jenisn reservoirnya melalui metode kualitatif dengan analisa komposisi hidrokarbon reservoir, karakteristik fluida reservoir dan data PVT. Pada penelitian yang dilakukan, analisa komposisi hidrokarbon mulai dari karbon C1 hingga C7+, data karakteristik fluida reservoir yaitu GLR, API, dan SG gas. Karena reservoir ZX adalah reservoir gas basah ( wet gas reservoir ), dilakukan pengkoreksian kumulatif dari gas yang diproduksi dari Gpdry menjadi Gpwet dengan metode vapor equivalent dengan nilai Veq didapatkan sebesar 1690.               Dalam penelitian, penentuan jenis tenaga dorong dari reservoir ZX menggunakan metode energy plot dan P/Z Vs Gp. Hasil metode energy plot tidak terdapat water influx yang menandakan jenis tenaga dorong pada reservoir gas adalah depletion gas drive dan sesuai dengan analisa pada garis plot metode P/Z Vs Gp yang menandakan jenis tenaga dorong depletion gas drive. Perhitungan isi awal gas di tempat pada penelitian digunakan metode volumetrik, Material Balance 3113,135 BSCF dan memiliki nilai recovery factor dari metode Material Balance adalah 80,523%.

Reservoir X is located in West Tanjung Jabung Regency, Jambi, Indonesia, with initial pressure is 2,028 psia, and a temperature is 226°F. The reservoir has been produced from February 2018 to the present (February 2021), with cumulative gas production of 5.17 Bscf. Based on the Plan Of Development (POD) study in 2016, the initial gas in place was determined volumetrically to be 49,92 Bscf. To compare the initial gas in place, it is deemed necessary to recalculate the initial gas in place by utilizing another method. The calculation of Initial Gas In Place (IGIP) is conducted by using the P/Z method. In this method, the Initial Gas in Place is obtained 49.01 Bscf. Based on analyzing the phase diagrams and the prevailing reservoir conditions, reservoir X indicated a dry gas reservoir. Such reservoir drive mechanism is a depletion drive, determined from the P/Z vs Gp plot, generating a straight line. Based on the assumed abandonment pressure value of 300 psia, the estimated ultimate recovery value is 41.93 Bscf, with the recovery factor value of 87.65% and the remaining reserves of 36.76 Bscf.