A Drilling Fluid Suitable for Tight Sandstone Reservoirs

A technology for tight sandstone reservoirs and drilling fluids, which is applied in the field of drilling fluids and low-permeability tight sandstone reservoirs. It can solve the problems of easy invasion of clay particles into reservoirs, decreased reservoir permeability, and decreased oil and gas production. Reduce mutual damage, ensure suspension and carrying, and reduce friction

Active Publication Date: 2017-12-01
PETROCHINA CO LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In the traditional water-based drilling fluid system, bentonite slurry is often used, and solid particles such as barite powder are used as density regulators to adjust the density of the drilling fluid system. Therefore, this type of drilling fluid system usually has a relatively high solid content. However, the solid phase particles in the drilling fluid, especially the highly dispersed clay particles, are easy to invade the reservoir, causing damage to the reservoir, greatly reducing the permeability of the reservoir, and resulting in a sharp decline in oil and gas production.

Method used

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  • A Drilling Fluid Suitable for Tight Sandstone Reservoirs
  • A Drilling Fluid Suitable for Tight Sandstone Reservoirs
  • A Drilling Fluid Suitable for Tight Sandstone Reservoirs

Examples

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Embodiment 1

[0042] This embodiment provides a kind of drilling fluid suitable for tight sandstone reservoirs, the density of this drilling fluid is about 1.16g / cm 3 , by mass percentage, it includes: 0.5% bentonite, 0.6% strong inhibitory coating agent IND10 (a higher molecular weight polymer formed by copolymerization of vinyl monomers and vinyl monomers containing sulfonic acid groups), 0.6 % polyamine polymer NH-1, 0.5% xanthan gum XC, 1.5% Redu1, 1.5% non-fluorescence anti-slump fluid loss agent KH-931, 0.4% HAR-D, 3% compound Calcium carbonate (according to the maximum permeability of the rock core used for evaluation is 132.2×10 -3 μm 2 , through calculation, select 3000 mesh calcium carbonate particles, 800 mesh calcium carbonate particles and 400 mesh calcium carbonate particles with a mass ratio of 60:15:25, as bridging particles and filling particles for compounding), 2% non-fluorescent white asphalt NFA-25, 2% polyalcohol JLX and 50% biopolyalkoxide, the balance is water.

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Embodiment 2

[0066] In this example, the drilling fluid suitable for tight sandstone reservoirs provided in Example 1 was used in field application experiments in the third member of Sankaisha in Well Shuang233 of Liaohe Oilfield.

[0067] Well Shuang233 is a risk exploration well arranged by CNPC in the western sag of the Liaohe Depression. The purpose of drilling this well is to confirm the oil and gas content of the sand bodies of the third member of Shahejie Formation (Es3) in the southern block of Shuang602. Since this well is an exploratory well, the third member of the Shahejie Formation is a typical tight sandstone reservoir with low porosity and ultra-low permeability. At the same time, this reservoir is also a well section prone to drilling accidents, and the content of clay minerals is relatively high, so the sensitivity of the reservoir is relatively strong. Water lock damage is prone to occur, so it is very important to protect oil and gas layers and ensure downhole safety duri...

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Abstract

The invention provides a drilling fluid suitable for tight sandstone reservoirs. In terms of mass percentage, the composition of the drilling fluid includes: 0.5%-2% bentonite, 0.5%-2.5% coating inhibitor, 0.5%-1% flow regulator, 3%-4% filter reducer Lost agent, 0.4%-0.8% waterproof locking agent, 4%-10% temporary plugging agent, 40%-50% biological polyalkoxide, 0%-50% weighting agent, and the balance is water. The density of the liquid is 1.16g / cm3-1.55g / cm3. The drilling fluid suitable for tight sandstone reservoirs provided by the invention can effectively prevent the pollution of tight sandstone reservoirs and ensure the safety of downhole operations.

Description

technical field [0001] The invention relates to a drilling fluid used in petroleum drilling engineering, in particular to a drilling fluid for low-permeability tight sandstone reservoirs, and belongs to the technical field of petroleum exploitation. Background technique [0002] The proportion of oil and gas resources in low-permeability tight sandstone in my country's oil and gas resources is constantly expanding, and the distribution is wide. However, the exploitation of oil and gas resources here is difficult. The development of such oil and gas reservoirs is of great significance to the sustainable and stable development of my country's oil industry. [0003] Tight sandstone reservoirs generally have the characteristics of high water sensitivity, high stress sensitivity, high capillary pressure, high water saturation, low porosity, low permeability, and fractures. During the drilling of oil and gas wells, the damage to low-permeability tight reservoirs is widespread, som...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09K8/24
Inventor 吴军康徐厚英孙睿解宇宁董婉唐明方新强周晓宇任勋郭定雄张洪君袁鹏王浩郑猛韩金轩
Owner PETROCHINA CO LTD
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