（低渗透油藏水窜通道研究——以三塘湖油田为例）

摘要

The physics of fluid flow deviate from conventional law in low permeability reservoirs because of small pore size，fine throat，high filtration resistance，which results in high injection pressure，low injection capacity，thus low production with rapid decline. The reservoir heterogeneity i.e.，the presence of high permeable layers and natural fractures within the strata adds another challenges，which in later stage of water flooding turned out to be so called“water channel”，an easy pathway for the circulation of injected water，thus production wells suffering high watercut and rapid decline in oil recovery. These undesired water production through the water channel between injection and the nearby off set production wells cause severe blow to oil recovery. This water channeling phenomena leads to high water cut in production wells，pressure drop and resist the injected fluid to penetrate into low permeable layers (oil rich region) thus ，bypassing the oil in the formation，hence the poor sweep efficiency and total oil recovery. Here in this thesis we have studied the mechanism of excessive water production occuring through water channels，their diagnostic methods and further formulated the recipe，“Polymer Gel” to plug these water channels. Our approach used to diagnosis water channel is production data analysis from the field and further synthetic model to validate the approach. The gel plugging of these high conductive channels resist the water flow into high permeable layers (channels)，eventually leading to injection fluid diversion，thus allowing both the areal and vertical sweep improvement. A numerical simulation model for water channeling has been presented here to understand the dynamic behavior of the reservoir，which guide us to take timely measures to plug or shutoff these water channels. Our numerical model is built using COMSOL Multiphysics where the flow is described by the Navier-Stokes equation in the channel region and a Forchheimer-corrected version of the Brinkman equations in the porous region to distinguish the impact of corrected physics. And further，design a numerical simulation model using CMG-STARS replicating the water channeling features for evaluation of conformance control. Our experimental work using sandpack model has also been meaningful in both designing the recipe for plugging the channels as well as understand the physics of gel propagation in porous media，eventually，measure the ultimate recovery . The plugging capacity of polymer gel was 96.6 % for our sand pack of permeability 180x10-3 2?m . The oil recovery during primary water flooding recorded as 49.2%along with 96%water cut，the polymer gel flooding at 0.5 PV resulted in an incremental of 3%of oil . The secondary water flooding resulted in equal fraction of oil and water cut while the tertiary water flooding was able to produce 1.1 %of oil recovery at the water cut of 98%. Thus，the water channeling issue has been studied numerically and then put forward the remedial measure to plug these channel was successfully studied in our lab.

目录

第一个书签之前

3.1. Background and Theory of Oil recovery

3.1.1 Immiscible Displacement: Vertical and Volume

3.1.2.1 Water Injection Oil Recovery Calculations:

(a) Why this Work?

(b) Application of the demonstration:

3.3 Model description and Input parameters for Sin

3.4 Field scale model for Water Channel and Interp

3.5 Model results: Obtained figures and graphs

3.6. Results and discussions

3.7. Further rooms for model Improvement

4.1.1 The Preparation of The Gel Base Solution

4.1.2 Sydansk’s code and Physical description of G

4.1.3 Measurement of the Gel Strength by Breakthro

4.1.3 Sensitivity analysis

4.1.3.1 Influence of Different Cross-Linker Concen

4.1.3.2 Influence of Additive Concentration on ge

4.1.3.3 Influence of Polymer Concentration on gel

4.2. Sandpack study to understand the plugging eff

4.2.2 Presentations of Data and Results

(a)Water flooding

4.3.2.1 Influence of the concentration of CTAB and

4.3.2.2 Influence of the concentration of NaSal an

4.3.2.3 Influence of the concentration of NaCl and

4.4.2 Presentations of Data and Results

(a)Water flooding