Optimization of Operation Parameters for Helical Flow Cleanout with Supercritical CO2 in Horizontal Wells Using Back-Propagation Artificial Neural Network

Abstract

Sand production and blockage are common during the drilling and production of horizontal oil and gas wells as a result of formation breakdown. The use of high-pressure rotating jets and annular helical flow is an effective way to enhance horizontal wellbore cleanout. In this paper, we propose the idea of using supercritical CO2 (SC-CO2) as washing fluid in water-sensitive formation. SC-CO2 is manifested to be effective in preventing formation damage and enhancing production rate as drilling fluid, which justifies tis potential in wellbore cleanout. In order to investigate the effectiveness of SC-CO2 helical flow cleanout, we perform the numerical study on the annular flow field, which significantly affects sand cleanout efficiency, of SC-CO2 jets in horizontal wellbore. Based on the field data, the geometry model and mathematical models were built. Then a numerical simulation of the annular helical flow field by SC-CO2 jets was accomplished. The influences of several key parameters were investigated, and SC-CO2 jets were compared to conventional water jets. The results show that flow rate, ambient temperature, jet temperature, and nozzle assemblies play the most important roles on wellbore flow field. Once the difference between ambient temperatures and jet temperatures is kept constant, the wellbore velocity distributions will not change. With increasing lateral nozzle size or decreasing rear/forward nozzle size, suspending ability of SC-CO2 flow improves obviously. A back-propagation artificial neural network (BP-ANN) was successfully employed to match the operation parameters and SC-CO2 flow velocities. A comprehensive model was achieved to optimize the operation parameters according to two strategies: cost-saving strategy and local optimal strategy. This paper can help to understand the distinct characteristics of SC-CO2 flow. And it is the first time that the BP-ANN is introduced to analyze the flow field during wellbore cleanout in horizontal wells.

Experimental study on critical sand production pressure gradient at different production stages of high temperature and high pressure tight sandstone gas reservoir

“…In the development process of sandstone gas reservoirs, sand production is a common issue. [1][2][3][4] Sand production can have a significant adverse impact on the normal production of gas wells in sandstone gas reservoirs. [5][6][7][8][9] It may result in equipment damage, production interruptions, and pose safety concerns.…”

“…In the development process of sandstone gas reservoirs, sand production is a common issue 1‐4 . Sand production can have a significant adverse impact on the normal production of gas wells in sandstone gas reservoirs 5‐9 .…”

“…were conducted to thoroughly investigate the sand production patterns in sandstone reservoirs under the combined influence of different effective stresses and production pressure differentials. The results indicate: (1) under the simultaneous increase of effective pressure and production pressure differential, sand production near the wellbore (r = 0.1 m) becomes more likely in the reservoir; (2) in actual reservoirs without fractures near the wellbore (r = 0.1 m), sand production phenomena do not occur; (3) reservoirs with fractures near the wellbore (r = 0.1 m) are more prone to sand production, under an effective stress of 90 MPa, with specimens containing fractures exhibiting a 76.48% lower critical sand production pressure gradient compared to those without fractures; (4) when the pore fluid pressure is 95 MPa, the maximum gas production rate for Well X without sand production is 12.4 Â 10 4 m 3 /d.…”

Production Flow Optimization By Using Theory of Constraints

“…Product flow optimization is very important in the production process in industry, because it deals with the effectiveness and efficiency within a company [1,2]. It is known that production planning is very crucial in the success of the company, especially in the context of measuring the ability of a company to provide the products and its balance with the production process in the factory [3,4]. Thus, the compatibility between raw materials, production processes, and machine capacity must be carefully considered.…”

Intelligent assignation strategy of collaborative optimization for flatness control

“…Since the intermediate roll bending is adjusted by five units in the direction of decreasing bending force, the work roll bending have to be adjusted by more units for offsetting the effect of the intermediate roll bending. Therefore, the effective regulation is decreased and the adjusting ability is weakened [16][17][18][19][20][21][22][23][24][25][26][27]. If this happens frequently, roll attrition will be serious and roll performance will be getting worse [28][29][30][31][32][33][34][35].…”