WETTABILITY AND OIL-WATER CONTACT DETERMINATION IN CARBONATE RESERVOIR NGIMBANG FORMATION, K FIELD, MADURA

• Main Author: HIMAYATILLAH (NIM : 22215015), NADIAH
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/29476
• Institution: Institut Teknologi Bandung

In a reservoir, wettability has been recognized as one of the controlling parameters of the remaining oil-in-place. Brine salinity, oil chemistry, and rock lithology are believed play a significant role on rock wettability. Generally, wettability is measured in laboratorium, but while the core sample is distributed from reservoir to laboratorium and measurement condition in laboratorium are different with the original reservoir condition could make wettability property on core sample changed so it needs further evaluation to know the cause of wettability changes on rock and also the impact of wettability changes to the other parameters. <br /> <br /> <br /> Wettability evaluation is made by interpretating data such as relative permeability, electrical properties, capillary pressure, hydrocarbon composition, and fluid level distribution from plot between reservoir pressure and depth which is strengthen by well log analisys data. Carbonate reservoir on Ngimbang Formation has a carbonate rock characteristic such as moldic and vuggy pore types. Micropore on carbonate rock will impact with relative permeability measurement result and it will be different with relative permeability measurement result on sandstone. In electrical properties and capillary pressure measurements, there are differences between the temperature and fluid system that used between laboratorium measurement and original reservoir. It will make wettability interpretation show water wet characteristic, so it needs further evaluation to wettability measurement, such as parameter from water saturation calculation which are tortuosity factor (a), cementation exponent (m), and saturation exponent (n) using various methods. On hydrocarbon components, there are some compounds that actively play on rock wettability changes it needs to be interpretated. From evaluations show that carbonate reservoir on Ngimbang Formation has oil wet wettability. <br /> <br /> <br /> From wettability analysis, will support on transition zone determination and formation fluid contact. While developing a field, depth prediction of formation fluid contact and rock characteristic from a reservoir are very important to know because they will use as one of reserve calculation from reservoir. Transition zone in a carbonate rock formation usually still has highly oil production, so another approach is needed to estimate oil flow through transition zone. Many methods have been discovered to predict transition zone from a reservoir. Generally, fluid contact determinates only from pressure and production test while drilling a well. As the needs grow, measuring fluid contact must be clarificated with another method to get an accurate result. <br /> <br /> <br /> Fluid contact (oil-water contact) determination in this thesis is performed by combining analysis result data from log, core, pressure and production test from Well P-2 and P-3. Capillary pressure curve against water saturation can be created by using interpretation result from pressure against depth and comparing with well log interpretation result, which is can be used as further reffered to determine fluid contact. For the future, hopefully this study can provide awareness of needed to pay attention and maintain core samples condition carefully so there is no mistake in representing the initial condition of reservoir <br />