A New Mechanism of Formation Damage in Sandstone Matrix Acidizing Caused by Apatite; A Phosphate Cementing Material

2014 ◽  
Author(s):  
Armin Sakipour ◽  
Hisham A. Nasr-El-Din
Keyword(s):  
Formation Damage ◽  
Mechanism Of Formation ◽  
Matrix Acidizing ◽  
Cementing Material

DEVELOPMENT OF WELLBORE TREATMENT TECHNOLOGY FOR IMPROVING PRODUCTION EFFICIENCY FROM AUSTRALIAN OIL AND GAS WELLS

1994 ◽  
Vol 34 (1) ◽  
pp. 79
Author(s):  
M.M. Rahman ◽  
F.A. Khan ◽  
S.S. Rahman
Keyword(s):  
Production Efficiency ◽  
Oil And Gas ◽  
Threshold Value ◽  
Honeycomb Structure ◽  
Formation Damage ◽  
Treatment Technology ◽  
Matrix Acidizing ◽  
Porosity And Permeability ◽  
Permeability Impairment ◽  
Completion Fluids

Low permeability or formation damage during drilling and completion procedures is often a serious threat to the economic development of a series of Australian oil and gas reserves. In this paper the Pacoota Sandstone in the Amadeus Basin has been considered and the effects of clay mineral morphology, water shock, type and concentration of different salts and varying flow velocity on fines migration were studied. Possible formation damage due to completion fluids and remedial measures such as matrix acidizing were also evaluated.The Pacoota Sandstone has been found to be sensitive to the salt concentration of permeating fluids. If the concentration falls below a threshold value, permeability begins to decrease drastically. Permeability impairment may further be aggravated if the flow rate of the permeating fluid reaches beyond a critical value. It has also been observed that the typical completion fluid reduces the permeability of the near wellbore region to almost half the original permeability. Use of CMHEC base chalk mud, however, reduces the water loss and consequently the permeability impairment by forming an internal filter cake with a typical honeycomb structure. Mud acid with less than 2.5 per cent HF acid concentration has been found to be insufficient to enhance porosity and permeability of the studied sandstone, rather it reduces the permeability by creating formation fines. Afterflush with EGMBE (10 per cent by volume) and HCl acid also helps to clean-up the small fines created during acidizing. The overall increase in porosity and permeability occurs mainly due to formation of large pore channels by matrix dissolution.

Matrix Acidizing with Gelled Acid

2012 ◽  
Author(s):  
Issham Ismail ◽  
Wei Loon Kweh
Keyword(s):  
Xanthan Gum ◽  
Research Study ◽  
High Viscosity ◽  
Injection Rate ◽  
Formation Damage ◽  
Polymer Gel ◽  
Matrix Acidizing ◽  
Steel Core ◽  
Core Holder ◽  
Viscosity Polymer

Suatu uji kaji makmal telah dilakukan untuk membandingkan kecekapan asid gel dan asid lumpur konvensional dalam merawat kerosakan formasi yang disebabkan oleh lumpur dasar air. Suatu sistem pengasidan telah dibina untuk mengkaji kesan kadar alir dan kelikatan asid gel terhadap batu pasir Berea. Peralatan utama yang membentuk sistem pengasidan ialah pemegang teras, sel lumpur, injap, dan tiub 3 mm. Semua komponen ini diperbuat daripada keluli kalis karat. Bendalir perawat yang digunakan dalam uji kaji terdiri daripada asid lumpur (3% HF–12% HCl), asid hidroklorik, dan gel polimer (gam xanthan). Keputusan uji kaji menunjukkan bahawa polimer dengan kelikatan kurang daripada 73 cP memberikan kecekapan yang lebih baik berbanding kelikatan yang melebihi 73 cP. Ini terbukti apabila nisbah kebolehtelapan mencapai 3.5 pada kelikatan gel 73 cP berbanding 1.5 sahaja pada kelikatan 126 cP. Perbezaan nisbah kebolehtelapan yang ketara berlaku kerana polimer yang terlalu likat cenderung untuk memalam liang secara kekal. Asid gel berjaya merawat kerosakan formasi dengan lebih berkesan berbanding asid lumpur, terutama apabila gel polimer berkelikatan 73 cP dialirkan pada kadar alir 0.28 ml/saat, berbanding kadar alir yang lebih rendah. Kata kunci: Teknik lencongan; asid gel; pengasidan; gel polimer A laboratory investigation was conducted to compare the efficiency of gelled acid with conventional/plain mud acid in removing the formation damage induced by water-based mud. An acidizing system was developed to study the effect of flow/injection rate and gel viscosity on Berea sandstone. The main equipments used in this research study were stainless steel core holder, mud cells, valves, and 3 mm tubing. The treatment fluids used were mud acid (3% HF–12% HCl), hydrochloric acid, and polymer gel (xanthan gum). The experimental results revealed that polymer gel with viscosity lower than 73 cP gave better performance as compared to polymer gel with viscosity greater than 73 cP. At gel viscosity of 73 cP, the permeability ratio was 3.5 compared to 1.5 only at viscosity of 126 cP. This was due to the permanent plugging by the high viscosity polymer gel in the core after the injection. Gelled acid has shown tremendous improvement in removing formation damage, where polymer gel with viscosity of 73 cP was found to give better treatment at flow rate of 0.28 ml/s as compared to lower flow rates. Key words: Diversion technique; galled acid; acidizing; polymer gel

Regarding the mechanism of formation of nonmetallic inclusions conglomerates of system Al2O3-MgO

2019 ◽  
Vol 75 (12) ◽  
pp. 1341-1351
Author(s):  
A. A. Safronov ◽  
V. S. Dub ◽  
V. V. Orlov ◽  
K. L. Kosyrev ◽  
A. S. Loskutov ◽  
...  
Keyword(s):  
Nonmetallic Inclusions ◽  
Mechanism Of Formation

Assessment of ability to varnish turbine oils

2020 ◽  
Vol 06 ◽  
pp. 28-33
Author(s):  
I.V. Mitin ◽  
◽  
I.R. Tatur ◽  
K.U. Smirnov ◽  
A.M. Suloev ◽  
...  
Keyword(s):  
Antioxidant Properties ◽  
Mechanism Of Formation ◽  
Critical Situation ◽  
Antioxidant Content ◽  
Turbine Equipment

The reasons for the formation of varnish deposits of turbine oils are determined. It is shown that the performance of turbine oils is determined by methods of ASTM D7843 (MPC) and ASTM D6971 (RUL) can be assessed, the process of formation of varnish deposits, the level of antioxidant properties, antioxidant content of, amend, and extend the oil change, and to predict critical situation in the operation of turbine equipment. The mechanism of formation of varnish deposits in turbine oils is proposed.

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